asp.net web development

Ref and Out Parameters In C#

2009-12-16T01:21:00.000-08:00

Value Parameters

Passing Value Types by Value

We often call the class methods through the class instances and by passing parameters. These parameters have all been passed by value. While we pass the value types of a parameter, this means that a copy of the value's contents has been passed. As only a copy of the contents is available, the external variable's value cannot be modified from within the method.

The following example code demonstrates the use of value parameters with variables that are value types. In this sample, a value type variable is declared and its value is assigned. This variable is then used as the value of a parameter. The variable is passed to the method parameter by value and the parameter's value is changed within the method, but the original variable remains unaffected.

Public class CallMathod

public void CallMethod()

    int original = 100;

    CallingMathod obj = new CallingMathod();

    obj.showValue(original);

    Label1.Text="Original: "+ original.ToString();;

Public class CallingMathod

static void showValue(int valueToShow)

    valueToShow *=2;

    Label2.Text="Double: "+ valueToShow.ToString();

 OUTPUT

Double: 200

Original: 100

Passing Reference Types by Value

When we pass the reference types by value rather value types by value, a copy of the reference is made. This means that any changes to the object's properties that occur within the method will be reflected outside of the method too. This is because both the external variable and the variable within the method contain the same references to the same underlying object data in memory. However, if the variable inside the method is assigned a completely new value, and therefore a different reference to the external variable, this change is not reflected outside of the method.

To demonstrate, consider the following code. This uses a "StudentClass" class that contains a single property for the student's roll number. When calling the GetRollNumber method, the Student is passed by reference. Increasing the Roll Number property within the method is visible outside of the method too. However, when the GetNewNumber method is called, the reassigned object is not seen externally to the method.

Public class CallMathod

public void CallMethod()

        Student objStudent = new Student ();

        objStudent.rollNumber = 004512;

        GetRollNumber(objStudent);

        Label1.Text ="Roll Number: "+ objStudent.rollNumber;

        GetNewNumber(objStudent);

        Console.WriteLine("Roll Number: {0}", objStudent.rollNumber);

         OUTPUT

        Diameter: 004513

        Diameter: 004513

    static void GetRollNumber(Student objSt)

        objSt.rollNumber++;

    static void GetNewNumber(Student objSt)

        objSt = new Student();

        objSt.rollNumber = 1;

Public class Student

    private int _rollNumber;

    public int rollNumber

get

            return _rollNumber;

set

            _rollNumber = value;

Reference Parameters

Passing Value Types by Reference

An alternative to passing parameters by value is passing by reference. When using reference parameters for value types a copy of the value is not made. Instead, the variable used in the parameter is itself passed to the called method. This makes the behaviour similar to using reference types in value parameters; any changes to the value of the parameter variable is also seen outside of the method.

A reference parameter is declared using the ref keyword before the parameter type and name. This prefix is also used when calling the method.

The following sample code is based upon the first example in this article but by using a reference parameter rather than a value parameter, the results seen are different.

static void CalleeMethod()

    int original = 100;

    CallingMathod obj = new CallingMathod();

    obj.showValue(ref original);

    Label1.Text = "Original: "+original.ToString();

Public class CallingMathod

static void showValue(int valueToShow)

    valueToShow *=2;

    Label2.Text="Double: "+ valueToShow.ToString();

 OUTPUT

Double: 200

Original: 200

Passing Reference Types by Reference:

Reference type data can be passed to reference parameters. In this case, rather than passing a copy of the reference to the method, as when using value parameters, the reference variable itself is passed. In this situation, property changes within the method are reflected outside of the method as expected. However, if the variable is reassigned within the method, the variable outside of the method is also reassigned.

By modifying the earlier example relating to the Student class to use reference parameters, this can be demonstrated. In the following code the student’s rollNumber is increased by 1 as is was previously with the reference parameters showing no apparent difference in functionality. When the GetNewNumber method is called, the student variable is reassigned as a completely new object.

Public class CallMathod

public void CallMethod()

        Student objStudent = new Student ();

        objStudent.rollNumber = 004512;

        GetRollNumber(ref objStudent);

        Label1.Text ="Roll Number: "+ objStudent.rollNumber;

        GetNewNumber(objStudent);

        Console.WriteLine("Roll Number: {0}", objStudent.rollNumber);

         OUTPUT

        Diameter: 004513

        Diameter: 000001

    static void GetRollNumber(ref Student objSt)

        objSt.rollNumber++;

    static void GetNewNumber(ref Student objSt)

        objSt = new Student();

        objSt.rollNumber = 000001;

Public class Student

    private int _rollNumber;

    public int rollNumber

get

            return _rollNumber;

set

            _rollNumber = value;

Output Parameters

When we need to return more than one value from a method, one value can be returned using the normal return command with additional values being extracted using output parameters.

An output parameter is declared using the out keyword before the parameter type and name. When called, the out keyword is used again as a prefix to the variable being passed as a parameter. The behavior seen is similar to passing by reference in that the variable must be assigned a value within the method. This value will then be reflected in the output parameter.

static void CalleeMethod()

    decimal x = 10.00;

    decimal y = 200.00;

    decimal area;

    decimal perimeter;

    CallingMathod obj = new CallingMathod();

    area =obj.GetArea(x,y,out perimeter);

    Label1.Text = "Area: "+ area.ToString();

    Label2.Text = "Perimeter: "+ perimeter.ToString();

Public class CallingMathod

static decimal GetArea(int x,int y,out int perimeter)

    perimeter = 2*(x+y);

    return (x*y);

 OUTPUT

Area: 2000.00

Perimeter: 420.00





Colclussion:

  OUT :

   Variable gets value initialized after going into the method.

   Later the same value is returned to the main method.

        Ref :

   Variable should be initialized before going into the method.

   Later same value or modified value will be returned to the main method

Data Insert By XML

2009-09-08T02:47:00.000-07:00

I have created two types of Xml based data insert Update etc..here.Basically for Bulck insert we use such process to enter or update data inside database and can avoide the hectick parameter passing process by passing the whole xml as a single string.We collect data and generate the dynamic xml and pass it to the stolred procedure.

Here is my class architecture.

For the Faculty there exists one to many mapping between Faculty - College (Consider guest lecturer) and Faculty-Department.So List collections are taken for College and Department to save Faculty data.
have a look at my Faculty class methods

#endregion
#region Internal Methods
internal string GetXML()
{
XmlDocument xDoc = new XmlDocument();
XmlElement xStudentDetail;
xStudentDetail = (XmlElement)xDoc.CreateElement("FacultyDetails");
//this.IsActive = true;
xStudentDetail.SetAttribute("FacultyDetailsID", this.IdNo.ToString());
xStudentDetail.SetAttribute("PersonalAddress", this.PersonalAddress.ToString());
xStudentDetail.SetAttribute("Name", this.Name.ToString());
xStudentDetail.SetAttribute("OtherCharges", this.OtherCharges.ToString());
if (this.CollegeDetails != null)
{
XmlElement xStudentDetails;
xStudentDetails = (XmlElement)xDoc.CreateElement("CollegeDetails");
foreach (College objCollegeDetails in this.CollegeDetails)
{
xStudentDetails.InnerXml = xStudentDetails.InnerXml + objCollegeDetails.GetXML();
}
xRentAgreement.AppendChild(xStudentDetails);
}
xDoc.AppendChild(xStudentDetail);
return xDoc.InnerXml;
}
///

/// This internal method is used for saving the Student details into the database
///

