我想知道是否可以设置无边框表单的客户区。比如说我定义了一个这样的表单：
代码
public class MyForm : Form
{
public MyForm()
{
this.FormBorderStyle = FormBorderStyle.None;
}
}
结果
我想要做的是指定客户区，以便表单有一个框架（就像标准的 windows 框架，但自定义绘制）。
结果
本质上，蓝色区域将成为非客户区域，而灰色区域将保留为客户区域。
我试图设置客户区，但这似乎只是调整了整个表单的大小，因此不会留下“非客户”区域
这可能吗？
这是可能的，但是我不知道这与 WindowStyle 设置为无边框的 Windows 窗体的效果如何。使用 PInvoke（平台调用）函数，您可以删除窗口主题，这将为您提供一个非常基本的 Windows 窗体。然后，您可以使用各种 PInvoke 函数来操作窗口窗体的非客户区。
我建议您通读这些主题。它们是为使用 C++ 的 Win32 应用程序设计的，但 PInvoke 是使用托管代码 (C#) 调用这些本机 API 的过程
WM_NCCALCSIZE：https ://msdn.microsoft.com/en-us/library/windows/desktop/ms632634(v=vs.85).aspx
WM_NCPAINT：https ://msdn.microsoft.com/en-us/library/windows/desktop/dd145212(v=vs.85).aspx
GetDCEx：https ://msdn.microsoft.com/en-us/library/windows/desktop/dd144873(v=vs.85).aspx
GetWindowDC：https ://msdn.microsoft.com/en-us/library/windows/desktop/dd144947(v=vs.85).aspx
设置窗口主题： https ://msdn.microsoft.com/en-us/library/windows/desktop/bb759827(v= vs.85).aspx
这个例子非常粗略，但它提供了基本的功能。我不知道 SetWindowTheme 如何在 Windows 8 或 8.1 上工作，但在 Windows 7 中，它为 Windows 提供了“经典”主题。
public partial class MyForm : Form
{
//Window Messages
public const uint WM_NCPAINT = 0x85;
public const uint WM_NCCALCSIZE = 0x83;
public const uint WM_NCHITTEST = 0x84;
//GetDCEx Flags
public const int DCX_WINDOW = 0x00000001;
public const int DCX_CACHE = 0x00000002;
public const int DCX_PARENTCLIP = 0x00000020;
public const int DCX_CLIPSIBLINGS = 0x00000010;
public const int DCX_CLIPCHILDREN = 0x00000008;
public const int DCX_NORESETATTRS = 0x00000004;
public const int DCX_LOCKWINDOWUPDATE = 0x00000400;
public const int DCX_EXCLUDERGN = 0x00000040;
public const int DCX_INTERSECTRGN = 0x00000080;
public const int DCX_INTERSECTUPDATE = 0x00000200;
public const int DCX_VALIDATE = 0x00200000;
//RECT Structure
[System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)]
public struct RECT
{
public int left, top, right, bottom;
}
//WINDOWPOS Structure
[System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)]
public struct WINDOWPOS
{
public IntPtr hwnd;
public IntPtr hwndinsertafter;
public int x, y, cx, cy;
public int flags;
}
//NCCALCSIZE_PARAMS Structure
[System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)]
public struct NCCALCSIZE_PARAMS
{
public RECT rgrc0, rgrc1, rgrc2;
public WINDOWPOS lppos;
}
//SetWindowTheme UXtheme Function
[System.Runtime.InteropServices.DllImport("uxtheme.dll", ExactSpelling = true, CharSet = System.Runtime.InteropServices.CharSet.Unicode)]
public static extern int SetWindowTheme(
IntPtr hWnd,
String pszSubAppName,
String pszSubIdList);
//GetWindowRect User32 Function
[System.Runtime.InteropServices.DllImport("user32.dll", ExactSpelling = true)]
[return: System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.Bool)]
public static extern bool GetWindowRect(
IntPtr hwnd,
out RECT lpRect
);
//GetWindowDC User32 Function
[System.Runtime.InteropServices.DllImport("user32.dll", ExactSpelling = true)]
public static extern IntPtr GetWindowDC(
IntPtr hWnd
);
//GetDCEx User32 Function
[System.Runtime.InteropServices.DllImport("user32.dll", ExactSpelling = true)]
public static extern IntPtr GetDCEx(
IntPtr hWnd,
IntPtr hrgnClip,
int flags
);
//Window Procedure Hook
protected override void WndProc(ref Message m)
{
//Don't style window in designer...
