Find list of all active drives via GetLogicalDriveStrings?

Question

Visual Basic

Hello.
You need to find a list of all active drives via GetLogicalDriveStrings. I found this code on nete:

Public Class Form1
    Private Declare Function GetLogicalDriveStrings Lib "kernel32" Alias "GetLogicalDriveStringsA" (ByVal nBufferLength As Long, ByVal lpBuffer As String) As Long

    Private Function GetDriveStrings() As String
        Dim result As Long ' Result of our api calls
        Dim strDrives As String ' String to pass to api call
        Dim lenStrDrives As Long ' Length of the above string
        result = GetLogicalDriveStrings(0, strDrives)
        strDrives = String(result, 0)
        lenStrDrives = result
        result = GetLogicalDriveStrings(lenStrDrives, strDrives)
        If result = 0 Then
            GetDriveStrings = ""
        Else
            GetDriveStrings = strDrives
        End If
    End Function

    Private Sub Command1_Click()
        Dim strDrives As String
        strDrives = GetDriveStrings()
        If strDrives = "" Then
            MsgBox("No Drives were found!", vbCritical)
        Else
            DisplayDriveTypes(strDrives)
        End If
    End Sub

    Private Sub DisplayDriveTypes(drives As String)
        Dim pos As Long
        Dim drive As String
        ListBox1.Clear()
        pos = 1
        Do While Not Mid$(drives, pos, 1) = Chr(0)
            drive = Mid$(drives, pos, 3)
            pos = pos + 4
            ListBox1.AddItem(UCase(drive))
        Loop
    End Sub
End Class

But the following errors appear:
Error 1 "String" is a class type and cannot be used as an expression. C:\Users\vilen\AppData\Local\Temporary Projects\WindowsApplication1\Form1.vb 9 21 WindowsApplication1
Error 2 Requires "." C:\Users\vilen\AppData\Local\Temporary Projects\WindowsApplication1\Form1.vb 9 27 WindowsApplication1
Error 3 'Clear' is not a member of 'System.Windows.Forms.ListBox'. C:\Users\vilen\AppData\Local\Temporary Projects\WindowsApplication1\Form1.vb 32 9 WindowsApplication1
Error 4 'AddItem' is not a member of 'System.Windows.Forms.ListBox'. C:\Users\vilen\AppData\Local\Temporary Projects\WindowsApplication1\Form1.vb 37 13 WindowsApplication1 I am
using Visual Basic 2010.
How to correct errors?
Thanks in advance.