本篇文章借阅了网上的其他文章，我自己又实践修改之后总结如下：
1.首先我们先建立一个验证码页面（取名Vcode.aspx）
我们进入到他的后台（Vcode.aspx.cs）书写验证码的生成方法：
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Drawing;using System.Drawing.Imaging;public partial class VCode : System.Web.UI.Page{protected void Page_Load(object sender, EventArgs e){VCode v = new VCode();string code = v.CreateVerifyCode(); //取随机码 v.CreateImageOnPage(code, this.Context); // 输出图片 Session["CheckCode"] = code; }#region 验证码长度(默认6个验证码的长度)int length = 4;public int Length{get { return length; }set { length = value; }}#endregion#region 验证码字体大小(为了显示扭曲效果，默认40像素，可以自行修改)int fontSize = 40;public int FontSize{get { return fontSize; }set { fontSize = value; }}#endregion#region 边框补(默认1像素)int padding = 2;public int Padding{get { return padding; }set { padding = value; }}#endregion#region 是否输出燥点(默认不输出)bool chaos = true;public bool Chaos{get { return chaos; }set { chaos = value; }}#endregion#region 输出燥点的颜色(默认灰色)Color chaosColor = Color.LightGray;public Color ChaosColor{get { return chaosColor; }set { chaosColor = value; }}#endregion#region 自定义背景色(默认白色)Color backgroundColor = Color.White;public Color BackgroundColor{get { return backgroundColor; }set { backgroundColor = value; }}#endregion#region 自定义随机颜色数组Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };public Color[] Colors{get { return colors; }set { colors = value; }}#endregion#region 自定义字体数组string[] fonts = { "Arial", "Georgia" };public string[] Fonts{get { return fonts; }set { fonts = value; }}#endregion#region 自定义随机码字符串序列(使用逗号分隔)string codeSerial = "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,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";public string CodeSerial{get { return codeSerial; }set { codeSerial = value; }}#endregion#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 ） /// </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#region 生成校验码图片public Bitmap CreateImageCode(string code){int fSize = FontSize;int fWidth = fSize + Padding;int imageWidth = (int)(code.Length * fWidth) + 4 + Padding * 2;int imageHeight = fSize * 2 + Padding;System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);Graphics g = Graphics.FromImage(image);g.Clear(BackgroundColor);Random rand = new Random();//给背景添加随机生成的燥点 if (this.Chaos){Pen pen = new Pen(ChaosColor, 0);int c = Length * 10;for (int i = 0; i < c; i++){int x = rand.Next(image.Width);int y = rand.Next(image.Height);g.DrawRectangle(pen, x, y, 1, 1);}}int left = 0, top = 0, top1 = 1, top2 = 1;int n1 = (imageHeight - FontSize - Padding * 2);int n2 = n1 / 4;top1 = n2;top2 = n2 * 2;Font f;Brush b;int cindex, findex;//随机字体和颜色的验证码字符 for (int i = 0; i < code.Length; i++){cindex = rand.Next(Colors.Length - 1);findex = rand.Next(Fonts.Length - 1);f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);b = new System.Drawing.SolidBrush(Colors[cindex]);if (i % 2 == 1){top = top2;}else{top = top1;}left = i * fWidth;g.DrawString(code.Substring(i, 1), f, b, left, top);}//画一个边框 边框颜色为Color.Gainsboro g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);g.Dispose();//产生波形（Add By ） image = TwistImage(image, true, 8, 4);return image;}#endregion#region 将创建好的图片输出到页面public void CreateImageOnPage(string code, HttpContext context){System.IO.MemoryStream ms = new System.IO.MemoryStream();Bitmap image = this.CreateImageCode(code);image.Save(ms, ImageFormat.Jpeg);context.Response.ClearContent();context.Response.ContentType = "image/Jpeg";context.Response.BinaryWrite(ms.GetBuffer());ms.Close();ms = null;image.Dispose();image = null;}#endregion#region 生成随机字符码public string CreateVerifyCode(int codeLen){if (codeLen == 0){codeLen = Length;}string[] arr = CodeSerial.Split(',');string code = "";int randValue = -1;Random rand = new Random(unchecked((int)DateTime.Now.Ticks));for (int i = 0; i < codeLen; i++){randValue = rand.Next(0, arr.Length - 1);code += arr[randValue];}return code;}public string CreateVerifyCode(){return CreateVerifyCode(0);}#endregion }
2.我们新建一个登录页面（取名Login.aspx），在他的前台页面添加一个image控件
我这里加的是html控件 也可以加.net控件
<img id="img_code" src="Vcode.aspx" alt="点击刷新验证码" onclick="f_refreshtype()" width="70px"/>
然后你再运行Login页面就可以看到你的图片变成了图片验证码。
3.验证码的点击刷新：
我们进入到Login的前台页面（Login.aspx），在他的头部head引入JQuery
接着在引入JQuery下面添加js代码：
注意：getElementById中添加的id要和你添加的image的id一样。
函数名字f_refreshtype()要和你img控件里写的οnclick="f_refreshtype()一样
<script src="../js/jquery.js" type="text/javascript"></script><script src="../js/jquery.min.js" type="text/javascript"></script><script language="javascript" type="text/javascript">function f_refreshtype() {var Image1 = document.getElementById("img_code");if (Image1 != null) {Image1.src = Image1.src + "?";}}</script>
4.验证验证码输入是否正确
在点击事件的动态代码里写
string vCode = Session["CheckCode"].ToString();//获取生成的验证码if (输入验证码的控件.Text.Trim().ToUpper() == vCode.ToUpper()){//验证码正确} else{//验证码错误}
