Yesterday I was answering some questions in ASP.NET forums. One of the questions I answered was “How can I access a TextBox control in a web user control from an .aspx page”.
Today I decided to post this blog to explain how you can do it.
It’s like a piece of cake. I create a web user control named “WebUserControl.ascx” and add a TextBox to it like following:
<%@ Control Language="C#" AutoEventWireup="true"
CodeFile="WebUserControl.ascx.cs" Inherits="WebUserControl" %>
<asp:TextBox runat="server" ID="TB_Test"></asp:TextBox>
Then, I create a web form named “Default.aspx” and add my user control to it:
<%@ Page Language="C#" AutoEventWireup="true"
CodeFile="Default.aspx.cs" Inherits="_Default" %>
<%@ Register src="WebUserControl.ascx"
tagname="WebUserControl" tagprefix="uc1" %>
<!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 runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<uc1:WebUserControl ID="WebUserControl1" runat="server" />
<asp:Button ID="Button1" runat="server"
onclick="Button1_Click" Text="Button" />
</div>
</form>
</body>
</html>
As you can see, I also added a button control that reads value of our TextBox in web user control and then write it to the page. Let’s see the event handler of Button1.Click:
protected void Button1_Click(object sender, EventArgs e)
{
TextBox t = (TextBox)WebUserControl1.FindControl("TB_Test");
Response.Write(t.Text);
}
The nice part is the use of FindControl method that gives a control that I’m looking for.
Finally, I just used a simple cast in order to convert the returned control from FindControl method. Because my control was a TextBox, I created a variable as a TextBox and then fill it with my casted control. When I cast it, I can access all properties and methods related to this control.