///
internal int SaveFacultyInfo()
{
DataAccess dataAccess = null;
DataSet dsFaculty;
int iFunctionId = 0;
try
{
DataAccess = new DataAccess(_connectionString);
SqlParameter[] sqlParams = new SqlParameter[1];
sqlParams[0] = new SqlParameter("@sFacultyXML", this.GetXML());
dsFaculty = dataAccess.ExecuteDataSet("spSaveFacultyDetails", CommandType.StoredProcedure, sqlParams);
foreach (DataRow dr in dsFaculty.Tables[0].Rows)
{
iFunctionId = Convert.ToInt32(dr[0]);
}
}
finally
{
if (dataAccess != null)
{
if (dataAccess.DataConn != null)
{
//Close the dataset connection
dataAccess.DataConn.Close();
}
}
}
return iFunctionId;
}

///

/// This internal method is used for getting the student details from the database
///

///
internal void GetFacultyInfo()
{
DataAccess dataAccess = null;
DataSet dsFaculty;
DataRow[] drs;
try
{
DataAccess = new DataAccess(_connectionString);
SqlParameter[] sqlParams = new SqlParameter[1];
sqlParams[0] = new SqlParameter("@sFId", studentId);
dsFaculty = dataAccess.ExecuteDataSet("spGetFacultyDetails", CommandType.StoredProcedure, sqlParams);
}
finally
{
if (dataAccess != null)
{
if (dataAccess.DataConn != null)
{
//Close the dataset connection
dataAccess.DataConn.Close();
}
}
}
}
#endregion
}
}

the GetXML() method will collect the information and populate it into a XML

#region Internal Methods
internal string GetXML()
{
XmlDocument xDoc = new XmlDocument();
XmlElement xStudentDetail;
xStudentDetail = (XmlElement)xDoc.CreateElement("FacultyDetails");
//this.IsActive = true;
xStudentDetail.SetAttribute("FacultyDetailsID", this.IdNo.ToString());
xStudentDetail.SetAttribute("PersonalAddress", this.PersonalAddress.ToString());
xStudentDetail.SetAttribute("Name", this.Name.ToString());
xStudentDetail.SetAttribute("OtherCharges", this.OtherCharges.ToString());
if (this.CollegeDetails != null)
{
XmlElement xStudentDetails;
xStudentDetails = (XmlElement)xDoc.CreateElement("CollegeDetails");
foreach (College objCollegeDetails in this.CollegeDetails)
{
xStudentDetails.InnerXml = xStudentDetails.InnerXml + objCollegeDetails.GetXML();
}
xRentAgreement.AppendChild(xStudentDetails);
}
xDoc.AppendChild(xStudentDetail);
return xDoc.InnerXml;
}
For Collecting the College information there is also a GetXML method inside College Class.It will add the ollege info as a child node to the faculty XML.

#region Internal Methods
///

/// this method will get the object in xml format
///

///
/// Subhamay Sur
internal string GetXML()
{
XmlDocument xDoc = new XmlDocument();
XmlElement xCollege;
xCollege = (XmlElement)xDoc.CreateElement("CollegeInfo");
xCollege.SetAttribute("CollegeInfo", this.CollegeID.ToString());
xCollege.SetAttribute("UniversityRegNo", this.UniversityRegNo.ToString());
xCollege.SetAttribute("CollegeName", this.CollegeName.ToString());
xCollege.SetAttribute("CollegeAddress", this.CollegeAddress.ToString());
xCollege.SetAttribute("CollegeStatus", this.CollegeStatus.ToString());
xCollege.SetAttribute("IsAICTEApproved", this.IsAICTEApproved.ToString());
xCollege.SetAttribute("IsWBSEBApproved", this.IsWBSEBApproved.ToString());
if (this.DepartmentDetails != null)
{
XmlElement xDeparmentDetails;
xDeparmentDetails = (XmlElement)xDoc.CreateElement("DepartmentDetails");
foreach (Department objDepartmentDetails in this.FacultyDetails)
{
xDeparmentDetails.InnerXml = xDeparmentDetails.InnerXml + objDepartmentDetails.GetXML();
}
xCollege.AppendChild(xCollegeDetails);
}
xDoc.AppendChild(xCollege);
return xDoc.InnerXml;
}

#endregion
To save this string formatted string the Stored Procedure will be like

INSERT INTO #TempFaculty
(
[PersonalAddress],
[Department],
[Name],
[OtherCharges]
)
SELECT
T.F.value('@PersonalAddress','VARCHAR(200)'),
T.F.value('@Name','VARCHAR(200)'),
T.F.value('@OtherCharges','decimal(14, 2)')
FROM @sFacultyXML.nodes('/FacultyDetails') T(F)

CREATE TABLE #TempTableRentAgreementVendorMap
(
[RentAgreementID] INT,
[VendorNo] VARCHAR(200),
[AmountShareRent] DECIMAL(14, 2),
[AmountShareMaintenance] DECIMAL(14, 2),
[AmountShareOthers] DECIMAL(14, 2)
)
INSERT INTO #TempTableFacultyCollegeMap
(
[CollegeId],
[UniversityRegNo],
[CollegeName],
[CollegeAddress],
[IsAICTEApproved] ,
[IsWBSEBApproved]
)
SELECT
T.F.value('@CollegeId','INT'),
T.F.value('@UniversityRegNo','VARCHAR(200)'),
T.c.value('@CollegeName','decimal(14, 2)'),
T.F.value('@CollegeAddress','decimal(14, 2)'),
T.F.value('@IsAICTEApproved','decimal(14, 2)') ,
T.F.value('@IsWBSEBApproved','decimal(14, 2)')
FROM @sFacultyXML.nodes('/FacultyDetails/CollegeInfo') T(F)

