CODEWITHSUNDEEP
c#
PositiveGuy
PositiveGuy

Reputation: 47763

Reuse an object

I'm wondering if this is good, bad?

SelectRecipientResponse user = SomeUtil.SelectRecipient(p.Email, p.ListID.ToString());
bool userIsInList = user.ExistsInList;
bool userIsOptedOut = user.IsOptedOut;

user = null;
user = SomeUtil.SelectRecipient(p.Email, _masterSuppressionListID);
bool userIsInSupressionList = user.ExistsInList;

so I'm using one instance of user to check to see if they are in 2 lists. Lists I am checking are over a 3rd party API. I want to do one check, null out that object and reuse it again.

Does this seem typical? I'm just trying to code this smartly so wanted to see what one thinks about this technique above.

Upvotes: 0

Views: 2522

Answers (4)

Noon Silk
Noon Silk

Reputation: 55122

It's completely acceptable to re-assign variables, though there is absolutely no legitimate reason to assign null to the variable, then assign it to something else.

In terms of readability, when I am re-using local variables, I don't generally assign it on the first declaration.

I'll typically write:

SqlParameter param;

param = new SqlParameter(...);
param.Value = "";

... // and again

param = new SqlParameter(...);
param.Value = "";

In this way, it's kind of clear that it's being re-used (or at least re-assigned). Works for me, anyway, and it means that I can happily re-order things (if it becomes relevant) without too much trouble.

Upvotes: 0

JeremyWeir
JeremyWeir

Reputation: 24378

You're asking for trouble when some other developer comes back in a year and starts working with user further down in the method not noticing that you overwrote it with a second assignment. Name your variable what it is. This would probably qualify as unnecessary premature optimization.

Upvotes: 1

Alex Martelli
Alex Martelli

Reputation: 882171

Actually, you're using the same variable, i.e. the name user, to refer (in separate zones of your code) to (possibly-)separate instances of SelectRecipientResponse, since each call to SelectRecipient is (or may well be) returning a distinct one. No big problem with that. And no need to set user explicitly to null before reassigning it, either.

Upvotes: 4

Andrew Hare
Andrew Hare

Reputation: 351566

This is fine because you aren't reusing the object, you are simply reusing the local variable that holds the reference to the object.

That being said, I personally feel that it would be better to simply create a second variable to hold the second reference as I find that more readable.

Upvotes: 6

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