if (DesignMode)
base.WndProc(ref m);
//Handle Message
switch ((uint)m.Msg)
{
case WM_NCCALCSIZE: WmNCCalcSize(ref m); break;
case WM_NCPAINT: WmNCPaint(ref m); break;
default: base.WndProc(ref m); break;
}
}
//Handle Creation
protected override void OnHandleCreated(EventArgs e)
{
//Base Procedure...
base.OnHandleCreated(e);
//Remove Theme
SetWindowTheme(this.Handle, string.Empty, string.Empty);
}
//WM_NCCALCSIZE
private void WmNCCalcSize(ref Message m)
{
//Get Window Rect
RECT formRect = new RECT();
GetWindowRect(m.HWnd, out formRect);
//Check WPARAM
if (m.WParam != IntPtr.Zero) //TRUE
{
//When TRUE, LPARAM Points to a NCCALCSIZE_PARAMS structure
var nccsp = (NCCALCSIZE_PARAMS)System.Runtime.InteropServices.Marshal.PtrToStructure(m.LParam, typeof(NCCALCSIZE_PARAMS));
//We're adjusting the size of the client area here. Right now, the client area is the whole form.
//Adding to the Top, Bottom, Left, and Right will size the client area.
nccsp.rgrc0.top += 30; //30-pixel top border
nccsp.rgrc0.bottom -= 4; //4-pixel bottom (resize) border
nccsp.rgrc0.left += 4; //4-pixel left (resize) border
nccsp.rgrc0.right -= 4; //4-pixel right (resize) border
//Set the structure back into memory
System.Runtime.InteropServices.Marshal.StructureToPtr(nccsp, m.LParam, true);
}
else //FALSE
{
//When FALSE, LPARAM Points to a RECT structure
var clnRect = (RECT)System.Runtime.InteropServices.Marshal.PtrToStructure(m.LParam, typeof(RECT));
//Like before, we're adjusting the rectangle...
//Adding to the Top, Bottom, Left, and Right will size the client area.
clnRect.top += 30; //30-pixel top border
clnRect.bottom -= 4; //4-pixel bottom (resize) border
clnRect.left += 4; //4-pixel left (resize) border
clnRect.right -= 4; //4-pixel right (resize) border
//Set the structure back into memory
System.Runtime.InteropServices.Marshal.StructureToPtr(clnRect, m.LParam, true);
}
//Return Zero
m.Result = IntPtr.Zero;
}
//WM_NCPAINT
private void WmNCPaint(ref Message m)
{
//Store HDC
IntPtr HDC = IntPtr.Zero;
Graphics gfx = null;
//Check the WPARAM
if(m.WParam == (IntPtr)1)
{
//For reasons unknown to me, the update region doesn't contain valid data and calling GetDCEx will do nothing.
//So I call GetWindowDC and exclude the area using System.Drawing.Graphics instead.
//Graphics Object from HDC
HDC = GetWindowDC(m.HWnd);
gfx = Graphics.FromHdc(HDC);
//Exclude Client Area
gfx.ExcludeClip(new Rectangle(4, 30, Width - 8, 34)); //Exclude Client Area (GetWindowDC grabs the WHOLE window's graphics handle)
}
else
{
//Graphics Object from HDC
HDC = GetDCEx(m.HWnd, m.WParam, DCX_WINDOW | DCX_INTERSECTRGN);
gfx = Graphics.FromHdc(HDC);
}
//Call Paint
using (PaintEventArgs ncPaintArgs = new PaintEventArgs(gfx, new Rectangle(0, 0, Width, Height)))
MyForm_NCPaint(this, ncPaintArgs);
//Return Zero
m.Result = IntPtr.Zero;
}
public MyForm()
{
InitializeComponent();
}
private void MyForm_NCPaint(object sender, PaintEventArgs e)
{
//Clear
e.Graphics.Clear(Color.Green);
}
}
