public int NumR;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = FeasXConst.MAX_NUM_DS)]
public UInt32[] RH;
public int NumD;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = FeasXConst.MAX_NUM_DS)]
public Q_PROPERTIES[] D;
public int NumSchedules;
[MarshalAs(UnmanagedType.ByValArray, ArraySubType =UnmanagedType.Struct,SizeConst=MAX_NUM_AP_S)] public AP_S[] ApS; // } ;

and unmanaged dll's function
int Func (int Foo, TRIAL_RESULTS_AP[] Bar);

I can not marshal TRIAL_RESULTS_AP. Actually, the only part I have problem with is AP_S->ProblemArr.
I've tried to substitute AP_S struct with AP_S_subst struct with following signature (and corresponding TRIAL_RESULTS_AP_subst):

public struct AP_S_subst
{
public int N;
public IntPtr problemPtr;
} ;

and make wrapper for the original Func - Func_wrapper which will take origianl structure and Marshal data directly to the problemPtr using following code:

for (int j = 0; j < PrevResults[i].ApS.Length; j++)
{
/*... rest ofassignment*/
PrevResults_F[i].ApS[j].problemPtr= Marshal.AllocHGlobal(Convert.ToInt32(Marshal.SizeOf(new AP_LS()) * MAX_NUM_FLIGHTS_FROM_AP)); long count = PrevResults_F[i].ApS[j].problemPtr.ToInt64(); foreach (AP_LS a in PrevResults[i].ApS[j].Leg)
{
IntPtr some = new IntPtr(count);
Marshal.StructureToPtr(a, some, true);
count += Marshal.SizeOf(typeof(AP_LS));
}
}

but this does not work either!!

Thank you for any help.