User Controls - How to pass data?

Question

I have 2 user controls on my form. When the user enters a date into a textbox on the first user control I need to pass that to the second user control which loads a datagrid. So far I've not been successfull in passing data between user controls. Please can you give me a C# sample that would do this? I need to do this without using ViewState, Session variables or Cookies. Thanx