c# – C/C++LI：防止非托管资源的托管包装上的垃圾收集

// unmanaged C++ class
class NativeDog
{
    NativeDog(...); // constructor
    ~NativeDog(); // destructor
    ...
}

// C++/CLI wrapper class
ref class ManagedDog
{
    NativeDog* innerObject; // unmanaged,but private,won't be seen from C#
    ManagedDog(...)
    {
        innerObject = new NativeDog(...);
        ...
    }

    ~ManagedDog() // destructor (like Dispose() in C#)
    {
        // free unmanaged resources
        if (innerObject)
            delete innerObject;
    }

    !ManagedDog() // finalizer (like Finalize() in C#,in case
    {             // the user forgets to dispose)
        ~ManagedDog(); // call destructor
    }
}

一切都很好,我使用这样的课程：

// in C++/CLI
// this function is called from C++ code
void MyLibrary::FeedDogNative(NativeDog* nativedog)
{
    ... // (***)
}
// this function is called from C#,passes on the dog to the native function
void MyLibrary::FeedDogManaged(ManagedDog^ dog)
{
    NativeDog* rawdog = dog->innerObject;
    MyLibrary::FeedDogNative(rawdog);
}

// C# client code
void MyFunc()
{
    ManagedDog dog = new ManagedDog(...);
    MyLibrary.FeedDogManaged(dog);
}

看看有什么问题？我一开始没有,直到很奇怪的事情不时发生.基本上,如果在调用MyFunc()之后,程序被GC暂停,而它位于本机函数FeedDogNative(上面标记(***))的某个位置,则会认为可以收集托管的包装器,因为它将不再被使用,没有在C#MyFunc(它是一个局部变量,不会在FeedDogManaged调用后使用),不在FeedDogManaged中.所以这实际上是发生在场合的. GC调用Finalizer,它会删除本机狗对象,即使FeedDogNative尚未完成使用！所以我的非托管代码现在使用一个已删除的指针.

我该如何防止这种情况？我可以想到一些方法(例如,在FeedDogManaged结束时假装使用狗的虚拟呼叫),但是推荐的方法是什么？