Setting the Window size

hi

in a simple SDI-Application created by the MFC-wizard, how do I set the windowsize upon the initialization of the program?
I´ve tried inserting the following commands in the CView::PreCreateWindow function:

CWnd* mywin = AfxGetMainWnd(); // Points to my only application window ( I think )
mywin->SetWindowPos(mywin, 300,300,200,100,SWP_SHOWWINDOW);

It runs ok but does not do anything at all. Where should this statement be located or what would be the correct command?

thx