.NET MVC 验证码

效果差不多就这样，接下来直接上代码。

验证码生成器


public class ValidateCode
{
    public static ValidateCode Default = new ValidateCode();
    public int ImageWidth { get; set; }
    public int ImageHeight { get; set; }
    public string Letters { get; set; }
    public int CodeLength { get; set; }
    private Random r = new Random();
    public ValidateCode()
    {
        ImageWidth = 200;
        ImageHeight = 60;
        CodeLength = 6;
        Letters = "abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ1234567890";
    }
    public string GetValidationCode()
    {
        //合法随机显示字符列表
        System.Text.StringBuilder s = new System.Text.StringBuilder();
        //将随机生成的字符串绘制到图片上
        for (int i = 0; i < CodeLength; i++)
        {
            s.Append(Letters.Substring(r.Next(0, Letters.Length - 1), 1));
        }
        return s.ToString();
    }
    public byte[] GetValidationImage(string codeString)
    {
        //设置输出流图片格式
        var b = new System.Drawing.Bitmap(ImageWidth, ImageHeight);
        var g = System.Drawing.Graphics.FromImage(b);
        int ColorR = r.Next(0, 255);
        int ColorG = r.Next(0, 255);
        int ColorB = r.Next(0, 255);

        g.FillRectangle(new System.Drawing.SolidBrush(System.Drawing.Color.FromArgb(ColorR, ColorG, ColorB)), 0, 0, 200, 60);
        var font = new System.Drawing.Font(System.Drawing.FontFamily.GenericSerif, 48, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Pixel);

        //合法随机显示字符列表

        //将随机生成的字符串绘制到图片上
        for (int i = 0; i < codeString.Length; i++)
        {
            int sR = r.Next(0, 255);
            int sG = r.Next(0, 255);
            int sB = r.Next(0, 255);
            while (Math.Abs(sR - ColorR) < 35) sR = r.Next(0, 255);
            while (Math.Abs(sG - ColorG) < 35) sG = r.Next(0, 255);
            while (Math.Abs(sB - ColorB) < 35) sB = r.Next(0, 255);
            g.DrawString(codeString[i].ToString(), font, new System.Drawing.SolidBrush(System.Drawing.Color.FromArgb(sR, sG, sB)), i * (200 / codeString.Length - 2), r.Next(0, 15));
        }

        //生成干扰线条
        var pen = new System.Drawing.Pen(new System.Drawing.SolidBrush(System.Drawing.Color.FromArgb(r.Next(0, 255), r.Next(0, 255), r.Next(0, 255))), 2);
        for (int i = 0; i < 10; i++)
        {
            g.DrawLine(pen, new System.Drawing.Point(r.Next(0, 199), r.Next(0, 59)), new System.Drawing.Point(r.Next(0, 199), r.Next(0, 59)));
        }

        var stream = new System.IO.MemoryStream();
        b.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
        g.Dispose();
        b.Dispose();
        //输出图片流
        return stream.ToArray();
    }
}

使用方法


public ActionResult validateCode()  //创建一个action用于返回验证码图片
{
    string validateCode = ValidateCode.Default.GetValidationCode();     //获取验证码
    Session["LoginValidateCode"] = validateCode;    //将验证码保存到Session中
    return File(ValidateCode.Default.GetValidationImage(validateCode), @"image/jpeg");  //返回验证码图片
}
//直接将这个action 的地址赋值给img标签就可以了，例如 <img src="http://localhost:5695/home/validateCode" alt="">

public ActionResult Login(string validateCode)
{
    if (String.IsNullOrEmpty(Session["LoginValidateCode"].ToString()))
    {
        return Content("你登录页面停留的时间过久页已经超时");
    }
    else if (!Session["LoginValidateCode"].ToString().Equals(validateCode, StringComparison.CurrentCultureIgnoreCase))
    {
        return Content("验证码错误");
    }

    return RedirectToAction("Index");   //成功
}