Question

我在Windows窗体上的控件上画了一条线，如下所示：

            // Get Graphics object from chart
            Graphics graph = e.ChartGraphics.Graphics;

            PointF point1 = PointF.Empty;
            PointF point2 = PointF.Empty;

            // Set Maximum and minimum points
            point1.X = -110;
            point1.Y = -110;
            point2.X = 122;
            point2.Y = 122;

            // Convert relative coordinates to absolute coordinates.
            point1 = e.ChartGraphics.GetAbsolutePoint(point1);
            point2 = e.ChartGraphics.GetAbsolutePoint(point2);

            // Draw connection line
            graph.DrawLine(new Pen(Color.Yellow, 3), point1, point2);

我想知道是否可以画一条虚线而不是一条规则的实线？

Answer 1

一旦你找出定义短划线的格式：

float[] dashValues = { 5, 2, 15, 4 };
Pen blackPen = new Pen(Color.Black, 5);
blackPen.DashPattern = dashValues;
e.Graphics.DrawLine(blackPen, new Point(5, 5), new Point(405, 5));

浮点数组中的数字表示不同颜色的短划线长度。因此，对于一个简单的2个像素的破折号（黑色）和两个像素的每一个，你的aray看起来像：{2,2}然后重复模式。如果您想要5宽的2像素的破折号，您可以使用｛5,2｝

在您的代码中，它看起来像：

// Get Graphics object from chart
Graphics graph = e.ChartGraphics.Graphics;

PointF point1 = PointF.Empty;
PointF point2 = PointF.Empty;

// Set Maximum and minimum points
point1.X = -110;
point1.Y = -110;
point2.X = 122;
point2.Y = 122;

// Convert relative coordinates to absolute coordinates.
point1 = e.ChartGraphics.GetAbsolutePoint(point1);
point2 = e.ChartGraphics.GetAbsolutePoint(point2);

// Draw (dashed) connection line
float[] dashValues = { 4, 2 };
Pen dashPen= new Pen(Color.Yellow, 3);
dashPen.DashPattern = dashValues;
graph.DrawLine(dashPen, point1, point2);

Answer 2

I think you can accomplish this by changing the pen you use to draw your line. So, replace the last 2 lines in your example with:

        var pen = new Pen(Color.Yellow, 3);
        pen.DashStyle = DashStyle.Dash;
        graph.DrawLine(pen, point1, point2);

Answer 3

Pen的公共属性定义为

public DashStyle DashStyle { get; set; }

如果要绘制虚线，可以设置DasStyle.Dash。

Answer 4

笔DashPattern将执行此操作。在此处查找示例

Answer 5

在更现代的C#中：

var dottedPen = new Pen(Color.Gray, width: 1) { DashPattern = new[] { 1f, 1f } };

Answer 6

要回答有关使用后面的代码生成虚线的问题，请执行以下操作：

        Pen dashPenTest = new(Brushes.DodgerBlue, 1);

        Line testLine = new()
        {
            Stroke = dashPenTest.Brush, //Brushes.Aqua,
            StrokeThickness = dashPenTest.Thickness,//1,
            StrokeDashArray = new DoubleCollection() { 8,4 },
            X1 = 0,
            X2 = canvas.Width,
            Y1 = 10,
            Y2 = 10
        }; 
        canvas.Children.Add(testLine);

这个答案利用了xaml中画布的生成：

        <Canvas x:Name ="canvas" Background="White" Height="300" Width="300">

这里的重要方法是“StrokeDashArray”，它为绘制的线生成破折号。此处提供了更多信息：形状.StrokeDashArray

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