实现：获取指定窗口句柄小工具

对话框头文件中

    HICON m_hIcon;
    HCURSOR mCursor; //定义鼠标
    RECT rect; //定义鼠标形状
    HWND hDest; //获得的目标句柄

BOOL CMy9Dlg::OnInitDialog()
{
    CDialogEx::OnInitDialog();
....
    mCursor = LoadCursor(NULL, IDC_SIZEALL); //默认带有箭头
    GetDlgItem(IDC_STATIC)->GetWindowRect(&rect);

...

void CMy9Dlg::OnLButtonDown(UINT nFlags, CPoint point)
{
    if (point.x >= rect.left && point.x <= rect.right || point.y >= rect.top && point.y <= rect.bottom) {
        SetCapture(); //开始捕获
        SetCursor(mCursor); //当范围匹配，就对当前光标进行改变
    }
    CDialogEx::OnLButtonDown(nFlags, point);
}

void CMy9Dlg::OnLButtonUp(UINT nFlags, CPoint point)
{
    POINT pt = point;
    CString mString;
    wchar_t sName[64];
    wchar_t sContent[64];
    ReleaseCapture();
    ClientToScreen(&pt);
    hDest = ::WindowFromPoint(pt); //获取指定POINT的窗口的句柄
    mString.Format(_T("0x%.8x"), hDest);
    SetDlgItemText(IDC_EDIT1, mString);

    GetClassName(hDest, sName, MAX_PATH); //获取类名
    SetDlgItemText(IDC_EDIT2, sName); 
    
    ::SendMessage(hDest, WM_GETTEXT, (WPARAM)64, (LPARAM)sContent); //获取标题
    SetDlgItemText(IDC_EDIT3, sContent);


    CDialogEx::OnLButtonUp(nFlags, point);
}