Bind DropDownList Using Cache Value

2009-09-03T22:26:00.000-07:00

Here I have created an AppCacheManager Class where i define some methods for Insert to Cache,Remove From Cache,Refresh Cache etc..
We need to use a synchronization primitive lock which is provided by the .NET Framework. Basically this mechanism allows a thread to acquire a lock on an instance of an object. Which means, only one thread can acquire a lock on the object and other threads have to wait until the original thread releases the lock .But if we lock the cache object directly it will be a huge performance issue.Acctullay we have to make sure that a)multiple threads can read cache data simultaneously, b)only one thread is allowed to update the cache at a time c) When a thread is updating the cache, all the threads that want to read the cache data should wait until the update is complete
The .NET framework provides another thread synchronization primitive called ReaderWriterLock
My Cache Manager Class is like that
using System;
using System.Collections.Generic;
using System.Collections;
using System.Text;
using System.Data;
using System.Web.Caching;
using System.Threading;
using System.Reflection;
using AppConfigurationManagement
namespace CacheManagement
{
// contains the methods for cache management for Add ,Remove,Refresh
public static class AppCacheManager
{
private static System.Web.Caching.Cache _CacheManager = System.Web.HttpContext.Current.Cache;
private static ReaderWriterLock _ReadWriteLock;
static AppCacheManager ()
{
_ReadWriteLock = new ReaderWriterLock();
if (System.Web.HttpContext.Current != null)
{
_CacheManager = System.Web.HttpContext.Current.Cache;
}
else
{
_CacheManager = System.Web.HttpRuntime.Cache;
}
}
// Method to add object in cache
public static void AddToCache(EnumeratorsConfiguration.CacheKey key, object keyData)
{
try
{
// Aquire Writer Lock
_ReadWriteLock.AcquireWriterLock(60000);
_CacheManager.Insert(key.ToString(), keyData);
}
finally
{
if (_ReadWriteLock.IsWriterLockHeld)
{
_ReadWriteLock.ReleaseWriterLock();
}
}
}
/// Method to remove object from cache,
/// it removes object for all keys which starts with value of key
public static void RemoveFromCache(EnumeratorsConfiguration.CacheKey key)
{
try
{
_ReadWriteLock.AcquireWriterLock(60000);
System.Collections.IDictionaryEnumerator dicEnum;
dicEnum = _CacheManager.GetEnumerator();
while(dicEnum.MoveNext() == true)
{
if (((string)dicEnum.Key).StartsWith(key.ToString()))
{
_CacheManager.Remove((string)dicEnum.Key);
}
}
}
finally
{
//Release the write lock
if (_ReadWriteLock.IsWriterLockHeld)
{
_ReadWriteLock.ReleaseWriterLock();
}
}
}
/// Method to remove object from cache,
/// it removes object for all keys which starts with value of key
public static void RemoveFromCache()
{
try
{
_ReadWriteLock.AcquireWriterLock(60000);
System.Collections.IDictionaryEnumerator dicEnum;
dicEnum = _CacheManager.GetEnumerator();
while (dicEnum.MoveNext() == true)
{
if (IsCacheable(dicEnum.Key.ToString()))
_CacheManager.Remove((string)dicEnum.Key);
}
}
finally
{
//Release the write lock
if (_ReadWriteLock.IsWriterLockHeld)
{
_ReadWriteLock.ReleaseWriterLock();
}
}
}
public static DataTable GetCacheList()
{
try
{
_ReadWriteLock.AcquireWriterLock(60000);
System.Collections.IDictionaryEnumerator dicEnum;
dicEnum = _CacheManager.GetEnumerator();
DataTable dtCache = new DataTable();
dtCache.Columns.Add("Key");
while (dicEnum.MoveNext() == true)
{
if (IsCacheable(dicEnum.Key.ToString()))
{
DataRow drCache = dtCache.NewRow();
drCache["Key"] = dicEnum.Key.ToString();
dtCache.Rows.Add(drCache);
}
}
return dtCache;
}
finally
{
//Release the write lock
if (_ReadWriteLock.IsWriterLockHeld)
{
_ReadWriteLock.ReleaseWriterLock();
}
}
}
// It retrieves a object from cache for a key
public static object RetrieveFromCache(EnumeratorsConfiguration.CacheKey key)
{
try
{
_ReadWriteLock.AcquireReaderLock(60000);
return _CacheManager.Get(key.ToString());
}
finally
{
if (_ReadWriteLock.IsReaderLockHeld)
{
_ReadWriteLock.ReleaseReaderLock();
}
}
}
/// Rerurns whether the specified key Exists in cache.
public static bool ExistsInCache(EnumeratorsConfiguration.CacheKey key)
{
try
{
if (_CacheManager.Get(key.ToString()) != null)
{
return true;
}
else
{
return false;
}
}
catch (Exception ex)
{
return false;
}
}
}
}
Now let us say I want to bind a dropdownlist by the values stored in the cache.Here is way how I can do thatHere we are taking an Enum for the Cache Key Settings. If there exists various Chache Key ,we can use an Enum for that

using System;
using System.Collections.Generic;
using System.Text;
namespace AppConfigurationManagement
{
public static class EnumeratorsConfiguration
{
#region Enum
public enum CacheKey
{
Location = 1,
Region =2,
Branch = 3
}
#endregion
}
}

Now let us call the Cache Methods.If the data for the specified cache key remains in the cache then we will call it ,otherwise we will add the value to the cache.

using System;
using System.Collections.Generic;
using System.Text;
using AppConfigurationManagement;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using BusinessEntity;
namespace BusinessLogic
{
public static class AppMetadataManager
{
#region Public Methods
/// Contains the methods for Metadata Management
public static object GetMetadata(EnumeratorsConfiguration.CacheKey key)
{
object metadata = null;
try
{
if (AppCacheManager.ExistsInCache(key) && ConfigurationManager.AppSettings["EnableCache"].ToString() == "1")
{
/*if the data is in cache returns that from the cache*/
metadata = AppCacheManager.RetrieveFromCache(key);
if (metadata == null)
metadata = GetMetadataFromDB(key);
}
else
{
metadata = GetMetadataFromDB(key);
}
}
catch (Exception e)
{
throw new Exception() ;
}
return metadata;
}
/// Flushes the Metadata
public static void FlushMetadata(EnumeratorsConfiguration.CacheKey key)
{
if (AppCacheManager.ExistsInCache(key))
{
AppCacheManager.RemoveFromCache(key);
}
}
private static object GetMetadataFromDB(EnumeratorsConfiguration.CacheKey key)
{
object metadata = null;
/*data is not in cache, so get the data from the database and put that in cache*/
switch (key)
{
case EnumeratorsConfiguration.CacheKey.Location:
DataSet dsLocation = BackEndManager.GetLocationList();
AppCacheManager.AddToCache(key, dsLocation);
metadata = dsLocation;
break;
case EnumeratorsConfiguration.CacheKey.Region :
List lstRegion = BackEndManager.GetRegionList();
AppCacheManager.AddToCache(key, lstRegion);
metadata = lstRegion;
break;
}
return metadata;
}
#endregion
}
}

Now in our Page_Load Event we can do the following
protected void Page_Load(object sender, EventArgs e)
{
ddlRegion.Items.Clear();
ddlRegion.Items.Add(new ListItem("---Select---", "0"));
List lstRegion = (List)MetadataManager.GetMetadata(ConfigurationEnumerators.CacheKey.Region);
foreach (Region objRegion in lstRegion)
{
ListItem li = new ListItem();
li.Text = objRegion.Name.ToString();
li.Value = objRegion.RegionID.ToString();
ddlRegion.Items.Add(li);
}
ddlRegion.DataBind();
}
I will post Upadte and Remove Cache very soon
However, the problem with the MS Caching application block is that it carries a lot of overhead and has a lot of features that may not be useful for your application

Bind DropdownList by an Enum

2009-08-27T05:37:00.000-07:00

i have an enum like using System;using System.Collections.Generic;using System.Text; namespace ConfigurationManager{ public static class ConfigurationEnumerators
{
public enum EventTypeValues
{
Red= 1,
Green= 2,
Yellow= 3,
White= 4,
Blue = 5,
Violate = 0
}
}
}
This is a color type enum.Now i am going to populate a dropdown list by this Color Enumarator ddlColorType.Items.Insert(0, "------Select------");
foreach (string str in Enum.GetNames(typeof(ConfigurationEnumerators.EventTypeValues)))
{
ddlCarType.Items.Insert((int)Enum.Parse(typeof( ConfigurationEnumerators.EventTypeValues), str ),str.ToString());
}
The dropdownlist is populated by the enum with the string at its TextField and the int value at its Index fieldNow it is possible to collect the selected dropdownlist value by ddlColorType.SelectedIndex property

Commma Elemination from Comma Separatoe

2009-08-24T21:02:00.000-07:00

string ids= string.Empty;
foreach (User objUser in dtUser)
{
ids= ids+ obiUser.UserId.ToString() + ",";
}
if (ids.Length > 0)
{
ids= ids.Substring(0, ids.Length - 1);
}

Just devide the whole string into a substring upto the leangth -1 and place it to a string

Enumaretion with C#

2009-08-23T22:57:00.000-07:00

Enums Defined

Enums are lists of strongly typed constants with members that has symbolic names, corresponding integral values.
The System.Enum .NET Framework Class Library type is the base class of enum types and contains methods that allow you to work with enums in different ways, such as working with a list of names or values, converting from value to name, and converting from name to value.
Enum base types can be changed and member values can be specified.
Enums make working with strongly typed constants via symbolic names easy.
Enums are value types, which mean they contain their own value, can't inherit or be inherited from, and assignment copies the value of one enum to another.

