Winfrom中From控件的重绘

重绘目的：

• 1. 满足非默认主题下的标题栏样式
• 2. 在保留停靠功能的同时进行重绘。

代码如下：

 public partial class FormEx: Form
     {
         public FormEx()
         {
             InitializeComponent();
             TitleBar.GetType().GetProperty("DoubleBuffered", BindingFlags.Instance | BindingFlags.NonPublic).SetValue(TitleBar, true, null);
             Icon = Properties.Resources.shark;
             CloseButtonImage = Properties.Resources.close;
             MaximumButtonImage = Properties.Resources.window_max;
             MaximumNormalButtonImage = Properties.Resources.window;
             MinimumButtonImage = Properties.Resources.window_min;
             CaptionBackgroundColor = Color.FromArgb(, , );
             CaptionHeight = ;
             BackColor = Color.White;
             ControlBackColor = Color.Transparent;
             this.TransparencyKey = boderColor;
             ControlActivedColor = DrawHelper.GetNearColor(Color.White, , -, -, -);

             TitleBar.SendToBack();

             base.SetStyle(
              ControlStyles.UserPaint |
              ControlStyles.AllPaintingInWmPaint |
              ControlStyles.OptimizedDoubleBuffer |
              ControlStyles.ResizeRedraw |
              ControlStyles.SupportsTransparentBackColor|
              ControlStyles.DoubleBuffer, true);
             base.AutoScaleMode = AutoScaleMode.None;
         }

         #region 公开变量
         [Category("标题栏"), Description("关闭按钮图片")]
         public Image CloseButtonImage { get; set; }

         [Category("标题栏"), Description("最大化按钮图片")]
         public Image MaximumButtonImage { get; set; }

         [Category("标题栏"), Description("最大化默认按钮图片")]
         public Image MaximumNormalButtonImage { get; set; }

         [Category("标题栏"), Description("最小化按钮图片")]
         public Image MinimumButtonImage { get; set; }

         [Category("标题栏"), Description("标题栏按钮鼠标悬浮背景色"), DefaultValue(typeof(Color), "#000000")]
         public Color ControlActivedColor { get; set; }

         [Category("标题栏"), Description("标题栏按钮默认状态背景色"), DefaultValue(typeof(Color))]
         public Color ControlBackColor { get; set; }

         private int captionHeight;
         [Category("标题栏"), Description("标题栏高度"), DefaultValue(typeof(int), "")]
         public int CaptionHeight { get { return captionHeight; } set { captionHeight = value; TitleBar.Height = value; } }

         [Category("标题栏"), Description("标题位置")]
         public ContentAlignment TitleAlign { set; get; } = ContentAlignment.MiddleLeft;

         private Color captionBackgroundColor;
         [Category("标题栏"), Description("标题栏背景颜色"), DefaultValue(typeof(Color), "White")]
         public Color CaptionBackgroundColor
         {
             get { return captionBackgroundColor; }
             set
             {
                 captionBackgroundColor = value;
                 TitleBar.BackColor = captionBackgroundColor;
             }
         }
         #endregion

         #region 私有变量

         private MouseState _mouseState = MouseState.Out;
         private Rectangle closeRect = Rectangle.Empty;      //关闭按钮范围
         private Rectangle maxRect = Rectangle.Empty;        //最大化按钮范围
         private Rectangle minRect = Rectangle.Empty;        //最小化按钮范围
         private Rectangle captionRect;                      //标题范围

         private int btnH = ;              //按钮大小
         private int boderWidth = ;         //边框宽度
         private Color boderColor = Color.FromArgb(, , );
         #endregion

         #region 重绘事件
         private void TitleBar_Paint(object sender, PaintEventArgs e)
         {
             captionRect = new Rectangle(, , TitleBar.Width, TitleBar.Height);
             DrawTitle(e.Graphics);
             DrawControlButton(e.Graphics);
         }

         protected override void OnPaint(PaintEventArgs e)
         {
             base.OnPaint(e);
             DrawBound(e.Graphics);
         }

         /// <summary>
         /// 绘制边框
         /// </summary>
         private void DrawBound(Graphics g)
         {
             Pen pen = new Pen(boderColor, boderWidth * );
             Rectangle rectangle = new Rectangle(, , Width, Height);
             g.DrawRectangle(pen, rectangle);
             pen = new Pen(Color.Black, );
             rectangle = new Rectangle(boderWidth - , boderWidth - , Width - boderWidth *  + , Height - boderWidth *  + );
             g.DrawRectangle(pen, rectangle);
             Padding = new Padding(boderWidth);
         }

