ASP.NET中實現直接從網頁上下載檔案

函數名：ResponseFile
功能  ：用戶端從伺服器端下載一個檔案
傳回值：返回True表示伺服器響應成功，返回False表示失敗
參數  ：
        PageResponse       響應用戶端的Response對象，用Page.Response引用
        DownloadFileName   用戶端下載檔案的檔案名稱
        LocalFilePath      伺服器端待下載檔案的路徑
        DownloadBuffer     伺服器端讀取檔案的緩衝區大小，單位為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