There have been many times when I needed a list of system drives in my apps.  The quick & dirty way used to be to place a hidden DriveListBox on the form and then scroll through the List array.  Well, that is simply unprofessional.  In addition, it doesn't work when you need the drive information in a class or a DLL or a formless application. 

In addition, you must be able to tell a floppy drive from a network drive.  So I built a class that is so simple, an idiot can use it.  All it requires you to do is instantiate it - it does the rest. Then you simply scroll through various collections.  There is the AllDrives collection which lists all the drives found on the system.  The class also breaks the drives down into specialized collections: FloppyDrives, LocalHardDrives, CDRomDrives, NetworkDrives, RemovableDrives and even RamDiskDrives (from the good ol' DOS days).  

Download the code or simply cut and paste from below.

1. Createa new project.
2. Add a button to the form called Command1 and change the caption to Retrieve Drive List
3. Add class to the project and call it clsDriveAssignment

Option Explicit

Public AllDrives As New Collection
Public LocalHardDrives As New Collection
Public FloppyDrives As New Collection
Public RemovableDrives As New Collection
Public NetworkDrives As New Collection
Public CDRomDrives As New Collection
Public RamDiskDrives As New Collection

'APIs for retrieving drives
Private Declare Function GetLogicalDriveStrings _
     Lib "kernel32" Alias "GetLogicalDriveStringsA" _
    (ByVal nBufferLength As Long, _
     ByVal lpBuffer As String) As Long

Private Declare Function GetDriveType _
     Lib "kernel32" Alias "GetDriveTypeA" _
    (ByVal nDrive As String) As Long

Private Const DRIVE_REMOVABLE = 2
Private Const DRIVE_FIXED = 3
Private Const DRIVE_REMOTE = 4
Private Const DRIVE_CDROM = 5
Private Const DRIVE_RAMDISK = 6

Private Sub FillDriveCollection()
    Dim arrayAllDrives() As String
    Dim x As Integer
    
    
    GetAllDrives arrayAllDrives()
    
    For x = 1 To UpperBound(arrayAllDrives())
        Select Case GetDriveType(arrayAllDrives(x))
            Case 0:
            'The drive type cannot be determined
            Case 1
            'The root directory does not exist
            Case DRIVE_REMOVABLE:
                Select Case LCase$(Left$(arrayAllDrives(x), 1))
                    Case "a", "b" 'Floppy drive
                        FloppyDrives.Add arrayAllDrives(x)
                    Case Else     'Removable drive
                        RemovableDrives.Add arrayAllDrives(x)
                End Select
            Case DRIVE_FIXED  'Hard drive; can not be removed
                LocalHardDrives.Add arrayAllDrives(x)
            Case DRIVE_REMOTE   'Remote (network) drive
                NetworkDrives.Add arrayAllDrives(x)
            Case DRIVE_CDROM    'CD-ROM drive
                CDRomDrives.Add arrayAllDrives(x)
            Case DRIVE_RAMDISK  'RAM disk
                RamDiskDrives.Add arrayAllDrives(x)
        End Select
        AllDrives.Add arrayAllDrives(x)
    Next
End Sub

Private Function UpperBound(SampleArray() As String) As Long
    Dim Temp As Long
    On Error Resume Next
    
    Temp = UBound(SampleArray)
    If Err = 0 Then
        UpperBound = Temp
    Else
        UpperBound = 0  'if error just set it to 0, because all the arrays are 1-based
    End If
End Function

 Private Sub GetAllDrives(DriveArray() As String)
    Dim sAllDrives As String
    Dim iDriveCount As Integer
 
    'get the list of all available drives
    'returns Null separated list of drives
    'plus a Null at the end
    sAllDrives = GetDriveLetters()
 
    'split the list of drives into an array
    DriveArray = Split2Array(sAllDrives, Chr$(0))
    
    iDriveCount = UpperBound(DriveArray)
    'if iDriveCounter = 0 Or 1 Then nothing was found
    'other than Null at the end (in case of 1)
    
    If iDriveCount > 1 Then
        'great - data found - get rid of the array element with the Null
        ReDim Preserve DriveArray(1 To iDriveCount - 1)
    End If
End Sub


Private Function GetDriveLetters() As String
    'returns a single string of available drive letters
    'each separated by Null, plus a Null at the end
    
    Dim Temp As String
  
    Temp = Space$(64)
    GetLogicalDriveStrings Len(Temp), Temp
    GetDriveLetters = Trim$(Temp)

End Function

Function Split2Array(ByVal Text As String, Optional ByVal Delimiter As String = " ", _
    Optional ByVal Limit As Long = -1, Optional CompareMethod As _
    VbCompareMethod = vbBinaryCompare) As Variant
    
    'provides functionality identical to Split function in VB6
    
    ReDim res(1 To 100) As String
    Dim resCount As Long
    Dim length As Long
    Dim startIndex As Long
    Dim endIndex As Long
    
    length = Len(Text)
    startIndex = 1
    resCount = 1
    
    Do While startIndex <= length And resCount <> Limit
        ' get the next delimiter
        endIndex = InStr(startIndex, Text, Delimiter, CompareMethod)
        If endIndex = 0 Then endIndex = length + 1
        
        ' make room in the array, if necessary
        If resCount > UBound(res) Then
            ReDim Preserve res(1 To resCount + 99) As String
        End If
        ' store the new element
        res(resCount) = Mid$(Text, startIndex, endIndex - startIndex)
        resCount = resCount + 1
        
        startIndex = endIndex + Len(Delimiter)
    Loop
    
    ' trim unused values
    ReDim Preserve res(1 To resCount - 1) As String

    ' return the array inside a Variant
    Split2Array = res()

End Function

Private Sub Class_Initialize()
    FillDriveCollection
End Sub



Private Sub Class_Terminate()
    Set AllDrives = Nothing
    Set LocalHardDrives = Nothing
    Set FloppyDrives = Nothing
    Set RemovableDrives = Nothing
    Set NetworkDrives = Nothing
    Set CDRomDrives = Nothing
    Set RamDiskDrives = Nothing
End Sub

Private Sub Command1_Click()
    Dim oDrvList As clsDriveAssignment
    Dim x As Integer
    
    Me.Cls
    
    Set oDrvList = New clsDriveAssignment
    With oDrvList
        Print "All Drives: " & .AllDrives.Count
        For x = 1 To .AllDrives.Count
            Print "  " & .AllDrives(x);
        Next
        
        Print: Print
        Print "Floppy Drives: " & .FloppyDrives.Count
        For x = 1 To .FloppyDrives.Count
            Print "  " & .FloppyDrives(x);
        Next
        
        Print: Print
        Print "Local Hard Drives: " & .LocalHardDrives.Count
        For x = 1 To .LocalHardDrives.Count
            Print "  " & .LocalHardDrives(x);
        Next
        
        Print: Print
        Print "CD-ROM Drives: " & .CDRomDrives.Count
        For x = 1 To .CDRomDrives.Count
            Print "  " & .CDRomDrives(x);
        Next
        
        Print: Print
        Print "Network Drives: " & .NetworkDrives.Count
        For x = 1 To .NetworkDrives.Count
            Print "  " & .NetworkDrives(x);
        Next
        
        Print: Print
        Print "Removable Drives: " & .RemovableDrives.Count
        For x = 1 To .RemovableDrives.Count
            Print "  " & .RemovableDrives(x);
        Next
        
        Print: Print
        Print "RAM Drives: " & .RamDiskDrives.Count
        For x = 1 To .RamDiskDrives.Count
            Print "  " & .RamDiskDrives(x);
        Next
    End With
    Set oDrvList = Nothing
    
End Sub