A Snap Size Dialog Class

While creating a fairly complex resizable dialog application, I became annoyed with the amount the controls flickered while being sized. What I wanted was something along the lines of the rubber band sizing available with Plus!, where the contents of the application are sized only when the dragging action is finished.

The solution I came up with sizes the contents of the dialog only when the dragging action is finished, whether or not “Size window contents while dragging” is checked in the Plus! settings.

1. Add SnapDlg.h to your StdAfx.h.
2. Derive your dialog class from CSnapDlg.
3. Change your dialog’s constructor to call CSnapDlg’s constructor:

CSnapDialogDlg::CSnapDialogDlg(CWnd* pParent /*=NULL*)
   : CSnapDlg(CSnapDialogDlg::IDD, pParent)

4. Change your dialog’s message map to flow through CSnapDlg:

BEGIN_MESSAGE_MAP(CSnapDialogDlg, CSnapDlg)

5. Overload the virtual function SizeDialog() to size your dialog’s contents.
6. Make sure your dialog’s OnSize, OnSizing, OnInitDialog, and OnCaptureChanged handlers call the member functions of CSnapDlg instead of CDialog.

Download demo project – 32 KB

Download source – 2 KB