类似于`this`的子窗口的东西 [英] Something for a child window analogous to `this`

问题描述

我是编程的新手.我正在写一个基于对话框的应用程序，上面有一个静态控件.使用

I am a newcomer to programming. I am writing a dialog based application which has a static control on it. Using

Using
void CMy1stDlg::OnMouseMove(UINT nFlags, CPoint point)
{
    if (this == GetCapture())
    {
        CClientDC aDC(this);
        aDC.SetPixel(point, RGB(255,0,0));
    }   
}

我可以创建如下结果

I can create results like

但是我想要的是鼠标的位置仅在静态窗口内绘制.我在MSDN中找不到对this的引用，也不知道为什么以下方法失败.

However what I want is that the locus of mouse is only drawn within the static window. I can't find the reference to this in MSDN and I don't know why the following method fails.

void CMy1stDlg::OnMouseMove(UINT nFlags, CPoint point)
{
    CWnd* pMYSTATIC = GetDlgItem (IDC_MYSTATIC);    //IDC_MYSTATIC is the ID of the static control
    if (pMYSTATIC == GetCapture())
    {
        CClientDC aDC(pMYSTATIC);
        aDC.SetPixel(point, RGB(255,0,0));
    }   
}

我如何得到想要的东西?是否有任何方法可以为静态窗口获取类似于this的内容?我将不胜感激.

How can I get what I want? Are there any methods to get something for the static window analogous to this? I will appreciate any help with these.

推荐答案

好的，请尝试以下操作:

OK, try this:

void CMy1stDlg::OnMouseMove(UINT nFlags, CPoint point)
{
    CRect rect;
    // Get static control's rectangle
    GetDlgItem(IDC_MYSTATIC)->GetWindowRect(&rect);
    // Convert it to client coordinates
    ScreenToClient(&rect);
    // Check if mouse pointer is inside the static window, if so draw the pixel
    if (rect.PtInRect(point))
    {
        CClientDC dc(this);
        dc.SetPixel(point.x, point.y, RGB(255,0,0));
    }
}

此代码可能还需要进行一些修复，例如，在检查是否绘制像素之前，将矩形缩小(缩小到仅用于客户的区域).

This code may need some fixes too, eg shrink the rectangle (to its client-only area), before checking whether to draw the pixel.

请注意，您无需检查GetCapture()；如果您的对话框没有捕获鼠标，则无论如何都不会收到此消息.

Please note that you don't need to check GetCapture(); if your dialog hasn't captured the mouse it won't be receiving this message anyway.

此外，所有这些功能都是Windows SDK功能的包装，例如ClientDC()类，基本上包装了GetDC()/ReleaseDC().

Also, all these functions are wrappers of Windows SDK ones, eg the ClientDC() class, basically wraps GetDC()/ReleaseDC().

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