本文以在chart控件上和窗体上画矩形为例子讲述了C# GDI在控件上绘图的方法。分享给大家供大家参考。具体方法如下：

具体的实现方法就不多解释了，备注很详细，代码也很简单。

主要功能代码如下：

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; 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(0, 0); //鼠标第一点 public Point secondPoint = new Point(0, 0); //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); } } }

希望本文所述对大家的C#程序设计有所帮助