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TextBox.OnTextChanged Method

Raises the TextChanged event. This allows you to handle the event directly.

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in system.web.dll)

protected virtual void OnTextChanged (
	EventArgs e
)
protected void OnTextChanged (
	EventArgs e
)
protected function OnTextChanged (
	e : EventArgs
)

Parameters

e

A EventArgs that contains event information.

The TextChanged event is raised when the content of the text box changes between posts to the server.

NoteNote

A TextBox control must persist some values between posts to the server for this event to work correctly. Be sure that view state is enabled for this control.

Raising an event invokes the event handler through a delegate. For more information, see Raising an Event.

The OnTextChanged method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors When overriding OnTextChanged in a derived class, be sure to call the base class's OnTextChanged method so that registered delegates receive the event.

The following code example demonstrates how to override the OnTextChanged method so that it always marks a custom TextBox server control as having been modified.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page Language="C#" AutoEventWireup="True" %>
<HTML>
	<HEAD>
		<title>Custom TextBox - OnTextChanged - C# Example</title>
	</HEAD>
	<body>
		<form id="Form1" method="post" runat="server">
			<h3>Custom TextBox - OnTextChanged - C# Example</h3>
			
			<aspSample:CustomTextBoxOnTextChanged 
			  id="TextBox1" 
			  autopostback=true
			  runat="server">Hello World!
			</aspSample:CustomTextBoxOnTextChanged>
			
		</form>
	</body>
</HTML>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSL" %>
<%@ Page Language="VJ#" AutoEventWireup="True" %>
<HTML>
    <HEAD>
        <title>Custom TextBox - OnTextChanged - VJ# Example</title>
    </HEAD>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom TextBox - OnTextChanged - VJ# Example</h3>
            
            <aspSample:CustomTextBoxOnTextChanged 
              id="TextBox1" 
              autopostback=true
              runat="server"
              text="Hello World!">
            </aspSample:CustomTextBoxOnTextChanged>
            
        </form>
    </body>
</HTML>

using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
  public sealed class CustomTextBoxOnTextChanged : System.Web.UI.WebControls.TextBox
  {
    private bool isDirty = false;

    protected override void OnTextChanged(System.EventArgs e)
    {
      // Call the base OnTextChanged method.
      base.OnTextChanged(e);

      // Change the dirty flag to True.
      isDirty = true;
    }
  }
}

package Samples.AspNet.JSL.Controls; 

public class CustomTextBoxOnTextChanged
    extends System.Web.UI.WebControls.TextBox
{
    private boolean isDirty = false;

    protected void OnTextChanged(System.EventArgs e)
    {
        // Call the base OnTextChanged method.
        super.OnTextChanged(e);
        // Change the dirty flag to True.
        isDirty = true;
    } //OnTextChanged
} //CustomTextBoxOnTextChanged

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

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