DownloadFile tramite System.net.WebClient non funziona

Question

Non riesco a scaricare alcun file con il codice seguente:

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    DownloadFile("http://mirror.switch.ch/ftp/mirror/videolan/vlc/2.0.3/vlc-2.0.3.tar.xz", "C:\TEST\vlc-2.0.3.tar.xz")
End Sub

Public Sub DownloadFile(ByVal _URL As String, ByVal _SaveAs As String)
        Dim _WebClient As New System.Net.WebClient()
        _WebClient.DownloadFile(_URL, _SaveAs)
End Sub

.

I seguenti errori si apriranno: (Tradotto dal tedesco all'inglese):

Dal pop-up di errore Microsoft:

==> A non trattata EXE) da Digitare "System.net.WebException" è apparso in System.dll.

e al debugger:

==> Exociation: attivato: "È stato specificato un argomento non valido" (system.net.sochets.socketException) System.Net.Sochets.Socket.Socket.Socket.SexPexception è stato attivato."È stato specificato un argomento non valido"

Codice completo:

Imports System
Imports System.Net

Public Class Form2
    Dim str_hd As String

    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load


        For Each drive As System.IO.DriveInfo In My.Computer.FileSystem.Drives
            Dim dbl_capacity As Double
            Dim dbl_free As Double
            Dim dbl_used As Double

            If drive.IsReady Then
                dbl_capacity = drive.TotalSize / 1073741824
                dbl_free = drive.TotalFreeSpace / 1073741824
                dbl_used = dbl_capacity - dbl_free

                dbl_capacity = Fix(dbl_capacity * 1) / 1
                dbl_free = Fix(dbl_free * 10) / 10
                dbl_used = Fix(dbl_used * 10) / 10


                str_hd = str_hd & "Laufwerk " & drive.Name & "  -  " _
                        & drive.VolumeLabel & vbCrLf _
                        & "Benutzt: " & dbl_used & " GB" & " / " & dbl_capacity & " GB" & vbCrLf & "Frei: " _
                        & dbl_free & "GB" & vbCrLf & "-------------------------------" & vbCrLf
            End If
        Next

        txtbox_hd.Text = str_hd

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Form1.Close()
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        DownloadFile("http://www.aerztekammer-hamburg.de/berufsrecht/Berufsordnung.pdf", "C:\TEST\Berufsordnung.pdf")
    End Sub



    Public Sub DownloadFile(ByVal _URL As String, ByVal _SaveAs As String)
            Dim _WebClient As New System.Net.WebClient()
            _WebClient.DownloadFile(_URL, _SaveAs)
    End Sub

End Class

.

Answer 1

Esistono la cartella C:\TEST?Inoltre, dalla documentazione:

.

Quando si utilizza questo metodo in un'applicazione di livello centrale, ad esempio una pagina ASP.NET, si riceverà un errore se l'account in cui l'applicazione esegue non ha l'autorizzazione per accedere al file.

Wenn Sie Diese Methode in Einer Anwendung Der Verwenden, z.B. EINER ASP.NET-Seite, Erhalten Sie Eine Fehlermeldung, Wenn Das Konto, Unter Dem Die Anwendung Ausgeführt Wird, Nicht Über Die Berechtigung Zum Zugriff Auf Dietei Verfügt.