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
///
/// 在from上画矩形
///
Graphics g;
///
/// 在chart1控件上画矩形
///
Graphics g2;
///
/// 在窗体上按下鼠标事件
///
///
///
private void data_MouseDown(object sender, MouseEventArgs e)
{
begin = true;
firstPoint = new Point(e.X, e.Y);
}
///
/// 在窗体上鼠标移动开始绘图
///
///
///
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);
}
}
///
/// 鼠标松开停止绘图
///
///
///
private void data_MouseUp(object sender, MouseEventArgs e)
{
begin = false;
}
///
/// 在chart控件上移动鼠标绘图
///
///
///
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);
}
}
///
/// 鼠标松开停止绘图
///
///
///
private void chart1_MouseUp(object sender, MouseEventArgs e)
{
begin = false;
}
///
/// 在chart控件上按下鼠标
///
///
///
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
