如何 boost::bind 到传递并返回 std::string 的托管类的成员？

我正在尝试做一些非常类似的事情this https://stackoverflow.com/questions/163757/how-to-use-boostbind-in-c-cli-to-bind-a-member-of-a-managed-class但我正在努力将字符串传递给回调或从回调传递字符串。

这是我尝试运行的代码的精简版本：

using namespace System;
using namespace System::Runtime::InteropServices;

#pragma unmanaged

// The unmanaged boost function prototype the native library wants to bind to
typedef boost::function<std::string(const std::string&)> MyNativeCallback;

// The unmanaged library I'm trying to wrap
class MyUnmanagedClass
{
    public:
        MyUnmanagedClass() {}

        void RegisterCallback(MyNativeCallback callback);
};

// Taken from here: https://stackoverflow.com/questions/163757/how-to-use-boostbind-in-c-cli-to-bind-a-member-of-a-managed-class
typedef std::string(__stdcall *ChangeCallback)(std::string);
public delegate std::string ChangeHandler(std::string);

#pragma managed

// The managed callback we'll eventually trigger if all this works.
public delegate String^ ManagedHandler(String^);

// A managed wrapper to bridge the gap and provide a managed call in response to the unmanaged callback
public ref class MyManagedClass
{
protected:

    MyUnmanagedClass* m_responder;

public:
    event ManagedHandler^ OnChange;

public:
    MyManagedClass():
        m_responder(new MyUnmanagedClass())
    {
        // Example code I'm trying to adapt from here: https://stackoverflow.com/questions/163757/how-to-use-boostbind-in-c-cli-to-bind-a-member-of-a-managed-class
        ChangeHandler^ handler = gcnew ChangeHandler(this, &MyManagedClass::HandleRequest);
        GCHandle gch = GCHandle::Alloc(handler);
        System::IntPtr ip = Marshal::GetFunctionPointerForDelegate(handler);
        ChangeCallback cbFunc = static_cast<ChangeCallback>(ip.ToPointer());

        MyNativeCallback handlerToBind = boost::bind(cbFunc, _1); // <-- This fails with 'error C2825'
        m_responder->RegisterCallback(handlerToBind);
    }

    std::string HandleRequest(std::string s)
    {
        OnChange(nullptr);
        return nullptr;
    }
};

...这给了我以下错误：

1>C:\boost_1_55_0\boost/bind/bind.hpp(69): error C2825: 'F': must be a class or namespace when followed by '::'
1>          C:\boost_1_55_0\boost/bind/bind_template.hpp(15) : see reference to class template instantiation 'boost::_bi::result_traits<R,F>' being compiled
1>          with
1>          [
1>              R=boost::_bi::unspecified,
1>              F=std::basic_string<char,std::char_traits<char>,std::allocator<char>> (__stdcall *)(std::string)
1>          ]
1>          c:\projects\zephir-git\zephirsoftware-gitlab\lcufirmware\managedzeromqdataforwarding\Responder.h(54) : see reference to class template instantiation 'boost::_bi::bind_t<R,F,L>' being compiled
1>          with
1>          [
1>              R=boost::_bi::unspecified,
1>              F=std::string (__stdcall *)(std::string),
1>              L=boost::_bi::list1<boost::arg<1>>
1>          ]
1>C:\boost_1_55_0\boost/bind/bind.hpp(69): error C2039: 'result_type' : is not a member of '`global namespace''
1>C:\boost_1_55_0\boost/bind/bind.hpp(69): error C2146: syntax error : missing ';' before identifier 'type'
1>C:\boost_1_55_0\boost/bind/bind.hpp(69): error C2208: 'boost::_bi::type' : no members defined using this type
1>C:\boost_1_55_0\boost/bind/bind.hpp(69): fatal error C1903: unable to recover from previous error(s); stopping compilation

我不禁觉得我已经快要得到这个了，但我还缺少一些东西吗？

通过一些实验和一些更详细的检查解决了这个问题关于不同形式的文档bind http://www.boost.org/doc/libs/1_63_0/libs/bind/doc/html/bind.html#bind.faq.Q_forms.

这是按预期工作的结果代码：

using namespace System;
using namespace System::Runtime::InteropServices;

#pragma unmanaged

// The unmanaged boost function prototype the native library wants to bind to
typedef boost::function<std::string(const std::string&)> MyNativeCallback;

// The unmanaged library I'm trying to wrap
class MyUnmanagedClass
{
    public:
        MyUnmanagedClass() {}

        void RegisterCallback(MyNativeCallback callback);
};

typedef std::string(__stdcall *ChangeCallback)(std::string);
public delegate std::string ChangeHandler(std::string);

#pragma managed

// The managed callback we'll eventually trigger if all this works.
public delegate std::string ManagedHandler(const std::string&);

// A managed wrapper to bridge the gap and provide a managed call in response to the unmanaged callback
public ref class MyManagedClass
{
protected:

    MyUnmanagedClass* m_responder;

public:
    event ManagedHandler^ OnChange;

public:
    MyManagedClass():
        m_responder(new MyUnmanagedClass())
    {
        // Example code I'm trying to adapt from here: http://stackoverflow.com/questions/163757/how-to-use-boostbind-in-c-cli-to-bind-a-member-of-a-managed-class
        ChangeHandler^ handler = gcnew ChangeHandler(this, &MyManagedClass::HandleRequest);
        GCHandle gch = GCHandle::Alloc(handler);
        System::IntPtr ip = Marshal::GetFunctionPointerForDelegate(handler);
        ChangeCallback cbFunc = static_cast<ChangeCallback>(ip.ToPointer());

        MyNativeCallback handlerToBind = boost::bind<std::string>(cbFunc, _1);
        m_responder->RegisterCallback(handlerToBind);
    }

    std::string HandleRequest(const std::string& s)
    {
        return OnChange(s);
    }
};