原文实例讲述了ASP.NET创建动态缩略图的方法。广州网站制作公司分享给大家供大家参考。

提示：

1. 导入 System.IO 
2. 创建 类C lass "CreateThumbnails" 
or any class and place following function inside that class
You need one function to response call back to main function
Function ImageAbortDummyCallback() As Boolean 
Return False 
End Function

具体代码如下：

Function CreateJPEGThumbnail(ByVal inSourceFile As String, ByVal inDestinationFile As String, ByVal ThumbWidth As Integer, ByVal 

ThumbHeight As Integer) As Boolean
  Dim imageFile As System.Drawing.Image
  Dim outputFstream As New FileStream(inSourceFile, FileMode.Open, FileAccess.Read) 
  'Exposes a System.IO.Stream around a file, supporting both synchronous and asynchronous read and write operations.
  Dim ImageAbortCallBack As System.Drawing.Image.GetThumbnailImageAbort 
  'This method returns true if it decides that the System.Drawing.Image.GetThumbnailImage method should prematurely stop execution; 

otherwise, it returns false.
  imageFile = System.Drawing.Image.FromStream(outputFstream)
  ImageAbortCallBack = New System.Drawing.Image.GetThumbnailImageAbort(AddressOf ImageAbortDummyCallback)
  imageFile = imageFile.GetThumbnailImage(ThumbWidth, ThumbHeight, ImageAbortCallBack, IntPtr.Zero) 
  'IntPtr = A platform-specific type that is used to represent a pointer or a handle.
  imageFile.Save(inDestinationFile, System.Drawing.Imaging.ImageFormat.Jpeg)
  outputFstream.Close()
  outputFstream = Nothing
  imageFile = Nothing
End Function