C# Null Comparison: Why Prefer 'null != variable' Over 'variable != null'?

Null comparison in C#: Why use the unusual order of "null != variables"?

In C# programming, you often see null value comparison written as "null != variable" instead of the more common "variable != null". This approach stems from a historical problem left over from its predecessor, the C language.

In C language, due to the lack of suitable compiler configuration, when the assignment operator "=" is accidentally used instead of the comparison operator "==", it may cause unnoticeable errors. To solve this problem, developers have adopted the practice of placing constant values ​​on the left side of comparison operators, such as "5 == x". This way, any potential typing errors will result in invalid code.

While this approach may have been necessary in the past, modern programming languages ​​like C# have improved type checking mechanisms that eliminate the risk of such errors. Also, an "if" statement in C# expects its condition to be a boolean expression, so the order of comparisons doesn't matter.

Therefore, in C#, there is no performance or logical difference between "null != variable" and "variable != null". Which one you choose depends on personal preference or potential confusion in the context of your code. However, it is recommended to use the more intuitive and readable "variable != null" format to avoid unnecessary ambiguity or idioms from older languages.

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