Can session call dispose method on session ending time?

Question

I want to know if IDisposable objects will dispose on session ending.

I know, I can dispose on Session ending event myself. But I want to write an IDisposable class.

For example, I have

public class MyObject : IDisposable
{
    // some properties

    public void Dispose()
    {
        // disposing
    }
}

and I need to dispose this object on session ending time :

    protected void Session_End(object sender, EventArgs e)
    {
        if (Session["key"] != null)
            ((MyObject)Session["key"]).Dispose();
    }

So, I want to know on session ending time that operation will automatically or I need write as above.

Answer 1

Session_End does not automatically dispose of IDisposable objects, so your Session_End solution is correct.

However:

• Session_End is only called when you use "inproc" sessions (but for the other types you would need a serializable object)
• It's only called after the session timeout has expired, so you kept this resource for an extra 20 minutes (or whatever your timeout is)

So try and find a solution that doesn't require you to store IDisposable objects in Session.

Answer 2

An instance of a class which implements the IDisposable interface will only be "disposed" whenever you call the Dispose method, whether directly or indirectly via the using construct. It's not something which happens automatically whenever an object falls out of scope.

For example, this would be bad practice;

public void SomeMethodCalledDuringSession()
{
    var resourceHog = new ResourceHog(); // where ResourceHog : IDisposable
    // Perform operations
}

The object is never disposed properly here, regardless of your ASP.NET session ending. However, you can call Dispose directly when you're finished, or a better idea is to do this;

public void SomeMethodCalledDuringSession()
{
    using(var resourceHog = new ResourceHog()) // where ResourceHog : IDisposable
    {
        // Perform operations
    }
}

This translates into a try ... finally pattern, with the call to Dispose in the finally clause, ensuring that it gets called (apart from a few rare situations).

Edit : I would also read this; http://nitoprograms.blogspot.co.uk/2009/08/how-to-implement-idisposable-and.html