Question

Given the following test interface (C#):

public interface ITest
{
    UInt32 Simple(UInt32 someArg);

    byte* Read(UInt32 count);
    void Write(byte* buf, UInt32 count);

    byte[] ReadArray(UInt32 count);
    void WriteArray(byte[] buf);
}

Can I implement this interface in c++/cli? I’ve tried a million different ways; currently I have this:

typedef unsigned __int32 uint32;
typedef unsigned char byte;

public ref class CTest : public ITest
{
  virtual uint32 Simple(uint32 someArg);

  virtual byte * Read(uint32 count);
  virtual void Write(byte * buf, uint32 count);

  virtual System::Array<byte>^ ReadArray(uint32 count);
  virtual void WriteArray(System::Array<byte>^ buf);
}

The VC2010 compiler complains bitterly about all of the methods except CTest::Simple, claiming I haven’t implemented the interface.

Can someone show me the c++/cli magic to implement an interface that passes either byte* or byte[] (preferably both)? I’m at my wit’s end…

Answer 1

The following compiles:

public ref class CTest : public ITest
{
public:
    virtual unsigned Simple(unsigned someArg) { return 0u; }

    virtual unsigned char* Read(unsigned count) { return nullptr; }
    virtual void Write(unsigned char* buf, unsigned count) { }

    virtual array<unsigned char>^ ReadArray(unsigned count) { return nullptr; }
    virtual void WriteArray(array<unsigned char>^ buf) { }
};

Your main problem is the fact that your CTest member functions are private and thus ineligible to implement the interface. The other problems are mostly related to using System::Array<> rather than array<> (which is short for cli::array<>).