C# 实现ASP.NET网站图片验证码生成与显示

using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Text;
using System.Drawing.Drawing2D;
using System.Drawing.Text;
using System.Drawing;
public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {

        //创建一个包含随机内容的验证码文本
        Random rd = new Random();
        int leng = rd.Next(4, 6);
        char[] arr = "0123456789ABCDEFGHIJKLMNPQRSTUVWXYZ".ToCharArray();
        StringBuilder mystr = new StringBuilder();
        for (int i = 0; i < leng; i++)
        {
            mystr.Append(arr[rd.Next(arr.Length)]);
        }
        string text = mystr.ToString();