问题:

MyEnum.Item.ToString();
nameof(MyEnum.Item);

Which style is preferred? Is there any practical difference between the two?

回答1:

The first is a run-time call that will realise at runtime it needs to return the string "Item", and do so.

The second is another way to write "Item" straight into the code.

The second would be slightly faster, but prior to C#6 would not have been available. To put "Item" in the code manually would have therefore been an optimisation that risked an error, while nameof() would catch such an error at compile-time.

As such while the approach of using the name directly might once have been considered taking a risk, that risk is gone, and it has a slight edge.

ToString() though remains the only way to output the string based on a variable or expression of the MyEnum type.

回答2:

.ToString() is evaluated at runtime and can be called with your own format.

nameof() is evaluated at compile-time and will inject a string literal that will never change.

回答3:

If you're not obfuscating your code, pretty much the same... the moment you obfuscate your code however, ToString() will likely produce garbage, while nameof() will retrieve the name you requested / expected.

More info on MSDN