How to erase bkground while drawing text

I m working on application which requires automatic scrolling text in a cycle.I m using doc/view for this.I am using WM_TIMER message n drawing the text..but while drawing text on WM_TIMER message its not erasing the previous drawn text..
Thanks in advance.

hi!

Are u calling an UpdateWindow() after drawing the text ?

hi,
ya i m calling updatewindow() after drawing text..