C# 忽略 null 检查？

Question

Who can explain to me this irrational lame beauty of C# logic in blazor-server?

Answer 1

What is club , and does it perhaps have a static == operator overload that is not null-safe? For example, the following is possible and broken:

bool == (Foo x, Foo y) => x.Id == y.Id;

It is broken because it doesn't consider that x and/or y could be null . Using club == null will call this broken operator, causing a NRE.

A good way to check is to use club is object instead of club != null , as the is object / is null syntax never calls static == operator overloads.

Answer 2

Maybe You should compare club to null like this:

if (!(club is null) && club.Id > 0)

I think NullReferenceException is caused by == operator, which can use methods that are not "null safe".

Answer 3

To ensure the reference is null you can use:

ReferenceEquals(myObject, null)

It is a static method from the Object class itself so basically it can be used everywhere.

Most of the time it will give you the same result as:

myObject == null

But since the "==" can be overloaded you can have strange behavior. See operator overload .