WPF最大化避免覆盖任务栏

原文: WPF最大化避免覆盖任务栏

WPF当窗体WindowStyle=”None”时，最大化会覆盖掉任务栏。如何解决这个问题呢？

我在Google里面搜到一篇文章，要用到Win32 API，通过让WPF窗体WM_GETMINMAXINFO消息挂接一个钩子来处理。

 

 public static void RepairWindowBehavior(Window wpfWindow)

     {

         if (wpfWindow == null )

             return ;

  

         wpfWindow.SourceInitialized += delegate

         {

             IntPtr handle = ( new WindowInteropHelper(wpfWindow)).Handle;

             HwndSource source = HwndSource.FromHwnd(handle);

             if (source != null )

             {

                 source.AddHook(WindowProc);

             }

         };

     }

  

     private static IntPtr WindowProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)

     {

         switch (msg)

         {

             case 0x0024:

                 WmGetMinMaxInfo(hwnd, lParam);

                 handled = true ;

                 break ;

         }

  

         return (IntPtr)0;

     }

  

     private static void WmGetMinMaxInfo(IntPtr hwnd, IntPtr lParam)

     {

         MINMAXINFO mmi = (MINMAXINFO)Marshal.PtrToStructure(lParam, typeof (MINMAXINFO));

  

         int MONITOR_DEFAULTTONEAREST = 0x00000002;

         IntPtr monitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);

  

         if (monitor != IntPtr.Zero)

         {

             MONITORINFO monitorInfo = new MONITORINFO();

             GetMonitorInfo(monitor, monitorInfo);

             RECT rcWorkArea = monitorInfo.rcWork;

             RECT rcMonitorArea = monitorInfo.rcMonitor;

             mmi.ptMaxPosition.x = Math.Abs(rcWorkArea.left - rcMonitorArea.left);

             mmi.ptMaxPosition.y = Math.Abs(rcWorkArea.top - rcMonitorArea.top);

             mmi.ptMaxSize.x = Math.Abs(rcWorkArea.right - rcWorkArea.left);

             mmi.ptMaxSize.y = Math.Abs(rcWorkArea.bottom - rcWorkArea.top);

         }

  

         Marshal.StructureToPtr(mmi, lParam, true );

     }

  

     [DllImport( "user32" )]

     internal static extern bool GetMonitorInfo(IntPtr hMonitor, MONITORINFO lpmi);

     [DllImport( "User32" )]

     internal static extern IntPtr MonitorFromWindow(IntPtr handle, int flags);

  

     #region Nested type: MINMAXINFO

     [StructLayout(LayoutKind.Sequential)]

     internal struct MINMAXINFO

     {

         public POINT ptReserved;

         public POINT ptMaxSize;

         public POINT ptMaxPosition;

         public POINT ptMinTrackSize;

         public POINT ptMaxTrackSize;

     }

     #endregion

  

     #region Nested type: MONITORINFO

     [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]

     internal class MONITORINFO

     {

         public int cbSize = Marshal.SizeOf( typeof (MONITORINFO));

         public RECT rcMonitor;

         public RECT rcWork;

         public int dwFlags;

     }

     #endregion

  

     #region Nested type: POINT

     [StructLayout(LayoutKind.Sequential)]

     internal struct POINT

     {

         public int x;

         public int y;

         public POINT( int x, int y)

         {

             this .x = x;

             this .y = y;

         }

     }

     #endregion

  

     #region Nested type: RECT

     [StructLayout(LayoutKind.Sequential, Pack = 0)]

     internal struct RECT

     {

         public int left;

         public int top;

         public int right;

         public int bottom;

  

         public static readonly RECT Empty;

  

         public int Width

         {

             get { return Math.Abs(right - left); }

         }

         public int Height

         {

             get { return bottom - top; }

         }

  

         public RECT( int left, int top, int right, int bottom)

         {

             this .left = left;

             this .top = top;

             this .right = right;

             this .bottom = bottom;

         }

  

         public RECT(RECT rcSrc)

         {

             left = rcSrc.left;

             top = rcSrc.top;

             right = rcSrc.right;

             bottom = rcSrc.bottom;

         }

  

         public bool IsEmpty

         {

             get

             {

                 return left >= right || top >= bottom;

             }

         }

  

         public override string ToString()

         {

             if ( this == Empty)

             {

                 return "RECT {Empty}" ;

             }

             return "RECT { left : " + left + " / top : " + top + " / right : " + right + " / bottom : " + bottom + " }" ;

         }

  

         public override bool Equals( object obj)

         {

             if (!(obj is Rect))

             {

                 return false ;

             }

             return ( this == (RECT)obj);

         }

  

         public override int GetHashCode()

         {

             return left.GetHashCode() + top.GetHashCode() + right.GetHashCode() + bottom.GetHashCode();

         }

  

         public static bool operator ==(RECT rect1, RECT rect2)

         {

             return (rect1.left == rect2.left && rect1.top == rect2.top && rect1.right == rect2.right && rect1.bottom == rect2.bottom);

         }

  

         public static bool operator !=(RECT rect1, RECT rect2)

         {

             return !(rect1 == rect2);

         }

     }

     #endregion

}

通过调用WindowHelper.RepairWindowBehavior(Window)方法注册Win32消息事件，以后调用this.WindowState = WindowState.Maximized;就可以解决最大化避免覆盖任务栏的问题了。