Class is not available in this context because it is Friend

Question

I am trying to create an instance of a legacy c++ class in VB.NET. I have followed the instructions on the following webpage: http://windowsdevcenter.com/pub/a/dotnet/2004/03/29/mcpp_part3.html?page=2

1) Created a Visual C++ project with one file (MFoo.cpp) and the following code:

class Foo 
{ public: 
// constructor 
Foo(void) {} 
// destructor 
~Foo(void) {} 
// some method 
void DoSomeFoo(){} }; 

__gc class MFoo 
{ public: Foo * _foo; 
public: 
    // constructor 
    MFoo() { _foo = new Foo();} 
    // destructor 
    ~MFoo() { delete _foo; } 
    // method 
    void ManagedDoSomeFoo() { _foo->DoSomeFoo(); } };

2) Built the project in Visual C++ producing a DLL 3) Created a reference to the DLL (created in part 2) in a VB.NET application

I now get an error when I try to create an instance of the C++ object i.e. Dim foo As New MFoo. The error is: MFoo is not available in this context because it is Friend.

Answer 1

You need to declare the the class MFoo as public, replace the line __gc class MFoo with public __gc class MFoo