asp.net简单生成验证码的方法

2020-01-17 23:03:03

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本文实例讲述了asp.net简单生成验证码的方法。分享给大家供大家参考，具体如下：

1.新建一个一般处理程序

namespace WebApplication1{ /// <summary> /// $codebehindclassname$ 的摘要说明 /// </summary> [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] public class Handler1 : IHttpHandler, IRequiresSessionState {  public void ProcessRequest(HttpContext context)  {   context.Response.ContentType = "image/gif";   //建立Bitmap对象，绘图   Bitmap basemap = new Bitmap(100, 30);   Graphics graph = Graphics.FromImage(basemap);   graph.FillRectangle(new SolidBrush(Color.White), 0, 0, 100, 30);   Font font = new Font(FontFamily.GenericSerif, 24, FontStyle.Bold, GraphicsUnit.Pixel);   Random r = new Random();   string letters = "ABCDEFGHIJKLMNPQRSTUVWXYZ";   string letter;   StringBuilder s = new StringBuilder();   //添加随机的五个字母   for (int x = 0; x < 5; x++)   {    letter = letters.Substring(r.Next(0, letters.Length - 1), 1);    s.Append(letter);    graph.DrawString(letter, font, new SolidBrush(Color.Black), x * 19, r.Next(0, 8));   }   //混淆背景   Pen linePen = new Pen(new SolidBrush(Color.Black), 2);   for (int x = 0; x < 6; x++)    graph.DrawLine(linePen, new Point(r.Next(0, 99), r.Next(0, 29)), new Point(r.Next(0, 99), r.Next(0, 29)));   //将图片保存到输出流中     basemap.Save(context.Response.OutputStream, ImageFormat.Gif);   context.Session["CheckCode"] = s.ToString(); //如果没有实现IRequiresSessionState，则这里会出错，也无法生成图片   context.Response.End();  }  public bool IsReusable  {   get   {    return false;   }  } }}

2.前台代码

<html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div>  <asp:TextBox ID="txtCode" runat="server"></asp:TextBox>  <img id="imgCode" alt="看不清？点击换一张" src="Handler1.ashx" style="cursor:pointer" onclick="this.src=this.src+'?'" /><br />  <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" /> </div> </form></body></html>

希望本文所述对大家asp.net程序设计有所帮助。

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