CODEWITHSUNDEEP
c#.net
GaryX
GaryX

Reputation: 737

Acceptable name for extension method that accept null

I really don't like to call String.IsNullOrEmpty(str). That makes me need to think "String" class first, then call it on the object "str".

I like to call str.IsNullOrEmpty(), which doesn't need me to think "String" class.

The problem is that extension method accept null instance to call on, which is not the usual case when you call a normal method.

My question what do you think will be a convetion name for extension methods that accept null?

  1. For string, that is easy, "IsNullOrEmpty()" (anything that contains "IsNull") sounds good for me.

  2. For others, like GetDisplayName(), do we name it as "NullOrGetDisplayName" ?

Upvotes: 0

Views: 174

Answers (5)

Trap
Trap

Reputation: 12372

I just don't understand your way of thinking here. Writing something like nullObject.IsNullOrWhatever() simply doesn't make any sense. You may or may not like the static form, but your solution feels really wrong to me.

Upvotes: 1

Noon Silk
Noon Silk

Reputation: 55062

Firstly, your thinking is wrong and you should adjust it. It is not correct to think of calling a method on a null object; indeed that's the very reason why you want to see if it is null!

Secondly, a method implies that it accepts null in the parameters it has. I don't think a naming convention is appropriate here. You may be able to eliminate null from your classes via, say, Spec#.

Upvotes: 2

Jason Williams
Jason Williams

Reputation: 57892

I'd go for mystring.IsNullOrEmpty() for methods that can query "null" objects - it is obviously checking if the string is null, and as long as you are consistent with your naming throughout your codebase, nobody will have any trouble understanding/learning what it means.

For methods that apply something to an object and ignore null objects, I'd use "Safe", as in SafeGetDisplayName() - this is a common and long-used standard (c.f. GetSafeHandle() in MFC)

Upvotes: 1

Guffa
Guffa

Reputation: 700152

The Nullable class has a method named GetValueOrDefault. The same form may be usable for some extension methods: GetDisplayNameOrDefault or perhaps more specific GetDisplayNameOrNull or GetDisplayNameOrEmpty.

Upvotes: 0

Rian Schmits
Rian Schmits

Reputation: 3206

How about NullSafeGetDisplayName or GetDisplayNameNullSafe, indicating that's it's safe to call even when the object it's being called on is null?

Upvotes: 1

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