下面代码文件名是ValidateCode.ashx
public class ValidateCode : IHttpHandler, IRequiresSessionState { /// <summary> /// 验证码|使用事例:<img src="../tools/ValidateCode.ashx" onclick="this.src='../tools/ValidateCode.ashx'"alt="看不清验证码,请单击" style="cursor: hand; width: 52px; height: 18px;" /> /// </summary> /// <param name="context"></param> public void ProcessRequest(HttpContext context) { context.Response.Cache.SetCacheability(HttpCacheability.NoCache); context.Response.ContentType = "text/plain"; int w = Common.CFun.GetQueryInt("w", HttpContext.Current); w = w > 0 ? w : 63; int h = Common.CFun.GetQueryInt("h", HttpContext.Current); h = h > 0 ? h : 30; string checkCode = GenerateCheckCode(); context.Session["CheckCode"] = checkCode;//将验证码写入Session Bitmap image = CreateCheckCodeImage(checkCode, w, h); System.IO.MemoryStream ms = new System.IO.MemoryStream(); image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); context.Response.ClearContent(); context.Response.ContentType = "image/Gif"; context.Response.BinaryWrite(ms.ToArray()); } /// <summary> /// 得到验证码 /// </summary> /// <param name="context"></param> /// <returns></returns> private string GenerateCheckCode() { int number; char code; string checkCode = String.Empty; System.Random random = new Random(); for (int i = 0; i < 4; i++) { number = random.Next(); if (number % 2 == 0) code = (char)('0' + (char)(number % 10)); else if (number % 3 == 0) code = (char)('A' + (char)(number % 26)); else code = (char)('a' + (char)(number % 26)); checkCode += code.ToString(); } return checkCode.ToUpper(); } /// <summary> /// 生成验证码图片 /// </summary> /// <param name="checkCode"></param> /// <param name="context"></param> private Bitmap CreateCheckCodeImage(string checkCode, int w = 54, int h = 30) { System.Drawing.Bitmap image = new System.Drawing.Bitmap(w, h); Graphics g = Graphics.FromImage(image); g.Clear(Color.WhiteSmoke);//清除背景色 Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };//定义随机颜色 string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" }; Random rand = new Random(); int z = 0;//干扰线条数 for (int i = 0; i < z; i++) { int x1 = rand.Next(image.Width); int x2 = rand.Next(image.Width); int y1 = rand.Next(image.Height); int y2 = rand.Next(image.Height); g.DrawLine(new Pen(Color.LightGray, 1), x1, y1, x2, y2);//根据坐标画线 } for (int i = 0; i < checkCode.Length; i++) { int cindex = rand.Next(7); int findex = rand.Next(5); Font f = new System.Drawing.Font(font[findex], 14, System.Drawing.FontStyle.Bold); Brush b = new System.Drawing.SolidBrush(c[cindex]); int ii = 4; if ((i + 1) % 2 == 0) { ii = 2; } g.DrawString(checkCode.Substring(i, 1), f, b, 3 + (i * (14)), ii); } image = TwistImage(image, true, 5, 1); g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1); return image; } #region 产生波形滤镜效果 private const double PI = 3.1415926535897932384626433832795; private const double PI2 = 6.283185307179586476925286766559; /// <summary> /// 正弦曲线Wave扭曲图片(Edit By 51aspx.com) /// </summary> /// <param name="srcBmp">图片路径</param> /// <param name="bXDir">如果扭曲则选择为True</param> /// <param name="nMultValue">波形的幅度倍数,越大扭曲的程度越高,一般为3</param> /// <param name="dPhase">波形的起始相位,取值区间[0-2*PI)</param> /// <returns></returns> 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; } #endregion public bool IsReusable { get { return false; } } }
以下调用方法
<span class="ckcinput"> <img id="checkCodeImg" src="/ValidateCode.ashx" align="absmiddle" onclick="changeCC()"alt="看不清验证码,请单击" style="cursor: pointer; width: 56px; height: 30px; margin-top: 5px;margin-left: 2px;" /> </span>
JS代码方法
function changeCC() { $("#checkCodeImg").attr("src", "/ValidateCode.ashx?" + Math.random()); }