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TextBox.TextChanged Event

Occurs when the content of the text box changes between posts to the server.

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

public event EventHandler TextChanged
<asp:TextBox OnTextChanged="EventHandler" />

Implements

IEditableTextControl.TextChanged

The TextChanged event is raised when the content of the text box changes between posts to the server. The event is only raised if the text is changed by the user; the event is not raised if the text is changed programmatically.

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.

For more information about handling events, see Consuming Events.

TopicLocation
How to: Respond to Changes in a TextBox Web Server ControlBuilding ASP .NET Web Applications
How to: Respond to Changes in a TextBox Web Server ControlBuilding ASP .NET Web Applications

The following example shows how you can use this event to respond to changes in the TextBox control. The code displays the contents of the Text property of a TextBox control (called TextBox1) in a label (called Label1) when the Text property is changed. User input in a Web Forms page can include potentially malicious client script. By default, the Web Forms page validates that user input does not include script or HTML elements. For more information, see How to: Protect Against Script Exploits in a Web Application by Applying HTML Encoding to Strings.

protected void TextBox1_TextChanged(object sender, EventArgs e)
{
   Label1.Text = Server.HtmlEncode(TextBox1.Text);
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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