Simply if a single number needs a definition to make it easier to read then weuse a constant like

public const int myVar = 0;
if more than one related number needs a definition, then we can use an Enumeration

Difference Between ‘Enum’ and ‘enum’
The C# type, enum, inherits the Base Class Library type, Enum. Use the C# type, enum, to define new enums and use Enum, to implement static enum methods.

Creating an Enum
Declaration
[attributes] [modifiers] enum identifier [:base-type]
{
enumerator-list [,]
}

· The attributes is optional and is used to hold additional declarative information.
The modifier is optional. The allowed modifiers are new, public, protected, internal and private.
The keyword enum must be followed by an identifier that names the enum.
The base-type of an enumeration may be one of the following; byte, sbyte, short, ushort, int, uint, long or ulong. If no base-type is declared, than the default of int is used.
The enumerator-list contains the identifiers which are separated by commas
The first enumerator begins at zero by default and each enumerator following is increased by 1. This can be overridden so that each member of the enumerator-list contains its own unrelated value.
Two items in an enumeration can hold the same value, however, this will cause problems if you use an automated switch statement where all elements are added.

Example
using System;
using System.Collections.Generic;
using System.Text;

// declares the enum

public enum Universe{

Planet,

Stars,

Satellite

}

// demonstrates how to use the enum

class CreateEnum{

static void Main()

{

// create and initialize

// instance of enum type

Universe varUniverse = Universe.Planet;

// make decision based

// on enum value

switch (varUniverse)

{

case varUniverse.Planet:

Console.WriteLine("Enum Picks the planet.");

break;

case varUniverse.Stars:

Console.WriteLine("Enum pics the Stars.");

break;

case varUniverse.Satellite:

Console.WriteLine("Enum picks the Satellite.");

break;

}

Console.ReadLine();

}

}
Here I have declared an enum by using the enum keyword having a type identifier (Universe).The enum contains a comma separated list of values enclosed within curly braces.
This enum is of type Universe and we use it to declare the varUniverse variable in the Main method. Since an enum is a value type, we can assign a value (Universe.Planet) to it directly, similar to the simple types such as int or double.

Using Enums
Enum can be customized by changing its base type and its member values. By default, the list type of an enum is int.During enum declaration you can change this default by the base types include byte, sbyte, short, ushort, int, uint, long, and ulong.
Another modification you can make to an enum is to set the value of any enum member. By default, the first member of an enum takes zero.You can change it to any number you want.Two or more list member can have the same value.But it would some logical error through your programme thereafter.
using System;

// declares the enum

public enum Universe

{

Planet=1,

Stars,

Satellite

}

// demonstrates how to use the enum
class CreateEnum{
static void Main()
{
// create and initialize
// instance of enum type
Universe varUniverse = Universe.Planet;
// make decision based
// on enum value
switch (varUniverse)
{
case varUniverse.Planet:
Console.WriteLine("Enum Picks the planet.");
break;
case varUniverse.Stars:
Console.WriteLine("Enum pics the Stars.");
break;
case varUniverse.Satellite:
Console.WriteLine("Enum picks the Satellite.");
break;
}
Console.ReadLine();
}
}

The first member of the Universe enum, Planet, has its value changed to 1. You are restricted from creating forward references, circular references, and duplicate references in enum members.

As the default value of Planet is changed to 1, so the rest values are Stars=2, Satellite=3

Changing Enum Base Type

using System;
// declares the enum
public enum Universe : byte
{
Planet=1,
Stars,
Satellite
}
// demonstrates how to use the enumclass CreateEnum{ static void Main() { // create and initialize // instance of enum type Universe varUniverse = Universe.Planet; // make decision based // on enum value switch (varUniverse) { case varUniverse.Planet: Console.WriteLine("Enum Picks the planet."); break; case varUniverse.Stars: Console.WriteLine("Enum pics the Stars."); break; case varUniverse.Satellite: Console.WriteLine("Enum picks the Satellite."); break; } Console.ReadLine(); }}

Read Child Node From a XML and Bind a DropDown List By this

2009-07-02T03:05:00.000-07:00

My xml file is Like that

Root Node := Weather_Data
Parent Nade : = Weather

Child Node Under Parent "Weather"
ChildNode : City
ChildNode :Weather

public ArrayList ReadValue(string tag, string key)
{
string _file = "Weather.xml";
ArrayList arr = new ArrayList();
string _path = Server.MapPath("~/");
//load the document into a stream
FileStream stream = new FileStream(_path + _file, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
XmlDocument doc = new XmlDocument();
//load the stream into an XML Document
doc.Load(stream);
//variable to hold the value
string returnValue = string.Empty;
//get all the elements for the specified tag
XmlNodeList nodeList = doc.GetElementsByTagName(tag);
//loop through the document
for (int i = 0; i < nodeList.Count; i++)
{
for (int j = 0; j < nodeList[i].ChildNodes.Count; j++)
{
//check to see if we have a match
if (nodeList[i].ChildNodes[j].Name == key)
{
returnValue = nodeList[i].ChildNodes[j].InnerText;
arr.Add(nodeList[i].ChildNodes[j].InnerText);
//break;
}
}
}
return arr;
}

Call the above method for bind your DropdownList Like

ArrayList arrList= ReadValue("Weather", "City");
DropDownList1.DataSource = arrList;
DropDownList1.DataBind();

Hope This will help you

HTTPWeb Request and Responses With Source Code

2009-07-01T23:13:00.000-07:00

HTTP REQUEST /RESPONSES

Basically, an HTTP client initiates a request through web browser. It establishes a Transmission Control Protocol (TCP) connection to a particular port on a host server (port 80 by default). An HTTP server that port waits for the client's request message. After receiving the request, the server sends back a status line, such as "HTTP/1.1 200 OK", and a message of its own, the body of which is may be the requested resource, an error message, or some other information.

Resource accessing by the HTTP are identified using Uniform Resource Identifier (URI)or, more specifically, Uniform Resource Locator (URL) by the http: or https URI schemas.

HTTP REQUEST STYLE

1.Request line (such as GET)
2.Header ( such as Accept-Language: en)
3.Empty Line
4.Optional message body

HTTP REQUEST METHODS

Hyper Text Transfer Protocol (HTTP) defines eight methods for the next action for existing resource.I am giving you a short description on that eight methods.

HEAD
It is almost like a get request without the response body. This is useful for retrieving meta-information written in response headers, without sending the entire content.

GET
Get requests a representation of the specified resource.

POST
Post submits data to be processed from your form to the requesting resources. The data is included in the body of the request. It may create a new resource or update the existing resources or both.

PUT
Put uploads a representation of the specified resource.

DELETE
It deletes the specified resource.

TRACE
It returns back to the received request, so that a client can see what intermediate servers are adding or changing in existing the request.

OPTIONS
It returns the HTTP methods that the server supports for specified URL. This can be used to check the functionality of a web server by requesting '*' instead of a specific resource.

CONNECT
Converts the request connection to a transparent TCP/IP tunnel, usually to facilitate SSL-encrypted communication (HTTPS) through an unencrypted HTTP proxy.

