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HtmlTextArea.ServerChange Event

Occurs when the content of the HtmlTextArea control changes between posts to the server.

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

public event EventHandler ServerChange
/** @event */
public void add_ServerChange (EventHandler value)

/** @event */
public void remove_ServerChange (EventHandler value)

JScript supports the use of events, but not the declaration of new ones.

The ServerChange event is raised when the content of the HtmlTextArea control changes between posts to the server. This event is commonly used to perform data validation on the text box.

NoteNote

This event is only raised when the user initiates a post to the server, such as clicking a submit button. This event does not cause a post to the server to occur.

NoteNote

The control must have viewstate enabled for the ServerChange event to work correctly.

For more information about handling events, see Consuming Events.

The following code example demonstrates how to specify and create a custom event handler for the ServerChange event. A message is displayed when the value entered in the HtmlTextArea control exceeds 10 characters.

<%@ Page Language="C#" AutoEventWireup="True" %>

<script runat="server">

  void Server_Change(Object sender, EventArgs e)
  {

    // The ServerChange event is commonly used for data validation.
    // This method determines whether the comment entered into the
    // HtmlTextArea control is longer than 20 characters.
    if (TextArea1.Value.Length > 20)
      Span1.InnerHtml = "Your comment cannot exceed 20 characters.";
    else
      Span1.InnerHtml = "You wrote: <br>" + TextArea1.Value;

  }

</script>

<html>
<head>
   <title>HtmlTextArea ServerChange Example</title>
</head>
<body>

   <form runat="server">

      <h3>HtmlTextArea ServerChange Example</h3>

      Enter your comments: <br>

      <textarea id="TextArea1"
                onserverchange="Server_Change" 
                runat="server"/>

      <br>

      <input type="submit"  
             value="Submit" 
             runat="server"/>

      <p>

      <span id="Span1" 
            runat="server" />

   </form>

</body>
</html>

<%@ Page Language="C#" AutoEventWireup="True" %>

<script runat="server">

  void Server_Change(Object sender, EventArgs e)
  {
    // The ServerChange event is commonly used for data validation.
    // This method determines whether the comment entered into the
    // HtmlTextArea control is longer than 20 characters.
    if (TextArea1.Value.Length > 20)
    {
      Span1.InnerHtml = "Your comment cannot exceed 20 characters.";
    }
    else
    {
      Span1.InnerHtml = "You wrote: <br>" + TextArea1.Value;
    }

  }

  void Page_Load(Object sender, EventArgs e)
  {

    // Create an EventHandler delegate for the method you want to
    // handle the event, and then add it to the list of methods
    // called when the event is raised.
    TextArea1.ServerChange +=
      new System.EventHandler(this.Server_Change);

  }

</script>

<html>
<head>
   <title>HtmlTextArea ServerChange Example</title>
</head>
<body>

   <form runat="server">

      <h3>HtmlTextArea ServerChange Example</h3>

      Enter your comments (20 or fewer characters): <br>

      <textarea id="TextArea1"
                runat="server"/>

      <br>

      <input type="submit"  
             value="Submit" 
             runat="server"/>

      <p>

      <span id="Span1" 
            runat="server" />

   </form>

</body>
</html>

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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