给WPF程序增加玻璃效果

在Vista中增加了一种Aero新界面，也就是我们所说的玻璃效果，这种效果比较酷，我也常常喜欢在自己写的小程序中加入这种效果。

　　　　

实现这种效果并不难，也就是两个API，MSDN的文章将玻璃框扩展到 WPF 应用程序详细介绍了如何实现这种效果。在google上拿"C# DwmExtendFrameIntoClientArea"做关键字，也能搜到一大把。

我一般是用的CodeProject的文章Adding Glass Effect to WPF using Attached Properties上所述的那样，通过依赖属性注入这种效果，只要在窗口中加一句话src:GlassEffect.IsEnabled="True"即可使能这种效果，用起来非常方便。通过这种方式实现起来的效果如下：

　　　　

看起来一起都非常简单，但这种方法只是仅仅实现了玻璃效果，还有几个不完善的地方：

1. 这种方法只能实现全屏玻璃效果，不能实现部分玻璃效果。
2. 实现玻璃效果后，我们往往还需要隐藏标题栏中的图标和文字。
3. 那些玻璃化的部分不能像标题栏那样通过鼠标拖动窗口。

因此，我将那个代码改动了一下，增加了上述功能，代码如下：  

代码

     public   class  GlassInfo: System.Windows.Markup.MarkupExtension
    {
         public   int  TopMargin {  get ;  set ; }
         public   bool  ShowIcon {  get ;  set ; }
         public   bool  ShowTitle {  get ;  set ; }

         public  GlassInfo()
        {
            TopMargin  =   - 1 ;
            ShowIcon  =   true ;
            ShowTitle  =   true ;
        }

         public   override   object  ProvideValue(IServiceProvider serviceProvider)
        {
             return   this ;
        }
    }
    
     public   class  GlassEffect
    {
         public   static  GlassInfo GetInfo(DependencyObject obj)
        {
             return  (GlassInfo)obj.GetValue(InfoProperty);
        }

         public   static   void  SetInfo(DependencyObject obj, GlassInfo value)
        {
            obj.SetValue(InfoProperty, value);
        }

         public   static   readonly  DependencyProperty InfoProperty  =
            DependencyProperty.RegisterAttached( " Info " ,  typeof (GlassInfo),  typeof (GlassEffect),  new  FrameworkPropertyMetadata(OnIsEnabledChanged));


         public   static   void  OnIsEnabledChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
        {
             if  (System.ComponentModel.DesignerProperties.GetIsInDesignMode(obj))
                 return ;
            
            (obj  as  Window).Loaded  +=  (s, e)  =>  ApplyGlassEffect(obj  as  Window, args.NewValue  as  GlassInfo);

            EnableMouseDrag(obj  as  Window,(args.NewValue  as  GlassInfo).TopMargin);
        }

         static   void  ApplyGlassEffect(Window window, GlassInfo info)
        {
             if  ( ! DwmIsCompositionEnabled())
                 return ;

            var originalBackground  =  window.Background;
            window.Background  =  Brushes.Transparent;

             try
            {
                IntPtr mainWindowPtr  =   new  WindowInteropHelper(window).Handle;
                HwndSource mainWindowSrc  =  HwndSource.FromHwnd(mainWindowPtr);
                mainWindowSrc.CompositionTarget.BackgroundColor  =  Color.FromArgb( 0 ,  0 ,  0 ,  0 );

                var margins  =  info.TopMargin  ==   - 1   ?   new  MARGINS( - 1 ,  - 1 ,  - 1 ,  - 1 ) :  new  MARGINS { Top  =  info.TopMargin };
                DwmExtendFrameIntoClientArea(mainWindowPtr,  ref  margins);

                ApplyWindowThemeAttribute(info, mainWindowPtr);
            }
             catch  (DllNotFoundException)
            {
                window.Background  =  originalBackground;
            }
        }

         static   void  ApplyWindowThemeAttribute(GlassInfo info, IntPtr mainWindowPtr)
        {
            WTA_OPTIONS ops  =   new  WTA_OPTIONS();

             //  We Want To Hide the Caption and the Icon
            ops.Flags  =  WTNCA_NODRAWCAPTION  |  WTNCA_NODRAWICON  |  WTNCA_NOSYSMENU;

             //  If we set the Mask to the same value as the Flags, the Flags are Added. If Not They are Removed
             if  ( ! info.ShowTitle)
            {
                ops.Mask  |=  WTNCA_NODRAWCAPTION;
            }
             if  ( ! info.ShowIcon)
            {
                ops.Mask  |=  WTNCA_NODRAWICON  |  WTNCA_NOSYSMENU;
            }

