Getting the MDI area

I'd like to resize an mdi child form to be the height of it's parent's MDI area, but obviously frm.mdiparent.height returns the height of the parent form including the menubar and titlebar.

How would I go about getting the height and width of the MDI area of a form? Thanks.

just see the size..with photoshop or something like that..

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Well obviously i could do that but I would kinda rather do it with code as the MDI form is resizable..........