Manually destroy C# objects

c# destructor idisposable using
East of Nowhere picture East of Nowhere · Dec 31, 2009 · Viewed 76.2k times · Source

I am fairly new to learning C# (from Java & C++ background) and I have a question about manual garbage disposal: is it even possible to manually destroy an object in C#? I know about the IDisposable interface, but suppose I'm dealing with a class which I didn't write and it doesn't implement it? It wouldn't have a .Dispose() method, so that and using { } is out, and .Finalize is always either protected or private so that's not an option either.

(I am just trying to learn what is possible in C# in this case. I suppose if all else fails I could inherit the hypothetical ImNotDisposable class so that it does implement IDisposable.)

Answer

Joel Coehoorn picture Joel Coehoorn · Dec 31, 2009

You don't manually destroy .Net objects. That's what being a managed environment is all about.

In fact, if the object is actually reachable, meaning you have a reference you can use to tell the GC which object you want to destroy, collecting that object will be impossible. The GC will never collect any object that's still reachable.

What you can do is call GC.Collect() to force a general collection. However, this almost never a good idea.

Instead, it's probably better to simply pretend any object that doesn't use unmanaged resources and is not reachable by any other object in your program is immediately destroyed. I know this doesn't happen, but at this point the object is just a block of memory like any other; you can't reclaim it and it will eventually be collected, so it may just as well be dead to you.

One final note about IDisposable. You should only use it for types that wrap unmanaged resources: things like sockets, database connections, gdi objects, etc, and the occasional event/delegate subscription.

Related questions

Using the Destructor/Dispose of the base class?

In C#, as mentioned in the Documentation, and this nice post's accepted answer, it's stated that classes don't inherit the Destructor of their parent class. The question : If I want to make sure to dispose the private elements of the …

Read More
When should I create a destructor?

For example: public class Person { public Person() { } ~Person() { } } When should I manually create a destructor? When have you needed to create a destructor?

Read More
In C# what is the difference between a destructor and a Finalize method in a class?

What is the difference, if there is one, between a destructor and a Finalize method in a class? I recently discovered that Visual Studio 2008 considers a destructor synonymous with a Finalize method, meaning that Visual Studio won't let you simultaneously …

Read More