         /// <summary>
         /// 绘制控制按钮
         /// </summary>
         private void DrawControlButton(Graphics g)
         {
             int x = ClientSize.Width - btnH -  - boderWidth;
             if (CloseButtonImage != null)
             {
                 DrawButtonImage(ref closeRect, ref x, _mouseState == MouseState.CloseHover, g, CloseButtonImage);
             }
             if (MaximizeBox)
             {
                 if (WindowState == FormWindowState.Maximized && MaximumNormalButtonImage != null)
                     DrawButtonImage(ref maxRect, ref x, _mouseState == MouseState.MaxHover, g, MaximumNormalButtonImage);
                 else if (MaximizeBox && WindowState != FormWindowState.Maximized && MaximumButtonImage != null)
                     DrawButtonImage(ref maxRect, ref x, _mouseState == MouseState.MaxHover, g, MaximumButtonImage);
             }
             if (MinimizeBox && MinimumButtonImage != null)
             {
                 DrawButtonImage(ref minRect, ref x, _mouseState == MouseState.MinHover, g, MinimumButtonImage);
             }
         }

         private void DrawButtonImage(ref Rectangle rect, ref int x, bool isHover, Graphics g, Image image)
         {
             //rect = new Rectangle(x, (captionHeight - btnH) / 2, btnH, btnH);
             rect = new Rectangle(x, , btnH, btnH);
             Brush brush = new SolidBrush(isHover ? ControlActivedColor : ControlBackColor);
             g.FillRectangle(brush, rect);
             g.DrawImage(image, rect);
             if (image == CloseButtonImage)
                 rect = new Rectangle(x, , btnH + boderWidth, btnH);
             x -= btnH;
         }

         /// <summary>
         /// 绘制标题
         /// </summary>
         private void DrawTitle(Graphics g)
         {
             int x = ;
             if (ShowIcon && Icon != null)
             {
                 g.SmoothingMode = SmoothingMode.AntiAlias;
                 ImageAttributes image = new ImageAttributes();
                 image.SetWrapMode(WrapMode.TileFlipXY);
                 using (Bitmap bitmap = Icon.ToBitmap())
                 {
                     Rectangle rec = new Rectangle(x, (captionHeight - btnH) / , CaptionHeight - , CaptionHeight - );
                     g.DrawImage(bitmap, rec, , , bitmap.Width, bitmap.Height, GraphicsUnit.Pixel, image);
                 }
                 x += ;
             }
             if (!string.IsNullOrEmpty(Text))
             {
                 int fontHeight = Size.Ceiling(g.MeasureString("Text", TitleBar.Font)).Height;
                 int fontWidth = Size.Ceiling(g.MeasureString(Text, TitleBar.Font)).Width;
                 Brush brush = new SolidBrush(ForeColor);
                 if (TitleAlign == ContentAlignment.MiddleLeft)
                     g.DrawString(Text, TitleBar.Font, brush, x, (CaptionHeight - fontHeight) / );
                 else if (TitleAlign == ContentAlignment.TopCenter)
                     g.DrawString(Text, TitleBar.Font, brush, (Width - fontWidth)/, boderWidth);

             }
         }
         #endregion

         #region 其他事件
         private void TitleBar_MouseClick(object sender, MouseEventArgs e)
         {
             if (e.Clicks !=  || e.Button != MouseButtons.Left)
                 return;
             switch (_mouseState)
             {
                 case MouseState.CloseHover:
                     Close();
                     break;
                 case MouseState.MaxHover:
                     WindowState = WindowState == FormWindowState.Maximized ? FormWindowState.Normal : FormWindowState.Maximized;
                     return;
                 case MouseState.MinHover:
                     WindowState = FormWindowState.Minimized;
                     return;
             }
             _mouseState = MouseState.Normal;
         }

         private void TitleBar_MouseDown(object sender, MouseEventArgs e)
         {
             if (_mouseState != MouseState.CaptionHover)
                 return;

