public byte[] GetVerifyCode(out string code)

         {

             code = string.Empty;

             int codeW = ;

             int codeH = ;

             int fontSize = ;

             string chkCode = string.Empty;

             Random rnd = new Random();

             //颜色列表，用于验证码、噪线、噪点

             System.DrawingCore.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" };

             //验证码的字符集，去掉了一些容易混淆的字符

             char[] character = { '', '', '', '', '', '', '', 'a', 'b', 'd', 'e', 'f', 'h', 'k', 'm', 'n', 'r', 'x', 'y', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };

             //生成验证码字符串

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

             {

                 chkCode += character[rnd.Next(character.Length)];

             }

             code = chkCode;

             //创建画布

             Bitmap bmp = new Bitmap(codeW, codeH);

             Graphics g = Graphics.FromImage(bmp);

             g.Clear(Color.White);

             //画噪线

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

             {

                 int x1 = rnd.Next(codeW);

                 int y1 = rnd.Next(codeH);

                 int x2 = rnd.Next(codeW);

                 int y2 = rnd.Next(codeH);

                 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 < chkCode.Length; i++)

             {

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

                 Font ft = new Font(fnt, fontSize);

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

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

             }

             //将验证码图片写入内存流，并将其以 "image/Png" 格式输出

             MemoryStream ms = new MemoryStream();

             try

             {

                 bmp.Save(ms, ImageFormat.Png);

                 return ms.ToArray();

             }

             catch (Exception)

             {

                 return null;

             }

             finally

             {

                 g.Dispose();

                 bmp.Dispose();

             }

         }

  public IActionResult Code()

         {

             #region 反射SK支持的全部颜色

             //List<SKColor> colors = new List<SKColor>();

             //var skcolors = new SKColors();

             //var type = skcolors.GetType();

             //foreach (FieldInfo field in type.GetFields())

             //{

             //    colors.Add( (SKColor)field.GetValue(skcolors));

             //}

             #endregion

             //int maxcolorindex = colors.Count-1;

             string text = "1A3V";

             var zu = text.ToList();

             SKBitmap bmp = new SKBitmap(, );

             using (SKCanvas canvas = new SKCanvas(bmp))

             {

                 //背景色

                 canvas.DrawColor(SKColors.White);

                 using (SKPaint sKPaint = new SKPaint())

                 {

                     sKPaint.TextSize = ;//字体大小

                     sKPaint.IsAntialias = true;//开启抗锯齿

                     sKPaint.Typeface = SKTypeface.FromFamilyName("微软雅黑", SKTypefaceStyle.Bold);//字体

                     SKRect size = new SKRect();

                     sKPaint.MeasureText(zu[].ToString(), ref size);//计算文字宽度以及高度

                     float temp = (bmp.Width/ - size.Size.Width)/;

                     float temp1 = bmp.Height - (bmp.Height - size.Size.Height) / ;

                     Random random = new Random();

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

                     {

                         sKPaint.Color = new SKColor((byte)random.Next(,), (byte)random.Next(, ), (byte)random.Next(, ));

                         canvas.DrawText(zu[i].ToString(), temp + *i, temp1, sKPaint);//画文字

                     }

                     //干扰线

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

                     {

                         sKPaint.Color = new SKColor((byte)random.Next(, ), (byte)random.Next(, ), (byte)random.Next(, ));

                         canvas.DrawLine(random.Next(, ), random.Next(, ), random.Next(, ), random.Next(, ), sKPaint);

                     }

                 }

                 //页面展示图片

                 using (SKImage img = SKImage.FromBitmap(bmp))

                 {

                     using (SKData p = img.Encode())

                     {

                         return File(p.ToArray(), "image/Png");

                     }

                 }

             }

         }