C# 上传文件并生成缩略图

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        #region 上传文件并生成缩略图        /// <summary>        /// 上传文件并生成缩略图        /// </summary>        /// <param name="paramFileUpload">上传控件</param>        /// <param name="paramVirtualPath">上传目标虚拟路径</param>        /// <param name="paramDirectory">用户自定义创建文件夹</param>        /// <param name="paramOriginalDirectory">存放原始文件夹</param>        /// <param name="paramThumbnailDirectory">存放缩略图文件夹</param>        /// <param name="tWidth">缩略图默认宽度</param>        /// <param name="tHeight">缩略图默认高度</param>        private string UploadAndThumbnail(FileUpload paramFileUpload, string paramVirtualPath, string paramDirectory, string paramOriginalDirectory, string paramThumbnailDirectory, int tWidth, int tHeight, string paramFileName)        {            string returnValue = string.Empty;//返回值            string imgType;//文件类型            string fullFileName = paramFileUpload.PostedFile.FileName; //上传文件名            imgType = fullFileName.Substring(fullFileName.LastIndexOf(".") + 1).ToLower();//文件类型            string UserPath = Server.MapPath(paramVirtualPath).ToString() + "\\" + paramDirectory;//存放文件目录            //如果文件夹不存在则创建            if (!Directory.Exists(UserPath))            {                Directory.CreateDirectory(UserPath);            }            string originalImagePath = UserPath + "\\" + paramOriginalDirectory;//原始路径            if (!Directory.Exists(originalImagePath))            {                Directory.CreateDirectory(originalImagePath);            }            string thumbnailPath = UserPath + "\\" + paramThumbnailDirectory;            if (!Directory.Exists(thumbnailPath))            {                Directory.CreateDirectory(thumbnailPath);            }            // 获取上传图像的文件名            string fileName = paramFileName;            if (imgType == "jpg" || imgType == "jpeg" || imgType == "bmp" || imgType == "png" || imgType == "icon")            {                try                {                    //生成原图                    byte[] oFileByte = new byte[paramFileUpload.PostedFile.ContentLength];                    Stream oStream = paramFileUpload.PostedFile.InputStream;                    System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream);                    int oWidth = oImage.Width;//原图宽度                    int oHeight = oImage.Height;//原图高度                    if (tWidth == 0)                    {                        tWidth = 100;                    }                    if (tHeight == 0)                    {                        tHeight = 100;                    }                    //按比例计算出缩略图的宽度和高度                    if (oWidth >= oHeight)                    {                        tHeight = (int)Math.Floor(Convert.ToDouble(oHeight) * (Convert.ToDouble(tWidth) / Convert.ToDouble(oHeight)));                    }                    else                    {                        tWidth = (int)Math.Floor(Convert.ToDouble(oWidth) * (Convert.ToDouble(tHeight) / Convert.ToDouble(oHeight)));                    }                    //生成缩略图                    Bitmap tImage = new Bitmap(tWidth, tHeight);                    Graphics g = Graphics.FromImage(tImage);                    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;//设置高质量插值法                    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量，低速度呈现平滑程度                    g.Clear(Color.Transparent);//清空画布并以透明背景色填充                    g.DrawImage(oImage, new Rectangle(0, 0, tWidth, tHeight), new Rectangle(0, 0, oWidth, oHeight), GraphicsUnit.Pixel);                    string oPath = originalImagePath + "\\" + fileName + ".jpg";                    string tPath = thumbnailPath + "\\" + fileName + ".jpg";                    //以JPG格式保存图像                    oImage.Save(oPath, System.Drawing.Imaging.ImageFormat.Jpeg);                    tImage.Save(tPath, System.Drawing.Imaging.ImageFormat.Jpeg);                    returnValue = "上传成功！";                    //释放资源                                        oImage.Dispose();                    g.Dispose();                    tImage.Dispose();                }                catch (Exception ex)                {                    returnValue = "由于网络原因，上载文件错误 " + ex.Message;                }            }            else            {                returnValue = "你选择的图像格式错误!";            }            return returnValue;        }        #endregion
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