WPF在Canvas中绘图实现折线统计图

最近在WPF中做一个需要实现统计的功能，其中需要用到统计图，之前也没有接触过，度娘上大多都是各种收费或者免费的第三方控件，不想用第三方控件那就自己画一个吧。

在园子还找到一篇文章，思路来自这篇文章，文章链接：http://www.cnblogs.com/endlesscoding/p/6670432.html  

不过根据我的需求，数据每次都在变化，所以都只能从后台绑定，先来看一下完成后的效果吧

 

可以看到，数据源是一年内一到十二月的金额，所以X轴是固定的，而Y轴标尺是根据数据源的最大值向上取100。再来计算每个标尺该显示的数值。

数据点的显示，也是根据提供数据的比例，来计算出像素值的

 

从头开始吧，先来说xaml，xaml中需要一个Canvas控件，之后所有的图形就是画在这里面

不会用Canvas的话可以先学习下官方文档：https://msdn.microsoft.com/zh-cn/library/system.windows.controls.canvas(v=vs.110).aspx

 1 <Grid Height="400" Width="645"> 2                         <Grid.ColumnDefinitions> 3                             <ColumnDefinition Width="150" /> 4                             <ColumnDefinition Width="330"/> 5                             <ColumnDefinition Width="*"/> 6                         </Grid.ColumnDefinitions> 7                         <Grid.RowDefinitions> 8                             <RowDefinition Height="25" /> 9                             <RowDefinition />10                         </Grid.RowDefinitions>11                         <j:JLabel Label="企业账号：" Grid.Column="0" Grid.Row="0">12                             <TextBlock Text="{Binding Userid}" HorizontalAlignment="Left"  Foreground="Red"/>13                         </j:JLabel>14                         <j:JLabel Label="企业名称：" Grid.Column="1" Grid.Row="0">15                             <TextBlock Text="{Binding Username}" HorizontalAlignment="Left" Foreground="Red"/>16                         </j:JLabel>17                         <j:JLabel Label="总金额（元）：" Grid.Column="2" Grid.Row="0">18                             <TextBlock Text="{Binding Pay_Total}" HorizontalAlignment="Left" Foreground="Red"/>19                         </j:JLabel>20                         <Canvas x:Name="chartCanvas" Margin="5" Grid.Column="0" Grid.Row="1" Grid.ColumnSpan="4">21                         </Canvas>22                     </Grid>

先来画横纵坐标和箭头吧，x1,y1,x2,y2这四个参数是Line在Canvas中的起点终点位置像素值

同样，Line类官方文档：https://msdn.microsoft.com/zh-cn/library/system.windows.shapes.line(v=vs.110).aspx

 1         /// <summary> 2         /// 生成横纵坐标及箭头 3         /// </summary> 4         private void DrawArrow() 5         { 6             Line x_axis = new Line();//x轴 7             Line y_axis = new Line();//y轴 8             x_axis.Stroke = System.Windows.Media.Brushes.Black; 9             y_axis.Stroke = System.Windows.Media.Brushes.Black;10             x_axis.StrokeThickness = 3;11             y_axis.StrokeThickness = 3;12             x_axis.X1 = 40;13             x_axis.Y1 = 320;14             x_axis.X2 = 600;15             x_axis.Y2 = 320;16             y_axis.X1 = 40;17             y_axis.Y1 = 320;18             y_axis.X2 = 40;19             y_axis.Y2 = 30;20             this.chartCanvas.Children.Add(x_axis);21             this.chartCanvas.Children.Add(y_axis);22 23             Line y_scale1 = new Line(); //坐标原点直角24             y_scale1.Stroke = System.Windows.Media.Brushes.Black;25             y_scale1.StrokeThickness =1;26             y_scale1.X1 = 40;27             y_scale1.Y1 = 310;28             y_scale1.X2 = 44;29             y_scale1.Y2 = 310;30             y_scale1.StrokeStartLineCap = PenLineCap.Triangle;31             this.chartCanvas.Children.Add(y_scale1);32 33             Path x_axisArrow = new Path();//x轴箭头34             Path y_axisArrow = new Path();//y轴箭头35             x_axisArrow.Fill = new SolidColorBrush(Color.FromRgb(0, 0, 0));36             y_axisArrow.Fill = new SolidColorBrush(Color.FromRgb(0, 0, 0));37             PathFigure x_axisFigure = new PathFigure();38             x_axisFigure.IsClosed = true;39             x_axisFigure.StartPoint = new Point(600, 316);                          //路径的起点40             x_axisFigure.Segments.Add(new LineSegment(new Point(600, 324), false)); //第2个点41             x_axisFigure.Segments.Add(new LineSegment(new Point(610, 320), false)); //第3个点42             PathFigure y_axisFigure = new PathFigure();43             y_axisFigure.IsClosed = true;44             y_axisFigure.StartPoint = new Point(36, 30);                          //路径的起点45             y_axisFigure.Segments.Add(new LineSegment(new Point(44, 30), false)); //第2个点46             y_axisFigure.Segments.Add(new LineSegment(new Point(40, 20), false)); //第3个点47             PathGeometry x_axisGeometry = new PathGeometry();48             PathGeometry y_axisGeometry = new PathGeometry();49             x_axisGeometry.Figures.Add(x_axisFigure);50             y_axisGeometry.Figures.Add(y_axisFigure);51             x_axisArrow.Data = x_axisGeometry;52             y_axisArrow.Data = y_axisGeometry;53             this.chartCanvas.Children.Add(x_axisArrow);54             this.chartCanvas.Children.Add(y_axisArrow);55 56             TextBlock x_label =new TextBlock();57             TextBlock y_label =new TextBlock();58             TextBlock o_label =new TextBlock();59             x_label.Text = "月";60             y_label.Text = "元";61             o_label.Text = "0";62             Canvas.SetLeft(x_label, 610);63             Canvas.SetLeft(y_label, 20);64             Canvas.SetLeft(o_label, 20);65             Canvas.SetTop(x_label, 317);66             Canvas.SetTop(y_label, 4);67             Canvas.SetTop(o_label, 312);68             x_label.FontSize = 14;69             y_label.FontSize = 14;70             o_label.FontSize = 14; 71             this.chartCanvas.Children.Add(x_label);72             this.chartCanvas.Children.Add(y_label);73             this.chartCanvas.Children.Add(o_label);74 75         }