CREATING REQUEST AND GETTING RESPONSES

// Create a request for the URL.
WebRequest request = WebRequest.Create("http://www.google.com");
// If required by the server, set the credentials.
request.Credentials = CredentialCache.DefaultCredentials;
// Get the response.
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
// Display the status.
if (response.StatusDescription == "OK")
{
// Get the stream containing content returned by the server.
Stream dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader(dataStream);
// Read the content.
string responseFromServer = reader.ReadToEnd();
// Display the content.
Console.WriteLine(responseFromServer);
// Cleanup the streams and the response.
reader.Close();
dataStream.Close();
response.Close();
}

CREATING REQUEST AND GETTING RESPONSES WITH AUTHENTICATION

 strId = UserId_TextBox.Text;
string strName = Name_TextBox.Text;

ASCIIEncoding encoding=new ASCIIEncoding();
string postData="userid="+strId;
postData += ("&username="+strName);
byte[]  data = encoding.GetBytes(postData);

// Prepare web request...
HttpWebRequest myRequest =
(HttpWebRequest)WebRequest.Create("https://www.sandbox.paypal.com/cgi-bin/webscr");
myRequest.Method = "POST";
myRequest.ContentType="application/x-www-form-urlencoded";
myRequest.ContentLength = data.Length;
Stream newStream=myRequest.GetRequestStream();
// Send the data.
newStream.Write(data,0,data.Length);
newStream.Close();

// Write the request back IPN strings
StreamWriter stOut = new StreamWriter(req.GetRequestStream(), Encoding.ASCII);
stOut.Write(strNewValue);
stOut.Close();

//send the request, read the response
HttpWebResponse strResponse = (HttpWebResponse)req.GetResponse();
Stream IPNResponseStream = strResponse.GetResponseStream();
Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
StreamReader readStream = new StreamReader(IPNResponseStream, encode);

char[] read = new char[257];
// Reads 256 characters at a time.
int count = readStream.Read(read, 0, 256);
readStream.Close();
strResponse.Close();

Check URL Exsists Or Not(HttpWebResponse Status)

2009-07-01T23:10:00.000-07:00

Import the base class "System.Net" at the begining

string URL = TextBox1.Text;
try
{
//Create a HTTP Web Request for the URL.
WebRequest request = WebRequest.Create(URL);
request.Proxy = null;
//Get the HTTP Web Response.
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
//Display the status.
Response.Write(response.StatusDescription);

if (response.StatusDescription == "OK")
{
Response.Write("\n Site Exists.");
}
else
{
Response.Write("Does Not Exists.");
}
}
catch (Exception ex)
{
throw new Exception("Request Incomplete..Please Contact with your System Administrator :" + ex);
}

Asp.Net Authentication

2009-06-27T03:53:00.000-07:00

Authentication is a process to check the user’s identity.The authenticated user information is stored in HttpContext.User.Identity

There are three types of authentication in Asp.Net

. Forms authentication

· Windows authentication

· Passport authentication

. Custom Authentication

Forms authentication

This authentication is based on cookies where the user name and the password are stored either in a file or in the database. After a user get authenticated, the credentials are stored in a cookie to in that session. This authentication supports both session and persistent cookies.

Windows authentication

This authentication relies upon IIS.After IIS authenticates a client, it passes a security token key to ASP.NET. ASP.NET constructs and attaches an object of the WindowsPrincipal Class to the application context based on the security token it receives from IIS

Pussport authentication

Passport authentication provider is a centralized authentication service provided by Microsoft that offers a single logon and core profile services for member sites. Passport is basically a forms-based authentication service. In this mode of authentication the Passport service grants a site-specific key. The Passport logon server uses this key to encrypt and decrypt the query strings passed between the member site and the Passport logon server.

Authentication modes can be specified in the application’s web.config file as shown below:

Example1

configuration

      

    authentication mode="[Windows/Forms/Passport/None]">

    authentication>

  

configuration

Example2

configuration

  

    authentication mode="Forms"

    forms name="UserLogin"loginUrl="UserLogin.aspx"

    authorization

        deny users="?"

    authorization

  

configuration

OR
Example3

if (Verify (txtUserName.Text, txtPassword.Text))

{

  FormsAuthentication.RedirectFromLoginPage(txtUserName.Text, False);

    else

  lblMessage.Text = "Invalid UserName/Password specified...";

}



private Verify(string userName, string password)

{

      //Usual Code to connect to the DB 

      // and verify the user's credentials

}

Get Text Box/Dropdown Value By Javascript

2009-06-26T23:13:00.000-07:00

function GetValue()
{

// var test = document.getElementById('<%=txtMyTextBox.ClientID %>').value;
var test2 = document.getElementById('<%=DropDownList1.ClientID %>').value;
alert(test2);

}

Caching in Asp.Net

2009-05-14T02:49:00.000-07:00

ASP.NET supports two important forms of caching: Page (including sub-page) caching, and Data caching.

Page caching allows the server to store a copy of the output of a dynamic page, and to use this to respond to requests instead of running the dynamic code again. Sub-page caching does the same thing, but for parts of pages.

Data caching allows a web application to store commonly used objects so that they are available for use across all pages in the site. While it was possible to do this kind of thing in ASP, using the Application object, it’s a whole lot better in ASP.NET.

Page Caching :

Two types of page caching is there

a) Page Fragment Caching OR Partial Page Caching

b) Page Output Caching

Page Output Caching:

When we say that the output of a web page is cached, we imply that the web page output is stored in the cache memory. Whenever a new page request is made, the ASP.NET Cache Engine is activated. It checks whether there is a corresponding cache entry for this page. If one is found, it is known as a Cache hit, else, we say that a cache miss has occurred. If there is a cache hit, i.e., if the ASP.NET Cache engine finds a corresponding cache entry for this page, the page is rendered from the cache, otherwise, the page being requested is rendered dynamically.

Page Output caching can be specified in any of the two ways

1. By declaration

Where the Cached Data Stored?

when some makes a request from a website there are two types of cache that may satisfy the request without reaching the original server.

The first is the personal cache maintained by the user’s web browser (a ‘browser cache’).

The second is a shared cache present on the network between the user’s browser and the origin server (a ‘proxy cache’).

The page output cache maintained by ASP.NET on the web server is a further type of cache, but when you specify page caching - by setting the Location parameter - you can also make use of these first two sorts of caches.

The values of the OutputCacheLocation is given below.

Any [default]	The page can be cached on any of: the browser; the proxy server; the web server.
Client	The page is to be cached on the browser.
Client	The page can be cached on the browser or a proxy server.
None	The page is not to be cached.
Server	The page is to be cached on the web server.
ServerAndClient	The page can be cached on the browser or on the server.

when caching occurs elsewhere rather than on the server, treate manipulation of the HTTP 1.1 headers that deal with caching.

reference for details :‘Standard Caching over the Internet’ .

Cache Duration :

Pages remain in the cache for some length of time, determined by the Duration parameter. The value is set in seconds.

As we shall see later, if the page caching is set programmatically, rather than declaratively, one can also set a ‘Sliding Expiration’ value which increases the cache duration every time a page is requested.

2. By Program

Response.Cache.SetCacheability (HttpCacheability.Server);

It is also possible to set the OutputCache on all the pages in an ASP.NET application programmatically in the Global.asax page. Refer to the code snippet that follows:--

void Application_BeginRequest(object sender, EventArgs e)
{
HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.Server);
}

Page Fragment Caching :

It allows specific portions of the web page to be cached rather than caching the entire web page and is useful in situations where a particular web page can contain both static and dynamic content.

