C# Nullable arrays
Solution 1
Arrays are always reference types, as is string
- so they're already nullable. You only need to use (and only can use) Nullable<T>
where T is a non-nullable value type.
So you probably want:
public ActionResult Search(string searchString, int[] locationIds,
DateTime? startDate, DateTime? endDate)
Note that I've changed your parameter names to follow .NET naming conventions, and changed LocationId
to locationIds
to indicate that it's for multiple locations.
You might also want to consider changing the parameter type to IList<int>
or even IEnumerable<int>
to be more general, e.g.
public ActionResult Search(string searchString, IList<int> locationIds,
DateTime? startDate, DateTime? endDate)
That way a caller could pass in a List<int>
for example.
Solution 2
Arrays are reference types, so you don't have to do anything, you already can pass null
:
A method with the following signature can be called with all parameters as null
:
public ActionResult Search(string SearchString, int[] LocationIds,
DateTime? StartDate, DateTime? EndDate)
foo.Search(null, null, null, null);
Please note: I additionally removed the question mark after string
as it is a reference type as well.
Preston
Updated on April 18, 2020Comments
-
Preston about 4 years
I have a search function, but I would like
LocationID
to be an array of integers rather than just a single integer. I'm not sure how to do this since I want it to also be nullable. I've looked at doingint?[]
but then I'd have to check theHasValue
of every single entry. Is there a better way?This is what I currently have:
public ActionResult Search(string? SearchString, int? LocationId, DateTime? StartDate, DateTime? EndDate)