C# GDI在控件上绘图

本文以以在chart控件上和窗体上画矩形为例子

不多解释了，代码很简单。

还有一些童鞋要别的源码，给我发邮箱吧

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.IO;

using System.Configuration;

namespace WFApp2

{

    public partial class data : Form

    {

        public data()

        {

            InitializeComponent();

            //窗体

            g = this.CreateGraphics();

            //chart控件

            g2 = this.chart1.CreateGraphics();

        }

        public Point firstPoint = new Point(, );  //鼠标第一点

        public Point secondPoint = new Point(, );  //鼠标第二点

        public bool begin = false;   //是否开始画矩形

        /// <summary>

        /// 在from上画矩形

        /// </summary>

        Graphics g;

        /// <summary>

        /// 在chart1控件上画矩形

        /// </summary>

        Graphics g2;

        /// <summary>

        /// 在窗体上按下鼠标事件

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void data_MouseDown(object sender, MouseEventArgs e)

        {

            begin = true;

            firstPoint = new Point(e.X, e.Y);

        }

        /// <summary>

        /// 在窗体上鼠标移动开始绘图

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void data_MouseMove(object sender, MouseEventArgs e)

        {

            if (begin)

            {

                //清除窗体绘图面,相当于刷新了一次窗体界面然后重新绘制

                g.Clear(this.BackColor);

                //获取新的右下角坐标

                secondPoint = new Point(e.X, e.Y);

                //获取两个数中的大者或小者

                int minX = Math.Min(firstPoint.X, secondPoint.X);

                int minY = Math.Min(firstPoint.Y, secondPoint.Y);

                int maxX = Math.Max(firstPoint.X, secondPoint.X);

                int maxY = Math.Max(firstPoint.Y, secondPoint.Y);

                //画框

                g.DrawRectangle(new Pen(Color.Red), minX, minY, maxX - minX, maxY - minY);

                //ControlPaint.DrawReversibleFrame(new Rectangle(minX, minY, maxX - minX, maxY - minY),this.BackColor,FrameStyle.Dashed);

            }

        }

        /// <summary>

        /// 鼠标松开停止绘图

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void data_MouseUp(object sender, MouseEventArgs e)

        {

            begin = false;

        }

        /// <summary>

        /// 在chart控件上移动鼠标绘图

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void chart1_MouseMove(object sender, MouseEventArgs e)

        {

            if (begin)

            {

                //重新在chart上面绘图，此处不能用clear方法，clear会清除整个绘图界面chart控件会被清除

                this.Refresh();

                //获取新的右下角坐标

                secondPoint = new Point(e.X, e.Y);

                int minX = Math.Min(firstPoint.X, secondPoint.X);

                int minY = Math.Min(firstPoint.Y, secondPoint.Y);

                int maxX = Math.Max(firstPoint.X, secondPoint.X);

                int maxY = Math.Max(firstPoint.Y, secondPoint.Y);

                //画矩形

                g2.DrawRectangle(new Pen(Color.Red), minX, minY, maxX - minX, maxY - minY);

            }

        }

        /// <summary>

        /// 鼠标松开停止绘图

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void chart1_MouseUp(object sender, MouseEventArgs e)

        {

            begin = false;

        }

        /// <summary>

        /// 在chart控件上按下鼠标

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void chart1_MouseDown(object sender, MouseEventArgs e)

        {

            begin = true;

            firstPoint = new Point(e.X, e.Y);

        }

    }

}