asp.net中的比较完美的验证码

本文转载：http://blog.csdn.net/zjk20108023/article/details/7836174

要实现如图的效果的验证码，分以下步骤：

第一、布局好调用验证码的登录页面（命名：Login.aspx），注意：验证码位置可以是服务器控件 Image，也可以是html标签写的<img>，但是图片url就是一个页面（命名：ValidateCode.aspx）(将在下面讲述。)比如：<asp:Image ID=“vcImg”      ImageUrl="~/ValidateCode.aspx"   runat="server" />

第二、生成类文件 (命名：validatedCode）

[csharp] view plaincopyprint?

1. using System; 
2. using System.Data; 
3. using System.Configuration; 
4. using System.Linq; 
5. using System.Web; 
6. using System.Web.Security; 
7. using System.Web.UI; 
8. using System.Web.UI.HtmlControls; 
9. using System.Web.UI.WebControls; 
10. using System.Web.UI.WebControls.WebParts; 
11. using System.Xml.Linq; 
12. using System.Drawing; 
13. using System.IO; 
14. using System.Drawing.Imaging; 
16. /// <summary>
17. /// Summary description for validatedCode
18. /// </summary>
19. public class validatedCode 
20. {    
21.        #region  验证码长度(默认6个验证码的长度)
22. int length = 4; 
23. public int Length 
24.         { 
25. get { return length; } 
26. set { length = value; } 
27.         } 
28.         #endregion
30.         #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)
31. int fontSize = 40; 
32. public int FontSize 
33.         { 
34. get { return fontSize; } 
35. set { fontSize = value; } 
36.         } 
37.         #endregion
39.         #region 边框补(默认1像素)
40. int padding = 2; 
41. public int Padding 
42.         { 
43. get { return padding; } 
44. set { padding = value; } 
45.         } 
46.         #endregion
48.         #region 是否输出燥点(默认不输出)
49. bool chaos = true; 
50. public bool Chaos 
51.         { 
52. get { return chaos; } 
53. set { chaos = value; } 
54.         } 
55.         #endregion
57.         #region 输出燥点的颜色(默认灰色)
58.         Color chaosColor = Color.LightGray; 
59. public Color ChaosColor 
60.         { 
61. get { return chaosColor; } 
62. set { chaosColor = value; } 
63.         } 
64.         #endregion
66.         #region 自定义背景色(默认白色)
67.         Color backgroundColor = Color.White; 
68. public Color BackgroundColor 
69.         { 
70. get { return backgroundColor; } 
71. set { backgroundColor = value; } 
72.         } 
73.         #endregion
75.         #region 自定义随机颜色数组
76.         Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple }; 
77. public Color[] Colors 
78.         { 
79. get { return colors; } 
80. set { colors = value; } 
81.         } 
82.         #endregion
84.         #region 自定义字体数组
85. string[] fonts = { "Arial", "Georgia" }; 
86. public string[] Fonts 
87.         { 
88. get { return fonts; } 
89. set { fonts = value; } 
90.         } 
91.         #endregion
93.         #region 自定义随机码字符串序列(使用逗号分隔)
94. 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"; 
95. public string CodeSerial 
96.         { 
97. get { return codeSerial; } 
98. set { codeSerial = value; } 
99.         } 
100.         #endregion
102.         #region 产生波形滤镜效果
104. private const double PI = 3.1415926535897932384626433832795; 
105. private const double PI2 = 6.283185307179586476925286766559; 
107. /// <summary>
108. /// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）
109. /// </summary>
110. /// <param name="srcBmp">图片路径</param>
111. /// <param name="bXDir">如果扭曲则选择为True</param>
112. /// <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
113. /// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
114. /// <returns></returns>
115. public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase) 
116.         { 
117.             System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height); 
119. // 将位图背景填充为白色
120.             System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp); 
121.             graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height); 
122.             graph.Dispose(); 
124. double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width; 
126. for (int i = 0; i < destBmp.Width; i++) 
127.             { 
128. for (int j = 0; j < destBmp.Height; j++) 
129.                 { 
130. double dx = 0; 
131.                     dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen; 
132.                     dx += dPhase; 
133. double dy = Math.Sin(dx); 
135. // 取得当前点的颜色
136. int nOldX = 0, nOldY = 0; 
137.                     nOldX = bXDir ? i + (int)(dy * dMultValue) : i; 
138.                     nOldY = bXDir ? j : j + (int)(dy * dMultValue); 
140.                     System.Drawing.Color color = srcBmp.GetPixel(i, j); 
141. if (nOldX >= 0 && nOldX < destBmp.Width 
142.                      && nOldY >= 0 && nOldY < destBmp.Height) 
143.                     { 
144.                         destBmp.SetPixel(nOldX, nOldY, color); 
145.                     } 
146.                 } 
147.             } 
149. return destBmp; 
150.         } 
154.         #endregion
156.         #region 生成校验码图片
157. public Bitmap CreateImageCode(string code) 
158.         { 
159. int fSize = FontSize; 
160. int fWidth = fSize + Padding; 
162. int imageWidth = (int)(code.Length * fWidth) + 4 + Padding * 2; 
163. int imageHeight = fSize * 2 + Padding; 
165.             System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight); 
167.             Graphics g = Graphics.FromImage(image); 
169.             g.Clear(BackgroundColor); 
171.             Random rand = new Random(); 
173. //给背景添加随机生成的燥点
174. if (this.Chaos) 
175.             { 
177.                 Pen pen = new Pen(ChaosColor, 0); 
178. int c = Length * 10; 
180. for (int i = 0; i < c; i++) 
181.                 { 
182. int x = rand.Next(image.Width); 
183. int y = rand.Next(image.Height); 
185.                     g.DrawRectangle(pen, x, y, 1, 1); 
186.                 } 
187.             } 
189. int left = 0, top = 0, top1 = 1, top2 = 1; 
191. int n1 = (imageHeight - FontSize - Padding * 2); 
192. int n2 = n1 / 4; 
193.             top1 = n2; 
194.             top2 = n2 * 2; 
196.             Font f; 
197.             Brush b; 
199. int cindex, findex; 
201. //随机字体和颜色的验证码字符
202. for (int i = 0; i < code.Length; i++) 
203.             { 
204.                 cindex = rand.Next(Colors.Length - 1); 
205.                 findex = rand.Next(Fonts.Length - 1); 
207.                 f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold); 
208.                 b = new System.Drawing.SolidBrush(Colors[cindex]); 
210. if (i % 2 == 1) 
211.                 { 
212.                     top = top2; 
213.                 } 
214. else
215.                 { 
216.                     top = top1; 
217.                 } 
219.                 left = i * fWidth; 
221.                 g.DrawString(code.Substring(i, 1), f, b, left, top); 
222.             } 
224. //画一个边框 边框颜色为Color.Gainsboro
225.             g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1); 
226.             g.Dispose(); 
228. //产生波形（Add By 51aspx.com）
229.             image = TwistImage(image, true, 8, 4); 
231. return image; 
232.         } 
233.         #endregion
235.         #region 将创建好的图片输出到页面
236. public void CreateImageOnPage(string code, HttpContext context) 
237.         { 
238.             System.IO.MemoryStream ms = new System.IO.MemoryStream(); 
239.             Bitmap image = this.CreateImageCode(code); 
241.             image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); 
243.             context.Response.ClearContent(); 
244.             context.Response.ContentType = "image/Jpeg"; 
245.             context.Response.BinaryWrite(ms.GetBuffer()); 
247.             ms.Close(); 
248.             ms = null; 
249.             image.Dispose(); 
250.             image = null; 
251.         } 
252.         #endregion
254.         #region 生成随机字符码
255. public string CreateVerifyCode(int codeLen) 
256.         { 
257. if (codeLen == 0) 
258.             { 
259.                 codeLen = Length; 
260.             } 
262. string[] arr = CodeSerial.Split(','); 
264. string code = ""; 
266. int randValue = -1; 
268.             Random rand = new Random(unchecked((int)DateTime.Now.Ticks)); 
270. for (int i = 0; i < codeLen; i++) 
271.             { 
272.                 randValue = rand.Next(0, arr.Length - 1); 
274.                 code += arr[randValue]; 
275.             } 
277. return code; 
278.         } 
279. public string CreateVerifyCode() 
280.         { 
281. return CreateVerifyCode(0); 
282.         } 
283.         #endregion
284. } 

