How to dispose List<T>

15y22.8kVisual Basic .NET

Hi experts,

I am having List object. How I can dispose the list ?

For example,

List usersCollection =new List();

User user1 = new User();
User user2 = new User()

userCollection.Add(user1);
userCollection.Add(user2);

if I set , userCollection = null; what will happen?

foreach(User user in userCollection)
{
user = null;
}

Which one is best?

4 Replies

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Rajan M7y ago
If your item in list is un-managed object then you can call Dispose() on every object by iterating it.

foreach(User user in userCollection)
{
user.Dispose();
}

If the list object is managed object then you need not do anything. GC will take care.
0
Dorababu Meka15y ago
Best idea is to leave it to the garbage collector. Your foreach will do nothing since only the reference will be set to null not the element in the list. Setting the list to null could in fact cause garbage collection to occur later than it could have.

and a point to remember You cannot "dispose" a list since it isn't IDisposable
0
Vulpes15y ago
Yes, what Suthish said is essentially correct.

If you set userCollection to null and there are no other references to it, then it will be become elgible for garbage collection and will be destroyed in due course. All the User objects which are elements of the list will also be GC'd unless there are other existing references to them.

So, if there are no other references to the User objects and you want to ensure they are destroyed as soon as possible followed by the List itself, then you should iterate through the list and set each element to null and then userCollection itself to null. Notice though that you won't be able to use 'foreach' here because you would be assigning to the iteration variable which is not allowed - you'll need to use 'for' instead:

for(int i = 0; i < userCollection.Count; i++)
{
userCollection[i] = null;
}

userCollection = null;
0
Suthish Nair15y ago
If you have no external reference to usersCollection List, then GC will take care of this. Otherwise, you need to do the other step. Wait for more inputs also, for better answers.
0