ASP.NET验证码

using System; using System.Collections.Generic; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Drawing; public partial class Verify : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Random random = new Random(); int RadNum = random.Next(1000, 10000); Session["Verifycode"] = RadNum.ToString(); Bitmap image = new Bitmap(40, 16); Graphics g = Graphics.FromImage(image); g.Clear(Color.White); //绘制验证码 g.DrawString(RadNum.ToString(), new Font("黑体", 12), new SolidBrush(Color.Black), 0, 0); //绘制杂色 for (int i = 0; i < 100; i++) { int x = random.Next(image.Width); int y = random.Next(image.Height); image.SetPixel(x, y, Color.FromArgb(random.Next())); } //绘制划痕 for (int i = 0; i < 2; i++) { int x1 = random.Next(image.Width); int y1 = random.Next(image.Height); int x2 = random.Next(image.Width); int y2 = random.Next(image.Height); g.DrawLine(new Pen(Color.Black), x1, y1, x2, y2); } image.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Gif); } }

Verify.aspx页面 里面写着绘制的图形。

<img id="imgCode" onclick="src='/verify.aspx?s='+Math.random()" src="/verify.aspx"/>
html页面中用来显示验证码的地方