c# - !(x is null) 和 x is object 之间有区别吗

Question

!(x is null) 和 x is object 之间有区别吗？

是否存在返回不同结果的情况？

Answer 1

没有明显差异。它们都编译为相同的CIL。

自己检查一下here

_{注意:即使对于可空类型也是如此，如您所见 here}

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来自Standard ECMA-334 C# Language Specification

12.11.11 The is operator

The is operator is used to check if the run-time type of an object is compatible with a given type. The check is performed at runtime. The result of the operation E is T, where E is an expression and T is a type other than dynamic, is a Boolean value indicating whether E is non-null and can successfully be converted to type T by a reference conversion, a boxing conversion, an unboxing conversion, a wrapping conversion, or an unwrapping conversion.

更新

要完全简洁，正如 Alexei Levenkov 所指出的那样

!(1 is null) 与 1 is object 显示出一些差异，前者由于不可为空而无法编译可空