C#GDI+如何在WinForm上用鼠标来绘制图形？

[lq0922]

C#GDI+如何在WinForm上用鼠标来绘制图形？

[leixf2016]

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.IO;

using System.Threading;
using System.Drawing.Drawing2D;

namespace Test
{
    public partial class Form1 : Form
    {
        enum MouseState
        {
            None = 0,
            MouseLeftDown = 1,
            MouseRightDown = 2,
        }

        private MouseState _MouseState = MouseState.None;

        public Form1()
        {
            InitializeComponent();

            this.Load += new EventHandler(Form1_Load);
            this.MouseMove += new MouseEventHandler(Form1_MouseMove);
            this.MouseDown += new MouseEventHandler(Form1_MouseDown);
            this.MouseUp += new MouseEventHandler(Form1_MouseUp);
        }

        void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            _MouseState = MouseState.None;
            if (e.Button == System.Windows.Forms.MouseButtons.Right)
            {
                this.Refresh();
            }
        }

        void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == System.Windows.Forms.MouseButtons.Left)
            {
                _MouseState = MouseState.MouseLeftDown;
                return;
            }

            if (e.Button == System.Windows.Forms.MouseButtons.Right)
            {
                _MouseState = MouseState.MouseRightDown;
                return;
            }
        }

        void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (_MouseState == MouseState.None)
            {
                return;
            }

            if (_MouseState == MouseState.MouseLeftDown)
            {
                Console.WriteLine(e.X + ", " + e.Y);

                Graphics g = this.CreateGraphics();
                //g.DrawEllipse(new Pen(Color.Red, 2), new Rectangle(e.X - 1, e.Y - 1, 2, 2));
                g.DrawLine(new Pen(Color.Red, 2), new Point(e.X - 2, e.Y - 2), new Point(e.X, e.Y));
                g.Dispose();
                return;
            }
        }

        void Form1_Load(object sender, EventArgs e)
        {
            this.AutoScaleBaseSize = new Size(5, 13);
            this.ClientSize = new Size(800, 500);
        }
    }
}

实现功能：当鼠标按下左键并不松开的情况下，可以在工作区域画图，松开鼠标后停止画图，点击鼠标右键后，重新刷新界面。

BUG：当鼠标移动速度过快时，线条不连续，求解决！

[lq0922]

首先，感谢楼上的回帖！ 但是还有很多问题。

第一，我需要类似于word里面插入图形之后单击鼠标左键移动绘制指定图形
第二，绘制图形的时候鼠标单击左键移动会出现很多图形

[Trent1985]

用鼠标事件结合窗体的绘图事件就可以了!

[Trent1985]

这个是最简单的,你试一下:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication14
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void Form1_MouseMove(object sender, MouseEventArgs e)
{
Graphics g = this.CreateGraphics();
g.DrawEllipse(new Pen(Color.Red, 2), new Rectangle(e.X - 1, e.Y - 1, 2, 2));
g.Dispose();
}
}
}

[足球中国]

绘制的代码写到onpaint里就好了。