If you want to make it work with the designer, you'll have to use a custom control (CompositeControl) instead as the design-time support for the usercontrol is limited in VS, it always looks at the base class UserControl to parse any nested elements you define in your user control.

Since executing a delegate asynchronously means that the target method executes on a thread from the CLR's thread pool, you will not have fine-grain control over the worker thread. If you need the ability to manipulate the worker thread you should explicitly create it. Josh

I finally got it to work. After manually adding the Control to the Toolbox, and dropping it on my Form, the Project created a reference to the DLL but it did not show on the Form nor did it create variables in the Form for the Control. I think I eventually determined that there was an issue with the Resource file for the Control project so I fixed that and removed all references to the Control in the new Project. After dropping it on the Form this time, it worked.

You see, it's very simple. For someone who writes object models for a living, I've seen a lot that just don't make any sense (ex. Adobe, Maximizer, etc.). I hate when someone gives a method like "Remove" when I am working with a collection of Files (Remove what?). Instead, I like to rename the Method to "Delete" and implement the "Remove" method privately. The private method will simply call the Public method on the collection class. Don't get me wrong, I implement as much as the interface as I "can". There are some methods though that I DO like, however, the fact that you have to pass an object instead of my custom (strongly-typed) collection object (i.e. a custom File object for example). For example, if you Implement the IDictionary Interface, it uses this: IndexOf(object Key). What? Since the Keys SHOULD all be strings in my collection, why do I want to allow a programmer to pass a Guid, Int, or whatever else they can think of? If they want a guid, pass a Guid.ToString(). If you look at a lot of the pre-defined Collection classes Microsoft created, they also "hide" a lot of interface methods because they just don't make sense for the particular object, but you can still cast them to an Interface that they implement and use the Properties / Methods that way. Now, as to why I am implementing an IList? Well, It's nice to have a custom collection class that can be databound to a DataGrid or other controls.

Thanks Dave! That makes it less painful. Hal in AZ