设置登录时的图形验证码
首先建一个一般处理程序，命名为RandomCode.ashx
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Collections; 6 using System.Configuration; 7 using System.Data; 8 using System.Web; 9 using System.Web.UI; 10 using System.Web.UI.WebControls; 11 using System.Web.UI.WebControls.WebParts; 12 using System.Web.UI.HtmlControls; 13 using System.Drawing; 14 15 namespace IntegritySystem.Web.Tools 16 { 17 /// <summary> 18 /// RandomCode 的摘要说明 19 /// </summary> 20 public class RandomCode : IHttpHandler, System.Web.SessionState.IRequiresSessionState 21 { 22 public void ProcessRequest(HttpContext context) 23 { 24 string checkCode = GetRandomCode(5); 25 context.Session["CheckCode"] = checkCode; 26 SetPageNoCache(); 27 CreateImage(checkCode); 28 } 29 //获取验证码各个字母 30 private string GetRandomCode(int CodeCount) 31 { 32 string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,i,J,K,M,N,P,Q,R,S,T,U,W,X,Y,Z"; 33 string[] allCharArray = allChar.Split(','); 34 string RandomCode = ""; 35 int temp = -1; 36 Random rand = new Random(); 37 for (int i = 0; i < CodeCount; i++) 38 { 39 if (temp != -1) 40 { 41 rand = new Random(temp * i * ((int)DateTime.Now.Ticks)); 42 } 43 int t = rand.Next(33); 44 while (temp == t) 45 { 46 t = rand.Next(33); 47 } 48 temp = t; 49 RandomCode += allCharArray[t]; 50 } 51 return RandomCode; 52 } 53 54 //页面设置没有缓存 55 private void SetPageNoCache() 56 { 57 HttpContext.Current.Response.Buffer = true; 58 HttpContext.Current.Response.ExpiresAbsolute = System.DateTime.Now.AddSeconds(-1); 59 HttpContext.Current.Response.Expires = 0; 60 HttpContext.Current.Response.CacheControl = "no-cache"; 61 HttpContext.Current.Response.AppendHeader("Pragma", "No-Cache"); 62 } 63 64 //设置背景图片 65 private void CreateImage(string checkCode) 66 { 67 int iwidth = (int)(checkCode.Length * 14); 68 System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 30); 69 Graphics g = Graphics.FromImage(image); 70 Font f = new System.Drawing.Font("Arial", 15); 71 Brush b = new System.Drawing.SolidBrush(Color.Black); 72 Brush r = new System.Drawing.SolidBrush(Color.FromArgb(166, 8, 8)); 73 g.Clear(System.Drawing.ColorTranslator.FromHtml("#fff"));//背景色 74 char[] ch = checkCode.ToCharArray(); 75 for (int i = 0; i < ch.Length; i++) 76 { 77 if (ch[i] >= '0' && ch[i] <= '9') 78 { 79 g.DrawString(ch[i].ToString(), f, r, 8 + (i * 12), 3); 80 } 81 else 82 { 83 g.DrawString(ch[i].ToString(), f, b, 3 + (i * 12), 3); 84 } 85 } 86 System.IO.MemoryStream ms = new System.IO.MemoryStream(); 87 image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); 88 HttpContext.Current.Response.Cache.SetNoStore(); 89 HttpContext.Current.Response.ClearContent(); 90 HttpContext.Current.Response.ContentType = "image/Jpeg"; 91 HttpContext.Current.Response.BinaryWrite(ms.ToArray()); 92 g.Dispose(); 93 image.Dispose(); 94 } 95 public bool IsReusable 96 { 97 get 98 { 99 return false; 100 } 101 } 102 } 103 }
然后前台调用：
<input type="text" class="yzm" id="Codes" name="Codes" maxlength="6" style="width: 80px; float: left;" /> <img id="codeimg" alt="验证码" src="/Tools/RandomCode.ashx" title="点击" style=" margin-bottom:-5px; cursor:pointer;" onclick="EditCode(this)"/>
脚本点击事件：
function EditCode() { document.getElementById("codeimg").src="/Tools/RandomCode.ashx?id="+Math.random(); }
在就是后台验证就可以了：
1 if (Session["CheckCode"] != null) 2 { 3 if (Codes.ToLower() != Session["CheckCode"].ToString().ToLower()) 4 { 5 Message = "验证码输入错误，请输入正确的验证码!"; 6 return Json(new { Success = b, ErrorMessage = Message }, JsonRequestBehavior.AllowGet); 7 } 8 } 9 else 10 { 11 Message = "验证码输入错误，请输入正确的验证码!"; 12 return Json(new { Success = b, ErrorMessage = Message }, JsonRequestBehavior.AllowGet); 13 }
效果就是这样了，验证码个数可以调整：