             //  Set It, The Marshal.Sizeof() stuff is to get the right size of the custom struct, and in UINT/DWORD Form
            SetWindowThemeAttribute(mainWindowPtr, WindowThemeAttributeType.WTA_NONCLIENT,
                 ref  ops, ( uint )Marshal.SizeOf( typeof (WTA_OPTIONS)));
        }

         #region  设置任意位置拖动效果API
         const   int  WM_NCLBUTTONDOWN  =   0xA1 ;
         const   int  HT_CAPTION  =   0x2 ;

        [DllImportAttribute( " user32.dll " )]
         static   extern   int  SendMessage(IntPtr hWnd,
                          int  Msg,  int  wParam,  int  lParam);
        [DllImportAttribute( " user32.dll " )]
         static   extern   bool  ReleaseCapture();

         static   void  EnableMouseDrag(Window window, int  topMargin)
        {
            window.MouseLeftButtonDown  +=  (s, e)  =>
            {
                var win  =  s  as  Window;

                var point  =  e.GetPosition(win);
                 if  (point.Y  >  topMargin)
                     return ;
            
                Console.WriteLine(e.OriginalSource);
                var mainWindowPtr  =   new  WindowInteropHelper(win).Handle;
                ReleaseCapture();
                SendMessage(mainWindowPtr, WM_NCLBUTTONDOWN, HT_CAPTION,  0 );
            };
        }
         #endregion

         #region  设置玻璃效果API
        [StructLayout(LayoutKind.Sequential)]
         struct  MARGINS
        {
             public   int  Left;
             public   int  Right;
             public   int  Top;
             public   int  Bottom;

             public  MARGINS( int  left, int  right, int  top, int  bottom)
            {
                 this .Left  =  left;
                 this .Right  =  right;
                 this .Top  =  top;
                 this .Bottom  =  bottom;
            }

             public  MARGINS(Thickness margin)
            {
                 this .Left  =  ( int )margin.Left;
                 this .Right  =  ( int )margin.Right;
                 this .Top  =  ( int )margin.Top;
                 this .Bottom  =  ( int )margin.Bottom;
            }
        };


        [DllImport( " DwmApi.dll " )]
         static   extern   int  DwmExtendFrameIntoClientArea(IntPtr hwnd,  ref  MARGINS pMarInset);

        [DllImport( " dwmapi.dll " , PreserveSig  =   false )]
         static   extern   bool  DwmIsCompositionEnabled();

         public   static   readonly  DependencyProperty IsEnabledProperty  =
            DependencyProperty.RegisterAttached( " IsEnabled " ,
                 typeof (Boolean),
                 typeof (GlassEffect),
                 new  FrameworkPropertyMetadata(OnIsEnabledChanged)); 
         #endregion

         #region  设置标题栏属性

         ///  

         ///  Do Not Draw The Caption (Text)
         ///  

         public   static   uint  WTNCA_NODRAWCAPTION  =   0x00000001 ;
         ///  

         ///  Do Not Draw the Icon
         ///  

         public   static   uint  WTNCA_NODRAWICON  =   0x00000002 ;
         ///  

         ///  Do Not Show the System Menu
         ///  

         public   static   uint  WTNCA_NOSYSMENU  =   0x00000004 ;
         ///  

         ///  Do Not Mirror the Question mark Symbol
         ///  

         public   static   uint  WTNCA_NOMIRRORHELP  =   0x00000008 ;

         ///  

         ///  The Options of What Attributes to Add/Remove
         ///  

        [StructLayout(LayoutKind.Sequential)]
         struct  WTA_OPTIONS
        {
             public   uint  Flags;
             public   uint  Mask;
        }

         ///  

         ///  What Type of Attributes? (Only One is Currently Defined)
         ///  

         enum  WindowThemeAttributeType
        {
            WTA_NONCLIENT  =   1 ,
        };

         ///  

         ///  Set The Window's Theme Attributes
         ///  

         ///   The Handle to the Window
         ///   What Type of Attributes
         ///   The Attributes to Add/Remove
         ///   The Size of the Attributes Struct
         ///   If The Call Was Successful or Not
        [DllImport( " UxTheme.dll " )]
         static   extern   int  SetWindowThemeAttribute(IntPtr hWnd, WindowThemeAttributeType wtype,  ref  WTA_OPTIONS attributes,  uint  size); 
         #endregion

    }

 

使用示例如下：

<Window x:Class="WpfApplication.MainWindow"
    … …
    src:GlassEffect.Info="{util:GlassInfo TopMargin=32, ShowIcon=False, ShowTitle=False}">

最终效果如下：