验证码--点击验证码就换一个验证码---最简单的
html页面<form id="form1" runat="server"> <img src="Handler2.ashx"/> </form>
ashx页面，一般处理程序页面：
public class Handler2 : IHttpHandler { public void ProcessRequest(HttpContext context) { //context.Response.ContentType = "text/html";//返回一个text的东西，也就是string context.Response.ContentType = "image/JPEG"; using (System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(100, 50))//(100,50)是大小 { using(System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap) ) { Random rand = new Random(); int code = rand.Next(1111, 2222); string mycode = code.ToString(); // HttpContext.Current.Session["code_yes"] = mycode; g.DrawString(mycode,new System.Drawing.Font("宋体",50),System.Drawing.Brushes.Green,new System.Drawing.PointF(0,0)); bitmap.Save(context.Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg); } } } public bool IsReusable { get { return false; } } }
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