c# 中的析构函数

原文:https://www.geeksforgeeks.org/destructors-in-c-sharp/

C# 中的析构函数是类内的方法，用于在不再需要时销毁类的实例。析构函数由隐式调用。NET Framework 的垃圾收集器，因此程序员无法控制何时调用析构函数。当实例变量或对象不再可达时，它有资格被销毁。

要点:

  • Destructors are unique to their classes, that is, a class cannot have more than one destructor.
  • The destructor has no return type and is exactly the same as the class name (including the same case).
  • It is different from constructor because its name is preceded by tilde (~) .
  • The destructor does not accept any parameters and modifiers.
  • Cannot be defined in a structure. It is only used for classes.
  • Cannot overload or inherit.
  • Called when the program exits.
  • Internally, the destructor calls the Finalize method of the object base class.

语法:

class Example
{ 
    // Rest of the class
    // members and methods.

   // Destructor
   ~Example()
    {
        // Your code
    }

}

例 1:

// C# Program to illustrate how 
// a destructor works
using System;

namespace GeeksforGeeks {

class Complex {

    // Class members, private 
    // by default
    int real, img;

    // Defining the constructor
    public Complex()
    {
        real = 0;
        img = 0;
    }

    // SetValue method sets 
    // value of real and img
    public void SetValue(int r, int i)
    {
        real = r;
        img = i;
    }

    // DisplayValue displays 
    // values of real and img
    public void DisplayValue()
    {
        Console.WriteLine("Real = " + real);
        Console.WriteLine("Imaginary = " + img);
    }

    // Defining the destructor
    // for class Complex
    ~Complex()
    {
        Console.WriteLine("Destructor was called");
    }

} // End class Complex

// Driver Class
class Program {

    // Main Method
    static void Main(string[] args)
    {

        // Creating an instance of class 
        // Complex C invokes constructor
        Complex C = new Complex();

        // Calling SetValue method using
        // instance C Setting values of 
        // real to 2 and img to 3
        C.SetValue(2, 3);

        // Displaying values of real
        // and imaginary parts
        C.DisplayValue();

        // Instance is no longer needed
        // Destructor will be called

    } // End Main

} // End class Program

}

输出:

Real = 2
Imaginary = 3
Destructor was called

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