C# 创建验证码图片

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Web.UI.WebControls;

public class ValidateCodeCreator
    {
        /// <summary>
        ///     产生验证码
        /// </summary>
        /// <param name="codeLength">验证码长度</param>
        /// <returns></returns>
        public string CreateCode(int codeLength)
        {
            string so =
                "1,2,3,4,5,6,7,8,9,0,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
            string[] strArr = so.Split(',');
            string code = "";
            Random rand = new Random();
            for (int i = 0; i < codeLength; i++)
            {
                code += strArr[rand.Next(0, strArr.Length)];
            }
            return code;
        }

        /// <summary>
        ///     产生验证图片
        /// </summary>
        /// <param name="code"></param>
        public byte[] CreateCodeImage(string code)
        {
            Bitmap image = new Bitmap(50, 20);
            Graphics g = Graphics.FromImage(image);
            try
            {
                WebColorConverter ww = new WebColorConverter();
                g.Clear((Color) ww.ConvertFromString("#FAE264"));
                Random random = new Random();
                //画图片的背景噪音线
                for (int i = 0; i < 12; 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.LightGray), x1, y1, x2, y2);
                }
                Font font = new Font("Arial", 13, FontStyle.Bold | FontStyle.Italic);
                LinearGradientBrush brush = new LinearGradientBrush(
                    new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.Gray, 1.2f, true);
                g.DrawString(code, font, brush, 0, 0);
                //画图片的前景噪音点
                //for (int i = 0; i < 10; i++)
                //{
                //    int x = random.Next(image.Width);
                //    int y = random.Next(image.Height);
                //    image.SetPixel(x, y, Color.White);
                //}
                //画图片的边框线
                // g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                MemoryStream ms = new MemoryStream();
                image.Save(ms, ImageFormat.Gif);
                return ms.ToArray();
            }
            finally
            {
                g.Dispose();
                image.Dispose();
            }
        }
    }