2 dropdownlists in datagrid

Question

Hi all, I have created a simple ASP.NET page which contains: datagrid (editable) and 2 dropdownlists in column A and B in one row (when datagrid is in edit mode). Both lists were filled with data from datatable. Now i must make a modification: content of list B must depends on selected value of list A (they are in the same datarow). When I select something in list A, content of list B must change. How can I do that? Anyone can give me some clue? How to set order of bindings to make it work? I have tried to think out this problem myself but I think that I am not so good in .NET thank you, Ravenek (...the beginner in ASP.NET)