MFC 拖动无边框窗体

内容转载自https://www.bilibili.com/video/BV1AT4y137gS?p=35

hpp    

//定义全局变量
BOOL m_bMoving;
CPoint m_ptMouse;


cpp

CMFCApplication11Dlg::CMFCApplication11Dlg(CWnd* pParent /*=NULL*/)
    : CDialogEx(CMFCApplication11Dlg::IDD, pParent)
{
    m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);

    //在此处初始化
    m_ptMouse.x = m_ptMouse.y = 0;
    m_bMoving = FALSE;
}



/*
    鼠标左键按下消息
*/
void CMFCApplication11Dlg::OnLButtonDown(UINT nFlags, CPoint point)
{
    // TODO:  在此添加消息处理程序代码和/或调用默认值

    m_bMoving = TRUE;
    SetCapture();//捕获鼠标
    m_ptMouse = point;


    CDialogEx::OnLButtonDown(nFlags, point);
}


/*
    鼠标移动消息
*/
void CMFCApplication11Dlg::OnMouseMove(UINT nFlags, CPoint point)
{
    // TODO:  在此添加消息处理程序代码和/或调用默认值

    if (m_bMoving)
    {
        //计算鼠标移动的距离
        int x, y;
        x = point.x - m_ptMouse.x;
        y = point.y - m_ptMouse.y;

        if (abs(x) >= 2 || abs(y) >= 2)//控制移动大于两个像素在移动，避免连续移动的闪烁感
        {
            //获取窗口原来的位置
            RECT rc = { 0 };
            GetWindowRect(&rc);

            OffsetRect(&rc, x, y);//偏移矩形的位置
            MoveWindow(&rc, TRUE);//移动窗口
        }

    }

    CDialogEx::OnMouseMove(nFlags, point);
}


/*
    鼠标抬起消息
*/
void CMFCApplication11Dlg::OnLButtonUp(UINT nFlags, CPoint point)
{
    // TODO:  在此添加消息处理程序代码和/或调用默认值

    if (m_bMoving)
    {
        m_bMoving = FALSE;
        ReleaseCapture();//释放鼠标的捕获
    }

    CDialogEx::OnLButtonUp(nFlags, point);
}


/*
    窗口激活消息
*/
void CMFCApplication11Dlg::OnActivate(UINT nState, CWnd* pWndOther, BOOL bMinimized)
{
    CDialogEx::OnActivate(nState, pWndOther, bMinimized);

    // TODO:  在此处添加消息处理程序代码

    //窗口失去焦点，由激活状态，变为不激活状态
    if (nState == WA_INACTIVE && m_bMoving)
    {
        m_bMoving = FALSE;
        ReleaseCapture();//释放鼠标的捕获
    }
}