Question

I’ve created a regular ASP.NET user control, including the ascx file. For example:

MyUserControl.ascx MyUserControl.ascx.cs 

Then I try to render the control manually, at runtime, using code similar to the following code:

var testMyUserControl = new MyUserControl(); var textWriter =      new HtmlTextWriter(         new System.IO.StringWriter(new StringBuilder())); testMyUserControl.RenderControl(textWriter); Console.Write(textWriter.InnerWriter.ToString()); 

Nothing that I put in the ASCX file seems to render – either static HTML or any .NET controls.

However if I override the Render() method in the code-behind and manually output content, it does render.

What am I missing here?

Answer 1

You don’t need to render your control yourself. If you need to add it to the page dynamically, you do it like:

UserControl myControl = (UserControl) Page.LoadControl('~/Controls/MyControl.ascx'); Page.Controls.Add(myControl); 

Most likely you’ll want to place it in a certain part of the page, so instead of using Page.Controls, use a placeholder:

<asp:Placeholder ID='myPlaceHolder' runat='server' /> 

and use code like this:

myPlaceholder.Controls.Add(myControl); 

This is the best way to add a control dynamically, but if you can do it declaratively instead that would be a lot easier.

<%@ Register TagPrefix='my' TagName='Control' Src='~/Controls/MyControl.ascx' %>  <my:Control ID='myControl' runat='server' /> 

Remember: if you’re adding the control dynamically, be sure to re-add the control every page load.