How to Handle the Back Key for Dialog Boxes Without Edit Controls

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4/14/2010

When a user presses the Backkey in a dialog box that does not have any edit controls, the Backkey sends a Windows Embedded CE WM_COMMANDmessage with the command ID IDCANCELto the dialog box. The following code example illustrates how to handle the WM_COMMANDmessage.

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BOOL rb; int rc; { switch(LOWORD(wParam)) { // User closes the dialog box by pressing the Back key. { rb = EndDialog(hwnd, 0); if (rb == FALSE) // EndDialog failed. { rc = MessageBox(NULL, _T("Could not destroy dialog box."), _T("Error"), MB_OK); if (rc == 0) // Not enough memory to create MessageBox. return E_OUTOFMEMORY; return E_FAIL; // Replace with specific error handling. } else // EndDialog succeeded. return S_OK; } // case IDCANCEL } // switch break; // from case WM_COMMAND }

Copy Code

BOOL rb;
int rc;

{
	switch(LOWORD(wParam))
	{
		// User closes the dialog box by pressing the Back key.
		{
			rb = EndDialog(hwnd, 0);
			if (rb == FALSE)  // EndDialog failed.
			{
				rc = MessageBox(NULL, _T("Could not destroy dialog
box."),
								_T("Error"), MB_OK);
				if (rc == 0)  // Not enough memory to create
MessageBox.
					return E_OUTOFMEMORY;
				return E_FAIL;  // Replace with specific error
handling.
		}
			else  // EndDialog succeeded.
				return S_OK;
	}  // case IDCANCEL
}  // switch
	break;  // from case WM_COMMAND
}

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