c# 實現(xiàn)圓形的進度條(ProgressBar)

更新時間：2021年03月02日 09:31:35 作者：Hello——尋夢者！

這篇文章主要介紹了c# 如何實現(xiàn)圓形的進度條(ProgressBar)，幫助大家更好的理解和學習使用c#，感興趣的朋友可以了解下

在我們實際的工作中可能經(jīng)常使用到圓形的進度條，但是這是怎么實現(xiàn)的呢？其實這只不過是修改了一下ProgressBar的模板，我們在下面的代碼中我們將ProgressBar的Value值綁定到Border的Background上面，并且使用了一個ValueToProcessConverter的轉換器進行相應地轉換，這里重點介紹一下這個轉換器

<ProgressBar Name="pb" Minimum="0" Maximum="100" >
  <ProgressBar.Template>
    <ControlTemplate TargetType="ProgressBar">
     <Border Background="{TemplateBinding Value, Converter={StaticResource ValueToProcessConverter}, ConverterParameter=250}"/>
    </ControlTemplate>
  </ProgressBar.Template>
</ProgressBar>

下面介紹這部分的源碼，并做簡要的分析：

首先，獲取ProgressBar.Value，然后再獲取ConverterParameter=250這個值，通過這兩個值就能確定畫的圓環(huán)的大小和ProgressBar顯示的值，然后我們再調用DrawBrush(arg, 100, radius, radius, Thickness)這個函數(shù)來進行繪制，具體代碼如下：

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;
        }

　　這里需要注意的是絕不能直接實例化 DrawingContext；但可以通過某些方法（例如 DrawingGroup.Open 和 DrawingVisual.RenderOpen）獲取繪圖上下文。我們這里是使用DrawingGroup.Open的方法來進行相應的繪圖，然后在里面調用里DrawingGeometry這個函數(shù)，在這個函數(shù)中開始繪制一些DrawEllipse和DrawGeometry，在這個函數(shù)中我們講解一下FormattedText 這個類，使用 FormattedText 對象可以繪制多行文本，且可以單獨對該文本中的每個字符設置格式。

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();
       }

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();
        }
 
        /// <summary>
        /// 根據(jù)角度獲取坐標
        /// </summary>
        /// <param name="CenterPoint"></param>
        /// <param name="r"></param>
        /// <param name="angel"></param>
        /// <returns></returns>
        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;
        }
 
        /// <summary>
        /// 根據(jù)4個坐標畫出扇形
        /// </summary>
        /// <param name="bigFirstPoint"></param>
        /// <param name="bigSecondPoint"></param>
        /// <param name="smallFirstPoint"></param>
        /// <param name="smallSecondPoint"></param>
        /// <param name="bigRadius"></param>
        /// <param name="smallRadius"></param>
        /// <param name="isLargeArc"></param>
        /// <returns></returns>
        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;
        }
 
        /// <summary>
        /// 根據(jù)當前值和最大值獲取扇形
        /// </summary>
        /// <param name="value"></param>
        /// <param name="maxValue"></param>
        /// <returns></returns>
        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);
        }
 
        /// <summary>
        /// 畫扇形
        /// </summary>
        /// <param name="drawingContext"></param>
        /// <param name="value"></param>
        /// <param name="maxValue"></param>
        /// <param name="radiusX"></param>
        /// <param name="radiusY"></param>
        /// <param name="thickness"></param>
        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();
        }
 
        /// <summary>
        /// 根據(jù)當前值和最大值畫出進度條
        /// </summary>
        /// <param name="value"></param>
        /// <param name="maxValue"></param>
        /// <returns></returns>
        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;
        }
 
    }

以上就是c# 實現(xiàn)圓形的進度條(ProgressBar)的詳細內容，更多關于c# 實現(xiàn)進度條的資料請關注腳本之家其它相關文章！

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