C# Signature:

[DllImport("Netapi32.dll", CharSet=CharSet.Unicode, SetLastError=true)]
public static extern int NetDfsGetInfo(
    [MarshalAs(UnmanagedType.LPWStr)] string DfsEntryPath,    // DFS entry path for the volume
    [MarshalAs(UnmanagedType.LPWStr)] string ServerName,    // This parameter is currently ignored and should be NULL
    [MarshalAs(UnmanagedType.LPWStr)] string ShareName,    // This parameter is currently ignored and should be NULL.
    int Level,                        // Level of information requested
    out IntPtr Buffer                    // API allocates and returns buffer with requested info
    );

VB Signature:

<DllImport("Netapi32.dll", CharSet:=CharSet.Unicode, SetLastError:=True)> _
    Public Function NetDfsGetInfo( _
    <MarshalAs(UnmanagedType.LPWStr)> ByVal entryPath As String, _
    <MarshalAs(UnmanagedType.LPWStr)> ByVal serverName As String, _
    <MarshalAs(UnmanagedType.LPWStr)> ByVal shareName As String, _
    ByVal level As Integer, _
    ByRef buffer As IntPtr) As Integer

    End Function

User-Defined Types VB:

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)> _

    Public Structure DFS_INFO_3
    <MarshalAs(UnmanagedType.LPWStr)> Dim EntryPath As String
    <MarshalAs(UnmanagedType.LPWStr)> Dim Comment As String
    Dim State As UInt32
    Dim NumberOfStorages As UInt32
    Dim Storages As IntPtr
    End Structure

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)> _

    Public Structure DFS_STORAGE_INFO
    Dim state As Int32
    <MarshalAs(UnmanagedType.LPWStr)> Dim ServerName As String
    <MarshalAs(UnmanagedType.LPWStr)> Dim ShareName As String
    End Structure

VB.NET Signature

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

User-Defined Types VB.NET:

1):

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _

Public Structure DFSINFO_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

2):

<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

Notes:

Tips & Tricks:

Remember to free buffer, see NetApiBufferFree

Sample Code C++:

static void Main(string[] args)
{
    IntPtr buf;
    if (args[0] != "")
    {
        int res=NetDfsGetInfo(args[0], null, null, 4, out buf);      
        if (res == 0)
        {
            try
            {
              DFS_INFO_4 info = (DFS_INFO_4)Marshal.PtrToStructure(buf, typeof(DFS_INFO_4));
              Console.WriteLine("{0}, {1}, {2} ", info.EntryPath, info.Comment, info.NumberOfStorages);
              for (int i = 0; i < info.NumberOfStorages; i++)
               {
                IntPtr pStorage = new IntPtr(info.Storage.ToInt64() + i * Marshal.SizeOf(typeof(DFS_STORAGE_INFO)));
                DFS_STORAGE_INFO storage = (DFS_STORAGE_INFO)Marshal.PtrToStructure(pStorage, typeof(DFS_STORAGE_INFO));
                Console.WriteLine("  {0}, {1}, {2} ", storage.ServerName, storage.ShareName, storage.State);
               }
            }
            finally
            {
              NetApiBufferFree(buf);
            }
        }
    }
}

Sample Code VB.NET:

Public Function DFSInfo(ByVal DfsEntryPath)

    Dim b As New _DFS_INFO_3
    Dim c As New _DFS_STORAGE_INFO
    Dim err_code As Integer
    Dim bufPtf As IntPtr
    Dim bufPtf2 As IntPtr

    err_code = NetDfsGetInfo(DfsEntryPath, vbNull, vbNull, 3, bufPtf)
    b = CType(Marshal.PtrToStructure(bufPtf, GetType(_DFS_INFO_3)), _DFS_INFO_3)
    MsgBox(b.EntryPath)
    MsgBox(b.Comment)
    MsgBox(b.State)
    MsgBox(b.NumberOfStorages)
    bufPtf2 = b.storage

    For i As Integer = 0 To b.NumberOfStorages
       'Increment the buffer and re-cast for each server in the list
       c = CType(Marshal.PtrToStructure(bufPtf2, GetType(_DFS_STORAGE_INFO)), _DFS_STORAGE_INFO)
       b.Storages = b.Storages + Len(c)
        bufPtf2 = b.Storages

       MsgBox(c.ServerName)
        MsgBox(c.ShareName)
        MsgBox(c.State)
    Next

    End Function

Alternative Managed API:

Do you know one? Please contribute it!