C#生成图片验证码的代码

以下是一个简单的 C# 代码示例，用于生成数字验证码图像：

using System;
using System.Drawing;
using System.Drawing.Imaging;

namespace ImageVerificationCode
{
    public class VerificationCodeGenerator
    {
        public Bitmap GenerateVerificationCode(int length, int width, int height)
        {
            Random random = new Random();
            string verificationCode = string.Empty;
            for (int i = 0; i < length; i++)
            {
                verificationCode += random.Next(0, 9).ToString();
            }

            Bitmap bitmap = new Bitmap(width, height);
            Graphics graphics = Graphics.FromImage(bitmap);
            graphics.Clear(Color.White);

            Font font = new Font("Arial", 20, FontStyle.Bold);
            Brush brush = new SolidBrush(Color.Black);
            graphics.DrawString(verificationCode, font, brush, 10, 10);

            for (int i = 0; i < 100; i++)
            {
                int x1 = random.Next(width);
                int y1 = random.Next(height);
                int x2 = random.Next(width);
                int y2 = random.Next(height);
                Pen pen = new Pen(Color.Black);
                graphics.DrawLine(pen, x1, y1, x2, y2);
            }

            return bitmap;
        }
    }
}

使用方法：

VerificationCodeGenerator generator = new VerificationCodeGenerator();
Bitmap bitmap = generator.GenerateVerificationCode(4, 120, 40);
bitmap.Save("verification_code.bmp", ImageFormat.Bmp);

这将生成一个长度为4，宽120像素，高40像素的位图，并将其保存为BMP格式的图像文件。