asp.net验证码

最新推荐文章于 2025-12-01 22:23:46 发布

原创最新推荐文章于 2025-12-01 22:23:46 发布 · 356 阅读

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文章标签：

#asp.net #random #image #string #session #server

using System.Drawing; using System.Drawing.Drawing2D;

类：

/// <summary> /// 生成验证码 /// </summary> private void DrowCode() { Response.Cache.SetNoStore(); System.Drawing.Bitmap image = new System.Drawing.Bitmap(77, 20); Graphics g = Graphics.FromImage(image); Color[] borders = new Color[10] { Color.AliceBlue, Color.Aqua, Color.Black, Color.Brown, Color.DarkRed, Color.SkyBlue, Color.Silver, Color.Tan, Color.Violet, Color.SpringGreen }; try { Random random = new Random(); g.Clear(Color.White); //画图片的背景噪音线 for (int i = 0; i < 2; i++) { int x1 = random.Next(image.Width); int x2 = random.Next(image.Width); int y1 = random.Next(image.Height); int y2 = random.Next(image.Height); g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2); } string str = "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"; string[] codes = str.Split(','); string serial = string.Empty; for (int i = 0; i < 6; i++) // i 控制验证码字符个数 { serial += codes[random.Next(codes.Length)]; } Font font = new System.Drawing.Font("Verdana", 11, System.Drawing.FontStyle.Bold); System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); g.DrawString(serial, font, brush, random.Next(image.Width - 77), random.Next(image.Height - 20)); //画图片的前景噪音点 for (int i = 0; i < 50; i++) { int x = random.Next(image.Width); int y = random.Next(image.Height); image.SetPixel(x, y, Color.FromArgb(random.Next())); } //画图片的边框线 g.DrawRectangle(new Pen(borders[random.Next(borders.Length)]), 0, 0, image.Width - 1, image.Height - 1); System.IO.MemoryStream ms = new System.IO.MemoryStream(); image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); HttpContext.Current.Response.ClearContent(); HttpContext.Current.Response.ContentType = "image/Gif"; HttpContext.Current.Response.BinaryWrite(ms.ToArray()); Session["ValidateCode"] = serial.ToLower(); } finally { g.Dispose(); image.Dispose(); } }

调用：<asp:Image ID="Image1" runat="server" ImageUrl="~/Code.aspx" onclick="this.src='./Code.aspx'" ToolTip="点击更换" />