clipboard format

My Program is texteditor create form visual c++ 6.0 (mfcAppWizard (Richeditview)).
Now me can paste imgfile(file picture) onto document.
I need can paste only textfile.
please answer me urgent.
thankyou very much.

hClibMemory = GetClipboardData(CF_TEXT);
if(!hClibMemory) // if not text data just go away
{
return S4TK_PasteFailed;
}