Compiler Error C3265

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cannot declare a managed 'managed construct' in an unmanaged 'unmanaged construct'

You cannot include a managed object in an unmanaged context.

The following sample reproduces C3265:

// C3265_2.cpp
// compile with: /clr /LD
#include <vcclr.h>

ref class A { };

class B
// try the following line instead
// ref class B 
{
   A ^a;   // C3265
   // or embed the managed handle using gcroot
   // try the following line instead
   // gcroot<A^> a;
};

The following sample reproduces C3265:

// C3265.cpp
// compile with: /clr:oldSyntax /LD
#using <mscorlib.dll>
__gc class A { };

__nogc class B
// try the following line instead
// __gc class B 
{
   A *a;   // C3265
};

C3265 can also occur if you embed a managed pointer directly inside an unmanaged class. To fix this error, use gcroot:

// C3265b.cpp
// compile with: /clr:oldSyntax
#include <vcclr.h>
#using <mscorlib.dll>

namespace TestNS {
   __gc public class Test{};
}

template<class T>
struct Container {
  T* m_px;   // C3265
};
__gc public class ClassA {
public:
  ClassA (){}
   ~ClassA(){}

private:
   Container<TestNS::Test*>  vctTest;
   // try the following line instead
   Container<gcroot<TestNS::Test* > > vctTest2;
};