简单的上传图片并生成缩略图

页面：

  
    

   
     <
   
     form id
   
     =
   
     "
   
     form1
   
     "
   
      runat
   
     =
   
     "
   
     server
   
     "
   
     >
   
     
 
   
     <
   
     div
   
     >
   
     
 
   
     <
   
     asp:FileUpload ID
   
     =
   
     "
   
     FileUpload1
   
     "
   
      runat
   
     =
   
     "
   
     server
   
     "
   
      
   
     />
   
     
 
   
     <
   
     asp:Button ID
   
     =
   
     "
   
     Button1
   
     "
   
      runat
   
     =
   
     "
   
     server
   
     "
   
      Text
   
     =
   
     "
   
     UP
   
     "
   
      OnClick
   
     =
   
     "
   
     Button1_Click
   
     "
   
      
   
     />
   
     
 
   
     </
   
     div
   
     >
   
     

   
     </
   
     form
   
     >
  
    

后台：　　

  
    

   
     　　　　　protected
   
      
   
     void
   
      Button1_Click(
   
     object
   
      sender, EventArgs e)
 {
 UpImageFile(FileUpload1);
 }

 
   
     protected
   
      
   
     void
   
      UpImageFile(FileUpload fileLoad)
 {
 
   
     if
   
      (fileLoad.HasFile)
 {
 
   
     string
   
      fileType 
   
     =
   
      fileLoad.PostedFile.ContentType;
 
   
     if
   
      (fileType 
   
     ==
   
      
   
     "
   
     image/bmp
   
     "
   
      
   
     ||
   
      fileType 
   
     ==
   
      
   
     "
   
     image/pjpeg
   
     "
   
      
   
     ||
   
      fileType 
   
     ==
   
      
   
     "
   
     image/gif
   
     "
   
      
   
     ||
   
      fileType 
   
     ==
   
      
   
     "
   
     image/png
   
     "
   
     )
 {
 
   
     string
   
      loadPath 
   
     =
   
      fileLoad.PostedFile.FileName; 
   
     //
   
     等待上传文件的本地路径
   
     

   
      System.Drawing.Image img 
   
     =
   
      System.Drawing.Image.FromFile(loadPath);
 
   
     if
   
      (img.Height 
   
     >
   
      
   
     100
   
      
   
     ||
   
      img.Width 
   
     >
   
      
   
     100
   
     )
 {
 FileInfo info 
   
     =
   
      
   
     new
   
      FileInfo(loadPath);
 
   
     string
   
      fName 
   
     =
   
      info.Name; 
   
     //
   
     获取原文件名
   
     

   
      
   
     string
   
      fileName 
   
     =
   
      DateTime.Now.ToString(
   
     "
   
     yyMMddhhmmss
   
     "
   
     ) 
   
     +
   
      fName; 
   
     //
   
     在文件名中加入时间
   
     

   
      
   
     string
   
      imgPath 
   
     =
   
      Server.MapPath(
   
     "
   
     /UpFile/OrImages/
   
     "
   
     ) 
   
     +
   
      fileName; 
   
     //
   
     原文件路径
   
     

   
      
   
     string
   
      thPath 
   
     =
   
      Server.MapPath(
   
     "
   
     /UpFile/ThImages/
   
     "
   
     ) 
   
     +
   
      fileName; 
   
     //
   
     缩略图路径
   
     

   
      fileLoad.SaveAs(imgPath); 
   
     //
   
     保存原图片
   
     

   
      MakeThumnail(imgPath, thPath); 
   
     //
   
     生成缩略图
   
     

   
      }
 
   
     else
   
     
 {
 
   
     //
   
     图片尺寸太小
   
     

   
      }
 }
 
   
     else
   
     
 {
 
   
     //
   
     文件格式不对
   
     

   
      }

 }
 }

 
   
     protected
   
      
   
     void
   
      MakeThumnail(
   
     string
   
      orPath, 
   
     string
   
      thPath)
 {
 System.Drawing.Image img 
   
     =
   
      System.Drawing.Image.FromFile(orPath);
 
   
     int
   
      width 
   
     =
   
      
   
     100
   
     ; 
   
     //
   
     设置缩略图的宽为100
   
     

   
      
   
     int
   
      height 
   
     =
   
      img.Height 
   
     *
   
      width 
   
     /
   
      img.Width; 
   
     //
   
     缩略图的高按比例缩小
   
     

   
      System.Drawing.Image bitmap 
   
     =
   
      
   
     new
   
      System.Drawing.Bitmap(width, height); 
   
     //
   
     创建一个空位图
   
     

   
      System.Drawing.Graphics g 
   
     =
   
      System.Drawing.Graphics.FromImage(bitmap); 
   
     //
   
     创建画板
   
     

   
      g.InterpolationMode 
   
     =
   
      System.Drawing.Drawing2D.InterpolationMode.High; 
   
     //
   
     设定为高质量插值
   
     

   
      g.SmoothingMode 
   
     =
   
      System.Drawing.Drawing2D.SmoothingMode.HighQuality; 
   
     //
   
     指定高质量低速度呈现
   
     

   
      g.Clear(Color.Transparent);
 g.DrawImage(img, 
   
     new
   
      Rectangle(
   
     0
   
     , 
   
     0
   
     , width, height));
 
   
     try
   
     
 {
 bitmap.Save(thPath, System.Drawing.Imaging.ImageFormat.Jpeg); 
   
     //
   
     以JPG格式保存图片
   
     

   
      }
 
   
     catch
   
      (System.Exception e)
 {
 
   
     throw
   
      e;
 }
 
   
     finally
   
     
 {
 img.Dispose();
 bitmap.Dispose();
 g.Dispose();
 }
 }