Visual C++ .NET using C# library. Need help?

Question

I have a library a friend wrote in C# and I need to use it in C++.NET. I'm new to VC++.NET and I don't know how to declare my class so it can be used by all functions in my file.. Here's my code..

using namespace System;
using namespace ONEAPI;
namespace Bot{

    void InitializeBot();
    ONEAPI::Connection connection(true);
    int main(array<System::String ^> ^args)
    {
        Console::BackgroundColor = ConsoleColor::Black;
        InitializeBot();
        return 0;
    }
    void InitializeBot(){
        connection.StartConnection("127.0.0.1", 1274, "username",
            "B73955EE7A30E959819BAE2392F6F4441DF98C66A4026EF55287A81D1F815504",
            "R0Bo");
    }
}

I get this error:

Error 1 error C3145: 'connection' : global or static variable may not have managed type 'ONEAPI::Connection' Visual Studio 2010\Projects\1hubBot\1hubBot\1hubBot.cpp 10 1 1hubBot

In future please just put the text in the question, rather than using Pastie. I've edited it in for you this time... — Jon Skeet
– Jon Skeet, Commented Jul 6, 2011 at 19:44
@Troy: All you have to do is paste in the code, select it all, and click the "code format" button in the toolbar. It looks like a pair of curly braces: {}. All it's doing is indenting each line with 4 spaces--that's what the formatting engine uses to detect code blocks. — Cody Gray
– Cody Gray ♦, Commented Jul 7, 2011 at 8:17

Reed Copsey · Accepted Answer · 2011-07-06 19:44:25Z

2

You can't use a managed type ("Connection") within a static or global - it has to exist inside of a ref class or as a local. This is a requirement of C++/CLI.

You'll need to put your code into a managed class, and use it there. I recommend going through a C++/CLI Tutorial, as it will explain this fairly quickly.

answered Jul 6, 2011 at 19:44

Reed Copsey

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Comments

ChrisV · Accepted Answer · 2011-07-07 18:49:51Z

-1

You can't have managed types at global- or file-scope. Wrap the Connection object in an unmanaged (regular C++-style) class and create a global instance of that instead.

EDIT: After looking up the appropriate compiler mumbo-jumbo, here's what I came up with:

#include <vcclr.h>
using namespace System;
using namespace ONEAPI;

namespace Bot {
    class ConnectionWrapper {
    public:
        static gcroot<ONEAPI::Connection^> connection;
    };

    gcroot<ONEAPI::Connection^> ConnectionWrapper::connection = gcnew Connection(true);

    void InitializeBot() {
        ConnectionWrapper::connection->StartConnection(...);
    }
}

edited Jul 7, 2011 at 18:49

answered Jul 6, 2011 at 19:45

ChrisV

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3 Comments

Zarat Over a year ago

No need to create a global instance of a dummy class if he puts it into a static field of said class.

Troy Over a year ago

Now it says "error C3265: cannot declare a managed 'connection' in an unmanaged 'ConnectionWrapper'

ChrisV Over a year ago

Try using gcroot<Connection> like the MSDN page for C3265 suggests.

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