asp.net实现上传图片时判断图片的模式GRB或CMYK的方法

Bitmap bmp = new Bitmap(allow_fileStream); //文件路径allowUpload = stringHelper.IsCMYK(bmp) == "true" ? false : true; //返回true字符串则图片不是RGB模式的public string IsCMYK(System.Drawing.Image img){    string isCmyk;    if ((GetImageFlags(img).IndexOf("Ycck") > -1) || (GetImageFlags(img).IndexOf("Cmyk") > -1))    {      isCmyk = "true";    }    else    {      isCmyk = "false";    }    return isCmyk;}public string GetImageFlags(System.Drawing.Image img){    ImageFlags FlagVals = (ImageFlags)Enum.Parse(typeof(ImageFlags), img.Flags.ToString());    return FlagVals.ToString();}