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using System;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace myControls
{
public class CustomTextBox : WebControl, IPostBackDataHandler
{
public event EventHandler TextChanged;
public string Text {
get
{
if (ViewState["Text"] == null)
return String.Empty;
else
return (string)ViewState["Text"];
}
set { ViewState["Text"] = value; }
}
protected override void AddAttributesToRender(HtmlTextWriter writer)
{
writer.AddAttribute(HtmlTextWriterAttribute.Type, "text");
writer.AddAttribute(HtmlTextWriterAttribute.Value, Text);
writer.AddAttribute(HtmlTextWriterAttribute.Name, this.UniqueID);
base.AddAttributesToRender(writer);
}
protected override HtmlTextWriterTag TagKey
{
get
{
return HtmlTextWriterTag.Input;
}
}
public bool LoadPostData(string postDataKey, System.Collections. Specialized.NameValueCollection postCollection)
{
if (postCollection[postDataKey] != Text)
{
Text = postCollection[postDataKey];
return true;
}
return false;
}
public void RaisePostDataChangedEvent()
{
if (TextChanged != null)
TextChanged(this, EventArgs.Empty);
}
}
}
File: Default.aspx
<%@ Page Language="C#" %>
<%@ Register TagPrefix="custom" Namespace="myControls" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void CustomTextBox1_TextChanged(object sender, EventArgs e)
{
lblResults.Text = CustomTextBox1.Text;
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Show CustomTextBox</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<custom:CustomTextBox
id="CustomTextBox1"
OnTextChanged="CustomTextBox1_TextChanged"
Runat="server" />
<asp:Button id="btnSubmit"
Text="Submit"
Runat="server" />
<hr />
<asp:Label
id="lblResults"
Runat="server" />
</div>
</form>
</body>
</html>
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