重写Checkbox 改写选择框的大小

    /* 作者：Starts_2000* 日期：2009-07-30* 网站：http://www.csharpwin.com CS 程序员之窗。* 你可以免费使用或修改以下代码，但请保留版权信息。* 具体请查看 CS程序员之窗开源协议（http://www.csharpwin.com/csol.html）。*/[ToolboxBitmap(typeof(CheckBox))]public class CheckBoxEx : CheckBox{private Color _baseColor = Color.FromArgb(51, 161, 224);private ControlState _controlState;private static readonly ContentAlignment RightAlignment =ContentAlignment.TopRight |ContentAlignment.BottomRight |ContentAlignment.MiddleRight;private static readonly ContentAlignment LeftAligbment =ContentAlignment.TopLeft |ContentAlignment.BottomLeft |ContentAlignment.MiddleLeft;public CheckBoxEx(): base(){SetStyle(ControlStyles.UserPaint |ControlStyles.AllPaintingInWmPaint |ControlStyles.OptimizedDoubleBuffer |ControlStyles.ResizeRedraw |ControlStyles.SupportsTransparentBackColor, true);}public Color BaseColor{get { return _baseColor; }set{_baseColor = value;base.Invalidate();}}protected virtual int DefaultCheckButtonWidth{get { return 30; }}internal ControlState ControlState{get { return _controlState; }set{if (_controlState != value){_controlState = value;base.Invalidate();}}}protected override void OnMouseEnter(EventArgs e){base.OnMouseEnter(e);ControlState = ControlState.Hover;}protected override void OnMouseLeave(EventArgs e){base.OnMouseLeave(e);ControlState = ControlState.Normal;}protected override void OnMouseDown(MouseEventArgs e){base.OnMouseDown(e);if (e.Button == MouseButtons.Left && e.Clicks == 1){ControlState = ControlState.Pressed;}}protected override void OnMouseUp(MouseEventArgs e){base.OnMouseUp(e);if (e.Button == MouseButtons.Left && e.Clicks == 1){if (ClientRectangle.Contains(e.Location)){ControlState = ControlState.Hover;}else{ControlState = ControlState.Normal;}}}protected override void OnPaint(PaintEventArgs e){base.OnPaint(e);base.OnPaintBackground(e);Graphics g = e.Graphics;Rectangle checkButtonRect;Rectangle textRect;CalculateRect(out checkButtonRect, out textRect);g.SmoothingMode = SmoothingMode.AntiAlias;Color backColor = ControlPaint.Light(_baseColor);Color borderColor;Color innerBorderColor;Color checkColor;bool hover = false;if (Enabled){switch (ControlState){case ControlState.Hover:borderColor = _baseColor;innerBorderColor = _baseColor;checkColor = GetColor(_baseColor, 0, 35, 24, 9);hover = true;break;case ControlState.Pressed:borderColor = _baseColor;innerBorderColor = GetColor(_baseColor, 0, -13, -8, -3);checkColor = GetColor(_baseColor, 0, -35, -24, -9);hover = true;break;default:borderColor = _baseColor;innerBorderColor = Color.Empty;checkColor = _baseColor;break;}}else{borderColor = SystemColors.ControlDark;innerBorderColor = SystemColors.ControlDark;checkColor = SystemColors.ControlDark;}using (SolidBrush brush = new SolidBrush(Color.White)){g.FillRectangle(brush, checkButtonRect);}if (hover){using (Pen pen = new Pen(innerBorderColor, 2F)){g.DrawRectangle(pen, checkButtonRect);}}switch (CheckState){case CheckState.Checked:DrawCheckedFlag(g,checkButtonRect,checkColor);break;case CheckState.Indeterminate:checkButtonRect.Inflate(-1, -1);using (GraphicsPath path = new GraphicsPath()){path.AddEllipse(checkButtonRect);using (PathGradientBrush brush = new PathGradientBrush(path)){brush.CenterColor = checkColor;brush.SurroundColors = new Color[] { Color.White };Blend blend = new Blend();blend.Positions = new float[] { 0f, 0.4f, 1f };blend.Factors = new float[] { 0f, 0.3f, 1f };brush.Blend = blend;g.FillEllipse(brush, checkButtonRect);}}checkButtonRect.Inflate(1, 1);break;}using (Pen pen = new Pen(borderColor)){g.DrawRectangle(pen, checkButtonRect);}Color textColor = Enabled ? ForeColor : SystemColors.GrayText;TextRenderer.DrawText(g,Text,Font,textRect,textColor,GetTextFormatFlags(TextAlign, RightToLeft == RightToLeft.Yes));}private void CalculateRect(out Rectangle checkButtonRect, out Rectangle textRect){checkButtonRect = new Rectangle(0, 0, DefaultCheckButtonWidth, DefaultCheckButtonWidth);textRect = Rectangle.Empty;bool bCheckAlignLeft = (int)(LeftAligbment & CheckAlign) != 0;bool bCheckAlignRight = (int)(RightAlignment & CheckAlign) != 0;bool bRightToLeft = RightToLeft == RightToLeft.Yes;if ((bCheckAlignLeft && !bRightToLeft) ||(bCheckAlignRight && bRightToLeft)){switch (CheckAlign){case ContentAlignment.TopRight:case ContentAlignment.TopLeft:checkButtonRect.Y = 2;break;case ContentAlignment.MiddleRight:case ContentAlignment.MiddleLeft:checkButtonRect.Y = (Height - DefaultCheckButtonWidth) / 2;break;case ContentAlignment.BottomRight:case ContentAlignment.BottomLeft:checkButtonRect.Y = Height - DefaultCheckButtonWidth - 2;break;}checkButtonRect.X = 1;textRect = new Rectangle(checkButtonRect.Right + 2,0,Width - checkButtonRect.Right - 4,Height);}else if ((bCheckAlignRight && !bRightToLeft)|| (bCheckAlignLeft && bRightToLeft)){switch (CheckAlign){case ContentAlignment.TopLeft:case ContentAlignment.TopRight:checkButtonRect.Y = 2;break;case ContentAlignment.MiddleLeft:case ContentAlignment.MiddleRight:checkButtonRect.Y = (Height - DefaultCheckButtonWidth) / 2;break;case ContentAlignment.BottomLeft:case ContentAlignment.BottomRight:checkButtonRect.Y = Height - DefaultCheckButtonWidth - 2;break;}checkButtonRect.X = Width - DefaultCheckButtonWidth - 1;textRect = new Rectangle(2, 0, Width - DefaultCheckButtonWidth - 6, Height);}else{switch (CheckAlign){case ContentAlignment.TopCenter:checkButtonRect.Y = 2;textRect.Y = checkButtonRect.Bottom + 2;textRect.Height = Height - DefaultCheckButtonWidth - 6;break;case ContentAlignment.MiddleCenter:checkButtonRect.Y = (Height - DefaultCheckButtonWidth) / 2;textRect.Y = 0;textRect.Height = Height;break;case ContentAlignment.BottomCenter:checkButtonRect.Y = Height - DefaultCheckButtonWidth - 2;textRect.Y = 0;textRect.Height = Height - DefaultCheckButtonWidth - 6;break;}checkButtonRect.X = (Width - DefaultCheckButtonWidth) / 2;textRect.X = 2;textRect.Width = Width - 4;}}private void DrawCheckedFlag(Graphics graphics, Rectangle rect, Color color){PointF[] points = new PointF[3];points[0] = new PointF(rect.X + rect.Width / 4.5f,rect.Y + rect.Height / 2.5f);points[1] = new PointF(rect.X + rect.Width / 2.5f,rect.Bottom - rect.Height / 3f);points[2] = new PointF(rect.Right - rect.Width / 4.0f,rect.Y + rect.Height / 4.5f);using (Pen pen = new Pen(color, 2F)){graphics.DrawLines(pen, points);}}private Color GetColor(Color colorBase, int a, int r, int g, int b){int a0 = colorBase.A;int r0 = colorBase.R;int g0 = colorBase.G;int b0 = colorBase.B;if (a + a0 > 255) { a = 255; } else { a = Math.Max(a + a0, 0); }if (r + r0 > 255) { r = 255; } else { r = Math.Max(r + r0, 0); }if (g + g0 > 255) { g = 255; } else { g = Math.Max(g + g0, 0); }if (b + b0 > 255) { b = 255; } else { b = Math.Max(b + b0, 0); }return Color.FromArgb(a, r, g, b);}internal static TextFormatFlags GetTextFormatFlags(ContentAlignment alignment,bool rightToleft){TextFormatFlags flags = TextFormatFlags.WordBreak |TextFormatFlags.SingleLine;if (rightToleft){flags |= TextFormatFlags.RightToLeft | TextFormatFlags.Right;}switch (alignment){case ContentAlignment.BottomCenter:flags |= TextFormatFlags.Bottom | TextFormatFlags.HorizontalCenter;break;case ContentAlignment.BottomLeft:flags |= TextFormatFlags.Bottom | TextFormatFlags.Left;break;case ContentAlignment.BottomRight:flags |= TextFormatFlags.Bottom | TextFormatFlags.Right;break;case ContentAlignment.MiddleCenter:flags |= TextFormatFlags.HorizontalCenter |TextFormatFlags.VerticalCenter;break;case ContentAlignment.MiddleLeft:flags |= TextFormatFlags.VerticalCenter | TextFormatFlags.Left;break;case ContentAlignment.MiddleRight:flags |= TextFormatFlags.VerticalCenter | TextFormatFlags.Right;break;case ContentAlignment.TopCenter:flags |= TextFormatFlags.Top | TextFormatFlags.HorizontalCenter;break;case ContentAlignment.TopLeft:flags |= TextFormatFlags.Top | TextFormatFlags.Left;break;case ContentAlignment.TopRight:flags |= TextFormatFlags.Top | TextFormatFlags.Right;break;}return flags;}}/// <summary>/// 控件的状态。/// </summary>internal enum ControlState{/// <summary>///  正常。/// </summary>
        Normal,/// <summary>/// 鼠标进入。/// </summary>
        Hover,/// <summary>/// 鼠标按下。/// </summary>
        Pressed,/// <summary>/// 获得焦点。/// </summary>
        Focused,}