C# Winform畫線

在Winform中實現的效果如下：

 

代碼請參考：

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;//定義連線之間的兩點，PointStart：起始點；PointEnd：結束點；
        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);//灰色畫筆，寬度為1
            pen.DashStyle = DashStyle.Custom;
            pen.DashPattern = new float[] { 9f, 1f };//虛線：實體和空白的比例
            pen.StartCap = LineCap.RoundAnchor;//圓點開始
            pen.EndCap = LineCap.ArrowAnchor;//結束為箭頭
            Graphics g = CreateGraphics();
            //指定畫圖的呈現質量
            g.SmoothingMode = SmoothingMode.HighQuality;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.CompositingQuality = CompositingQuality.HighQuality;
            PointEnd.X = e.X;
            PointEnd.Y = e.Y;
            g.Clear(BackColor);//清除之前的畫線
            g.DrawLine(pen, PointStart.X, PointStart.Y, PointEnd.X, PointEnd.Y);//畫線
        }

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