​ Public Function NextAvailDrive() As String
' alle logischen Laufwerke
Dim sDrives As String = Join(Directory.GetLogicalDrives(), "")
Dim sNextDrive As String = ""

' nach 1. nicht verwendetes Laufwerk suchen
' beginnend ab C:
For i As Integer = 68 To 90
If Not sDrives.Contains(Chr(i) & ":") Then
sNextDrive = Chr(i) & ":" : Exit For
End If
Next

Return sNextDrive
End Function
Public Function AddNetworkDrive(ByVal Drive As String, _
ByVal UncPath As String, _
Optional ByVal Username As String = "", _
Optional ByVal Password As String = "") As Boolean

Dim p As New Process()
Try
With p.StartInfo
.FileName = "net"
If Username.Length > 0 Then
' Netzlaufwerk mit Benutzername und Kennwort erstellen
.Arguments = String.Format("use {0} ""{1}"" /user:""{2}"" {3}", _
Drive, UncPath, Username, Password)
Else
' Netzlaufwerk ohne Benutzername und Kennwort erstellen
.Arguments = String.Format("use {0} ""{1}""", Drive, UncPath)
End If
.UseShellExecute = False
.CreateNoWindow = True
End With
p.Start()
Return True

Catch ex As Exception
Return False
End Try
Application.DoEvents()
End Function
Public Sub RemoveNetworkDrive(ByVal Drive As String)
Dim p As New Process()
Try
With p.StartInfo
.FileName = "net"
.Arguments = String.Format("use " & Drive & " /DELETE")
.UseShellExecute = False
.CreateNoWindow = True
End With
p.Start()
Catch ex As Exception
End Try
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
AddNetworkDrive(strDrive, "\\192.168.61.3\backup")

Dim lw As New System.IO.DriveInfo(strDrive)
Dim TotalFreeSpace As Long = lw.TotalFreeSpace
Dim TotalSize As Long = lw.TotalSize
Dim DriveSpaceUsed As Long = TotalSize - TotalFreeSpace
la_ges.Text = Math.Round(TotalSize.ToString / 1024 / 1024 / 1024, 2)
la_ben.Text = Math.Round(DriveSpaceUsed.ToString / 1024 / 1024 / 1024, 2)
la_fre.Text = Math.Round(TotalFreeSpace.ToString / 1024 / 1024 / 1024, 2)
la_proz.Text = Math.Round(1 - DriveSpaceUsed / TotalSize * -100, 2) & "%"

ProgressBar1.Maximum = la_ges.Text
ProgressBar1.Value = la_ben.Text
RemoveNetworkDrive(strDrive)
End Sub