Question

In C# I have seen enums used in a flag format before. Such as with the Regex object.

Regex regex = new Regex("expression", RegexOptions.Something | RegexOptions.SomethingElse);

If I have a custom enum:

enum DisplayType
{
    Normal,
    Inverted,
    Italics,
    Bold
}

How would i format a method to accept multiple enums for one argument such as the syntax for Regex? i.e SomeMethod(DisplayType.Normal | DisplayType.Italics);.

Answer 1

Use the FlagsAttribute. The MSDN documentation explains everything. No point repeating it here.

For your example, you’d say:

[Flags]
enum DisplayType {
    None = 0,
    Normal = 1,
    Inverted = 2,
    Italics = 4,
    Bold = 8
}