如何在调整表单大小时将默认值设置为最小大小

Question

对不起，因为我的英语很差！

我使用WM_SIZE消息调整表单大小，如何设置表单的最小大小？我希望表单的最小大小为200x100这是我的代码：

protected override void WndProc(ref Message m)
{
const int RESIZE_HANDLE_SIZE = 10;
switch (m.Msg)
{
case 0x0084/*NCHITTEST*/ :
base.WndProc(ref m);
if ((int)m.Result == 0x01/*HTCLIENT*/)
{
Point screenPoint = new Point(m.LParam.ToInt32());
Point clientPoint = this.PointToClient(screenPoint);
if (clientPoint.Y <= RESIZE_HANDLE_SIZE)
{
if (clientPoint.X <= RESIZE_HANDLE_SIZE)
m.Result = (IntPtr)13/*HTTOPLEFT*/ ;
else if (clientPoint.X < (Size.Width - RESIZE_HANDLE_SIZE))
m.Result = (IntPtr)12/*HTTOP*/ ;
else
m.Result = (IntPtr)14/*HTTOPRIGHT*/ ;
}
else if (clientPoint.Y <= (Size.Height - RESIZE_HANDLE_SIZE))
{
if (clientPoint.X <= RESIZE_HANDLE_SIZE)
m.Result = (IntPtr)10/*HTLEFT*/ ;
else if (clientPoint.X < (Size.Width - RESIZE_HANDLE_SIZE))
m.Result = (IntPtr)2/*HTCAPTION*/ ;
else
m.Result = (IntPtr)11/*HTRIGHT*/ ;
}
else
{
if (clientPoint.X <= RESIZE_HANDLE_SIZE)
m.Result = (IntPtr)16/*HTBOTTOMLEFT*/ ;
else if (clientPoint.X < (Size.Width - RESIZE_HANDLE_SIZE))
m.Result = (IntPtr)15/*HTBOTTOM*/ ;
else
m.Result = (IntPtr)17/*HTBOTTOMRIGHT*/ ;
}
}
return;
}
base.WndProc(ref m);
}

Answer 1

如果您想要pInvoke解决方案(我在当前代码中看到IntPtr、NCHITTEST等(，可以尝试WM_GETMINMAXINFO消息。首先，我们想要MINMAXINFO和POINTstructs:

using System.Runtime.InteropServices;
...
[StructLayout(LayoutKind.Sequential)]
internal struct POINT {
public int X;
public int Y;
public POINT(int x, int y) {
X = x;
Y = y;
}
}
[StructLayout(LayoutKind.Sequential)]
internal struct MINMAXINFO {
public POINT ptReserved;
public POINT ptMaxSize;
public POINT ptMaxPosition;
public POINT ptMinTrackSize;
public POINT ptMaxTrackSize;
}   

然后

protected override void WndProc(ref Message m) {
... 
switch (m.Msg) {
...
case 0x0024: { // WM_GETMINMAXINFO 
MINMAXINFO info = Marshal.PtrToStructure<MINMAXINFO>(m.LParam);
info.ptMinTrackSize = new POINT(
Math.Max(200, info.ptMinTrackSize.X),  // smallest X (width)
Math.Max(100, info.ptMinTrackSize.Y)); // smallest Y (height)
Marshal.StructureToPtr(info, m.LParam, true);
break;
}
...
}