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标题: ASP.NET中实现直接从网页上下载文件 [打印本页]

作者: 三颗残牙 时间: 2009-3-16 18:39
标题: ASP.NET中实现直接从网页上下载文件
函数名：ResponseFile
功能  ：客户端从服务器端下载一个文件
返回值：返回True表示服务器响应成功，返回False表示失败
参数  ：
      PageResponse    响应客户端的Response对象，用Page.Response引用
      DownloadFileName 客户端下载文件的文件名
      LocalFilePath    服务器端待下载文件的路径
      DownloadBuffer    服务器端读取文件的缓冲区大小，单位为KB

Public Function ResponseFile(ByRef PageResponse As HttpResponse, ByVal DownloadFileName As String, ByVal LocalFilePath As String, ByVal DownloadBuffer As Long) As Boolean
      Dim Reader As System.IO.FileStream

      Dim Buffer() As Byte
      Dim FileLength As Long
      Dim FileBuffer As Long = 1024 * DownloadBuffer
      Dim ReadCount As Long
      ReadCount = FileBuffer
      ReDim Buffer(ReadCount - 1)
      Try
            Reader = System.IO.File.OpenRead(LocalFilePath)
            FileLength = Reader.Length
            Try
                     PageResponse.Buffer = False
                     PageResponse.AddHeader("Connection", "Keep-Alive")
                     PageResponse.ContentType = "application/octet-stream"
                     PageResponse.AddHeader("Content-Disposition", "attachment;filename=" + DownloadFileName)
                     PageResponse.AddHeader("Content-Length", FileLength.ToString)
                     While ReadCount = FileBuffer
                              ReadCount = Reader.Read(Buffer, 0, FileBuffer)
                              ReDim Preserve Buffer(ReadCount - 1)
                              PageResponse.BinaryWrite(Buffer)
                     End While
                     Response.End()
            Catch ex As Exception
                     Return False
            Finally
                     Reader.Close()
            End Try
      Catch ex As Exception
            Return False
      End Try
      Return True
End Function

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