现在很多的网站都有输入验证码的功能,那么我们看看这个是怎么做的!
功能显示就不多说了,直接正题:
一,生成验证码部分
①新建aspx页面,前台不需要写任何的东西
②在后台编辑代码:定义生成图片的方法CreateCheckCodeImage(string code),需要参数;生成随机验证码GenerateCheckCode()。
#region 生成图片 void CreateCheckCodeImage(string code) { var imageCode = new System.Drawing.Bitmap((int)Math.Ceiling((code.Length * 12.5)), 23); //定义图片的宽度和高度 var g = Graphics.FromImage(imageCode); //加载图片到画布上 try { var random = new Random(); g.Clear(Color.White); //清空图片背景色 //画图片的背景噪音线 for (int i = 0; i < 25; i++) { var x1 = random.Next(imageCode.Width); var x2 = random.Next(imageCode.Width); var y1 = random.Next(imageCode.Height); var y2 = random.Next(imageCode.Height); g.DrawLine(new Pen(Color.Silver), new Point(x1, y1), new Point(x2, y2)); } var font = new System.Drawing.Font("Arial", 12F, System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic); var brush = new System.Drawing.Drawing2D.LinearGradientBrush( new Rectangle(0, 0, imageCode.Width, imageCode.Height), Color.Blue, Color.DarkRed, 1.2F, true); g.DrawString(code, font, brush, 2, 2); //画图片的前景噪音点 for (int i = 0; i < 100; i++) { var x = random.Next(imageCode.Width); var y = random.Next(imageCode.Height); imageCode.SetPixel(x, y, Color.FromArgb(random.Next())); } //画图片的边框线 g.DrawRectangle(new Pen(Color.Silver), 0, 0, imageCode.Width - 1, imageCode.Height - 1); var ms = new System.IO.MemoryStream(); imageCode.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); Session.Add("code", code); Response.ClearContent(); Response.ContentType = "image/Jpeg"; Response.BinaryWrite(ms.ToArray()); } finally { g.Dispose(); imageCode.Dispose(); } } #endregion #region 生成数据验证码 private string GenerateCheckCode() { int number; char code; string checkCode = String.Empty; var random = new Random(); for (int i = 0; i < 5; i++) { number = random.Next(); if (number % 2 == 0) code = (char)('0' + (char)(number % 10)); else code = (char)('A' + (char)(number % 26)); checkCode += code.ToString(); } return checkCode; } #endregion
③在load中执行方法CreateCheckCodeImage(GenerateCheckCode()); //生成数字英文所要使用的方法
ps:需要的命名空间 using System.Drawing;
二,调用验证码
①直接与session["code"]进行匹配,一样的就ok,不一样就弹出验证码不匹配
if (!Session["code"].ToString().ToUpper().Trim().Equals(TextBoxCode.Value.ToUpper())) { System.Web.UI.ScriptManager.RegisterClientScriptBlock(UpdatePanel1, typeof(UpdatePanel), "提示", "<script type='text/javascript'>alert('校验码有误!');getimgcode();</script>", false); TextBoxCode.Focus(); return; }