asp.net 验证码 图片验证码

废话没有，代码（img.aspx.cs）：

using System;

using System.Data;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Drawing;



public partial class salt_img : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        string checkCode = CreateRandomCode(4);

        Session["CheckCode"] = checkCode;

        CreateImage(checkCode);

    }



    private string CreateRandomCode(int codeCount)

    {

        string allChar = "1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,P,R,S,T,U,W,X,Y,Z";

        string[] allCharArray = allChar.Split(',');

        string randomCode = "";

        int temp = -1;



        Random rand = new Random();

        for (int i = 0; i < codeCount; i++)

        {

            if (temp != -1)

            {

                rand = new Random(i * temp * ((int)DateTime.Now.Ticks));

            }

            int t = rand.Next(allCharArray.Length);

            if (temp == t)

            {

                return CreateRandomCode(codeCount);

            }

            temp = t;

            randomCode += allCharArray[t];

        }

        return randomCode;

    }



    private void CreateImage(string checkCode)

    {

        int iwidth = (int)(checkCode.Length * 13);

        System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 20);

        Graphics g = Graphics.FromImage(image);

        Font f = new System.Drawing.Font("Arial", 12, System.Drawing.FontStyle.Bold);

        Brush b = new System.Drawing.SolidBrush(Color.Black);

        //g.FillRectangle(new System.Drawing.SolidBrush(Color.Blue),0,0,image.Width, image.Height);

        g.Clear(Color.White);

        g.DrawString(checkCode, f, b, 3, 3);



        Pen blackPen = new Pen(Color.Black, 0);

        Random rand = new Random();

        for (int i = 0; i < 3; i++)//干扰线

        {

            int y = rand.Next(image.Height);

            g.DrawLine(blackPen, 0, y, image.Width, y);

        }



        System.IO.MemoryStream ms = new System.IO.MemoryStream();

        image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

        Response.ClearContent();

        Response.ContentType = "image/Jpeg";

        Response.BinaryWrite(ms.ToArray());

        g.Dispose();

        image.Dispose();

    }

}

 

 

代码：img.aspx  （只留下下面的其余全部删除）

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="img.aspx.cs" Inherits="salt_img" %>