Is it possible to use a user control in a custom server control? If so, how is it rendered to the browser?

Thanks in advance!

A user control lives as an ASCX file in the web project so it wouldn't normally be used in a compiled control. However... you could create an instance of such a control. The Page class has a method 'LoadControl' which takes a file as an argument. This will load an instance of a control that you could then add to a controls collection inside your custom control. Keep in mind however, that you will run into a potential problem with this: if the compiled control is in a different assembly and you need to reference the class type that represents the user control (the code behind the ASCX) you'll end up with a circular reference. Also in my opinion, by doing this you are kind of breaking the rules of building a custom server control by making it dependant on an external resource that you can't directly supply. The consumer of the custom control will have to have the user control file in their web project.

-Peter

My server control renders a table with x number of rows. I want to add a user control to each row of the table, last column. I do not know how many user controls I will need until runtime. How do I specify where the user control is placed in the server control's table cell?

You need to add it to the last column's cell's Controls collection in the appropriate order. As long as it's in the controls collection .NET will render it.