calling functions with complex structures from managed code

[oleop]

I am trying to call dll from the managed code.eveyrting works OK until i'm trying to use fucntions that use complex (containing arrays of structures) structures as a parameters.



Let's say

[DllImport("some.dll")]

private static extern int myFunc(ref STRUCT2 someStrust);

...



[StructLayout(LayoutKind.Sequential)]

public struct STRUCT1

{

public int x;

public UInt y;



}

[StructLayout(LayoutKind.Sequential)]

public struct STRUCT2

{

public int xx;

[MarshalAs (UnmanagedType.Struct, SizeConst = 4)]

public STRUCT1[] myInsideStruct;

}



.....

STRUCT2 myOutStruct;

myOutStruct.xx = 1;

myOutStruct.myInsideStruct = new STRUCT1[4];

//assign some values to myStruct.myInsideStruct[0], [1], etc.



//following line causes exception during the exectuion!!



myFunct(myOutStruct);



/* exception text: Cannot marshal field 'myInsideStruct' of type 'STRUCT2': Invalid managed/unmanaged type combination (Arrays fields must be paired with ByValArray or SafeArray). */



Any help?

And - does anyone know good source for Marshling and Interoperability explanation? Everything MSDN provides focuses on simplest cases wich do not help much in situations like this.



Thank you