MFC dialog 窗口的 拖放和伸缩

做项目的时候，遇到这样一个问题：

窗口要进行可以拖放和伸缩的功能，但是因为是以一张图片为背景的，

当设置 border 为resizing 的时候，虽然可以伸缩，但是在窗口的左边和上边都有一些框， 而这些框都是呈现出白色。

在网上所找的资料终于实现这一功能：

////添加如下3个消息 实现伸缩功能：
void CAboutDlg::OnNcLButtonDown(UINT nHitTest, CPoint point)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
if(nHitTest == HTTOP)
SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_TOP, MAKELPARAM(point.x, point.y));
else if(nHitTest == HTBOTTOM)
SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOM, MAKELPARAM(point.x, point.y));
else if(nHitTest == HTLEFT)
SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_LEFT, MAKELPARAM(point.x, point.y));
else if(nHitTest == HTRIGHT)
SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_RIGHT, MAKELPARAM(point.x, point.y));
else if(nHitTest == HTTOPLEFT)
SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_TOPLEFT, MAKELPARAM(point.x, point.y));
else if(nHitTest == HTTOPRIGHT)
SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_TOPRIGHT, MAKELPARAM(point.x, point.y));
else if(nHitTest == HTBOTTOMLEFT)
SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOMLEFT, MAKELPARAM(point.x, point.y));
else if(nHitTest == HTBOTTOMRIGHT)
SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOMRIGHT, MAKELPARAM(point.x, point.y));
CDialog::OnNcLButtonDown(nHitTest, point);
}
LRESULT CAboutDlg::OnNcHitTest(CPoint point)
{
CRect rect;
GetWindowRect(&rect);
if(point.x <= rect.left+3)
return HTLEFT;
else if(point.x >= rect.right-3)
return HTRIGHT;
else if(point.y <= rect.top+3)
return HTTOP;
else if(point.y >= rect.bottom-3)
return HTBOTTOM;
else if(point.x <= rect.left+10 && point.y <= rect.top+10)
return HTTOPLEFT;
else if(point.x >= rect.right-10 && point.y <= rect.top+10)
return HTTOPRIGHT;
else if(point.x <= rect.left+10 && point.y >= rect.bottom-10)
return HTBOTTOMLEFT;
else if(point.x >= rect.right-10 && point.y >= rect.bottom-10)
return HTBOTTOMRIGHT;
///下面的这一行必须得添加 要不然拖放功能无法实现
return   HTCAPTION;
}
BOOL CAboutDlg::OnSetCursor(CWnd* pWnd, UINT nHitTest, UINT message)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
if(nHitTest == HTCAPTION || nHitTest == HTSYSMENU ||
nHitTest == HTMENU || nHitTest == HTCLIENT)
{
SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_ARROW)));
}
else if(nHitTest == HTTOP || nHitTest == HTBOTTOM)
{
SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENS)));
}
else if(nHitTest == HTLEFT || nHitTest == HTRIGHT)
{
SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZEWE)));
}
else if(nHitTest == HTTOPLEFT || nHitTest == HTBOTTOMRIGHT)
{
SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENWSE)));
}
else if(nHitTest == HTTOPRIGHT || nHitTest == HTBOTTOMLEFT)
{
SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENESW)));
}
else
{
SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_ARROW)));
}
return 0;
}

参考地址：

伸缩：
http://blog.csdn.net/mynamelj/archive/2006/12/16/1445567.aspx
拖放：
http://topic.csdn.net/t/20010806/11/225414.html