c#中空数组_C＃可空数组-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_29629231/article/details/113003473

这篇博客讨论了如何在C#中将Search方法的LocationId参数从单个可空整数转换为可为空的整数数组。作者指出，由于数组本身已经是引用类型，因此默认就是可为空的。建议使用int[]而不是int?[]，并建议考虑使用IList或IEnumerable来提供更大的灵活性，允许传入各种类型的集合。

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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 doing int?[] but then I'd have to check the HasValue 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)

解决方案

Arrays are always reference types, as is string - so they're already nullable. You only need to use (and only can use) Nullable 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 or even IEnumerable to be more general, e.g.

public ActionResult Search(string searchString, IList locationIds,

DateTime? startDate, DateTime? endDate)

That way a caller could pass in a List for example.