一个简单的ASP.NET验证码

 /// <summary> /// 验证码生成类 /// </summary> public class verify_code : IHttpHandler, IRequiresSessionState { public void ProcessRequest(HttpContext context) { int codeW = 80; int codeH = 22; int fontSize = 16; string chkCode = string.Empty; //颜色列表，用于验证码、噪线、噪点 Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue }; //字体列表，用于验证码 string[] font = { "Times New Roman", "Verdana", "Arial", "Gungsuh", "Impact" }; //验证码的字符集，去掉了一些容易混淆的字符 char[] character = { '0', '1', '2', '3', '4', '5', '6', '8', '9' }; Random rnd = new Random(); //生成验证码字符串 for (int i = 0; i <4; i++) { chkCode += character[rnd.Next(character.Length)]; } //写入Session context.Session["sys_verify_code"] = chkCode; //创建画布 Bitmap bmp = new Bitmap(codeW, codeH); Graphics g = Graphics.FromImage(bmp); g.Clear(Color.White); //画噪线 for (int i = 0; i <4; i++) { int x1 = rnd.Next(codeW); int y1 = rnd.Next(codeH); int x2 = rnd.Next(codeW); int y2 = rnd.Next(codeH); Color clr = color[rnd.Next(color.Length)]; g.DrawLine(new Pen(clr), x1, y1, x2, y2); } //画验证码字符串 for (int i = 0; i <chkCode.Length; i++) { string fnt = font[rnd.Next(font.Length)]; Font ft = new Font(fnt, fontSize); Color clr = color[rnd.Next(color.Length)]; g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 18 + 2, (float)0); } //画噪点 for (int i = 0; i <100; i++) { int x = rnd.Next(bmp.Width); int y = rnd.Next(bmp.Height); Color clr = color[rnd.Next(color.Length)]; bmp.SetPixel(x, y, clr); } //清除该页输出缓存，设置该页无缓存 context.Respo<mark style="color:transparent">来源gaodaimacom搞#代%码网</mark>nse.Buffer = true; context.Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0); context.Response.Expires = 0; context.Response.CacheControl = "no-cache"; context.Response.AppendHeader("Pragma", "No-Cache"); //将验证码图片写入内存流，并将其以 "image/Png" 格式输出 MemoryStream ms = new MemoryStream(); try { bmp.Save(ms, ImageFormat.Png); context.Response.ClearContent(); context.Response.ContentType = "image/Png"; context.Response.BinaryWrite(ms.ToArray()); } finally { //显式释放资源 bmp.Dispose(); g.Dispose(); } } public bool IsReusable { get { return false; } } } 

 using System; using System.Drawing; using System.Drawing.Imaging; using System.IO; using System.Web; public partial class image : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { string tmp = RndNum(4); HttpCookie a = new HttpCookie("ImageV", tmp); Response.Cookies.Add(a); this.ValidateCode(tmp); } private void ValidateCode(string VNum) { Bitmap Img = null; Graphics g = null; MemoryStream ms = null; int gheight = VNum.Length * 12; Img = new Bitmap(gheight, 25); g = Graphics.FromImage(Img); //背景颜色 g.Clear(Color.White); //文字字体 Font f = new Font("Arial Black", 10); //文字颜色 SolidBrush s = new SolidBrush(Color.Black); g.DrawString(VNum, f, s, 3, 3); ms = new MemoryStream(); Img.Save(ms, ImageFormat.Jpeg); Response.ClearContent(); Response.ContentType = "image/Jpeg"; Response.BinaryWrite(ms.ToArray()); g.Dispose(); Img.Dispose(); Response.End(); } private string RndNum(int VcodeNum) { string Vchar = "0,1,2,3,4,5,6,7,8,9,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[] VcArray = Vchar.Split(new Char[] { ',' }); string VNum = ""; int temp = -1; Random rand = new Random(); for (int i = 1; i <vcodenum + 1; i++) { if (temp !=-1) rand=new random(i * temp unchecked((int)datetime.now.ticks)); } int t=rand.Next(35); -1 && t) return rndnum(vcodenum); t; vnum vcarray[t]; vnum;