Can I display a control in the MDI client window?

[readsuhang]

I am writting a MDI applcaition. I want to display a tree view control in the left part of the frame client window. After I create the tree control in the FrameWndProc ON_CREATE, the tree control is displayed. But I can never open the child windows.

Can I create the tree control in the frame client window? I am new to MDI.

[VictorN]

.... After I create the tree control in the FrameWndProc ON_CREATE, ...

Are using MFC?
If YES - then why are you using FrameWndProc ?
If NOT - then why do you mention ON_CREATE?

If you could use MFC then you life would be much easier, because AppWizard would make the most work for you creating the "frame" of the MDI app with the "Explorer" style...

[readsuhang]

I am not using MFC. MFC is not allowed in this projet.