c# 实现圆形的进度条(ProgressBar)

　　public class ValueToProcessConverter : IValueConverter

　　{

　　readonly double Thickness = 20;

　　private Point centerPoint;

　　private double radius;

　　readonly SolidColorBrush NormalBrush = new SolidColorBrush(Colors.White);

　　readonly SolidColorBrush EllipseBrush = new SolidColorBrush(Color.FromRgb(107, 132, 165));

　　string percentString;

　　private static readonly Typeface SuccessRateTypeface;

　　private const int SuccessRateFontSize = 65;

　　readonly double SuccessRateFontCorrectionValue = 12;

　　static ValueToProcessConverter()

　　{

　　SuccessRateTypeface = new Typeface(new FontFamily("MSYH"), new FontStyle(), new FontWeight(), new FontStretch());

　　}

　　public ValueToProcessConverter()

　　{

　　}

　　public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)

　　{

　　if (value is double && !string.IsNullOrEmpty((string)parameter))

　　{

　　double arg = (double)value;

　　double width = double.Parse((string)parameter);

　　radius = width / 2;

　　centerPoint = new Point(radius, radius);

　　return DrawBrush(arg, 100, radius, radius, Thickness);

　　}

　　else

　　{

　　throw new ArgumentException();

　　}

　　}

　　public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)

　　{

　　throw new NotImplementedException();

　　}

　　///

　　/// 根据角度获取坐标

　　///

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　　///

　　private Point GetPointByAngel(Point CenterPoint, double r, double angel)

　　{

　　Point p = new Point();

　　p.X = Math.Sin(angel * Math.PI / 180) * r + CenterPoint.X;

　　p.Y = CenterPoint.Y - Math.Cos(angel * Math.PI / 180) * r;

　　return p;

　　}

　　///

　　/// 根据4个坐标画出扇形

　　///

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　　private Geometry DrawingArcGeometry(Point bigFirstPoint, Point bigSecondPoint, Point smallFirstPoint, Point smallSecondPoint, double bigRadius, double smallRadius, bool isLargeArc)

　　{

　　PathFigure pathFigure = new PathFigure { IsClosed = true };

　　pathFigure.StartPoint = bigFirstPoint;

　　pathFigure.Segments.Add(

　　new ArcSegment

　　{

　　Point = bigSecondPoint,

　　IsLargeArc = isLargeArc,

　　Size = new Size(bigRadius, bigRadius),

　　SweepDirection = SweepDirection.Clockwise

　　});

　　pathFigure.Segments.Add(new LineSegment { Point = smallSecondPoint });

　　pathFigure.Segments.Add(

　　new ArcSegment

　　{

　　Point = smallFirstPoint,

　　IsLargeArc = isLargeArc,

　　Size = new Size(smallRadius, smallRadius),

　　SweepDirection = SweepDirection.Counterclockwise

　　});

　　PathGeometry pathGeometry = new PathGeometry();

　　pathGeometry.Figures.Add(pathFigure);

　　return pathGeometry;

　　}

　　///

　　/// 根据当前值和最大值获取扇形

　　///

　　///

　　///

　　///

　　private Geometry GetGeometry(double value, double maxValue, double radiusX, double radiusY, double thickness)

　　{

　　bool isLargeArc = false;

　　double percent = value / maxValue;

　　percentString = string.Format("{0}%", Math.Round(percent * 100, 2));

　　double angel = percent * 360D;

　　if (angel > 180) isLargeArc = true;

　　double bigR = radiusX + thickness / 2;

　　double smallR = radiusX - thickness / 2;

　　Point firstpoint = GetPointByAngel(centerPoint, bigR, 0);

　　Point secondpoint = GetPointByAngel(centerPoint, bigR, angel);

　　Point thirdpoint = GetPointByAngel(centerPoint, smallR, 0);

　　Point fourpoint = GetPointByAngel(centerPoint, smallR, angel);

　　return DrawingArcGeometry(firstpoint, secondpoint, thirdpoint, fourpoint, bigR, smallR, isLargeArc);

　　}

　　///

　　/// 画扇形

　　///

　　///

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　　private void DrawingGeometry(DrawingContext drawingContext, double value, double maxValue, double radiusX, double radiusY, double thickness)

　　{

　　drawingContext.DrawEllipse(null, new Pen(EllipseBrush, thickness), centerPoint, radiusX, radiusY);

　　drawingContext.DrawGeometry(NormalBrush, new Pen(), GetGeometry(value, maxValue, radiusX, radiusY, thickness));

　　FormattedText formatWords = new FormattedText(percentString, CultureInfo.CurrentCulture, FlowDirection.LeftToRight, SuccessRateTypeface, SuccessRateFontSize, NormalBrush);

　　Point startPoint = new Point(centerPoint.X - formatWords.Width / 2, centerPoint.Y - formatWords.Height / 2 - SuccessRateFontCorrectionValue);

　　drawingContext.DrawText(formatWords, startPoint);

　　drawingContext.Close();

　　}

　　///

　　/// 根据当前值和最大值画出进度条

　　///

　　///

　　///

　　///

　　private Brush DrawBrush(double value, double maxValue, double radiusX, double radiusY, double thickness)

　　{

　　DrawingGroup drawingGroup = new DrawingGroup();

　　DrawingContext drawingContext = drawingGroup.Open();

　　DrawingGeometry(drawingContext, value, maxValue, radiusX, radiusY, thickness);

　　DrawingBrush brush = new DrawingBrush(drawingGroup);

　　return brush;

　　}

　　}