一個C#生成簡單驗證碼的類

一個C#生成簡單驗證碼的類

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls.WebParts;
using System.Data;
using System.Web.Security;
using System.Collections;
using System.Drawing;

public partial class Code : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Session["label"] == null)
        {
            string str = "";
            string[] code = {"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","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"};

        //隨機產生字符串
        Random rand = new Random();
        for (int i = 0; i < 4; i++)
        {
            str = str + code[rand.Next(0, code.Length)];
        }
        CreateImage(str);

        foreach (var s in str)
        {
             str += s;
        }
        Session["str"] = str;
        //foreach (string s in str)
        //{
        //    str += s;
        //}
        //Session["str"] = str;
      //  Label1.Text = str;
      //  Session["label"] = Label1.Text;
    }
}
//畫驗證圖片
private void CreateImage(string checkcode)
{
    if (checkcode == null || checkcode.Length <= 0)
        return;

    int width = (int)(checkcode.Length * 25);
    System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling(checkcode.Length*32.5), 40);
    Graphics g = Graphics.FromImage(image);
    g.Clear(Color.White);
    //定義顏色
    Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
    //定義字體
    string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋體" };
    Random rand = new Random();

    //畫圖片的背景線
    for (int i = 0; i < 70; i++)
    {
        int x = rand.Next(image.Width);
        int y = rand.Next(image.Height);
        g.DrawLine(new Pen(Color.LightGray, 1), x, y, 10, 20);
    }
    //輸出不同字體和顏色的驗證碼字符
    for (int i = 0; i < checkcode.Length; i++)
    {
        int cindex = rand.Next(7);
        int findex = rand.Next(5);

        Font f = new System.Drawing.Font(font[findex], 23, System.Drawing.FontStyle.Bold);//23表示字體大小
        Brush brush = new System.Drawing.SolidBrush(c[cindex]);
        int ii = 4;
        if ((i + 1) % 2 == 0)
        {
            ii = 2;
        }
        g.DrawString(checkcode.Substring(i, 1), f, brush, 15 + (i * 12), ii);
    }

    //畫邊框，畫圖片的邊框線
    g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1);

    //輸出到瀏覽器
    System.IO.MemoryStream ms = new System.IO.MemoryStream();
    image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
    HttpContext.Current.Response.ContentType = "image/jpeg";
    HttpContext.Current.Response.BinaryWrite(ms.ToArray());
    g.Dispose();
    image.Dispose();
}



}</pre>