Possible to call DsEnumerateDomainTrusts from VB.NET?

[Luke Morehead]

I'm trying to use DsEnumerateDomainTrusts to generate a
list of trusted domains in VB.NET. The code I've listed
below generates the error, "An unhandled exception of
type 'System.NullReferenceException' occurred in
NetDisco.exe. Additional information: Object reference
not set to an instance of an object." Any ideas on how
to call this API function properly from VB.NET? Thank
you.

Luke Morehead

=-=-=-=-=-=-=-=-

Private Declare Function DsEnumerateDomainTrusts
Lib "netapi32.dll" Alias "DsEnumerateDomainTrustsW" ( _
ByVal lpszServerName As IntPtr, _
ByVal luFlags As UInt64, _
ByRef lpBuffer As IntPtr, _
ByRef pluDomainCount As IntPtr) As Integer

Private Const DS_DOMAIN_DIRECT_OUTBOUND = 2
Private Const NERR_Success = 0

Private Structure DS_DOMAIN_TRUSTS
Dim lpszNetBIOSDomainName As IntPtr
Dim lpszDNSDomainName As IntPtr
Dim luFlags As UInt64
Dim luParentIndex As UInt64
Dim luTrustType As UInt64
Dim luTrustAttributes As UInt64
Dim pSID As IntPtr
Dim gGUID As Guid
End Structure

Private Sub GetTrustedDomains(ByVal strDomainController
as String)
Dim lpDomainCount As IntPtr
Dim lpBuffer as IntPtr = IntPtr.Zero
Dim intResult as Integer
intResult = DsEnumerateDomainTrusts _
(Marshal.StringToHGlobalUni(strDomainController),
_
Convert.ToUInt64(DS_DOMAIN_DIRECT_OUTBOUND), _
lpBuffer, lpDomainCount)
If intResult = NERR_Success Then
Dim DomainTrusts As DS_DOMAIN_TRUSTS
Dim intDomainCount As Integer
Dim strTrustedDomain As String
intDomainCount = lpDomainCount.ToInt32
For i = 1 To intDomainCount
DomainTrusts = CType(Marshal.PtrToStructure _
(lpBuffer, GetType(DS_DOMAIN_TRUSTS)), _
DS_DOMAIN_TRUSTS)
Console.WriteLine("Trusted Domain: " & _
Marshal.PtrToStringUni
(DomainTrusts.lpszNetBIOSDomainName)
Next i
Else
Console.WriteLine("DsEnumerateDomainTrusts
failed: " _
& intResult)
End If
End Sub

 

[Stephen Martin]

I've made a few corrections to your code. This isn't tested but it should point you
in the right direction. You might want to check into the DirectoryServices
namespace for this type of thing rather than using interop to the underlying API.

Private Declare Auto Function DsEnumerateDomainTrusts _
Lib "netapi32.dll" (ByVal lpszServerName As String, _
ByVal luFlags As Integer, _
ByRef lpBuffer As IntPtr, _
ByRef pluDomainCount As Integer) As Integer

Private Declare Function NetApiBufferFree _
Lib "netapi32.dll" (ByRef lpBuffer As IntPtr) As Integer

Private Const DS_DOMAIN_DIRECT_OUTBOUND As Integer = 2
Private Const NERR_Success As Integer = 0

<StructLayout(LayoutKind.Sequential)> _
Private Structure DS_DOMAIN_TRUSTS
<MarshalAs(UnmanagedType.LPTStr)> Dim lpszNetBIOSDomainName As String
<MarshalAs(UnmanagedType.LPTStr)> Dim lpszDNSDomainName As String
Dim luFlags As Integer
Dim luParentIndex As Integer
Dim luTrustType As Integer
Dim luTrustAttributes As Integer
Dim pSID As IntPtr
Dim gGUID As Guid
End Structure

Private Sub GetTrustedDomains(ByVal strDomainController As String)
Dim lpDomainCount As Integer
Dim lpBuffer As IntPtr
Dim lpStruct As IntPtr
Dim intResult As Integer
Dim DomainTrusts As DS_DOMAIN_TRUSTS
Dim i As Integer

intResult = DsEnumerateDomainTrusts(strDomainController, _
DS_DOMAIN_DIRECT_OUTBOUND, lpBuffer, lpDomainCount)
If intResult = NERR_Success Then
lpStruct = lpBuffer
For i = 1 To lpDomainCount
DomainTrusts = CType(Marshal.PtrToStructure _
(lpStruct, GetType(DS_DOMAIN_TRUSTS)), DS_DOMAIN_TRUSTS)
Console.WriteLine("Trusted Domain: " & _
(DomainTrusts.lpszNetBIOSDomainName))
lpStruct = New IntPtr(lpStruct.ToInt64 + Marshal.SizeOf(DomainTrusts))
Next i
NetApiBufferFree(lpBuffer)
Else
Console.WriteLine("DsEnumerateDomainTrusts failed: " _
& intResult.ToString)
End If
End Sub

 

[Luke M]

Thanks for your insights, especially regarding the nuances of API data
type marshalling. That did the trick!

Luke