Export (0) Print
Expand All

IPostBackEventHandler.RaisePostBackEvent Method

When implemented by a class, enables a server control to process an event raised when a form is posted to the server.

[Visual Basic]
Sub RaisePostBackEvent( _
   ByVal eventArgument As String _
)
[C#]
void RaisePostBackEvent(
   string eventArgument
);
[C++]
void RaisePostBackEvent(
   String* eventArgument
);
[JScript]
function RaisePostBackEvent(
   eventArgument : String
);

Parameters

eventArgument
A String that represents an optional event argument to be passed to the event handler.

Remarks

The page passes the value of the eventArgument parameter to the RaisePostBackEvent method of the control that implements IPostBackEventHandler interface. This control also renders the HTML element that causes the postback to occur. If the control renders client-side script for postback, the argument from the script is passed in the eventArgument parameter. If the postback is caused by a simple submit, the eventArgument parameter is a null reference (Nothing in Visual Basic).

This method provides the functionality for many events implemented by HTML and Web server controls.

Example

[Visual Basic, C#, C++] The following example defines a custom button server control that causes postback, captures the postback event using the RaisePostBackEvent method, and raises a Click event on the server.

[Visual Basic] 
Imports System
Imports System.Web.UI
Imports System.Collections
Imports System.Collections.Specialized

Namespace CustomControls    
    
    <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> Public Class MyButton
        Inherits Control
        Implements IPostBackEventHandler
        
        ' Define the Click event.
        Public Event Click As EventHandler
        
        
        ' Invoke delegates registered with the Click event.
        Protected Overridable Sub OnClick(e As EventArgs)            
            RaiseEvent Click(Me, e)
        End Sub
        
        
        ' Define the method of IPostBackEventHandler that raises change events.
        Public Sub RaisePostBackEvent(eventArgument As String) _
        Implements IPostBackEventHandler.RaisePostBackEvent
        
            OnClick(New EventArgs())
        End Sub       
        
        
        Protected Overrides Sub Render(output As HtmlTextWriter)
            output.Write("<INPUT TYPE = submit name = " & Me.UniqueID & _
                " Value = 'Click Me' />")
        End Sub
        
    End Class
End Namespace


[C#] 
using System;
using System.Web.UI;
using System.Collections;
using System.Collections.Specialized;

namespace CustomControls {

   [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")]   
   public class MyButton: Control, IPostBackEventHandler {
      
      // Defines the Click event.
      public event EventHandler Click;
      
      //Invoke delegates registered with the Click event.
      protected virtual void OnClick(EventArgs e) {
         
         if (Click != null) {
            Click(this, e);
         }   
      }
      
      
      // Define the method of IPostBackEventHandler that raises change events.
      public void RaisePostBackEvent(string eventArgument){
         
         OnClick(new EventArgs());
      }
      
      
      protected override void Render(HtmlTextWriter output) {
         output.Write("<INPUT TYPE = submit name = " + this.UniqueID + 
            " Value = 'Click Me' />");   
      }
   }    
}
   

[C++] 
#using <mscorlib.dll>
#using <System.Web.dll>
#using <System.dll>
using namespace System;
using namespace System::Web::UI;
using namespace System::Collections;
using namespace System::Collections::Specialized;

[System::Security::Permissions::PermissionSet(System::Security::Permissions::SecurityAction::Demand, Name=S"FullTrust")]   
public __gc class MyButton: public Control, public IPostBackEventHandler {

   // Defines the Click event.
public:
   __event EventHandler* Click;

   //Invoke delegates registered with the Click event.
protected:
   virtual void OnClick(EventArgs* e) {

      if (Click != 0) {
         Click(this, e);
      }   
   }


   // Define the method of IPostBackEventHandler that raises change events.
public:
   void RaisePostBackEvent(String* eventArgument){

      OnClick(new EventArgs());
   }


protected:
   void Render(HtmlTextWriter* output) {
      output->Write(S"<INPUT TYPE = submit name = {0} Value = 'Click Me' />", this->UniqueID);   
   }
};    

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 2000, Windows XP Professional, Windows Server 2003 family

See Also

IPostBackEventHandler Interface | IPostBackEventHandler Members | System.Web.UI Namespace | Capturing Postback Events

Show:
© 2015 Microsoft