vb.net - NetDfsGetInfo を使用して DFS ターゲットのアクティブな UNC パスを見つける

Question

pinvoke.net のNetDfsGetInfoの例を使用しています。DFS ターゲットのアクティブな unc パスを検索します。2 つのターゲットを持つ DFS パスでサブ DFSInfo を呼び出すと、両方のターゲットがアクティブであることが返されます。私はインターネットを検索し、ServerName と ShareName を呼び出すための vbNull を vbNullString に置き換える提案を見つけましたが、これは違いはありません。

誰かが私が間違っていることを説明できますか? 私が使用しているコードは次のとおりです。

Option Explicit On
'Option Strict On

Imports System
Imports System.ComponentModel
Imports System.Runtime.InteropServices


Module modDFS
    Declare Unicode Function NetDfsGetInfo Lib "NETAPI32.DLL" ( _
        ByVal DfsEntryPath As String, _
        ByVal ServerName As String, _
        ByVal ShareName As String, _
        ByVal Level As Integer, _
        ByRef Buffer As IntPtr) As Integer

    Declare Unicode Function NetApiBufferFree Lib "netapi32.dll" _
    (ByVal buffer As IntPtr) As Long

    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
    Public Structure _DFS_INFO_3
        <MarshalAs(UnmanagedType.LPWStr)> Public EntryPath As String
        <MarshalAs(UnmanagedType.LPWStr)> Public Comment As String
        Public State As Int32
        Public NumberOfStorages As Int32
        Public storage As Int32
    End Structure

    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
    Public Structure _DFS_STORAGE_INFO
        Public State As Integer
        <MarshalAs(UnmanagedType.LPWStr)> Public ServerName As String
        <MarshalAs(UnmanagedType.LPWStr)> Public ShareName As String
    End Structure

    Public Sub DFSInfo(ByVal DfsEntryPath)
        Dim DfsInfo3 As New _DFS_INFO_3
        Dim DfsStorageInfo As New _DFS_STORAGE_INFO
        Dim err_code As Integer
        Dim bufPtf As IntPtr
        Dim bufPtf2 As IntPtr

        err_code = NetDfsGetInfo(DfsEntryPath, vbNullString, vbNullString, 3, bufPtf)
        DfsInfo3 = CType(Marshal.PtrToStructure(bufPtf, GetType(_DFS_INFO_3)), _DFS_INFO_3)
        bufPtf2 = DfsInfo3.storage

        For i As Integer = 0 To DfsInfo3.NumberOfStorages - 1
            'Increment the buffer and re-cast for each server in the list
            DfsStorageInfo = CType(Marshal.PtrToStructure(bufPtf2, GetType(_DFS_STORAGE_INFO)), _DFS_STORAGE_INFO)
            DfsInfo3.storage += Marshal.SizeOf(DfsStorageInfo)
            bufPtf2 = DfsInfo3.storage
            Debug.Print("\\" & DfsStorageInfo.ServerName & "\" & DfsStorageInfo.ShareName & " : " & DfsStorageInfo.State)
        Next

        NetApiBufferFree(bufPtf)

    End Sub
End Module