Graphics Class

System.Drawing 封装一个 GDI+ 绘图图面。 此类不能被继承。

https://docs.microsoft.com/zh-cn/dotnet/api/system.drawing.graphics?view=netframework-4.7.2#%E6%96%B9%E6%B3%95

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
  
public class Form1 : Form
{
    public Form1()
    {
        this.AutoScaleBaseSize = new Size(6, 14);
        this.ClientSize = new Size(400, 400);
        this.Paint += new PaintEventHandler(this.Form1_Paint);
        this.Click += new EventHandler( this.Draw );
    }
    static void Main() 
    {
        Application.Run(new Form1());
    }
    
    //Paint事件调用
    private void Form1_Paint(object sender, PaintEventArgs e)
    {
        Graphics g = e.Graphics;//传进来的对象不需要释放
        
        Brush brush = new SolidBrush(Color.Green);
        Font font = new Font("宋体", 25);
                
        g.DrawString("绘制", font, brush, 250, 20);        
    }
    
    //在已存在的窗体上创建Graphics对象
    //窗体控件，Click事件
    private void Draw(object sender, EventArgs e)
    {   
        Graphics g = this.CreateGraphics();
        
        Pen pen = new Pen(Color.Red, 2);
        Brush brush = new SolidBrush(Color.Blue);
        Font font = new Font("宋体", 25);
        Rectangle rect = new Rectangle(20, 120, 100, 160);
        
        g.DrawLine(pen, 20, 100, 100, 100);
        g.DrawRectangle(pen, rect);
        g.DrawString("GDI+图形编程", font, brush, 20, 20);
        
        brush.Dispose(); font.Dispose(); pen.Dispose();//释放对象
        g.Dispose();
    }   
}