c#控件编写（2）重写一个TabControl

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在重写TabControl的时候我们最先想到的是设置

this.DrawMode = TabDrawMode.OwnerDrawFixed;

然后重写

protected override void OnDrawItem(DrawItemEventArgs e)
{
     base.OnDrawItem(e);
}

这样重写后只是重写选项卡上的区域，这个区域并不包括边框，这样我们所重写的和边框不搭调，也无法达到我们想要的功能。

而更好的方法是重写整个控件

设置控件由用户绘制

private void SetStyles()
        {
            base.SetStyle(
                ControlStyles.UserPaint |
                ControlStyles.OptimizedDoubleBuffer |
                ControlStyles.AllPaintingInWmPaint |
                ControlStyles.ResizeRedraw |
                ControlStyles.SupportsTransparentBackColor, true);
            base.UpdateStyles();
        }

关键的地方在 ControlStyles.UserPaint 设置为true

重写OnPaint

  protected override void OnPaint(PaintEventArgs pe)
        {
            base.OnPaint(pe);

            pe.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
            pe.Graphics.InterpolationMode = InterpolationMode.HighQualityBilinear;
           // pe.Graphics.TextRenderingHint = TextRenderingHint.AntiAlias;
            //绘制背景

            Rectangle rect = this.ClientRectangle; 
            pe.Graphics.FillRectangle(new TextureBrush(Properties.Resources.bg), rect); 

            //绘制边线 
            int height = this.ItemSize.Height+3;
            Rectangle r = new Rectangle(DisplayRectangle.X - 1, DisplayRectangle.Y - 1, DisplayRectangle.Width + 1, DisplayRectangle.Height + 1);

            // pe.Graphics.DrawLine(new Pen(Color.FromArgb(157, 162, 168)), new Point(rect.X, rect.Y + height), new Point(rect.Right, rect.Y + height));
            pe.Graphics.DrawRectangle(new Pen(_lineColor), r);
            //绘制边框  

            //绘制标头

            foreach (TabPage tp in this.TabPages)
            {
                DrawTabPage(pe.Graphics, this.GetTabRect(this.TabPages.IndexOf(tp)),tp);
            } 
        }

this.GetTabRect函数可以获取的标签的位置，这个为我们重绘标签提供了很好的帮助

重绘标签

  private void DrawTabPage(Graphics graphics, Rectangle rectangle, TabPage tp)
        {
            //绘制底纹  

            StringFormat sf = new StringFormat();
            
            sf.Trimming = StringTrimming.EllipsisCharacter;
            sf.FormatFlags = StringFormatFlags.NoWrap;
            Rectangle rect = new Rectangle (rectangle.X ,rectangle .Y +2,rectangle .Width ,rectangle .Height -2); //标准区域
            Rectangle fontRect = new Rectangle(rectangle.X + 5, rectangle.Y+5, rectangle.Width - 10, tp .Font .Height);//文字区域
           
            if (this.SelectedTab.Equals(tp))
            {
                rect = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width, rectangle.Height);
                fontRect = new Rectangle(rectangle.X + 5, rectangle.Y + 5, rectangle.Width - 25, rectangle.Height - 7);
           
                //绘制边框   
                graphics.FillPath(new LinearGradientBrush(new Point(rect.X, rect.Y), new Point(rect.X, rect.Y + rect.Height), _ColorActivateA, _ColorActivateB), CreateTabPath(rect)); //填充颜色
                graphics.DrawString(tp.Text, tp.Font, new SolidBrush(tp.ForeColor), fontRect, sf); //文字绘制
 
                graphics.DrawPath(new Pen(_lineColor), CreateTabPath(rect));//绘制实边线  

                //掩盖下部的绘制 
                graphics.DrawLine(new Pen(_ColorActivateB, 3), rect.X, rect.Bottom + 1, rect.X + rect.Width, rect.Bottom + 1);

                //绘制图片
                Rectangle rectClose = GetCloseRect(rectangle);
            }
            else
            {
                //绘制边框   
                graphics.FillPath(new LinearGradientBrush (new Point (rect .X,rect .Y ),new Point (rect .X,rect .Y +rect .Height ),_ColorDefaultA,_ColorDefaultB), CreateTabPath(rect)); //填充颜色
                graphics.DrawString(tp.Text, tp.Font, new SolidBrush(tp.ForeColor), fontRect, sf); //文字绘制
               // graphics.DrawPath(new Pen(Color.Wheat, 2), CreateTabPath(rect));//绘制高光边线
                graphics.DrawPath(new Pen(_lineColor), CreateTabPath(rect));//绘制实边线  
            }

绘制关闭标签按钮

我们给标签加上了一个鼠标移上去显示关闭按钮的功能重写OnMouseMove的功能

    bool CloseEX = false;
        protected override void OnMouseMove(MouseEventArgs e)
        {

            if (TabPageMouseClose(e.Location) != CloseEX)
            {
                CloseEX = !CloseEX;
                this.Invalidate();
            }
 
            base.OnMouseMove(e);
        }

在鼠标移动过快的时候，会导致关闭按钮没有刷新，所有我们要在鼠标离开控件的时候让CloseEx=False并重绘制。

好到这一步我们就完成我我们的绘制工作。我在绘制的时候使用了渐变画刷用了5个参数来标识每个指定的颜色

private Color _lineColor = Color.FromArgb(157, 162, 168); //边线颜色 
private Color _ColorDefaultA = Color.FromArgb(231, 231, 231);//默认标签渐变 a
private Color _ColorDefaultB = Color.FromArgb(255, 255, 255);//默认标签渐变 b
private Color _ColorActivateA = Color.FromArgb(184, 203, 217);//点击渐变a
private Color _ColorActivateB = Color.FromArgb(255, 255, 255);//点击渐变a