How can you get a class such as myClass.cs, to create a control such as a listbox that wil be used in a placeholder control on an .aspx page where the .aspx page has yet to be created so the class doesn't know about it yet. (e.g so there are no dependencies in the class).. So if there are 10 .aspx pages, page1.aspx, page2.aspx, etc. , and each one has a control <asp:placeholder ID="PlaceHolder1".....>, how do you 1. code a class, myClass.cs to create a listbox that will be placed on any one of the above .aspx pages but in the <PlaceHolder1> control. (I know how to do it with a user control e.g. default.aspx and default.aspx.cs -- but how to do it with default.aspx, default.aspx.cs AND myClass.cs). 2. instantiate this code from myClass.cs from the page1.aspx.cs, page2.aspx.cs, etc.

1: Don't. Instead, make those pages call something in myClass.cs that returns your control. 2: See answer 1