如何在 C++/CLI 中使用 boost::bind 绑定托管类的成员 [英] How to use boost::bind in C++/CLI to bind a member of a managed class

问题描述

我在本机 C++ 类中使用 boost::signal，现在我正在 C++/CLI 中编写一个 .NET 包装器，以便我可以将本机 C++ 回调公开为 .NET 事件.当我尝试使用 boost::bind 获取托管类的成员函数的地址时，我收到编译器错误 3374，说除非我创建委托实例，否则我无法获取成员函数的地址.有谁知道如何使用 boost::bind 绑定托管类的成员函数?

I am using boost::signal in a native C++ class, and I now I am writing a .NET wrapper in C++/CLI, so that I can expose the native C++ callbacks as .NET events. When I try to use boost::bind to take the address of a member function of my managed class, I get compiler error 3374, saying I cannot take the address of a member function unless I am creating a delegate instance. Does anyone know how to bind a member function of a managed class using boost::bind?

为澄清起见，以下示例代码导致编译器错误 3374:

For clarification, the following sample code causes Compiler Error 3374:

#include <boost/bind.hpp>

public ref class Managed
{
public:
    Managed()
    {
        boost::bind(&Managed::OnSomeEvent, this);
    }

    void OnSomeEvent(void)
    {
    }
};

推荐答案

虽然您的答案有效，但它会将您的一些实现暴露给世界(Managed::OnSomeEvent).如果您不希望人们能够通过调用 OnSomeEvent() 来引发 OnChange 事件，您可以按如下方式更新您的托管类(基于 这个建议):

While your answer works, it exposes some of your implementation to the world (Managed::OnSomeEvent). If you don't want people to be able to raise the OnChange event willy-nilly by invoking OnSomeEvent(), you can update your Managed class as follows (based on this advice):

public delegate void ChangeHandler(void);
typedef void (__stdcall *ChangeCallback)(void);

public ref class Managed
{
public:
    Managed(Native* Nat);
    ~Managed();

    event ChangeHandler^ OnChange;

private:
    void OnSomeEvent(void);
    Native* native;
    Callback* callback;
    GCHandle gch;
};

Managed::Managed(Native* Nat)
 : native(Nat)
{
    callback = new Callback;

    ChangeHandler^ handler = gcnew ChangeHandler( this, &Managed::OnSomeEvent );
    gch = GCHandle::Alloc( handler );
    System::IntPtr ip = Marshal::GetFunctionPointerForDelegate( handler );
    ChangeCallback cbFunc = static_cast<ChangeCallback>( ip.ToPointer() );

    *callback = native->RegisterCallback(boost::bind<void>( cbFunc ) );
}

Managed::~Managed()
{
    native->UnregisterCallback(*callback);
    delete callback;
    if ( gch.IsAllocated )
    {
        gch.Free();
    }
}

void Managed::OnSomeEvent(void)
{
    OnChange();
}

注意使用的备用 bind<R>() 形式.

Note the alternate bind<R>() form that's used.

这篇关于如何在 C++/CLI 中使用 boost::bind 绑定托管类的成员的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！