C# 多线程画图 示例源码

【实例截图】

【核心代码】

using System;
using System.ComponentModel;
using System.Drawing;
using System.Threading;
using System.Windows.Forms;

namespace drawRegionByThread
{
    public partial class Form1 : Form
    {

        Thread drawThread = null;

        ThreadState drawThreadState = ThreadState.Unstarted;

        int x, y, size = 4; bool sub = false;

        void pDrawFuntion()
        {
            while (true)
            {
                if (ThreadState.Stopped == drawThreadState) { break; }
                if (ThreadState.StopRequested == drawThreadState) { drawThreadState = ThreadState.Stopped; continue; }
                if (ThreadState.SuspendRequested == drawThreadState) { continue; }
                if (ThreadState.Suspended == drawThreadState) { drawThreadState = ThreadState.Suspended; continue; }
                if (ThreadState.Running == drawThreadState)
                {
                    lock (this)
                    {
                        UpdateUI();
                    }
                }
            }
        }

        void UpdateUI()
        {
            try
            {
                Invoke(new Action(() => { Refresh(); }));
            }
            catch
            {

            }
        }

        public Form1()
        {
            InitializeComponent();
        }

        protected override void OnMouseDown(MouseEventArgs e)
        {
            x = e.X; y = e.Y; size = 4;
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            x = e.X; y = e.Y;
            if (sub)
                sub = !(6 > size--);
            else
                sub = 88 < size  ;
        }

        protected void drawCircle(Graphics g, int x, int y, int size = 4)
        {
            g.DrawEllipse(new Pen(new SolidBrush(Color.Lime), 2), new RectangleF(x - size, y - size, size * 2, size * 2));
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            lock (e)
            {
                drawCircle(e.Graphics, x, y, size);
                if (4 == size)
                {
                    e.Graphics.DrawString("MouseDown", new Font("楷体", 16), new SolidBrush(Color.Red), new PointF(10, 30));
                }
                else
                {
                    e.Graphics.DrawString("MouseMove", new Font("楷体", 16), new SolidBrush(Color.Red), new PointF(10, 30));
                }
            }
        }

        protected override void OnShown(EventArgs e)
        {
            drawThread = new Thread(pDrawFuntion);
            drawThread.IsBackground = true;
            drawThreadState = ThreadState.Running;
            drawThread.Start();
        }

        protected override void OnClosing(CancelEventArgs e)
        {
            drawThreadState = ThreadState.StopRequested;
        }
    }
}