             if (e.Clicks == )
             {
                 Win32API.ReleaseCapture();
                 Win32API.SendMessage(Handle, Win32API.WM_SYSCOMMAND, Win32API.SC_MOVE + Win32API.HTCAPTION, );
             }
             else if (e.Clicks ==  && e.Button == MouseButtons.Left)
             {
                 WindowState = WindowState == FormWindowState.Maximized ? FormWindowState.Normal : FormWindowState.Maximized;
             }
         }

         private void TitleBar_MouseMove(object sender, MouseEventArgs e)
         {
             Point p = new Point(e.X, e.Y);
             if (closeRect != Rectangle.Empty && closeRect.Contains(p))
                 _mouseState = MouseState.CloseHover;
             else if (minRect != Rectangle.Empty && minRect.Contains(p))
                 _mouseState = MouseState.MinHover;
             else if (maxRect != Rectangle.Empty && maxRect.Contains(p))
                 _mouseState = MouseState.MaxHover;
             else if (captionRect != Rectangle.Empty && captionRect.Contains(p))
                 _mouseState = MouseState.CaptionHover;
             else
                 _mouseState = MouseState.Normal;

             Invalidate(captionRect, true);
         }

         private void TitleBar_MouseLeave(object sender, EventArgs e)
         {
             _mouseState = MouseState.Out;
             Invalidate(captionRect, true);
         }

         private void FormEx_SizeChanged(object sender, EventArgs e)
         {
             Invalidate(captionRect, true);
         }
         #endregion

         #region 调整窗口大小

         protected override void SetBoundsCore(int x, int y, int width, int height, BoundsSpecified specified)
         {
             if (width == Width + )
                 return;
             base.SetBoundsCore(x, y, width, height, specified);
         }

         protected override void WndProc(ref Message m)
         {
             if (_mouseState == MouseState.CloseHover || _mouseState == MouseState.MinHover)
             {
                 base.WndProc(ref m);
                 return;
             }
             switch (m.Msg)
             {
                 case 0x0084:
                     base.WndProc(ref m);
                     Point vPoint = new Point((int)m.LParam & 0xFFFF,
                         (int)m.LParam >>  & 0xFFFF);
                     vPoint = PointToClient(vPoint);
                     if (vPoint.X <= )
                         if (vPoint.Y <= )
                             m.Result = (IntPtr)Win32API.Guying_HTTOPLEFT;
                         else if (vPoint.Y >= ClientSize.Height - )
                             m.Result = (IntPtr)Win32API.Guying_HTBOTTOMLEFT;
                         else m.Result = (IntPtr)Win32API.Guying_HTLEFT;
                     else if (vPoint.X >= ClientSize.Width - )
                         if (vPoint.Y <= )
                             m.Result = (IntPtr)Win32API.Guying_HTTOPRIGHT;
                         else if (vPoint.Y >= ClientSize.Height - )
                             m.Result = (IntPtr)Win32API.Guying_HTBOTTOMRIGHT;
                         else m.Result = (IntPtr)Win32API.Guying_HTRIGHT;
                     else if (vPoint.Y <= )
                         m.Result = (IntPtr)Win32API.Guying_HTTOP;
                     else if (vPoint.Y >= ClientSize.Height - )
                         m.Result = (IntPtr)Win32API.Guying_HTBOTTOM;
                     break;
                 case 0x0201:                    //鼠标左键按下的消息
                     m.Msg = 0x00A1;             //更改消息为非客户区按下鼠标
                     m.LParam = IntPtr.Zero;     //默认值
                     m.WParam = new IntPtr();   //鼠标放在标题栏内
                     base.WndProc(ref m);
                     break;
                 case 0x0083:
                     if (m.WParam != IntPtr.Zero)
                     {
                         NCCALCSIZE_PARAMS rcsize = (NCCALCSIZE_PARAMS)Marshal.PtrToStructure(m.LParam, typeof(NCCALCSIZE_PARAMS));
                         Marshal.StructureToPtr(rcsize, m.LParam, false);
                     }
                     m.Result = new IntPtr();
                     break;
                 default:
                     base.WndProc(ref m);
                     break;
             }
         }
         #endregion
     }

     public enum MouseState
     {
         Normal,
         MaxHover,
         MinHover,
         CloseHover,
         CaptionHover,
         Out,
     }

因为主要目的是为了保留窗体是停靠功能，所以不能使用无边框然后直接重绘标题栏。拦截了window绘制有效区域标题栏的消息，仍然存在很多不完善的地方，如拦截边框消息后没有重新绘制原边框位置的图形，导致了原区域的透明等等。