C# 改变无边框窗体的尺寸大小

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const int HTLEFT = 10;
const int HTRIGHT = 11;
const int HTTOP = 12;
const int HTTOPLEFT = 13;
const int HTTOPRIGHT = 14;
const int HTBOTTOM = 15;
const int HTBOTTOMLEFT = 0x10;
const int HTBOTTOMRIGHT = 17;

protected override void WndProc(ref Message m)
{
switch (m.Msg)
{
case 0x0084:
base.WndProc(ref m);
Point vPoint = new Point((int)m.LParam & 0xFFFF,
(int)m.LParam >> 16 & 0xFFFF);
vPoint = PointToClient(vPoint);
if (vPoint.X <= 5)
if (vPoint.Y <= 5)
m.Result = (IntPtr)HTTOPLEFT;
else if (vPoint.Y >= ClientSize.Height - 5)
m.Result = (IntPtr)HTBOTTOMLEFT;
else m.Result = (IntPtr)HTLEFT;
else if (vPoint.X >= ClientSize.Width - 5)
if (vPoint.Y <= 5)
m.Result = (IntPtr)HTTOPRIGHT;
else if (vPoint.Y >= ClientSize.Height - 5)
m.Result = (IntPtr)HTBOTTOMRIGHT;
else m.Result = (IntPtr)HTRIGHT;
else if (vPoint.Y <= 5)
m.Result = (IntPtr)HTTOP;
else if (vPoint.Y >= ClientSize.Height - 5)
m.Result = (IntPtr)HTBOTTOM;
break;
case 0x0201://鼠标左键按下的消息
m.Msg = 0x00A1;//更改消息为非客户区按下鼠标
m.LParam = IntPtr.Zero;//默认值
m.WParam = new IntPtr(2);//鼠标放在标题栏内
base.WndProc(ref m);
break;
default:
base.WndProc(ref m);
break;
}
}