Marshalling nested structures

[Youcef Laribi]

I'm new to .NET interop and I'm trying to call the following Win32 API in
"netapi32.dll"

DWORD DsGetDcName(LPCTSTR ComputerName, LPCTSTR DomainName,
GUID* DomainGuid, LPCTSTR
SiteName, ULONG Flags,
PDOMAIN_CONTROLLER_INFO *
DomainControllerInfo);

Where DOMAIN_CONTROLLER_INFO is defined as:

typedef struct _DOMAIN_CONTROLLER_INFO {
LPCTSTR DomainControllerName;
LPCTSTR DomainControllerAddress;
ULONG DomainControllerAddressType;
GUID DomainGuid;
LPCTSTR DomainName;
LPCTSTR DnsForestName;
ULONG Flags;
LPCTSTR DcSiteName;
LPCTSTR ClientSiteName;
} * PDOMAIN_CONTROLLER_INFO;

To call it from my C# program, I defined the following:

[StructLayout(LayoutKind.Sequential)]

public class GUID

{

public ulong Data1;

public ushort Data2;

public ushort Data3;

[MarshalAs(UnmanagedType.LPArray, SizeConst=8)]

public byte[] Data4;

}

[StructLayout(LayoutKind.Sequential)]

public class DOMAIN_CONTROLLER_INFO

{

public string DomainControllerName;

public string DomainControllerAddress;

public ulong DomainControllerAddressType;

[MarshalAs(UnmanagedType.Struct)]

public GUID DomainGuid;

public string DomainName;

public string DnsForestName;

public ulong Flags;

public string DcSiteName;

public string ClientSiteName;

}

And the prototype of the function as:

[DllImport("C:\\WINDOWS\\System32\\netapi32.dll")]

public static extern int DsGetDcName(string ComputerName, string DomainName,

[MarshalAs(UnmanagedType.LPStruct)] GUID DomainGuid,

string
SiteName, ulong Flags,

ref
DOMAIN_CONTROLLER_INFO DomainControllerInfo);

I get the following TypeLoadException exception when I make the call:

Exception occurred: System.TypeLoadException: Can not marshal field
DomainGuid of type TestProject.DOMAIN_CONTROLLER_INFO: The type definition
of this field has no layout information.

Any ideas why ? Thanks.

[NETMaster]

Note, C++ ULONG is not 'ulong' in C#...

I don't have a DC to test, but try this code:

// =========================================================================

[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto )]
public struct DOMAIN_CONTROLLER_INFO

{
public string DomainControllerName;
public string DomainControllerAddress;

public int DomainControllerAddressType;
public Guid DomainGuid;

public string DomainName;
public string DnsForestName;

public int Flags;

public string DcSiteName;
public string ClientSiteName;
}

[StructLayout(LayoutKind.Sequential)]
public class GuidAsClass // workaround: Guid as 'ref'/null
{
public Guid DomainGuid;
}

class NetApiTesting
{
[DllImport("netapi32.dll", ExactSpelling=true)]
public extern static int NetApiBufferFree( IntPtr bufptr );

[DllImport("netapi32.dll", CharSet=CharSet.Auto)]
public static extern int DsGetDcName( string ComputerName, string DomainName,
[In] GuidAsClass DomainGuid, string SiteName, int Flags, out IntPtr pDCI );

[MTAThread]
static void Main( string[] args )
{
DOMAIN_CONTROLLER_INFO dci;
IntPtr pDCI = IntPtr.Zero;

// GuidAsClass gid = new GuidAsClass();
// gid.DomainGuid = new Guid( "6B29FC40-CA47-1067-B31D-00DD010662DA" );
int ns = DsGetDcName( null, null, null, null, 0, out pDCI );
// todo: error handling
dci = (DOMAIN_CONTROLLER_INFO) Marshal.PtrToStructure( pDCI, typeof(DOMAIN_CONTROLLER_INFO) );
NetApiBufferFree( pDCI ); pDCI = IntPtr.Zero;

}
}
// =========================================================================

--
NETMaster (Thomas Scheidegger)
http://www.cetus-links.org/oo_csharp.html

"Youcef Laribi" <youcef...@ntlworld.com> wrote in message news:10246747...@proxy1.ctxuk.citrix.com...

[Youcef Laribi]

Thanks for your help, that did the trick !

youcef

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