Self-centering WTL property sheet

• Download demo executable - 26.3 Kb
• Download demo project - 11.9 Kb

Introduction

This is a very simple class that will automatically center a WTL property sheet. One frequently-asked question in the various WTL forums is "How do I centre a CPropertySheet object?". Most people tend to add a GetParent().CenterWindow() call to the first page in the property sheet, but in my mind this is a little awkward.

Instead, simply #include "propertysheetex.h" and use CPropertySheetEx as a drop in replacement for the standard WTL CPropertySheet class.

Code

The actual code for the class is straightforward:

class CPropertySheetEx : public CPropertySheet
{
private:
    bool m_bCentered;
public:    
    CPropertySheetEx(WTL::_U_STRINGorID title = 
          (LPCTSTR)NULL, UINT uStartPage = 0, HWND hWndParent = NULL)
        : CPropertySheet(title, uStartPage, hWndParent), m_bCentered(false)
    {
    }
    
    BEGIN_MSG_MAP(CPropertySheetEx)
        MESSAGE_HANDLER(WM_SHOWWINDOW, OnShowWindow)
        CHAIN_MSG_MAP(CPropertySheet)
    END_MSG_MAP()

    LRESULT OnShowWindow(UINT /*uMsg*/, WPARAM wParam, 
          LPARAM /*lParam*/, BOOL& bHandled)
    {
        // Centre?

        if (wParam == TRUE)
            Center();
        // Ensure base-class gets this message

        bHandled = FALSE;
        return 0;
    }

    void Center(void)
    {
        // Only do this once

        if (!m_bCentered)
        {
            CenterWindow();
            m_bCentered = true;
        }
    }
};