标尺，X轴以45为间隔单位，Y轴以10px为单位，且没5格显示一个大标尺

 1         /// <summary> 2         /// 作出x轴和y轴的标尺 3         /// </summary> 4         private void DrawScale() 5         { 6             for (int i = 1; i < 13; i++)//作12个刻度 7             { 8                 //原点 O=(40,320) 9                 Line x_scale = new Line(); //主x轴标尺10                 x_scale.StrokeEndLineCap = PenLineCap.Triangle;11                 x_scale.StrokeThickness = 1;12                 x_scale.Stroke = new SolidColorBrush(Color.FromRgb(0, 0, 0));13                 x_scale.X1 = 40 + i * 45;   14                 x_scale.X2 = x_scale.X1;  15                 x_scale.Y1 = 320;           16                 x_scale.StrokeThickness = 3;17                 x_scale.Y2 = x_scale.Y1 - 8;18                 this.chartCanvas.Children.Add(x_scale);19 20                 Line x_in = new Line();//x轴轴辅助标尺21                 x_in.Stroke = System.Windows.Media.Brushes.LightGray;22                 x_in.StrokeThickness = 0.5;23                 x_in.X1 = 40 + i * 45;24                 x_in.Y1 = 320;25                 x_in.X2 = 40 + i * 45;26                 x_in.Y2 = 30;27                 this.chartCanvas.Children.Add(x_in);28             }29             for (int j = 0; j < 30; j++ )30             {31                 Line y_scale = new Line(); //主Y轴标尺32                 y_scale.StrokeEndLineCap = PenLineCap.Triangle;33                 y_scale.StrokeThickness = 1;34                 y_scale.Stroke = new SolidColorBrush(Color.FromRgb(0, 0, 0));35 36                 y_scale.X1 = 40;            //原点x=4037                 if (j % 5 == 0)38                 {39                     y_scale.StrokeThickness = 3;40                     y_scale.X2 = y_scale.X1 + 8;//大刻度线41                 }42                 else43                 {44                     y_scale.X2 = y_scale.X1 + 4;//小刻度线45                 }46 47                 y_scale.Y1 = 320 - j * 10;  //每10px作一个刻度 48                 y_scale.Y2 = y_scale.Y1;    49                 this.chartCanvas.Children.Add(y_scale);50             }51             for (int i = 1; i < 6; i++)52             {53                 Line y_in = new Line();//y轴辅助标尺54                 y_in.Stroke = System.Windows.Media.Brushes.LightGray;55                 y_in.StrokeThickness = 0.5;56                 y_in.X1 = 40;57                 y_in.Y1 = 320 - i * 50;58                 y_in.X2 = 600;59                 y_in.Y2 = 320 - i * 50;60                 this.chartCanvas.Children.Add(y_in);61             }62 63         }

