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 ++类中使用了boost :: signal，现在我正在C ++ / CLI中编写一个.NET包装器，这样我就可以将本机C ++回调公开为.NET事件。当我尝试使用boost :: bind取代我的托管类的成员函数的地址时，我收到编译器错误3374，除非我正在创建一个委托实例，否则我无法使用成员函数的地址。有没有人知道如何使用boost :: bind绑定托管类的成员函数？

为了澄清，以下示例代码导致编译器错误3374：

  #include< boost / bind.hpp> 
 
 public ref class Managed 
 {
 public：
 Managed（）
 {
 boost :: bind（& Managed :: OnSomeEvent ， 这个）; 
} 
 
 void OnSomeEvent（void）
 {
} 
}; 
  

解决方案

虽然你的答案有效，但它暴露了一些你的实现到世界（Managed :: OnSomeEvent）。如果您不希望人们能够通过调用OnSomeEvent（）来提升OnChange事件，则可以如下更新受管类（基于这个建议）：

  public delegate void ChangeHandler（void）; 
 typedef void（__stdcall * ChangeCallback）（void）; 
 
 public ref class Managed 
 {
 public：
 Managed（Native * Nat）; 
〜Managed（）; 
 
事件ChangeHandler ^ OnChange; 
 
 private：
 void OnSomeEvent（void）; 
本机*本机; 
回调*回调; 
 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）; 
删除回调; 
 if（gch.IsAllocated）
 {
 gch.Free（）; 
} 
} 
 
 void Managed :: OnSomeEvent（void）
 {
 OnChange 
} 
  

请注意备用 bind< R>（） / code>表单。

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?

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)
    {
    }
};

解决方案

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();
}

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

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