DownloadFileAsync is downloading incomplete file

Question

• Partcode Targeted .net core is 4.0, using "visual studio 2017"

Sub DownloadFile()

        Dim wc As New WebClient
        Try
            Dim durl As String = "https://onedrive.live.com/download?cid=9B804CF9A004FFF3&resid=9B804CF9A004FFF3%212166&authkey=ABv40n0yI5bLOAo"""

            'wc.Headers.Add("user-agent", "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12 (.NET CLR 3.5.30729)")
            'wc.DownloadFile(durl, Application.StartupPath & "\Temp.rar")
            wc.DownloadFileAsync(New Uri(durl), "test.rar")

        Catch ex As Exception

            SendToLogFile("Download  " & ex.Message)
        End Try

    End Sub

• Problem: with wc.Headers.Add method downloaded file size was 78 kb, without headers download file size is 28 Kb. actual file size is 110kb or more . I tried in another pc assuming network/firewall issue but the result is same and incomplete.

• What I Tried : I tried the downloadfileasync method, the downloadfile method, and the My.Computer.Network.DownloadFile method, but they all resulted in a partial download. When I paste the url into Chrome or another browser, it works perfectly.

• I need this code to work on all Windows operating system versions

Answer 1

To do that you can use several techniques. Here a pair of those:

Try

    'Using HttpClient
    Using wc As HttpClient = New HttpClient()
        Dim bytes() As Byte = wc.GetByteArrayAsync("https://onedrive.live.com/download?cid=9B804CF9A004FFF3&resid=9B804CF9A004FFF3%212166&authkey=ABv40n0yI5bLOAo").Result
        Using sw As New MemoryStream(bytes)
            Using sr As Stream = File.Create("test.rar")
                sw.CopyTo(sr)
            End Using
        End Using
    End Using

    'Using WebClient
    Using wc As WebClient = New WebClient()
        Dim bytes() As Byte = wc.DownloadData("https://onedrive.live.com/download?cid=9B804CF9A004FFF3&resid=9B804CF9A004FFF3%212166&authkey=ABv40n0yI5bLOAo")
        Using sw As New MemoryStream(bytes)
            Using sr As Stream = File.Create("test1.rar")
                sw.CopyTo(sr)
            End Using
        End Using
    End Using

Catch ex As Exception
    Debug.WriteLine(ex.ToString)
End Try