Data Caching :

will be comming soon

Conclusion

Caching is a great tool that can be used to boost the performance web applications.

Cookies in Asp.Net

2009-05-14T01:28:00.000-07:00

Cookies

A Cookie is a small text file that the browser creates and stores on the hard drive of client machine. Cookie just one or more pieces of information stored as text strings. A Web server sends client a cookie and the browser stores it. The browser then returns the cookie to the server the next time the page is referenced. The most common use of a cookie is to store information about the User and preferences the user makes.

I order to create a cookie you have 2 variable must be defined as they are the cookie name and the duration of the cookie before it expired

How To Create Cookies In Asp.net & Get Cookie Value

protected void Page_Load(object sender, System.EventArgs e)
{
    HttpCookie myCookie= new HttpCookie("Address");
    myCookie["Country"] = "India";
    myCookie["City"] = "Kolkata";
    myCookie["Name"] = "Subhamay";
    myCookie.Expires = DateTime.Now.AddDays(2);
    Response.Cookies.Add(myCookie);
    Label1.Text = "I have Created My own Cookie successfully!";

    HttpCookie cookie = Request.Cookies["Address"];

    if (cookie != null)
    {
        string country = cookie["Country"];
        string city = cookie["City"];
        string name = cookie["Name"];
    
    }
}

Cookies With Key Value : A Different Approach

Creating New Cookie

HttpCookie myCookie = new HttpCookie("Cars");

add some key value to the cookie
myCookie.Values.Add("muffin", "chocolate");
myCookie.Values.Add("babka", "cinnamon");

add the cookie to cookie collectionResponse.Cookies.Add(myCookie);

//how to get the keys and values stored in a cookie:

Response.Write(myCookie.Value.ToString());

The output to using this with the previous created cookie is this: "muffin=chocolate&babka=cinnamon".

Set Life Time Of A cookie

myCookie.Expires = DateTime.Now.AddHours(12); Or

myCookie.Expires = DateTime.Now.AddDays(7);


If Cookie Expires property is not set then cookie will be created for the current
 browser instance

Setting the cookie's path

set a path for a cookie so that it will be available only for that path in your website

myCookie.Path = "/mydomain";

Setting the domain for a cookie

myCookie.Domain= "mydomain.mysite.com";

How To Destroy A Cookie

there is no method called delete or destroy ..So you can use

myCookie.Expires = DateTime.Now.AddDays(-1);
For Removing a subkey:

myCookie.Values.Remove("babka");

CheckBoxList

2009-05-12T01:03:00.000-07:00

Populate CheckBoxList (List Control)

Creates a group of check boxes. Properties and events are identical to other list controls, such as DropDownList

Remove CheckBoxList Item By Item Text:

if (CheckBoxList1.Items.FindByText(itemValue) != null)
      {
          string itemText = CheckBoxList1.Items.FindByText(itemValue).Text;
          ListItem li = new ListItem();
          li.Text = itemText;
          li.Value = itemValue;
          Label1.Text = "Removed Item Is: " + itemText;
          CheckBoxList1.Items.Remove(li);
      }

Remove CheckBoxList Item By Item Value

if (CheckBoxList1.Items.FindByValue(itemValue) != null)
      {
          string itemText = CheckBoxList1.Items.FindByValue(itemValue).Text;
          ListItem li = new ListItem();
          li.Text = itemText;
          li.Value = itemValue;
          Label1.Text = "Item Found and remove: " + itemText;
          CheckBoxList1.Items.Remove(li);
      }

Add ListItem with Item Text and Value in CheckBoxList:

protected void Button1_Click(object sender, System.EventArgs e)
   {
       ListItem li = new ListItem();
       li.Text = TextBox1.Text.ToString();
       li.Value = TextBox2.Text.ToString();
       CheckBoxList1.Items.Add(li);
       Label1.Text = "ListItem added in CheckBoxList";
      
   }

Use Theme & Skin In a Checkboxlist

runat="server"
BorderColor="Gray"
BorderWidth="2"
BackColor="White"
ForeColor="Black"
Font-Bold="true"
Font-Italic="true" RepeatColumns="3"
>

Programatically Bind CheckBoxList and Retrive Value with comma separator:

Bind:

chkInterest.DataSource = dataTable1
chkInterest.DataTextField = "Name"
chkInterest.DataValueField = "Id"
chkInterest.DataBind();

Retrieve:

protected void imgSubmit_Click(object sender, ImageClickEventArgs e)
{

string strInterests = "";
string strHobbies = "";

for (int i = 0; i < chkInterest.Items.Count; i++)
{
if (chkInterest.Items[i].Selected)
{
strInterests += chkInterest.Items[i].Text + ",";
}
}

strInterests = strInterests.Trim(new char[] { ',' });

for (int j = 0; j < chkListHobby.Items.Count; j++)
{
if (chkListHobby.Items[j].Selected)
{
strHobbies += chkListHobby.Items[j].Text + ",";
}

}

strHobbies = strHobbies.Trim(new char[] { ',' });

}

Array Class

2009-05-12T00:19:00.000-07:00

Creating Arrays

The Array class is abstract, so using constructor array class can not be created.To create an arrays we use the static CreateInstance() method.

By this way type of the elements in advance is not necessary to be known, as the type is passed to the CreateInstance() method as a Type object.

Array MyArray= Array.CreateInstance(typeof(int), 5); //( type of Array,Size of Array)
for (int i = 0; i < 5; i++)
{
MyArray.SetValue(33, i);
}

for (int i = 0; i < 5; i++)
{
Console.WriteLine(MyArray.GetValue(i));
}

Copying Arrays

Arrays are reference types, assigning an array variable to another one it need two varriable referencing to the same array. For copying arrays, the array implements the interface ICloneable. The Clone() method that is defined with this interface creates a shallow copy of the array.

If the array contains reference types, the elements are not copied, just the references

Car[] cars= {
new Car("Car", "Toyota"),
new Person("Bike", "Yahamaha")
};
Car[] CarClone = (Car[])CarClone .Clone();

int[] intArray1 = { 1, 2 };
int[] intArray2 = (int[])intArray1.Clone();

Sorting Arrays

The Array class implements a bubble-sort for sorting the elements in the array. The Sort() method requires the interface IComparable to be implemented by the elements in the array. Simple types such as System.String and System.Int32 implement IComparable, so you can sort elements containing these types.

string[] names = {
"Subhamay",
"Chaki",
"Alok",
"Gautam"
};

Array.Sort(names);

foreach (string name in names)
{
Console.WriteLine(name);
}

If you are using custom classes with the array, you must implement the interface IComparable. This interface defines just one method CompareTo() that must return 0 if the objects to compare are equal, a value smaller than 0 if the instance should go before the object from the parameter, and a value larger than 0 if the instance should go after the object from the parameter.

Array

2009-05-11T22:33:00.000-07:00

Simple Arrays

An array is a data structure that contains object/data of same type

Array Declaration

An array is declared by defining the type of the elements inside the array followed by empty brackets and a variable name; for example, an array containing integer elements is declared like this:


int [] sampleArray

Using Reference Types

arrays can be declared of a type of a custom class. Let Us take an example of "Product" class having two constructor an ToString() method

public class Product
{
public Product() //default constructor
{
}

public Product(string name, string description) //parametrized constructor
{
this.name = name;
this.description = description;
}

private string _name;
private string _description;

public string ProductName
{
get { return _name; }
set { _name = value; }
}

public string Description
{
get { return _description; }
set { _description = value; }
}

public override string ToString()
{
return name + " " + description;
}
}

Now Declaring an array of four is similar to declaring an array of int:

Product [] myProduct = new Product[4]

Here memory must be allocated for each array element otherwise a NullReferenceException will be thrown.