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Drawing;
using System.IO;
using System.Drawing.Imaging;

/// <summary>
/// Summary description for validatedCode
/// </summary>
public class validatedCode
{   
       #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 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

        #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 51aspx.com）
            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, System.Drawing.Imaging.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
}

PS：虽然不是我自己写的，但是可分享给大家。

代码中有注释，所以我就不多说了。

第三、生成调用类文件的网页（ValidateCode.aspx），在该页面的后台代码（ValidateCode.aspx.cs文件）的Page_Load事件中写如下代码：

[csharp] view plaincopyprint?

1. protected void Page_Load(object sender, EventArgs e) 
2. { 
3.     validatedCode v = new validatedCode(); 
4. string code = v.CreateVerifyCode();            //取随机码
5.     v.CreateImageOnPage(code, this.Context);       // 输出图片
6.     Session["CheckCode"] = code;                   //Session 取出验证码
7. } 

    protected void Page_Load(object sender, EventArgs e)
    {
        validatedCode v = new validatedCode();
        string code = v.CreateVerifyCode();            //取随机码
        v.CreateImageOnPage(code, this.Context);       // 输出图片
        Session["CheckCode"] = code;                   //Session 取出验证码
    }

第四、判断验证结果：Login.aspx页面的登录事件中添加验证

[csharp] view plaincopyprint?

1. protected void btnLogin_Click(object sender, EventArgs e) 
2.    { 
3. string vCode = Session["CheckCode"].ToString(); 
4. if (txtValidatedcode.Text.Trim().ToUpper() == vCode.ToUpper()) 
5.        { 
6.            ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "Startup", "alert('ValidatedCode is right!');", true); 
7.        } 
8.    }