1 [DefaultProperty("Text")] 2 [ToolboxData("<{0}:ValidateCode runat=server></{0}:ValidateCode>")] 3 public class ValidateCode : WebControl 4 { 5 /// <summary> 6 /// 记录随机生成的验证码 7 /// </summary> 8 private string _checkCode = string.Empty; 9 10 /// <summary> 11 /// 用于记录验证码的位数，初始值为4 12 /// </summary> 13 private int _codeLen = 4; 14 15 /// <summary> 16 /// Bindable：用于设置该属性是否可以绑定数据 17 /// Category：设置属性显示在“按分类顺序”模式时，分组的类别名称 18 /// Browsable：是否显示在控件的属性面板中 19 /// DefaultValue：指定属性的默认值 20 /// Description：指定属性的说明文字 21 /// </summary> 22 [Bindable(true), Category("Appearance"), Browsable(true), DefaultValue(true), Description("此属性用于设置验证码的长度")] 23 public int CodeLength 24 { 25 get 26 { 27 return _codeLen; 28 } 29 set 30 { 31 _codeLen = value; 32 } 33 } 34 35 /// <summary> 36 /// 生成随机验证码 37 /// </summary> 38 /// <returns></returns> 39 private string GetValidateCode() 40 { 41 //创建一个字符数组，用于存储组成验证码的数字和英文字母 42 char[] s = new char[]{'2','3','4','5','6','7','8','9','a' 43 ,'b','c','d','e','f','g','h','i','j','k','m','n','p','q' 44 ,'r','s','t','u','v','w','x','y','z','A','B','C','D','E','F','G' 45 ,'H','I','J','K','L','M','N','P','Q','R','S','T','U','V','W' 46 ,'X','Y','Z'}; 47 string num = "";//创建变量用于记录指定长度的验证码的值 48 Random r = new Random();//生成随机生成器 49 //根据用户需要的长度来定义验证码的位数 50 for (int i = 0; i < _codeLen; i++) 51 { 52 num += s[r.Next(0, s.Length)].ToString(); 53 } 54 return num;//返回生成的随机验证码的值 55 } 56 57 /// <summary> 58 /// 绘制图形验证码 59 /// </summary> 60 /// <param name="checkCode">随机生成的验证码</param> 61 private void CreateCheckCodeImage(string checkCode) 62 { 63 System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 14.5)), 22);//创建画布，用于绘制验证码 64 Graphics g = Graphics.FromImage(image);//声明Graphics对象 65 try 66 { 67 Random random = new Random(); //生成随机生成器 68 g.Clear(Color.White); //清空图片背景色 69 Font font = new System.Drawing.Font("宋体", 15, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));//设置字体 70 System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Green, Color.Red, 1.2f, true);//设置笔刷 71 g.DrawString(checkCode, font, brush, 0, 0);//将验证码绘制到画布中 72 for (int i = 0; i < 100; i++) //画图片的前景噪音点 73 { 74 int x = random.Next(image.Width); 75 int y = random.Next(image.Height); 76 image.SetPixel(x, y, Color.FromArgb(random.Next())); 77 } 78 HttpContext.Current.Response.Cookies["code"].Value = checkCode;//将验证码存入cookie中 79 //画图片的边框线 80 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); 81 System.IO.MemoryStream ms = new System.IO.MemoryStream();//创建内存流 82 image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);//将验证码图片存入内存流 83 Page.Response.Clear();//清除缓冲区流中所有内容输出 84 Page.Response.ContentType = "image/GIF";//设置输出流类型 85 Page.Response.BinaryWrite(ms.ToArray());//写入输出流 86 Page.Response.Flush();//向客户端发送输出流 87 ms.Close();//释放资源 88 ms.Dispose();//释放资源 89 Page.Response.End(); 90 } 91 catch (Exception ex) 92 { 93 throw ex; 94 } 95 finally 96 { 97 g.Dispose(); 98 image.Dispose(); 99 } 100 } 101 102 /// <summary> 103 /// 控件加载事件 104 /// </summary> 105 protected override void OnLoad(EventArgs e) 106 { 107 base.OnLoad(e); 108 try 109 { 110 string sn = Page.Request.QueryString["_ImageTag"];//获取页面传递的参数 111 if (sn != null)//判断参数是否为空，如果不为空时才能生成验证码，并绘制输出到页面 112 { 113 _checkCode = GetValidateCode();//生成验证码 114 CreateCheckCodeImage(_checkCode);//绘制输出到页面 115 } 116 else 117 { 118 //创建一个JavaScript函数用于生成随机数 119 string script = @"<script language='JavaScript'> 120 function getnum() 121 { 122 var num=Math.floor(Math.random()*100); 123 return num; 124 } 125 </script>"; 126 //将该方法注册到控件所在的页面中 127 Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "getnum", script); 128 } 129 } 130 catch { } 131 } 132 133 protected override void RenderContents(HtmlTextWriter output) 134 { 135 string CID = string.Empty; 136 try 137 { 138 if (string.IsNullOrEmpty(_checkCode))//首先判断是否生成了验证码 139 { 140 CID = this.UniqueID + "img";//设置页面IMG的ID值 141 //输出表格到页面 142 output.Write("<table cellpadding="0" cellspacing="0" >"); 143 output.Write("<tr>"); 144 output.Write("<td>"); 145 output.Write("<img border="0" src="{0}" id="{1}"/>", this.Page.Request.Path + "?_ImageTag=" + DateTime.Now.Second, CID);//输出img图片，并且指定其src地址，因为验证码控件是被输出到当前的页面中，所以接收当前页面地址作为图片的数据源 146 output.Write("</td>"); 147 output.Write("<td>"); 148 output.Write("<a style="cursor:pointer;font-size:small" onclick="document.getElementById('" + CID + "').src=" + "'" + this.Page.Request.Path + "?_ImageTag='" + "+getnum()" + """ + "> 看不清？</a>");//创建一个连接，单击后无刷新更换验证码 149 output.Write("</td>"); 150 output.Write("</tr>"); 151 output.Write("</table>"); 152 } 153 } 154 catch 155 { 156 output.Write("<table cellpadding="0" cellspacing="0" >"); 157 output.Write("<tr>"); 158 output.Write("<td>"); 159 output.Write("</td>"); 160 output.Write("<td>"); 161 //显示“看不清？”链接 162 output.Write("<a style="cursor:pointer;font-size:small"" + "> 看不清？</a>"); 163 output.Write("</td>"); 164 output.Write("</tr>"); 165 output.Write("</table>"); 166 } 167 } 168 169 /// <summary> 170 /// 公共方法用于验证输入的验证码是否正确 171 /// </summary> 172 public bool CheckSN(string sn) 173 { 174 bool flag = false; 175 if (HttpContext.Current.Request.Cookies["code"].Value != null)//如果cookie不为空 176 { 177 flag = sn.ToLower() == HttpContext.Current.Request.Cookies["code"].Value.ToString().ToLower();//判断记录的cookie与输入的验证码是否一致 178 } 179 return flag; 180 } 181 182 }