1using System;
  2using System.IO;
  3using System.Web.UI;
  4using System.Drawing;
  5using System.Drawing.Imaging;
  6using System.Drawing.Drawing2D;
  7
  8namespace Web.Common
  9{
 10    /**//// <summary>
 11    /// validate 的摘要说明。
 12    /// </summary>
 13    public class Validate: System.Web.UI.Page
 14    {
 15        private void Page_Load(object sender, EventArgs e)
 16        {
 17            string strValidateCode = ValidateCode(6);//取得随机字符串，并设置Session值
 18            DrawValidateCode(strValidateCode,50,100);//绘图
 19        }
 20    
 21        //绘图
 22        private void DrawValidateCode(string strValidateCode,int intFgNoise,int intBgNoise)
 23        {
 24            if(strValidateCode == null || strValidateCode.Trim() == String.Empty)
 25            {
 26                return;
 27            }
 28            else
 29            {
 30                //建立一个位图文件 确立长宽
 31                Bitmap bmpImage = new Bitmap((int)Math.Ceiling((strValidateCode.Length * 12.5)), 22);
 32                Graphics grpGraphics = Graphics.FromImage(bmpImage);
 33    
 34                try
 35                {
 36                    //生成随机生成器
 37                    Random rndRandom = new Random();
 38    
 39                    //清空图片背景色
 40                    grpGraphics.Clear(Color.White);
 41    
 42                    //画图片的背景噪音线
 43                    for(int i=0; i<intBgNoise; i++)
 44                    {
 45                        int int_x1 = rndRandom.Next(bmpImage.Width);
 46                        int int_x2 = rndRandom.Next(bmpImage.Width);
 47                        int int_y1 = rndRandom.Next(bmpImage.Height);
 48                        int int_y2 = rndRandom.Next(bmpImage.Height);
 49    
 50                        grpGraphics.DrawLine(new Pen(Color.Silver), int_x1, int_y1, int_x2, int_y2);
 51                    }
 52                    //把产生的随机数以字体的形式写入画面
 53                    Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));
 54                    LinearGradientBrush brhBrush = new LinearGradientBrush(new Rectangle(0, 0, bmpImage.Width, bmpImage.Height), Color.Blue, Color.DarkRed, 1.2f, true);
 55                    grpGraphics.DrawString(strValidateCode, font, brhBrush, 2, 2);
 56    
 57                    //画图片的前景噪音点
 58                    for(int i=0; i<intFgNoise; i++)
 59                    {
 60                        int int_x = rndRandom.Next(bmpImage.Width);
 61                        int int_y = rndRandom.Next(bmpImage.Height);
 62    
 63                        bmpImage.SetPixel(int_x, int_y, Color.FromArgb(rndRandom.Next()));
 64                    }
 65    
 66                    //画图片的边框线
 67                    grpGraphics.DrawRectangle(new Pen(Color.Silver), 0, 0, bmpImage.Width - 1, bmpImage.Height - 1);
 68    
 69                    MemoryStream memsMemoryStream = new MemoryStream();
 70                    bmpImage.Save(memsMemoryStream, ImageFormat.Gif);
 71                    Response.ClearContent();
 72                    Response.ContentType = "image/Gif";
 73                    Response.BinaryWrite(memsMemoryStream.ToArray());
 74                }
 75                finally
 76                {
 77                    grpGraphics.Dispose();
 78                    bmpImage.Dispose();
 79                }
 80            }
 81        }
 82    
 83        //取得随机字符串，并设置Session值
 84        private string ValidateCode(int intLength)
 85        {
 86            int intNumber;
 87            char chrCode;
 88            string strValidateCode = String.Empty;
 89    
 90            Random rndRandom = new Random();
 91    
 92            for(int i=0;i<intLength;i++)
 93            {
 94                intNumber = rndRandom.Next();
 95                if(intNumber % 2 == 0)
 96                {
 97                    chrCode = (char)('0' + (char)(intNumber % 10));//如果随机数是偶数 取余
 98                }
 99                else
100                {
101                    chrCode = (char)('A' + (char)(intNumber % 26));//如果随机数是奇数 选择从[A-Z]
102                }
103                strValidateCode += chrCode.ToString(); 
104            }
105    
106            Session["ValidateCode"] = strValidateCode;//设置Session["ValidateCode"]
107            //Response.Cookies.Add(new HttpCookie("strValidateCode",strValidateCode));
108    
109            return strValidateCode;
110        }
111
112        Web 窗体设计器生成的代码#region Web 窗体设计器生成的代码
113        override protected void OnInit(EventArgs e)
114        {
115            //
116            // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
117            //
118            InitializeComponent();
119            base.OnInit(e);
120        }
121        
122        /**//// <summary>
123        /// 设计器支持所需的方法 - 不要使用代码编辑器修改
124        /// 此方法的内容。
125        /// </summary>
126        private void InitializeComponent()
127        {    
128            this.Load += new System.EventHandler(this.Page_Load);
129
130        }
131        #endregion
132    }
133
134}
135