TextBox.TagKey Property

 
Use BaseTrue

Gets the HTML tag for the text box control. This property is protected.

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

protected override HtmlTextWriterTag TagKey { get; }

Property Value

Type: System.Web.UI.HtmlTextWriterTag

HtmlTextWriterTag.Textarea if the text box is multiline; otherwise, Input.

The following code example demonstrates how to use the TagKey property to create a custom text box.

System_CAPS_security Security Note

This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page Language="C#" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
    <head>
        <title>Custom TextBox - TagKey - C# Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom TextBox - TagKey - C# Example</h3>

            <aspSample:CustomTextBoxTagKey 
              id="TextBox1" 
              runat="server">Hello World!
            </aspSample:CustomTextBoxTagKey>

        </form>
    </body>
</html>
using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
  public sealed class CustomTextBoxTagKey : System.Web.UI.WebControls.TextBox
  {
    protected override System.Web.UI.HtmlTextWriterTag TagKey
    {
      get 
      {
        // If the TextMode is MultiLine, return a Textarea tag, 
        // else return an Input tag.
        if (this.TextMode == System.Web.UI.WebControls.TextBoxMode.MultiLine)
        {
          return System.Web.UI.HtmlTextWriterTag.Textarea;
        }
        else
        {
          return System.Web.UI.HtmlTextWriterTag.Input;
        }
      }
    }
  }
}

.NET Framework
Available since 1.1
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