Multidimensional Arrays

1-dimension array are indexed by a single integer. A multidimensional array is indexed by two or more integers.

How To Declare Two Dimension Array

int[,] myarray = new int[3, 3];
myarray[0, 0] = 1;
myarray[0, 1] = 2;
myarray[0, 2] = 3;
myarray[1, 0] = 4;
myarray[1, 1] = 5;
myarray[1, 2] = 6;
myarray[2, 0] = 7;
myarray[2, 1] = 8;
myarray[2, 2] = 9;

How To Declare Three Dimension Array


int[,,] threedim = {
                    { { 1, 2 }, { 3, 4 } },
                    { { 5, 6 }, { 7, 8 } },
                    { { 9, 10 }, { 11, 12 } }
                  };

Jagged Arrays

A 2-dimensional array has a rectangular size (for example 3 by 3 elements). A jagged array is more flexible in sizing the array. With a jagged array every row can have a different size.

a 2-dimensional array that has 3x3 elements with a jagged array. The jagged array can contains three rows where the first row would have elements, the second row would have elements, and the third would have three elements.

int[][] jagged = new int[3][];
jagged[0] = new int[2] { 1, 2 };
jagged[1] = new int[6] { 3, 4, 5, 6, 7, 8 };
jagged[2] = new int[3] { 9, 10, 11 };

Itaration through for loop

for (int row = 0; row < jagged.Length; row++)
{
for (int element = 0; element < jagged[row].Length; element++)
{
Console.WriteLine("row: {0}, element: {1}, value: {2}",
row, element, jagged[row][element]);
}
}

String and String Formatting

2009-02-20T00:47:00.000-08:00

Inm Asp.Net framework format inline string expressions, including String.Format[^], StringBuilder.AppendFormat[^], and TextWriter.Write[^] (and WriteLine[^]), which the Console[^] class inherits

DateTime String Formatting :

DateTime now = DateTime.Now;
string.Format("Short date: {0:d}", now);
string.Format("Long date:          {0:D}", now);
string.Format("Sortable date/time: {0:s}", now);
string.Format("Custom date:        {0:ddd, MMM dd, yyyy}", now);

Currency String Formatting($3.00) :

Currency:     String.Format("{0:C}", <>);
Decimal:      String.Format("{0:C}", <>);
Scientific:   String.Format("{1:E}", <>);
Fixed point:  String.Format("{1:F}", <>);
General:.     String.Format("{0:G}", <>);
Number:       String.Format("{0:N}", <>);
Percent:.     String.Format("{1:P}", <>);
Round-trip:   String.Format("{1:R}", <>);
Hexadecimal:  String.Format("{0:X}", <>);

2008-10-31T00:47:00.000-07:00

Put your DataTable value to ViewState such that you can rearrange the ViewState

ViewState["userDataSource"] = dtTemp;

public SortDirection GridViewSortDirection
{
get
{
if (ViewState["sortDirection"] == null)
ViewState["sortDirection"] = SortDirection.Ascending;
return (SortDirection)ViewState["sortDirection"];
}
set
{
ViewState["sortDirection"] = value;
}
}

private void SortGridView(string sortExpression, string direction)
{
DataTable dt = ((DataTable)ViewState["userDataSource"]);
DataView dv = new DataView(dt);
dv.Sort = sortExpression + " " + direction;

this.gvUser.DataSource = dv;
gvUser.DataBind();
}

protected void gvUser_Sorting(object sender, GridViewSortEventArgs e)
{

string sortExpression = e.SortExpression;
GridView dd = ((GridView)(object)sender);

if (GridViewSortDirection == SortDirection.Ascending)
{
GridViewSortDirection = SortDirection.Descending;
SortGridView(sortExpression, "DESC");
}
else
{
GridViewSortDirection = SortDirection.Ascending;
SortGridView(sortExpression, "ASC");
}

}

Pagination in DataList

2008-10-31T00:32:00.000-07:00

Generally DataList Control does not support pagination by its default properties..But if you need it you have to do it by mannual coding.

Add
PagedDataSource pds = new PagedDataSource();
at the top of your Page_Load(object sender, EventArgs e) event

Now Add these methods in your code behind page

public void BindDatalist() //Get Data and Set Page Size ,Page Index
{

//dlstFeatureAlbum.DataSource = FeatureAlbum.GetAlbums();
// dlstFeatureAlbum.DataBind();

DataTable dt = new DataTable();

dt = FeatureAlbum.GetAlbums();
pds.DataSource = dt.DefaultView;
pds.AllowPaging = true;
pds.PageSize = 24;//Convert.ToInt16(ddlPageSize.SelectedValue);
if (dt.Rows.Count <= 24)
{
divPageIndex.Visible = false;
}
if (dt.Rows.Count == 0)
{
lblEmptyList.Visible = true;
}
pds.CurrentPageIndex = CurrentPage;
lnkbtnNext.Enabled = !pds.IsLastPage;
lnkbtnPrevious.Enabled = !pds.IsFirstPage;

dlstFeatureAlbum.DataSource = pds;
dlstFeatureAlbum.DataBind();

doPaging();
}

//Code for Pagination

public int CurrentPage //this method is for storing the current page index
//to view state
{

get
{
if (this.ViewState["CurrentPage"] == null)
return 0;
else
return Convert.ToInt16(this.ViewState["CurrentPage"].ToString());
}

set
{
this.ViewState["CurrentPage"] = value;
}

}

private void doPaging() //Calculating total results and divide them into pages
{
DataTable dt = new DataTable();
dt.Columns.Add("PageIndex");
dt.Columns.Add("PageText");
for (int i = 0; i < pds.PageCount; i++)
{
DataRow dr = dt.NewRow();
dr[0] = i;
dr[1] = i + 1;
dt.Rows.Add(dr);
}

dlPaging.DataSource = dt;
dlPaging.DataBind();
}

protected void dlPaging_ItemCommand(object source, DataListCommandEventArgs e)
{
if (e.CommandName.Equals("lnkbtnPaging"))
{
CurrentPage = Convert.ToInt16(e.CommandArgument.ToString());
BindDatalist();
}
}

protected void lnkbtnPrevious_Click(object sender, EventArgs e) //navigation
{
CurrentPage -= 1;
BindDatalist();
}

protected void lnkbtnNext_Click(object sender, EventArgs e) //navigation
{
CurrentPage += 1;
BindDatalist();
}

protected void dlPaging_ItemDataBound(object sender, DataListItemEventArgs e)
{
LinkButton lnkbtnPage = (LinkButton)e.Item.FindControl("lnkbtnPaging");
if (lnkbtnPage.CommandArgument.ToString() == CurrentPage.ToString())
{
lnkbtnPage.Enabled = false;
lnkbtnPage.Font.Bold = true;
}
}

protected void ddlPageSize_SelectedIndexChanged(object sender, EventArgs e)
{
CurrentPage = 0;
BindDatalist();
}

