Invoke a DLL from C# and pass by reference a struct containing a StringBuilder....!!!

[ksakkos]

I would like to invoke a DLL written in C++ fron C#. The problem is that I need to pass by reference a structure that contrins a StringBuilder. How can I do it??

MY CODE IS THIS:

using System;
using System.Runtime.InteropServices;
using System.Text;

/// <summary>
/// Summary description for dllRPC.
/// </summary>
public class dllRPC
{
public struct ParRPC
{
public Int32 len;
public StringBuilder val;
//public string val;
}

public struct mensRPC
{
public Int32 par1;
public ParRPC par2;
}


public dllRPC()
{
//
// TODO: Add constructor logic here
//
}

[DllImport("VAX_RPC.dll")]

public static extern void ComandoVax(Int32 ntask, ref StringBuilder nhost, ref mensRPC mensaje);

}


WHEN LATER I DO THIS:

dllRPC.ComandoVax(ntask , ref nomvia , ref mens);

I TAKE THIS MESSAGE:

An unhandled exception of type 'System.TypeLoadException' occurred in Central_Alarmas.exe

Additional information: Can not marshal field par2 of type mensRPC: The type definition of this field has no layout information.


CAN SOMEONE HELP???

Thanx!!!

[kenobewan]

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