C# Winform画线

在Winform中实现的效果如下：

 

WPF画线参考：C# WPF画线 - 十年新 - 博客园 (cnblogs.com)

代码请参考：

using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace DrawLineDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public Point PointStart, PointEnd;//定义连线之间的两点，PointStart：起始点；PointEnd：结束点；
        public int Flag = 0;

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            Flag = 0;
        }

        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            Text = "Location：X=" + e.X.ToString() + ",Y=" + e.Y.ToString();
            if (Flag == 0)
                return;
            Pen pen = new Pen(Color.Gray, 1);//灰色画笔，宽度为1
            pen.DashStyle = DashStyle.Custom;
            pen.DashPattern = new float[] { 9f, 1f };//虚线：实体和空白的比例
            pen.StartCap = LineCap.RoundAnchor;//圆点开始
            pen.EndCap = LineCap.ArrowAnchor;//结束为箭头
            Graphics g = CreateGraphics();
            //指定画图的呈现质量
            g.SmoothingMode = SmoothingMode.HighQuality;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.CompositingQuality = CompositingQuality.HighQuality;
            PointEnd.X = e.X;
            PointEnd.Y = e.Y;
            g.Clear(BackColor);//清除之前的画线
            g.DrawLine(pen, PointStart.X, PointStart.Y, PointEnd.X, PointEnd.Y);//画线
        }

        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            Flag = 1;
            PointStart.X = e.X;
            PointStart.Y = e.Y;
        }
    }
}