C#生成验证码实例

常用生成验证码实例封装：

/// <summary>

/// 生成内存位图

/// </summary>

/// <param name="Code"></param>

/// <returns></returns>

public static Bitmap GetCode(out string Code)

{

    int imgWidth = ;

    int imgHeight = ;

    //获取随机字符

    Code = DateTimeHelper.GetCode_Ran();

    //颜色列表，用于验证码、噪线、噪点

    Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };

    //字体列表，用于验证码

    string[] font = { "Times New Roman", "MS Mincho", "Book Antiqua", "Gungsuh", "PMingLiU", "Impact" };

    Bitmap bmp = new Bitmap(imgWidth, imgHeight);

    Graphics g = Graphics.FromImage(bmp);

    g.Clear(Color.White);

    Random rnd = new Random();

    //画噪线

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

    {

        int x1 = rnd.Next(imgWidth);

        int y1 = rnd.Next(imgHeight);

        int x2 = rnd.Next(imgWidth);

        int y2 = rnd.Next(imgHeight);

        Color clr = color[rnd.Next(color.Length)];

        g.DrawLine(new Pen(clr), x1, y1, x2, y2);

    }

    //画验证码字符串

    for (int i = ; i < Code.Length; i++)

    {

        string fnt = font[rnd.Next(font.Length)];

        Font ft = new Font(fnt, );

        Color clr = color[rnd.Next(color.Length)];

        g.DrawString(Code[i].ToString(), ft, new SolidBrush(clr), (float)i * , (float));

    }

    //画噪点

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

    {

        int x = rnd.Next(bmp.Width);

        int y = rnd.Next(bmp.Height);

        Color clr = color[rnd.Next(color.Length)];

        bmp.SetPixel(x, y, clr);

    }

    //显式释放资源

    // bmp.Dispose();

    g.Dispose();

    return bmp;

}

/// <summary>

/// 生成位图，输出到响应流

/// </summary>

/// <param name="Response"></param>

/// <param name="Code"></param>

public static void GetCode(HttpResponseBase Response, out string Code)

{

    Code = string.Empty;

    Bitmap bit = GetCode(out Code);

    ////清除该页输出缓存，设置该页无缓存

    //Response.Buffer = true;

    //Response.ExpiresAbsolute = DateTime.Now.AddMilliseconds(0);

    //Response.Expires = 0;

    //Response.CacheControl = "no-cache";

    //Response.AppendHeader("Pragma", "No-Cache");

    Response.ClearContent();

    bit.Save(Response.OutputStream, ImageFormat.Png);

    Response.ContentType = "image/png";

    //释放资源

    bit.Dispose();

}