How to access a user control's fields and methods without regitering the control?

Question

Hello,

I have a ASP.Net project that is setup in such a way that it can be dropped into any site and "just work." All the paths are relative to the current file, not relative to the "~". The paths are determined by ThePath = this.TemplateSourceDirectory;

This is working for everything expect registering a custom control that is created and added to one of the pages. I can add the control just fine with the Page.LoadControl but I cant cast it as the correct type to access anything.

How can I add a reference to the class from within the code itself?

Answer 1

If you don't know the control's specific type ahead of time, this isn't possible. The class must derive from UserControl, so you can cast it to a UserControl and you'll have access to all the methods and properties on that class. If there's some special information or functionality you need to require all controls to have, and you need to be able to assume those are always present, then you will have to write your own class that derives from UserControl, and require all custom controls to derive from that instead:

//all custom controls must inherit from this
public abstract class SpecialControlBase : UserControl
{
    public abstract void DoSomethingSpecial();
}

Then you could cast all controls at load-time to this SpecialControlBase, and have access to the DoSomethingSpecial method.

But as far as the most-specific members of a class loaded at runtime, think about it - if I write my own control called RexsUserControl and drop it into your application, there's no way you could know what methods and fields I've put on my control, so you can't write any code that references those members specifically.

Answer 2

Rex M, If you register the control on the ASPX page, you can cast the control on the code behind.

In the ASPX:

<%@ Register TagPrefix="Mine" TagName="Ctrl" Src="~/Test/User/Controls/UserCtrl.ascx" %>

Then, in the ASPX.CS:

User_Controls_UserCtrl myUserCtrl = LoadControl("~/Test/User/Controls/UserCtrl.ascx");

however, if you don't register the control in the ASPX first, you get this error:

CS0246: The type or namespace name 'User_Controls_UserCtrl' could not be found (are you missing a using directive or an assembly reference?)