CODEWITHSUNDEEP
c#
Embedd_0913
Embedd_0913

Reputation: 16555

Does the following code have a memory leak?

I have the following code:

    Dictionary<string, Setup> dictSetups = new Dictionary<string, Setup>();
    Setup setup1 = new Setup();
    dictSetups.Add("setup1", setup1);

    using (MySetupForm myForm = new MySetupForm())
    {
        myForm.Setup = dictSetups["setup1"];
        if (myForm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
        {
            dictSetups["setup1"] = myForm.Setup;
        }                
    }

This is MySetupForm:

    public partial class MySetupForm : Form
    {
        public MySetupForm()
        {
            InitializeComponent();
        }

        public Setup Setup { get; set; }
    }

In the code above I am passing a reference of dictSetups["setup1"] to MySetupForm and then showing the form.

If the dialog result is OK I am updating the reference in my dictionary, my question is when I go out of using that means MySetupForm myForm is disposed, but

dictSetups["setup1"] is holding reference from myForm.Setup; , so will it be a memory leak or not ?

Upvotes: 0

Views: 131

Answers (3)

Servy
Servy

Reputation: 203823

There is no memory leak here.

When you say dictSetups["setup1"] = myForm.Setup; you are fetching the Setup object that myForm was referencing and storing a reference to that in the dictionary. It's not holding onto a reference to myForm. There would need to be a lambda or something along those lines to generate a closure for that to happen.

A memory leak is when an object has gone out of scope, thus preventing the release of it's memory, on an object for which the memory must be manually released. This is virtually impossible in C# because the garbage collector takes care of reclaiming memory for you. The program may be less memory efficient if it is holding onto references to objects with a large memory footprint when they are no longer needed (there is no way for us to tell if you're doing this in your code; we can't know what objects you'll actually need references to later and which you wont), but it's not actually a memory leak.

While it is possible to cause a memory leak in C#, it's really hard. You practically have to be actively trying to cause one for it to happen outside of a few narrow scopes. If you're interoping with unmanaged code then you may need to deal with the memory management of that code, and if you're in unsafe blocks you can cause all sorts of havok. Short of that, there's not really much you can do to cause a memory leak. You can't usually allocate memory in C# that the garbage collector can't reclaim, and I know of no bugs that prevent the GC from reclaiming memory when it should.

Upvotes: 1

Justin Niessner
Justin Niessner

Reputation: 245399

It's nearly impossible to tell for sure by the code you posted.

You should get a hold of a memory profiling tool and profile your application. That is the only real way to know if there is a memory leak, where it is, and the best way to fix it.

Upvotes: 2

Tigran
Tigran

Reputation: 62246

I would say, yes. This has a memory leak, in the context of code provided. What I mean by this is that Dictionary<string, Setup> dictSetups is global variable, that maintains its constant lifetime during application workflow.

In general, just from the code porvided, from the program context point of view, it's hard to say.

Upvotes: 1

Related Questions