I think what is confusing is that there is two ways to update a edit or static text box.

Method 1:
Use a CString. With a CString you set it and then when UpdateData is called, the CString gets copied into the control. The other way around to get the control into the CString.

Method 2:
Use a Control. Declare it as CEdit or CStatic, then use DDX_Control in the exchange. That way you don't need UpdateData, and you can call all the control methods, like SetWindowText.

I personally use the second method, gives a lot more control (no pun intended) over what you are doing.

-Erik