如何以无边框forms设置客户区（ClientRectangle）？

我想知道是否可以设置无边框表单的客户区。 比如说我定义一个这样的表单：

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（如标准的Windows框架，但自定义绘制）。

结果

基本上，蓝色区域将成为非客户区域，灰色区域将保留为客户区域。

我试图设置客户区，但这似乎只是调整整个表单的大小，因此，不会留下“非客户”区域

这可能吗？

Answer 1

这是可能的，但我不知道这与Windows窗体设置为无边框的Windows窗体有多好。 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Windows窗体的非客户端区域。

我建议你仔细阅读这些主题。 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

SetWindowTheme： https ：//msdn.microsoft.com/en-us/library/windows/desktop/bb759827（ v = vs。85）.aspx

这个例子非常粗糙，但它提供了基本function。 我不知道SetWindowTheme如何在Windows 8或8.1上运行，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); } }