What Does the [Flags] Attribute Really Do?

Question

What does applying [Flags] really do?

I know it modifies the behavior of Enum.ToString, but does it do anything else? (e.g. Different compiler or runtime behavior, e

Answer 1

Here's a list of concrete behavioral differences:

• Setting an enum with [flags] to None clears all the flags.
• The HasFlags method only works when this attribute is present.
• As Devio said, it changes the capabilities of the Parse and Format methods. He linked to this article. Apparently it also impacts that is shown in Debuggers.
• I thought [flags] probably had an impact on code generation in webservices, but it appears that this is not the case.
• To be clear, bitwise operations are allowed on any enumeration, with or without [flags]. But using it is the best practice.

More details: http://msdn.microsoft.com/en-us/library/ms229062.aspx