//End

Write XML from code behind

2008-10-31T00:30:00.000-07:00

public void CreateXMLFile(string FileName)
{
DataTable dt = new DataTable();
dt = FeatureAlbum.GetAlbums();
string path;
path = System.AppDomain.CurrentDomain.BaseDirectory.ToString() + FileName + ".xml";
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
System.IO.FileInfo fileName = new System.IO.FileInfo(path);
try
{
if (!fileName.Exists)
{
StreamWriter sw = new StreamWriter(path, true);
sw.WriteLine("");
sw.WriteLine("");
sw.Flush();
sw.Close();
}
doc.Load(path);
XmlElement newElem;
XmlElement newChElem;
XmlElement newSuperChElem;
XmlNode XNode;

for (int i = 0; i < dt.Rows.Count; i++)
{
newElem = doc.CreateElement("image");
doc.DocumentElement.AppendChild(newElem);
// newElem.SetAttribute("","");

newChElem = doc.CreateElement("filename");
newChElem.InnerText = dt.Rows[i]["Name"].ToString();
newElem.AppendChild(newChElem);

newChElem = doc.CreateElement("caption");
newChElem.InnerText = dt.Rows[i]["Description"].ToString();
newElem.AppendChild(newChElem);
}
//newChElem = doc.CreateElement("Time");
//newChElem.InnerText = "Time";
//newElem.AppendChild(newChElem);

XmlTextWriter writer = new XmlTextWriter(path, System.Text.Encoding.ASCII);
writer.Formatting = Formatting.Indented;
doc.Save(writer);
writer.Close();
}
catch (Exception ex)
{
//Your Catch block here...
}
}

Friend Function

2008-08-06T05:25:00.000-07:00

A friend function is not a class member and yet it can have access to private and protected members of a class. Friends are not called by using member selection operators such as “ . or ->” unless they are members of another class. Friend functions can be defined inside a class declaration. Friend functions declared within a class are inline just like other inline member functions. These functions act as though they were defined immediately after all class members have been seen but before the end of the class declaration. Even though friend functions are declared inside class declarations, they are not considered in the scope of the enclosing class. They are normally considered in the file scope. An entire class can be declared as a friend of another class.

To declare a function as a friend of a class, put the word “friend” before the function prototype in the class definition. For example, you want to show that ClassTwo is a friend of ClassOne, simply put the word “friend” in front of ClassTwo like:

friend class ClassTwo;

This line should be inside the definition of class ClassOne and declared explicitly. The friendship between ClassOne and ClassTwo is neither symmetric nor transitive. This means that ClassTwo is a friend of ClassOne but ClassOne cannot be assumed to be a friend of ClassTwo. Same concept applies when you have multiple classes connected by multiple friendships. Friendship can only go one way.

A partial example of friends accessing private members of a class goes something like this:

class ClassOne{
// friend declaration should appear before the declaration of public and private member function
friend void ClassTwo ( ClassOne &, int); // friend declaration
public:
Count( ) { x = 0; } // constructor
Void print( ) const { cout << x << endl;} // output
Private:
Int x; // data member
};

//ClassTwo is declared as a friend function of ClassOne
void ClassTwo( ClassOne &c, int val)
{
c.x = val;
}
int main( )
{
ClassOne counter;
counter.print ( );
ClassTwo( counter,10); // set x with a friend
Counter.print( );
Return 0;
}

The purpose of using friend function is to improve performance. Sometimes when a member function cannot be used in a certain operation, using friends would be able to solve that problem.

Devide Tree Menu in Two Diff Column

2008-08-05T00:06:00.001-07:00

public void GetCategoryTree()
{

BpBL.ProjectCategory objCat = new BpBL.ProjectCategory();

// PopulateTreeViewControl(categoryList);
DataTable dtTemp= new DataTable();
DataTable dtSubCat = new DataTable();
DataTable dtDemoTable1;
DataTable dtDemoTable2;

dtTemp=objCat.SelectMainCategory();
dtDemoTable1 = dtTemp.Clone();
dtDemoTable2 = dtTemp.Clone();
int count = Convert.ToInt32(dtTemp.Rows.Count);
int i=0;

foreach(DataRow drMain in dtTemp.Rows)
{

if (i++ % 2 == 0)
{
dtDemoTable1.LoadDataRow(drMain.ItemArray, true);
}
else
{
dtDemoTable2.LoadDataRow(drMain.ItemArray, true);
}
}
dtTemp.Clear();
TreeNode parentNode = null;
//Binding First Tree View
foreach (DataRow dr in dtDemoTable1.Rows)
{
parentNode = new TreeNode(dr["CategoryName"].ToString(), dr["Id"].ToString());
dtSubCat = objCat.SelectSubCategory(dr["Id"].ToString());
foreach (DataRow drSubcat in dtSubCat.Rows)
{
// TreeNode childNode = new TreeNode(product.ProductName, product.ProductID.ToString());
TreeNode childNode = new TreeNode(drSubcat["CategoryName"].ToString(), drSubcat["Id"].ToString());

parentNode.ChildNodes.Add(childNode);
}

parentNode.Collapse();

treeViewProjCat.ShowCheckBoxes = TreeNodeTypes.All;
treeViewProjCat.Nodes.Add(parentNode);

}

//Binding 2nd Tree View

foreach (DataRow dr in dtDemoTable2.Rows)
{
parentNode = new TreeNode(dr["CategoryName"].ToString(), dr["Id"].ToString());
dtSubCat = objCat.SelectSubCategory(dr["Id"].ToString());
foreach (DataRow drSubcat in dtSubCat.Rows)
{
// TreeNode childNode = new TreeNode(product.ProductName, product.ProductID.ToString());
TreeNode childNode = new TreeNode(drSubcat["CategoryName"].ToString(), drSubcat["Id"].ToString());

parentNode.ChildNodes.Add(childNode);
}

parentNode.Collapse();

treeViewProjCat2.ShowCheckBoxes = TreeNodeTypes.All;
treeViewProjCat2.Nodes.Add(parentNode);

}
}

execute parameterized stored procedure from code behind

2008-07-23T02:28:00.000-07:00

Add This to your Web.config file

SqlConnection conn = new SqlConnection(ConfigurationManager.AppSettings["ConStr"]);
SqlCommand cmd = new SqlCommand("spCheckProjectStatus", conn);
cmd.CommandType = CommandType.StoredProcedure;

SqlParameter sqlParam = new SqlParameter();
sqlParam = cmd.Parameters.Add("@ProjectId",SqlDbType.VarChar);
sqlParam.Direction = ParameterDirection.Input;
sqlParam.Value = dtTemp.Rows[i]["Pid"].ToString();

SqlParameter sqlParam2 = new SqlParameter();
sqlParam2 = cmd.Parameters.Add("@BiderId",SqlDbType.VarChar);
sqlParam2.Direction = ParameterDirection.Input;
sqlParam2.Value = dtTemp.Rows[i]["Bid"].ToString();

conn.Open();
SqlDataReader dr = cmd.ExecuteReader();
conn.Close();

hope this will help you....

Generate Random Key with integer and character

2008-07-22T21:06:00.000-07:00

use
System.Security;
System.Security.Cryptography;

in the include section

private string GetUniqueKey()
{

int maxSize = 8;
int minSize = 5;
char[] chars = new char[62];
string a;
a = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
chars = a.ToCharArray();
int size = maxSize;
byte[] data = new byte[1];
RNGCryptoServiceProvider crypto = new RNGCryptoServiceProvider();
crypto.GetNonZeroBytes(data);
size = maxSize;
data = new byte[size];
crypto.GetNonZeroBytes(data);
StringBuilder result = new StringBuilder(size);
foreach (byte b in data)
{
result.Append(chars[b % (chars.Length - 1)]);
}
return result.ToString();
}

hope it will help you