ASP.NET上传图片并生成缩略图-优快云博客

方法一：
002     /// asp.net上传图片并生成缩略图
003     /// </summary>
004     /// <param name="upImage">HtmlInputFile控件</param>
005     /// <param name="sSavePath">保存的路径,些为相对服务器路径的下的文件夹</param>
006     /// <param name="sThumbExtension">缩略图的thumb</param>
007     /// <param name="intThumbWidth">生成缩略图的宽度</param>
008     /// <param name="intThumbHeight">生成缩略图的高度</param>
009     /// <returns>缩略图名称</returns>
服务器端控件：fileupload
public string UpLoadImage(FileUpload fileupload,string sSavePath,string sThumbExtension,int intThumbWidth,int intThumbHeight)
public string UpLoadImage(HtmlInputFile upImage,string sSavePath,string sThumbExtension,int intThumbWidth,int intThumbHeight)
     {
         string sThumbFile ="";
         string sFilename ="";
         if(upImage.PostedFile !=null)
         {
             HttpPostedFile myFile = upImage.PostedFile;
             int nFileLen = myFile.ContentLength;
             if(nFileLen == 0)
                 return"没有选择上传图片";
             //获取upImage选择文件的扩展名
             string extendName = System.IO.Path.GetExtension(myFile.FileName).ToLower();
             //判断是否为图片格式
             if(extendName !=".jpg"&& extendName !=".jpge"&& extendName !=".gif"&& extendName !=".bmp"&& extendName !=".png")
                 return"图片格式不正确";

             byte[] myData =new Byte[nFileLen];
             myFile.InputStream.Read(myData,0 , nFileLen);
             sFilename = System.IO.Path.GetFileName(myFile.FileName);
             int file_append = 0;
             //检查当前文件夹下是否有同名图片,有则在文件名+
             while(System.IO.File.Exists(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sFilename)))
             {
                 file_append++;
                 sFilename = System.IO.Path.GetFileNameWithoutExtension(myFile.FileName)
                     + file_append.ToString() + extendName;
             }
             System.IO.FileStream newFile
                 =new System.IO.FileStream(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sFilename),
                 System.IO.FileMode.Create, System.IO.FileAccess.Write);
             newFile.Write(myData,0 , myData.Length);
             newFile.Close();
             //以上为上传原图
             try
             {
                 //原图加载
                 using(System.Drawing.Image sourceImage = System.Drawing.Image.FromFile(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sFilename)))
                 {
                     //原图宽度和高度
                     int width = sourceImage.Width;
                     int height = sourceImage.Height;
                     int smallWidth;
                     int smallHeight;
                     //获取第一张绘制图的大小,(比较原图的宽/缩略图的宽和原图的高/缩略图的高)
                     if(((decimal)width) / height <= ((decimal)intThumbWidth) / intThumbHeight)
                     {
                         smallWidth = intThumbWidth;
                         smallHeight = intThumbWidth * height / width;
                     }
                     else
                     {
                         smallWidth = intThumbHeight * width / height;
                         smallHeight = intThumbHeight;
                     }
                     //判断缩略图在当前文件夹下是否同名称文件存在
                     file_append =0 ;
                     sThumbFile = sThumbExtension + System.IO.Path.GetFileNameWithoutExtension(myFile.FileName) + extendName;
                     while(System.IO.File.Exists(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sThumbFile)))
                     {
                         file_append++;
                         sThumbFile = sThumbExtension + System.IO.Path.GetFileNameWithoutExtension(myFile.FileName) +
                             file_append.ToString() + extendName;
                     }
                     //缩略图保存的绝对路径
                     string smallImagePath = System.Web.HttpContext.Current.Server.MapPath(sSavePath) + sThumbFile;
                     //新建一个图板,以最小等比例压缩大小绘制原图
                     using(System.Drawing.Image bitmap =new System.Drawing.Bitmap(smallWidth, smallHeight))
                     {
                         //绘制中间图
                         using(System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap))
                         {
                             //高清,平滑
                             g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                             g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                             g.Clear(Color.Black);
                             g.DrawImage(
                             sourceImage,
                             new System.Drawing.Rectangle(0, 0, smallWidth, smallHeight),
                             new System.Drawing.Rectangle(0,0 , width, height),
                             System.Drawing.GraphicsUnit.Pixel
                             );
                         }
                         //新建一个图板,以缩略图大小绘制中间图
                         using(System.Drawing.Image bitmap1 =new System.Drawing.Bitmap(intThumbWidth, intThumbHeight))
                         {
                             //绘制缩略图
                             using(System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap1))
                             {
                                 //高清,平滑
                                 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                                 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                                 g.Clear(Color.Black);
                                 int lwidth = (smallWidth - intThumbWidth) /2 ;
                                 int bheight = (smallHeight - intThumbHeight) /2 ;
                                 g.DrawImage(bitmap,new Rectangle(0,0 , intThumbWidth, intThumbHeight), lwidth, bheight, intThumbWidth, intThumbHeight, GraphicsUnit.Pixel);
                                 g.Dispose();
                                 bitmap.Save(smallImagePath, System.Drawing.Imaging.ImageFormat.Jpeg);
                             }
                         }
                     }
                 }
             }
             catch
             {
                 //出错则删除
                 System.IO.File.Delete(System.Web.HttpContext.Current.Server.MapPath(sSavePath + sFilename));
                 return"图片格式不正确";
             }
             //返回缩略图名称
             return sThumbFile;
         }
         return"没有选择图片";
     }


