.NET 图片上传

  /// <summary>
/// asp.net上传图片并生成缩略图
/// </summary>
/// <param name="upImage">HtmlInputFile控件</param>
/// <param name="sSavePath">保存的路径,些为相对服务器路径的下的文件夹</param>
/// <param name="sThumbExtension">缩略图的thumb</param>
/// <param name="intThumbWidth">生成缩略图的宽度</param>
/// <param name="intThumbHeight">生成缩略图的高度</param>
/// <returns>缩略图名称</returns>
public string UpLoadImage(FileUpload upImage, string savePath, string sThumbExtension, int intThumbWidth, int intThumbHeight)
{
      if (upImage.HasFile)
      {
         if (upImage.PostedFile.ContentLength > 0 && upImage.PostedFile.ContentLength / 1024 < 1024)
         {
            string imgType = upImage.PostedFile.ContentType.ToString(); // 图片类型
            if (imgType.Equals("image/pjpeg") || imgType.Equals("image/gif") || imgType.Equals("image/png"))
            {
                  //取得上传文件的扩展名
                  string strExt = upImage.PostedFile.FileName.Substring(upImage.PostedFile.FileName.LastIndexOf("."));
                  // 自定义名称保存
                  string newImaName = (sThumbExtension + strExt).ToString();
                  // 保存到指定目录
                  string newsavePath = Server.MapPath(savePath);

                  System.Drawing.Image img = System.Drawing.Image.FromFile(upImage.PostedFile.FileName);
                  if (img.Width < intThumbWidth && img.Height < intThumbHeight)
                  {
                     return "图片的宽度和高度不符合(" + intThumbWidth + "*" + intThumbHeight+")";
                  }
                  else
                  {
                     upImage.PostedFile.SaveAs(newsavePath + newImaName);
                     return "上传图片成功.";
                  }


                  //try
                  //{
                  // //原图加载
                  // using (System.Drawing.Image sourceImage = System.Drawing.Image.FromFile(upImage.PostedFile.FileName))
                  // {
                  //       //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;
                  //       }

                  //       // 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();
                  //                   //缩略图保存的绝对路径
                  //                   bitmap1.Save(newsavePath, System.Drawing.Imaging.ImageFormat.Jpeg);
                  //             }
                  //          }
                  //       }

                  // }
                  //}
                  //catch(Exception ex)
                  //{
                  // return ex.Message.ToString();
                  //}

            }
            else
            {
                  return "图片类型不正确.";
            }

         }
         else
         {
            return "请选择不大于1M的图片.";
         }
      }
      else
      {
         return "没有选择图片";
      }
}

(/// <summary>
/// asp. Net upload pictures and generate thumbnails
/// </summary>
///< param name = "upimage" > htmlinputfile control < / param >
///< param name = "ssavepath" > the saved paths are the folders under the relative server path < / param >
///< param name = "sthumbextension" > thumb of thumbnail < / param >
///< param name = "intthumbwidth" > width of generated thumbnail < / param >
///< param name = "intthumbheight" > height of generated thumbnail < / param >
///< returns > thumbnail name < / returns >
public string UpLoadImage(FileUpload upImage, string savePath, string sThumbExtension, int intThumbWidth, int intThumbHeight)
{
if (upImage.HasFile)
{
if (upImage.PostedFile.ContentLength > 0 && upImage.PostedFile.ContentLength / 1024 < 1024)
{
string imgType = upImage. PostedFile. ContentType. ToString(); //  Picture type
if (imgType.Equals("image/pjpeg") || imgType. Equals("image/gif") || imgType. Equals("image/png"))
{
//Gets the extension of the uploaded file
string strExt = upImage. PostedFile. FileName. Substring(upImage.PostedFile.FileName.LastIndexOf("."));
//Custom name save
string newImaName = (sThumbExtension + strExt). ToString();
//Save to specified directory
string newsavePath = Server. MapPath(savePath);
System. Drawing. Image img = System. Drawing. Image. FromFile(upImage.PostedFile.FileName);
if (img.Width < intThumbWidth && img.Height < intThumbHeight)
{
Return "the width and height of the picture do not match (" + intthumbwidth + "*" + intthumbheight + ")";
}
else
{
upImage. PostedFile. SaveAs(newsavePath + newImaName);
Return "the picture was uploaded successfully.";
}
//try
//{
/// / original image loading
// using (System.Drawing.Image sourceImage = System.Drawing.Image.FromFile(upImage.PostedFile.FileName))
// {
/// / original width and height
//       int width = sourceImage. Width;
//       int height = sourceImage. Height;
//       int smallWidth;
//       int smallHeight;
/// / obtain the size of the first drawing (compare the width of the original drawing / the width of the thumbnail with the height of the original drawing / the height of the thumbnail)
//       if (((decimal)width) / height <= ((decimal)intThumbWidth) / intThumbHeight)
//       {
//          smallWidth = intThumbWidth;
//          smallHeight = intThumbWidth * height / width;
//       }
//       else
//       {
//          smallWidth = intThumbHeight * width / height;
//          smallHeight = intThumbHeight;
//       }
/// / create a new drawing board and draw the original drawing with the minimum equal scale compression size
//       using (System.Drawing.Image bitmap = new System.Drawing.Bitmap(smallWidth, smallHeight))
//       {
/// / draw the middle diagram
//          using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap))
//          {
/// / HD, smooth
//             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);
//          }
/// / create a new drawing board and draw the middle drawing with the size of thumbnail
//          using (System.Drawing.Image bitmap1 = new System.Drawing.Bitmap(intThumbWidth, intThumbHeight))
//          {
/// / draw thumbnails
//             using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap1))
//             {
/// / HD, smooth
//                   g.InterpolationMode = System. Drawing. Drawing2D. InterpolationMode. High;
//                   g.SmoothingMode = System. Drawing. Drawing2D. SmoothingMode. HighQuality;
//                   g.Clear(Color.Black);
//                   int lwidth = (smallWidth - intThumbWidth) / 2;
)

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