C++ 当前使用typedef名称。希望不是这个CBitmap：MakeObjGuard类似于MakePair-我希望函数能够推断参数类型并为给定参数生成正确的模板对象（就像MakePair生成std:：pair一样）。因此，我必须为MakeXXX函数提供的任何“

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当前使用typedef名称。希望不是这个CBitmap：MakeObjGuard类似于MakePair-我希望函数能够推断参数类型并为给定参数生成正确的模板对象（就像MakePair生成std:：pair一样）。因此，我必须为MakeXXX函数提供的任何“帮助”都需要在其参数列表中，而不是手动选择生成的模板（虽然这可以完成，但它是相反的）。我理解您的问题，但是，使用重载函数指针调用

MakeObjGuard

时会遇到与调用

MakeObjGuard

相同的问题。如果编译器不知道参数类型，就无法推断模板类型。至少目前，我对从您和其他人的帮助中获得的代码感到满意。你会得到最完整答案的官方答案。再次感谢：）好吧，再一次，在这种特殊情况下，不需要强制转换，不管它是否使用typedef。即使没有强制转换，编译器也需要选择适当的重载。

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

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

// 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);

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));
}

ScopeGuard guard_canvas = MakeSelectObjectGuard(memdc, &canvas);

//////////////////////////////////////////////////////////////////////////
//
// 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;
};

struct XXX {
    int member() { return 0; }
    int member(int) { return 1; }
};

int main() {     
    int (XXX::*pmfv)(void) = (int (XXX::*)())&XXX::member;
    int (XXX::*pmfi)(int) = (int (XXX::*)(int))&XXX::member;
    return 0;
}

auto pmf = (int (XXX::*)())&XXX::member;

void foo(int){
    std::cout << "int" << std::endl;
}

void foo(float){
    std::cout << "float" << std::endl;
}

int main()
{
    typedef void (*ffp)(float);

    ffp fp = (void (*)(float)) foo; // cast to a function pointer without a typedef

    ((ffp)fp)(0);
}

typedef CBitmap * (CDC::* SelectObjectBitmap)(CBitmap*); 

SelectObjectBitmap pmf = &CDC::SelectObject; 

SelectObjectBitmap pmf = &CDC::SelectObject;