Spaces in C# Enums

问题:

Is there any way to put spaces in a C# enum constant? I've read that you can do it in VB by doing this:

Public Enum EnumWithSpaces
  ConstantWithoutSpaces
  [Constant With Spaces]
End Enum

...and then access it like this:

Public Sub UsingEnumWithSpaces()

  Dim foo As EnumWithSpaces = EnumWithSpaces.[Constant With Spaces]

End Sub

That implies to me that the CLR can handle an enum with spaces.

Is there any way to do this in C#?

回答1:

This blog post might help you:

http://blog.spontaneouspublicity.com/2008/01/17/associating-strings-with-enums-in-c/

From the article:

But enums can't have spaces in C#!" you say. Well, I like to use the System.ComponentModel.DescriptionAttribute to add a more friendly description to the enum values. The example enum can be rewritten like this:

public enum States
{
    California,
    [Description("New Mexico")]
    NewMexico,
    [Description("New York")]
    NewYork,
    [Description("South Carolina")]
    SouthCarolina,
    Tennessee,
    Washington
}

Notice that I do not put descriptions on items where the ToString() version of that item displays just fine.

回答2:

CLR can handle absolutely any character in identifiers. However, C# restricts the identifier characters to those legal under the CLS, which space isn't. Same goes for VB.NET, by the way - spaces inside square brackets used to work in VB6, but they don't in VB.NET.

回答3:

If you're working with Visual C# 3.0 or above I've found it convenient to just extend the enum class and use a regex to inset spaces where neccessary:

public static class EnumExtension
{
    public static String ToDisplayString(this Enum e)
    {
        Regex regex = new Regex(@"([^\^])([A-Z][a-z$])");

        return regex.Replace(e.ToString(), new MatchEvaluator(m =>
        {
            return String.Format("{0} {1}", m.Groups[1].Value, m.Groups[2].Value);
        }));
    }
}

Notice this allows you to work with any enum as is without adding descriptions to every value.

String enumWithSpaces = MessageBoxButtons.OKCancel.ToDisplayString();