很不错的验证码显示页

很不错的验证码显示页

getCode.aspx

程序代码

using System;
using System.Drawing;

public partial class Control_getCode : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        createCheckCode(getCode(4));
    }
    private string getCode(int num)
    {
        string codeStr = string.Empty;
        //为了方便识别去除了 零 和 英文O
        string codeStrTmp = "a,b,c,d,e,f,g,h,i,j,k,l,m,n,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,P,Q,R,S,T,U,V,W,X,Y,Z,1,2,3,4,5,6,7,8,9";
        string[] codeArr = codeStrTmp.Split(',');
        Random rad = new Random();
        for (int i = 0; i < num; i++)
        {
            codeStr += codeArr[rad.Next(codeArr.Length)];
        }
        Session["getCode"] = codeStr;
        return codeStr;
    }

    private void createCheckCode(string checkCode)
    {
        if (checkCode == null || checkCode.Trim() == string.Empty) return;

        System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 20);
        Graphics g = Graphics.FromImage(image);
        try
        {
            //生成随机生成器
            Random random = new Random();
            //清空图片背景色
            g.Clear(Color.White);
            //画图片的背景噪音线
            for (int i = 0; i < 2; i++)
            {
                int x1 = random.Next(image.Width);
                int x2 = random.Next(image.Width);
                int y1 = random.Next(image.Height);
                int y2 = random.Next(image.Height);
                g.DrawLine(new Pen(Color.Black), x1, y1, x2, y2);
            }
            Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
            g.DrawString(checkCode, font, brush, 2, 2);
            //画图片的前景噪音点
            for (int i = 0; i < 50; i++)
            {
                int x = random.Next(image.Width);
                int y = random.Next(image.Height);
                image.SetPixel(x, y, Color.FromArgb(random.Next()));
            }
            //画图片的边框线
            g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            Response.ClearContent();
            Response.ContentType = "image/Gif";
            Response.BinaryWrite(ms.ToArray());
        }
        finally
        {
            g.Dispose();
            image.Dispose();
        }
    }
}

应用时加入 <img src="getCode.aspx" />