CStatic没有收到WM_CTLCOLOR

问题描述

我想我在这里缺少一些小东西.

I think I am missing something small here.

我正在尝试创建一个从CStatic继承并具有透明背景的类.我已设法创建该类的实例，并在父CView中显示它.但是，当我添加一个OnCtlColor消息处理程序通过Visual Studio上的类视图以使背景透明时，它永远不会触发.

I am trying to make a class which inherits from CStatic with a transparent background. I have managed create an instance of the class and it is displayed in the parent CView. However when I add a OnCtlColor message handler going through the class view on Visual Studio to make the background transparent, it never fires.

这是一个代码段:

Foo.h

class Foo: public CStatic
{
    DECLARE_DYNAMIC(Foo)

public:
    Foo();
    virtual ~Foo();
    virtual void CreateCtrl(CWnd * Parent, POINT TopLeft, SIZE sz);

protected:
    DECLARE_MESSAGE_MAP()
public: 
    afx_msg HBRUSH CtlColor(CDC* pDC, UINT nCtlColor);
    afx_msg BOOL OnEraseBkgnd(CDC* pDC);
};

Foo.cpp

void Foo::CreateCtrl(CWnd * Parent, POINT TopLeft, SIZE sz)
{
    CRect Rect(TopLeft, sz);
    Create(pItem->Value->GetBuffer(), WS_CHILD | WS_VISIBLE | SS_CENTER | SS_NOTIFY, Rect, Parent);
    ShowWindow(SW_SHOW);
}

BEGIN_MESSAGE_MAP(Foo, CStatic) 
    ON_WM_CTLCOLOR_REFLECT()
    ON_WM_ERASEBKGND()
END_MESSAGE_MAP()

HBRUSH Foo::CtlColor(CDC* pDC, UINT nCtlColor)
{
    pDC->SetBkMode(TRANSPARENT);
    return (HBRUSH)GetStockObject(NULL_BRUSH);
}

BOOL Foo::OnEraseBkgnd(CDC* pDC)
{
    return FALSE;
}

谁能建议我可能做错了什么?

Can anyone suggest what I might be doing wrong?

推荐答案

WM_CTLCOLOR发送到父窗口，而不是静态控件.

WM_CTLCOLOR is sent to the parent window, not to the static control.

要在静态控件类中捕获消息，您需要在消息映射中使用ON_WM_CTLCOLOR_REFLECT，请参阅 MSDN文档并使用HBRUSH Foo::CtlColor(CDC* pDC, UINT nCtlColor).

To catch the message in the static control class, you need to use ON_WM_CTLCOLOR_REFLECT in your message map, see MSDN Docs and use HBRUSH Foo::CtlColor(CDC* pDC, UINT nCtlColor).

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