方法二：
        /// <summary>
        /// 图片上传,带缩略图自定义处理
        /// </summary>
        /// <param name="fileupload">上传控件</param>
        /// <param name="pictureDirectoryAbsolutePath">站点下绝对目录路径 eg: "/pics/a/"</param>
        /// <param name="newPictureName">新命名图片（不带格式部分，格式维持原来的）</param>
        /// <param name="supportPictureType">eg: "|gif|jpg|png"，如果为空，默认支持以上三种</param>
        /// <param name="message">返回消息</param>
        /// <param name="isCreateDefaultThumb">是否立即生成缩略图</param>
        public static bool PictrueUpload(FileUpload fileupload, string pictureDirectoryAbsolutePath, string newPictureName, string supportPictureType,
                out string pictureAbsolutePath, out string message,
                bool isCreateDefaultThumb, string thumbPhysicalFullPath, int thumbWidth, int thumbHeight, out string thumbAbsolutePath)
        {
            message = "图片上传成功";
            pictureAbsolutePath = "";
            thumbAbsolutePath = "";
            #region 参数验证
            string picturePhysicalFullPath = "";
            if (string.IsNullOrEmpty(fileupload.FileName))
            {
                message = "请选择待上传图片";
                return false; ;
            }
            if (String.IsNullOrEmpty(pictureDirectoryAbsolutePath))
            {
                message = "pictureDirectoryAbsolutePath参数不能为空";
                return false;
            }
            if (String.IsNullOrEmpty(newPictureName))
            {
                message = "newPictureName参数不能为空";
                return false;
            }
            #endregion
            //存储目录创建
            string pictureDirectoryPhysicalPath = HttpContext.Current.Server.MapPath(pictureDirectoryAbsolutePath);
            if (!Directory.Exists(pictureDirectoryPhysicalPath))
            {
                Directory.CreateDirectory(pictureDirectoryPhysicalPath);
            }
            string fileName = fileupload.FileName.Trim();
            string typeName = fileName.Substring(fileName.LastIndexOf('.') + 1).ToLower();
            //上传图片格式验证
            if (!PictureSupportFormatToValidate(typeName, supportPictureType, out message))
            {
                return false;
            }
            //原始图片上传后的物理地址
            picturePhysicalFullPath = pictureDirectoryPhysicalPath + newPictureName + "." + typeName;
            //原始图片上传
            fileupload.SaveAs(picturePhysicalFullPath);
            //返回的图片绝对地址
            pictureAbsolutePath = pictureDirectoryAbsolutePath + newPictureName + "." + typeName;
            #region 缩略图处理
            //缩略图生成处理
            if (isCreateDefaultThumb)
            {
                if (String.IsNullOrEmpty(thumbPhysicalFullPath))
                {
                    string thumbDirectoryPhysicalPath = String.Format("{0}thumb/", pictureDirectoryPhysicalPath);
                    //缩略图目录创建
                    if (!Directory.Exists(thumbDirectoryPhysicalPath))
                    {
                        Directory.CreateDirectory(thumbDirectoryPhysicalPath);
                    }
                    //缩略图存储地址
                    thumbPhysicalFullPath = String.Format("{0}{1}.jpg", thumbDirectoryPhysicalPath, newPictureName);
                }
                using (StreamReader sr = new StreamReader(picturePhysicalFullPath))
                {
                    CustomPictureManager.ThumbAsJPG(sr.BaseStream, thumbPhysicalFullPath, thumbWidth, thumbHeight);
                    thumbAbsolutePath = pictureDirectoryAbsolutePath + "thumb/" + newPictureName + "." + typeName;
                }
            }
            #endregion 缩略图处理
            return true;
        }

.net 图片上传