How do I make dialog box in fixed position and not allow user drag but can maximum

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MFC

Dear All,
How do I make a dialog box with fixed position.
And it can't be changed position by any user drag the dialog box.
But allow user to press the maxium buttom on the uper-right side of dialog.

EX.
if I want the dialog be created in the center of the desktop.
It can't be moved.
It's always at the center.
But when I press the maxium buttom, it can be enlarge to cover the desktop like all others did.
and can restore it by press it again.
But it will be back to the center.

Thanks!!