Public dbconn As OleDbConnection
    Public cmd As New OleDbCommand
    Public da As New OleDbDataAdapter()
    Public dt As New DataTable
 
    Public Function getData(sql As String, Optional dbPath As String = "") As _
      DataTable
        Try
            Dim connectionstring As String = ""
            Dim cmd As New OleDbCommand
 
            If dbconn Is Nothing OrElse dbconn.State <> ConnectionState.Open Then
                dbconn = New OleDbConnection
                'Datenbank auswählen
                If dbPath = "" Then
                    dbPath = _iniDatabasePath
                End If
 
                'Connection-String definieren
                If dbPath.ToLower.EndsWith(".mdb") Then
                    connectionstring = "Provider=Microsoft.Jet.OLEDB.4.0; Data" & _
                      "Source=" & dbPath & ";"
                ElseIf dbPath.ToLower.EndsWith(".accdb") Then
                    connectionstring = "Provider=Microsoft.ACE.OLEDB.12.0; Data" & _
                      "Source=" & dbPath & ";"
                Else
                    Return Nothing
                End If
 
                dbconn.ConnectionString = connectionstring
                dbconn.Open()
 
                da = New OleDbDataAdapter
                dt = New DataTable
            End If
 
            'Daten holen und als DataTable zurückgeben
            cmd.CommandText = sql
            da.SelectCommand = cmd
            da.Fill(dt) '-> PROBLEMZONE
            Return dt
        Catch ex As Exception
            Return Nothing
        End Try
    End Function