Visual C++ .NET/Class/Destructor — различия между версиями

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м (1 версия)
 
(нет различий)

Версия 15:31, 26 мая 2010

Destructor and finalizer

 
#include "stdafx.h"
using namespace System;
using namespace System::Collections::Generic;
ref class MyClass{
    static List<MyClass^>^ instanceTrackingList;
    static MyClas(){
       instanceTrackingList = gcnew List<MyClass^>;
    }
    MyClass(String^ s)
    {
       Label = s;
       instanceTrackingList->Add( this );
    }
    property String^ Label;
    static int EnumerateInstances()
    {
       int i = 0;
       for each (MyClass^ r in instanceTrackingList)
       {
           i++;
           Console::WriteLine( r->Label );
       }
       return i;
    }
    ~MyClass()   // destructor
    {
       this->!MyClass();
    }
    !MyClass()   // finalizer
    {
       instanceTrackingList->Remove( this );
    }
};
int main(){
    MyClass r1("ABC");
    MyClass^ r2 = gcnew MyClass("XYZ");
    int count = MyClass::EnumerateInstances();
    Console::WriteLine("Object count: " + count);
    delete r2;
    count = MyClass::EnumerateInstances();
    Console::WriteLine("Object count: " + count);
}


Destructor demo

 
#include "stdafx.h"
using namespace System;
using namespace System::IO;
ref class MyClass
{
public:
    MyClass()
    {
        Closed = false;
    }
    ~MyClass()
    {
        if ( !Closed ) Close();
    }
    void Close()
    {
        // Release unmanaged resources
        Closed = true;
    }
private:
    bool Closed;
};
void main()
{
    MyClass^ myObject = gcnew MyClass();
    try
    {
        // Do something
    }
    finally
    {
        // Calls destructor
        delete myObject;
    }
}


Destructors and inheritance

 
#include "stdafx.h"
using namespace System;
ref class Base
{
   public:
     Base() {}
     ~Base() {  Console::WriteLine("~Base"); }
};
ref class Derived : Base
{
   public:
     Derived() { }
     ~Derived() {  Console::WriteLine("~Derived"); }
};
// The destructor will be called at the end of main.
int main()
{
   Derived d;
}