About the Hashtable Remove

Question

5.00/5 (1 vote)

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Sample code:

Hashtable h0 = new Hashtable();
h0.add(0,10);
Hashtable h1 = new Hashtable();
h1.add(0,h0);

h1.Remove(0);

Question:

Do I need to get the h0, remove the items in h0, then remove the h0 from h1? Or just remove the h0?

Posted 14-Aug-09 16:12pm

elvis_pan

Updated 25-Aug-09 10:32am

Sean Ewington

v2

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3 solutions

Solution 2

The hashtable only contains a reference to the object, not the object itself. Removing one hashtable reference from the other hastable (h0 from h1) only takes the reference to h0 out of h1. h0 itself remains unchanged (as do all references contained in h0).

Posted 21-Nov-09 10:48am

Rob Graham

Solution 3

I assume your question is about garbage collection. If so, just remove h0. Here's why...

By removing h0 from h1, you tell the garbage collector "hey, h0 is no longer referenced by anything, so you can garbage collect it". Once h0 is garbage collected, that means the boxed integer (10) is also not referenced, making it a candidate for garbage collection as well.

Garbage collection can be summarized as follows: if an object is no longer referenced by another object, it will be garbage collected (aka, released from memory). If there is some sort of circular referencing (such as variable A referencing variable B which then references variable A), then those objects will still be garbage collected so long as they aren't referenced by anything that the main threads can access.

Posted 21-Nov-09 13:41pm

AspDotNetDev

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Luc Pattyn · Accepted Answer · 2009-08-14T16:53:00

Solution 1

Hi,

no you don't need to dismantle an element that you want to remove from a collection.

BTW: you should consider using generic collections (such as Dictionary<T1,T2>), available since .NET 2.0; they are faster and safer.

:)

Posted 14-Aug-09 16:53pm

Luc Pattyn