刻度标签的话，X轴是固定的，并且其中用到了一个把阿拉伯数字转换为中文的方法 NumberToChinese()，

Y轴标尺标签，是用出入的 list<double>,计算出最大值再向上取100整，再分成五份，每份的值就是五个标签了

list最大值向上取100的方法：（除100向上取整再乘100）

Math.Ceiling(list.Max() / 100) * 100

 1         /// <summary> 2         /// 添加刻度标签 3         /// </summary> 4         private void DrawScaleLabel(List<double> list) 5         { 6             for (int i = 1; i < 13; i++) 7             { 8                 TextBlock x_ScaleLabel = new TextBlock(); 9                 x_ScaleLabel.Text = NumberToChinese(i.ToString());10                 if (x_ScaleLabel.Text == "一零")11                 {12                     x_ScaleLabel.Text = "十";13                     Canvas.SetLeft(x_ScaleLabel, 40 + 45 * i - 6);14                 }15                 else if (x_ScaleLabel.Text == "一一")16                 {17                     x_ScaleLabel.Text = "十一";18                     Canvas.SetLeft(x_ScaleLabel, 40 + 45 * i - 10);19                 }20 21                 else if (x_ScaleLabel.Text == "一二")22                 {23                     x_ScaleLabel.Text = "十二";24                     Canvas.SetLeft(x_ScaleLabel, 40 + 45 * i - 10);25                 }26                 else27                 {28                     Canvas.SetLeft(x_ScaleLabel, 40 + 45 * i - 6);29                 }30                 Canvas.SetTop(x_ScaleLabel, 320 + 2);31                 this.chartCanvas.Children.Add(x_ScaleLabel);32             }33 34             for (int i = 1; i < 6; i++)35             {36                 TextBlock y_ScaleLabel = new TextBlock();37                 double max = Math.Ceiling(list.Max() / 100) * 100;38                 y_ScaleLabel.Text = (i * (max/5)).ToString();39                 Canvas.SetLeft(y_ScaleLabel, 40 - 30);              40                 Canvas.SetTop(y_ScaleLabel, 320 - 5 * 10 * i - 6);  41 42                 this.chartCanvas.Children.Add(y_ScaleLabel);43             }44         }45 46         /// <summary>47         /// 数字转汉字48         /// </summary>49         /// <param name="numberStr"></param>50         /// <returns></returns>51         public static string NumberToChinese(string numberStr)52         {53             string numStr = "0123456789";54             string chineseStr = "零一二三四五六七八九";55             char[] c = numberStr.ToCharArray();56             for (int i = 0; i < c.Length; i++)57             {58                 int index = numStr.IndexOf(c[i]);59                 if (index != -1)60                     c[i] = chineseStr.ToCharArray()[index];61             }62             numStr = null;63             chineseStr = null;64             return new string(c);65         } 

 

接下来就是计算数据点了，难点在于计算像素点，X轴是固定的，所以不用关注

直接算好的X轴十二个数值

double[] left = { 85, 130, 175, 220, 265, 310, 355, 400, 445, 490, 535, 580 };

而Y轴就要自己算了，提供一个思路：

区域总像素 - 区域总像素 * （数值/最大值）

 1         /// <summary> 2         /// 计算数据点并添加 3         /// </summary> 4         /// <param name="list"></param> 5         private void DrawPoint(List<double> list) 6         { 7             double[] left = { 85, 130, 175, 220, 265, 310, 355, 400, 445, 490, 535, 580 }; 8             List<double> leftlist = new List<double>(); 9             leftlist.AddRange(left);10 11             for (int i = 1; i < 13; i++)12             { 13                 Ellipse Ellipse = new Ellipse();14                 Ellipse .Fill = new SolidColorBrush(Color.FromRgb(0, 0, 0xff));15                 Ellipse .Width = 8;16                 Ellipse .Height = 8;17                 Canvas.SetLeft(Ellipse,leftlist[i-1]- 4);18                 double y_Max = Math.Ceiling(list.Max() / 100) * 100;19                 Canvas.SetTop(Ellipse, 320 - 250 * (list[i-1] / y_Max) - 4); 20                 coordinatePoints.Add(new Point(leftlist[i-1], 320 - 250 * (list[i-1] / y_Max)));21                 this.chartCanvas.Children.Add(Ellipse);22                 //值显示23                 TextBlock EP_Label = new TextBlock();24                 EP_Label.Foreground = System.Windows.Media.Brushes.Red;25                 EP_Label.Text = list[i-1].ToString();26                 Canvas.SetLeft(EP_Label, leftlist[i-1] - 10);27                 Canvas.SetTop(EP_Label, 320 - 250 * (list[i-1] / y_Max) - 20);28                 this.chartCanvas.Children.Add(EP_Label);29             }30         }

在绘制数据点的时候，每一次的位置都保存了：  coordinatePoints.Add(new Point(leftlist[i-1], 320 - 250 * (list[i-1] / y_Max)));

先得定义：

/// <summary>        /// 折线图坐标点        /// </summary>        private PointCollection coordinatePoints = new PointCollection();

最后直接连连看就好了

 1         /// <summary> 2         /// 绘制连接折线 3         /// </summary> 4         private void DrawCurve() 5         { 6             Polyline curvePolyline = new Polyline(); 7  8             curvePolyline.Stroke = Brushes.Green; 9             curvePolyline.StrokeThickness = 2;10 11             curvePolyline.Points = coordinatePoints;12             this.chartCanvas.Children.Add(curvePolyline);13         }

 

由于我项目的关系，数据是从DataGrid控件行数据来的，所以每一次都不一样，只能在弹出窗体时调用这几个方法

由于每一都不一样，在窗口关闭时需要清空画布内的所有控件，否则画布内控件会一直覆盖

chartCanvas.Children.Clear();coordinatePoints.Clear();

 

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