Custom window frame with DWM: how to handle WM_NCCALCSIZE correctly

Question

I am trying to create my own window frame for my form using DWM. The platform is C # WinForms, Pinwoking DWM.

Following the MSDN article on creating a custom window frame with DWM, the following basic steps:

• Delete the standard frame (an area without a client), returning 0 in response to the WM_NCCALCSIZE message
• Extending the scope in the client area using the DwmExtendFrameIntoClientArea function

I process the WM_NCCALCSIZE message as follows:

protected override void WndProc(ref Message m)
{
   switch (m.Msg)
   {
       case WM_NCCALCSIZE:
            if (isDwmWindowFramePaintEnabled() && m.WParam != IntPtr.Zero)
            {
                m.Result = IntPtr.Zero;
            }
            else
            {
                base.WndProc(ref m);
            }
            return;
   }
}

According to the MSDN documentation for WM_NCCALCSIZE ,

wParam , 0 NCCALCSIZE_PARAMS , . , .

, . / , , . , :

• ,
• Windows
• WM_NCCALCSIZE , .

, , / . , DWM. , DWM .

, , , .

Answer 1

Windows Forms, . Form.SizeFromClientSize(int, int) AdjustWindowRectEx . :

• RestoreWindowBoundsIfNecessary WM_WINDOWPOSCHANGED
• SetClientSizeCore

:

• CreateParams :

  private bool createParamsHack;
  
  protected override CreateParams CreateParams
  {
      get
      {
          CreateParams cp = base.CreateParams;
          // Remove styles that affect the border size
          if (createParamsHack)
              cp.Style &= ~(int)(WS_BORDER | WS_CAPTION | WS_DLGFRAME | WS_THICKFRAME);
          return cp;
      }
  }
  

• WndProc WM_WINDOWPOSCHANGED:

      if (m.Msg == WM_WINDOWPOSCHANGED)
      {
          createParamsHack = true;
          base.WndProc(ref m);
          createParamsHack = false;
      }
  

• SetClientSizeCore:

  protected override void SetClientSizeCore(int x, int y)
  {
      createParamsHack = true;
      base.SetClientSizeCore(x, y);
      createParamsHack = false;
  }
  

SizeFromClientSize(Size), , .