有没有更好的方法来选择正确的方法重载?

typedef CBitmap * (CDC::* SelectObjectBitmap)(CBitmap*);
SelectObjectBitmap pmf = (SelectObjectBitmap)&CDC::SelectObject;

首先,必须创建一个typedef,然后必须使用它来强制编译器在获取其地址时选择正确的重载方法?

是否没有更自然、更完备的语法,例如:

SelecdtObjectBitmap pmf = &CDC::SelectObject(CBitmap*);

ScopeGuard 通常在我的代码中。一个明显的用途是确保所有临时CDC对象首先被选择到给定的DC中,然后在作用域出口处被删除,使我的代码即使在特殊情况下也不会泄漏-同时清理编写的代码(愚蠢的多个退出路径和try/catch等,以尝试处理从给定CDC中删除任何选定对象)。

因此,我目前被迫做的一个更完整的例子如下:

// get our client rect
CRect rcClient;
GetClientRect(rcClient);

// get the real DC we're drawing on
PAINTSTRUCT ps;
CDC * pDrawContext = BeginPaint(&ps);

// create a drawing buffer
CBitmap canvas;
canvas.CreateCompatibleBitmap(pDrawContext, rcClient.Width(), rcClient.Height());

CDC memdc;
memdc.CreateCompatibleDC(pDrawContext);

//*** HERE'S THE LINE THAT REALLY USES THE TYPEDEF WHICH i WISH TO ELIMINATE ***//
ScopeGuard guard_canvas = MakeObjGuard(memdc, (SelectObjectBitmap)&CDC::SelectObject, memdc.SelectObject(&canvas));

// copy the image to screen
pDrawContext->BitBlt(rcClient.left, rcClient.top, rcClient.Width(), rcClient.Height(), &memdc, rcClient.left, rcClient.top, SRCCOPY);

// display updated
EndPaint(&ps);

编辑:根据人们提供的答案,我相信我有一个解决方案来满足我的潜在需求:即为MakeGuard提供更自然的语法,从而为我推断出正确的SelectObject覆盖:

template <class GDIObj>
ObjScopeGuardImpl1<CDC, GDIObj*(CDC::*)(GDIObj*), GDIObj*> MakeSelectObjectGuard(CDC & dc, GDIObj * pGDIObj)
{
    return ObjScopeGuardImpl1<CDC, GDIObj*(CDC::*)(GDIObj*), GDIObj*>::MakeObjGuard(dc, (GDIObj*(CDC::*)(GDIObj*))&CDC::SelectObject, dc.SelectObject(pGDIObj));
}

这使得我的上述代码更改为:

ScopeGuard guard_canvas = MakeSelectObjectGuard(memdc, &canvas);

对于那些可能在这里寻找同一事物的非MFC版本的人:

//////////////////////////////////////////////////////////////////////////
//
// AutoSelectGDIObject
//  selects a given HGDIOBJ into a given HDC,
//  and automatically reverses the operation at scope exit
//
// AKA:
//  "Tired of tripping over the same stupid code year after year"
//
// Example 1:
//  CFont f;
//  f.CreateIndirect(&lf);
//  AutoSelectGDIObject select_font(*pDC, f);
//
// Example 2:
//  HFONT hf = ::CreateFontIndirect(&lf);
//  AutoSelectGDIObject select_font(hdc, hf);
//
// NOTE:
//  Do NOT use this with an HREGION.  Those don't need to be swapped with what's in the DC.
//////////////////////////////////////////////////////////////////////////

class AutoSelectGDIObject
{
public:
    AutoSelectGDIObject(HDC hdc, HGDIOBJ gdiobj) 
        : m_hdc(hdc)
        , m_gdiobj(gdiobj)
        , m_oldobj(::SelectObject(m_hdc, gdiobj))
    {
        ASSERT(m_oldobj != m_gdiobj);
    }

    ~AutoSelectGDIObject()
    {
        VERIFY(m_gdiobj == ::SelectObject(m_hdc, m_oldobj));
    }

private:
    const HDC       m_hdc;
    const HGDIOBJ   m_gdiobj;
    const HGDIOBJ   m_oldobj;
};

//////////////////////////////////////////////////////////

感谢所有回复的人&评论!:D