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  • 简单的验证码

    效果如图:
    未命名 
    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 WindowsFormsApplication8
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
    
            private void button1_Click(object sender, EventArgs e)
            {
                CreateCheckCodeImage(GenerateCheckCode());
            }
            private string GenerateCheckCode()
            {
                int number;
                char code;
                string checkCode = String.Empty;
                System.Random random = new Random();
                for (int i = 0; i < 5; i++)
                {   
                    number = random.Next();
                    if (number % 2 == 0)
                        code = (char)('0' + (char)(number % 10));
                    else
                        code = (char)('A' + (char)(number % 26));
                    checkCode += code.ToString();
                }
                return checkCode;
            }
            private void CreateCheckCodeImage(string checkCode)
            {
                if (checkCode == null || checkCode.Trim() == String.Empty)
                    return;
                //建立一个位图文件 确立长宽
                System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
                Graphics g = Graphics.FromImage(image);
                try
                {
                    //生成随机生成器
                    Random random = new Random();
                    //清空图片背景色
                    g.Clear(Color.White);
                    //画图片的背景噪音线
                    for (int i = 0; i < 25; i++)
                    {
                        int x1 = random.Next(image.Width);
                        int x2 = random.Next(image.Width);
                        int y1 = random.Next(image.Height);
                        int y2 = random.Next(image.Height);
                        g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
                    }
                    //把产生的随机数以字体的形式写入画面
                    Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
                    System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle
    
                    (0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
                    g.DrawString(checkCode, font, brush, 2, 2);
                    //画图片的前景噪音点
                    for (int i = 0; i < 100; i++)
                    {
                        int x = random.Next(image.Width);
                        int y = random.Next(image.Height);
                        image.SetPixel(x, y, Color.FromArgb(random.Next()));
                    }
                    //画图片的边框线
                    g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                    System.IO.MemoryStream ms = new System.IO.MemoryStream();
                    image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
                    //Response.ClearContent();
                    //Response.ContentType = "image/Gif";
                    //Response.BinaryWrite(ms.ToArr);
    
                    Graphics gg = this.CreateGraphics();
                    gg.DrawImage(image,10,10,100,50);
                }
                finally
                {
                    g.Dispose();
                    image.Dispose();
                }
            }
        }
    }
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  • 原文地址:https://www.cnblogs.com/wangshuai/p/1682818.html
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