C#验证码的使用

心已赠人 2021-09-14 03:58 253阅读 0赞

**1、C\#创建验证码**

**1.1 创建获取验证码页面（ValidateCode.aspx）**

<html xmlns="http://www.w3.org/1999/xhtml">
    <head runat="server">
        <title>获取验证码</title>
    </head>
    <body>
        <form id="form1" runat="server">
            <div>获取验证码</div>
        </form>
    </body>
    </html>

**1.2 编写获取验证码代码（ValidateCode.aspx.cs）**

/// <summary>
    /// 验证码类型(0-字母数字混合,1-数字,2-字母)
    /// </summary>
    private string validateCodeType = "0";
    /// <summary>
    /// 验证码字符个数
    /// </summary>
    private int validateCodeCount = 4;
    /// <summary>
    /// 验证码的字符集，去掉了一些容易混淆的字符
    /// </summary>
    char[] character = { '2', '3', '4', '5', '6', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };
    
    protected void Page_Load(object sender, EventArgs e)
    {
        //取消缓存
        Response.BufferOutput = true;
        Response.Cache.SetExpires(DateTime.Now.AddMilliseconds(-1));
        Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache);
        Response.AppendHeader("Pragma", "No-Cache");
        //获取设置参数
        if (!string.IsNullOrEmpty(Request.QueryString["validateCodeType"]))
        {
            validateCodeType = Request.QueryString["validateCodeType"];
        }
        if (!string.IsNullOrEmpty(Request.QueryString["validateCodeCount"]))
        {
            int.TryParse(Request.QueryString["validateCodeCount"], out validateCodeCount);
        }
        //生成验证码
        this.CreateCheckCodeImage(GenerateCheckCode());
    }
    
    private string GenerateCheckCode()
    {
        char code ;
        string checkCode = String.Empty;
        System.Random random = new Random();
    
        for (int i = 0; i < validateCodeCount; i++)
        {
            code = character[random.Next(character.Length)];
    
            // 要求全为数字或字母
            if (validateCodeType == "1")
            {
                if ((int)code < 48 || (int)code > 57)
                {
                    i--;
                    continue;
                }
            }
            else if (validateCodeType == "2")
            {
                if ((int)code < 65 || (int)code > 90)
                {
                    i--;
                    continue;
                }
            }
            checkCode += code;
        }
    
        Response.Cookies.Add(new System.Web.HttpCookie("CheckCode", checkCode));
        this.Session["CheckCode"] = checkCode;
        return checkCode;
    }
    
    private void CreateCheckCodeImage(string checkCode)
    {
        if (checkCode == null || checkCode.Trim() == String.Empty)
            return;
    
        System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length*15.0+40)), 23);
        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
    
        try
        {
            //生成随机生成器
            Random random = new Random();
    
            //清空图片背景色
            g.Clear(System.Drawing.Color.White);
    
            //画图片的背景噪音线
            for (int i = 0; i < 25; 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 System.Drawing.Pen(System.Drawing.Color.Silver), x1, y1, x2, y2);
            }
    
            System.Drawing.Font font = new System.Drawing.Font("Arial", 14, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new System.Drawing.Rectangle(0, 0, image.Width, image.Height), System.Drawing.Color.Blue, System.Drawing.Color.DarkRed, 1.2f, true);
    
            int cySpace = 16;
            for (int i = 0; i < validateCodeCount; i++)
            {
                g.DrawString(checkCode.Substring(i, 1), font, brush, (i + 1) * cySpace, 1);
            }
    
            //画图片的前景噪音点
            for (int i = 0; i < 100; i++)
            {
                int x = random.Next(image.Width);
                int y = random.Next(image.Height);
    
                image.SetPixel(x, y, System.Drawing.Color.FromArgb(random.Next()));
            }
    
            //画图片的边框线
            g.DrawRectangle(new System.Drawing.Pen(System.Drawing.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();
        }
    }

**2、验证码的使用**

**2.1 验证码的前段显示代码**

**2.2 创建验证码测试页面（ValidateTest.aspx）**

<html xmlns="http://www.w3.org/1999/xhtml">
    <head runat="server">
        <title>验证码测试</title>
    </head>
    <body>
        <form id="form1" runat="server">
        <div>
            <input runat="server" id="txtValidate" />
            <img src="/ValidateCode.aspx?ValidateCodeType=1&0.011150883024061309" οnclick="this.src='/ValidateCode.aspx?ValidateCodeType=1&'+Math.random();" id="imgValidateCode" alt="点击刷新验证码" title="点击刷新验证码" style="cursor: pointer;">
            <asp:Button runat="server" id="btnVal" Text="提交" οnclick="btnVal_Click"  />
        </div>
        </form>
    </body>
    </html>

**2.3 编写验证码测试的提交代码（ValidateTest.aspx.cs）**

protected void btnVal_Click(object sender, EventArgs e)
    {
        bool result = false;   //验证结果
        string userCode = this.txtValidate.Value; //获取用户输入的验证码
        if (String.IsNullOrEmpty(userCode))
        { 
            //请输入验证码
            return;
        }
    
        string validCode = this.Session["CheckCode"] as String;  //获取系统生成的验证码
        if (!string.IsNullOrEmpty(validCode))
        {
            if (userCode.ToLower() == validCode.ToLower())
            {
                //验证成功
                result = true;
            }
            else
            {
                //验证失败
                result = false;
            }
        }
    }