class Console.WriteLine Constructor Unreachable using

Destructor

In the C# language a destructor runs after a class becomes unreachable. It has the special "~" character in its name.

Destructor info

The exact time a destructor is executed is not specified. But it always runs when the class is not reachable in memory by any references.

An example

Let us begin by looking at this Example class. It contains a constructor "Example()" and also a destructor "~Example()".

Here The class Example is instantiated in the Main method. We write the method type to the console.

Result The output shows that the constructor is run and then the destructor is run before the program exits.

using System;

class Example
{
    public Example()
    {
        Console.WriteLine("Constructor");
    }

    ~Example()
    {
        Console.WriteLine("Destructor");
    }
}

class Program
{
    static void Main()
    {
        Example x = new Example();
    }
}Constructor
Destructor

Discussion

We next reference the C# specification. The destructor can be run at any time after the class instance becomes unreachable (such as when it goes out of scope).

Info When you implement IDisposable, you can use the "using" pattern. This lets us know exactly when clean up must occur.

So For this reason, the using pattern is preferable for cleaning up system resources (page 120).

Destructors versus `IDisposable`

Destructors have simpler syntax and don't require the using syntax. Most actions needed at type destruction are system cleanup tasks.

And These tasks are better suited to the explicit syntax of the using pattern.

Thus In complex programs that need special destruction logic, the using-dispose pattern is usually better.

A summary