Question

C# 网页生成随机验证码

C# 生成随机验证码  我要做一个注册页面，随机验证码应该如何生成，以及如何验证验证码， 验证码包含字母和数字请告诉指教

Answer 1

新建一个web窗体。下面是后台。没有前台。直接运行。看看在符不符合你的要求
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;

namespace FeiBoLaiTe.Admin
{
public partial class Yanzhengma : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
GenImg(GenCode(4));
}
}
private string GenCode(int num)
{
string[] source ={"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 code = "";
Random rd = new Random();
for (int i = 0; i < num; i++)
{
code += source[rd.Next(0, source.Length)];
}
return code;
}

//生成图片
private void GenImg(string code)
{
Bitmap myPalette = new Bitmap(45, 16);//定义一个画板

Graphics gh = Graphics.FromImage(myPalette);//在画板上定义绘图的实例

Rectangle rc = new Rectangle(0, 0, 45, 16);//定义一个矩形

gh.FillRectangle(new SolidBrush(Color.CornflowerBlue), rc);//填充矩形
gh.DrawString(code, new Font("宋体", 13), new SolidBrush(Color.White), rc);//在矩形内画出字符串

myPalette.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);//将图片显示出来

Session["code"] = code;//将字符串保存到Session中，以便需要时进行验证

gh.Dispose();
myPalette.Dispose();
}
}
}

Answer 2

验证码不是你想的那样直接生成字母和数字的随机数，他生成后还要压缩成图片 再前台用图片现实 这就是验证码 像你说的这种 有验证码跟无验证码是没什么区别的 很容易注入

Answer 3

建立个验证码生成的页面。。在需要调用的页面调用就好了。。