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(230, 230, 230);
            CaptionHeight = 30;
            BackColor = Color.White;
            ControlBackColor = Color.Transparent;
            this.TransparencyKey = boderColor;
            ControlActivedColor = DrawHelper.GetNearColor(Color.White, 0, -35, -24, -30);

            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), "30")]
        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 = 24;              //按钮大小
        private int boderWidth = 8;         //边框宽度
        private Color boderColor = Color.FromArgb(254, 254, 253);
        #endregion

        #region 重绘事件
        private void TitleBar_Paint(object sender, PaintEventArgs e)
        {
            captionRect = new Rectangle(0, 0, 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 * 2);
            Rectangle rectangle = new Rectangle(0, 0, Width, Height);
            g.DrawRectangle(pen, rectangle);
            pen = new Pen(Color.Black, 1);
            rectangle = new Rectangle(boderWidth - 1, boderWidth - 1, Width - boderWidth * 2 + 1, Height - boderWidth * 2 + 1);
            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 - 15 - 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, 0, btnH, btnH);
            Brush brush = new SolidBrush(isHover ? ControlActivedColor : ControlBackColor);
            g.FillRectangle(brush, rect);
            g.DrawImage(image, rect);
            if (image == CloseButtonImage)
                rect = new Rectangle(x, 0, btnH + boderWidth, btnH);
            x -= btnH;
        }

        /// <summary>
        /// 绘制标题
        /// </summary>
        private void DrawTitle(Graphics g)
        {
            int x = 6;
            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) / 2, CaptionHeight - 6, CaptionHeight - 6);
                    g.DrawImage(bitmap, rec, 0, 0, bitmap.Width, bitmap.Height, GraphicsUnit.Pixel, image);
                }
                x += 35;
            }
            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) / 2);
                else if (TitleAlign == ContentAlignment.TopCenter)
                    g.DrawString(Text, TitleBar.Font, brush, (Width - fontWidth)/2, boderWidth);


            }
        }
        #endregion

        #region 其他事件
        private void TitleBar_MouseClick(object sender, MouseEventArgs e)
        {
            if (e.Clicks != 1 || 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 == 1)
            {
                Win32API.ReleaseCapture();
                Win32API.SendMessage(Handle, Win32API.WM_SYSCOMMAND, Win32API.SC_MOVE + Win32API.HTCAPTION, 0);
            }
            else if (e.Clicks == 2 && 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 + 16)
                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 >> 16 & 0xFFFF);
                    vPoint = PointToClient(vPoint);
                    if (vPoint.X <= 10)
                        if (vPoint.Y <= 10)
                            m.Result = (IntPtr)Win32API.Guying_HTTOPLEFT;
                        else if (vPoint.Y >= ClientSize.Height - 10)
                            m.Result = (IntPtr)Win32API.Guying_HTBOTTOMLEFT;
                        else m.Result = (IntPtr)Win32API.Guying_HTLEFT;
                    else if (vPoint.X >= ClientSize.Width - 10)
                        if (vPoint.Y <= 10)
                            m.Result = (IntPtr)Win32API.Guying_HTTOPRIGHT;
                        else if (vPoint.Y >= ClientSize.Height - 10)
                            m.Result = (IntPtr)Win32API.Guying_HTBOTTOMRIGHT;
                        else m.Result = (IntPtr)Win32API.Guying_HTRIGHT;
                    else if (vPoint.Y <= 10)
                        m.Result = (IntPtr)Win32API.Guying_HTTOP;
                    else if (vPoint.Y >= ClientSize.Height - 10)
                        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(2);   //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(1);
                    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。