C#生成漂亮的验证码

直接上代码：

        using System;        
        using System.Collections.Generic;        
                
        using System.Web;        
        using System.Web.UI;        
        using System.Web.UI.WebControls;        
        using System.Drawing;        
        using System.IO;        
        using System.Drawing.Imaging;        
                
        namespace Web.ValidateCode        
        {        
                public partial class ValidateCode : System.Web.UI.Page        
                {        
                        private int letterWidth = 16;//单个字体的宽度范围          
                        private int letterHeight = 22;//单个字体的高度范围          
                        private int letterCount = 4;//验证码位数          
                        private char[] chars = "0123456789".ToCharArray();        
                        private string[] fonts = { "Arial", "Georgia" };        
                        ///

          
                        /// 产生波形滤镜效果          
                        ///

          
                        private const double PI = 3.1415926535897932384626433832795;        
                        private const double PI2 = 6.283185307179586476925286766559;        
                        protected void Page_Load(object sender, EventArgs e)        
                        {        
                                //防止网页后退--禁止缓存                  
                                Response.Expires = 0;        
                                Response.Buffer = true;        
                                Response.ExpiresAbsolute = DateTime.Now.AddSeconds(-1);        
                                Response.AddHeader("pragma", "no-cache");        
                                Response.CacheControl = "no-cache";        
                                string str_ValidateCode = GetRandomNumberString(letterCount);        
                                HttpCookie objCookie = new HttpCookie("ValidateCode");        
                                objCookie.Value = str_ValidateCode;        
                                objCookie.Path = "/";        
                                objCookie.Expires = DateTime.Now.AddSeconds(1200);        
                                Response.Cookies.Add(objCookie);        
                                CreateImage(str_ValidateCode);        
                
                        }        
                        public void CreateImage(string checkCode)        
                        {        
                                int int_ImageWidth = checkCode.Length * letterWidth;        
                                Random newRandom = new Random();        
                                Bitmap image = new Bitmap(int_ImageWidth, letterHeight);        
                                Graphics g = Graphics.FromImage(image);        
                                //生成随机生成器          
                                Random random = new Random();        
                                //白色背景          
                                g.Clear(Color.White);        
                                //画图片的背景噪音线          
                                for (int i = 0; i < 10; 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);        
                                }        
                
                                //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.FromArgb(random.Next()));        
                                }        
                                //随机字体和颜色的验证码字符          
                
                                int findex;        
                                for (int int_index = 0; int_index < checkCode.Length; int_index++)        
                                {        
                                        findex = newRandom.Next(fonts.Length - 1);        
                                        string str_char = checkCode.Substring(int_index, 1);        
                                        Brush newBrush = new SolidBrush(GetRandomColor());        
                                        Point thePos = new Point(int_index * letterWidth + 1 + newRandom.Next(3), 1 + newRandom.Next(3));//5+1+a+s+p+x          
                                        g.DrawString(str_char, new Font(fonts[findex], 12, FontStyle.Bold), newBrush, thePos);        
                                }        
                                //灰色边框          
                                g.DrawRectangle(new Pen(Color.LightGray, 1), 0, 0, int_ImageWidth - 1, (letterHeight - 1));        
                                //图片扭曲          
                                //image = TwistImage(image, true, 3, 4);          
                                //将生成的图片发回客户端          
                                MemoryStream ms = new MemoryStream();        
                                image.Save(ms, ImageFormat.Png);        
                                Response.ClearContent(); //需要输出图象信息 要修改HTTP头            
                                Response.ContentType = "image/Png";        
                                Response.BinaryWrite(ms.ToArray());        
                                g.Dispose();        
                                image.Dispose();        
                        }        
                        ///

          
                        /// 正弦曲线Wave扭曲图片          
                        ///

          
                        /// 图片路径          
                        /// 如果扭曲则选择为True          
                        /// 波形的幅度倍数，越大扭曲的程度越高，一般为3          
                        /// 波形的起始相位，取值区间[0-2*PI)          
                        ///           
                        public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)        
                        {        
                                System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);        
                
                                // 将位图背景填充为白色          
                                System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);        
                
                                graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);        
                
                                graph.Dispose();        
                
                                double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;        
                
                                for (int i = 0; i < destBmp.Width; i++)        
                                {        
                                        for (int j = 0; j < destBmp.Height; j++)        
                                        {        
                                                double dx = 0;        
                
                                                dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;        
                
                                                dx += dPhase;        
                
                                                double dy = Math.Sin(dx);        
                
                                                // 取得当前点的颜色          
                                                int nOldX = 0, nOldY = 0;        
                
                                                nOldX = bXDir ? i + (int)(dy * dMultValue) : i;        
                
                                                nOldY = bXDir ? j : j + (int)(dy * dMultValue);        
                
                                                System.Drawing.Color color = srcBmp.GetPixel(i, j);        
                                                if (nOldX >= 0 && nOldX < destBmp.Width && nOldY >= 0 && nOldY < destBmp.Height)        
                                                {        
                                                        destBmp.SetPixel(nOldX, nOldY, color);        
                                                }        
                                        }        
                                }        
                                return destBmp;        
                        }        
                        public Color GetRandomColor()        
                        {        
                                Random RandomNum_First = new Random((int)DateTime.Now.Ticks);        
                                System.Threading.Thread.Sleep(RandomNum_First.Next(50));        
                                Random RandomNum_Sencond = new Random((int)DateTime.Now.Ticks);        
                                int int_Red = RandomNum_First.Next(210);        
                                int int_Green = RandomNum_Sencond.Next(180);        
                                int int_Blue = (int_Red + int_Green > 300) ? 0 : 400 - int_Red - int_Green;        
                                int_Blue = (int_Blue > 255) ? 255 : int_Blue;        
                                  return Color.FromArgb(int_Red, int_Green, int_Blue);// 5+1+a+s+p+x          
                        }        
                        //    生成随机数字字符串          
                        public string GetRandomNumberString(int int_NumberLength)        
                        {        
                                Random random = new Random();        
                                string validateCode = string.Empty;        
                                for (int i = 0; i < int_NumberLength; i++)        
                                        validateCode += chars[random.Next(0, chars.Length)].ToString();        
                                return validateCode;        
                        }        
                                
                }        
        }