CODEWITHSUNDEEP
c#wpf
System.Data
System.Data

Reputation: 3968

Destroy controls

I use a for loop to generate some controls. Each control presents a special visualisation. I can not use controls like ListBox or somethink like that. I must use my approach. The generated controls are hosted in a Canvas. After a while, some controls are not longer needed. Some controls must be removed. I can manually remove a controls via 

c.Children.Remove( ... );

this line. How do I determine that the controls was really collected from be garbage collection? Maybe the control already exists in the memory ... . How do I ensure this?

The problem is that I generate data in tons!

Thanks in advance! :-)

Upvotes: 4

Views: 8035

Answers (5)

Robert Rossney
Robert Rossney

Reputation: 96702

As long as nothing holds a reference to a control, the garbage collector will get rid of it and you have nothing to worry about. Usually, removing a control from the collection that contains it all you need to do.

But you must be careful with event handlers. If object A subscribes to an event that object B raises, object B holds a reference to object A. If your controls subscribe to, say, Canvas.IsEnabledChanged, you can remove them from the Canvas, but the Canvas will still hold a reference to them so that it can notify them when IsEnabled changes, and they won't be garbage-collected. This is the most common cause of "memory leaks" in .NET applications. (They're not really memory leaks, but they might as well be.)

Upvotes: 1

Daniel Peñalba
Daniel Peñalba

Reputation: 31847

Depending on the control that you're using maybe you need to call Control.Dispose() to free all resources. Be careful is you are using unmanaged resources (Learn more)

I think this is not your case.

Then the garbage collector will collect the object for you.

Also, this article about how Garbage Collector works could be very interesting:

http://www.codeproject.com/KB/dotnet/Memory_Leak_Detection.aspx

Upvotes: 4

Martijn
Martijn

Reputation: 12092

if you're sure the objects arent referenced anywhere anymore, you can force a call to the garbage collector with gc.Collect()

Upvotes: 1

Vlad
Vlad

Reputation: 35584

You don't really need to. That's the sense of garbage collection: as soon as there are too many dead objects, garbage collection jumps in and cleans them out. Or doesn't clean: the GC knows better what and when to remove.

Upvotes: 2

jcolebrand
jcolebrand

Reputation: 16025

So if you call to Destroy the control, and you haven't maintained any other references to the control in memory (like in a hashtable of controls or something), then the GC will collect it.

Don't try and force the .NET GC to do something fancy, let it do its work in its own time as the library authors designed it. If you Destroy it, it will be gone, in due time.

Lastly, if you're concerned that it's still consuming memory, it will be time to start profiling your code, like for instance with RedGate Ants.

Upvotes: 4

Related Questions