Difference between null == x and x == null? [duplicate]

Answer 1

In this case, its personal preference in C#.

Yoda Conditionals

Answer 2

It's a rudiment from C++ days, where you could accidentally assign variable by using = instead of == and it would still pass the compiler cause you could pass almost anything into comparisons in C++. Do not use it in C#, cause it will not allow you to do so.

Valid C++:

if (p = NULL) // p gets assigned NULL and result is compared to 0

Invalid C#:

if (p = null) // can only use booleans in test

Answer 3

Absolutely identical in all aspects. Just a reversed way of doing the same thing.

Answer 4

Using null == x prevents accidentally mistyping and missing out one equals symbol and therefore assigning rather than testing for a value. You would end up with null = x which would not compile.

In any case, using Object.ReferenceEquals(x, null) is probably better anyway, as it would prevent cases where == has been overloaded.

Answer 5

Is there a performance difference or is it just personal preference?

No, absolutely no performance difference. It's only a matter of personal preference.