1.实现WM_NCHITTEST消息，实现四条边框的模拟
2.实现WM_NCLBUTTONDOWN，发送窗体拖曳变化的消息
具体阐述如下：
1. 实现WM_NCHITTEST消息，实现四条边框的模拟，参考代码如下：
LRESULT CNoBorderWndChangeSizeDlg::OnNcHitTest(CPoint point)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
CRect rect;
GetWindowRect(&rect);
CRect rect1 = rect;
rect1.DeflateRect(10, 10, -10, -10);
rect1.NormalizeRect();
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;
else if (!rect.IsRectEmpty())
{
LRESULT uRet = CWnd::OnNcHitTest(point);
uRet = (uRet == HTCLIENT) ? HTCAPTION : uRet;
return uRet;
}
else
{
return CWnd::OnNcHitTest(point);
}
return 0;
}
2. 实现WM_NCLBUTTONDOWN，发送窗体拖曳变化的消息
void CNoBorderWndChangeSizeDlg::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));
else if (nHitTest==HTCAPTION)
SendMessage(WM_SYSCOMMAND, SC_MOVE | 4, MAKELPARAM(point.x, point.y));
}
通常，使用上述的代码即可实现要求。
我们进行一下扩展。在窗体大小发生变化时，有两种表现形式：一种是出现虚线框，一种没有。这个选择依赖于操作系统，你可以右击桌面/属性/外观/效果中通过选择或取消“拖动时显示窗口内容”来表现这两种形式。那么如何在程序中实现而不依赖于当前机器的设置呢（这里的意思是不依赖手动选择“拖动时显示窗口内容”项），我们可以在OnNcLButtonDown函数中通过加入如下的代码实现:
if(nHitTest == HTTOP)
{
SystemParametersInfo(SPI_SETDRAGFULLWINDOWS, TRUE, NULL, 0);
SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_TOP, MAKELPARAM(point.x, point.y));
SystemParametersInfo(SPI_SETDRAGFULLWINDOWS, FALSE, NULL, 0);
}
这段代码意思是在拖动上边缘动作之前，设置“拖动时显示窗口内容”，当该动作结束后，恢复原来的设置。当然，更好的做法是你首先获取机器当前的选项是什么，函数依旧是SystemParametersInfo，只是选项变化，具体查看MSDN即可。