Custom Data Types

Question

I'd like to create some custom data types, but I don't think I'm asking the right question(s).

There are "compound Boolean" values used throughout .NET, and I want to design some of my own. I've been using a series of Boolean variables, which works, but just isn't the same.

Examples from .NET include: Color.Black Alignment.Centered [fontProperties].Bold* *I forget the actual name, but you get the idea

I want to make something like this:

ColorSortQualities

None
DistinguishColor
DistinguishNumberOfColors
DistinguishColorPattern

Once that's been declared, I could do this: if(searchOptions.ColorSortQualities == DistinguishColor) [do stuff]

What is this called?

Thanks!

Is it possible to have both 'DistinguishColor' and 'DistinguishColorPattern' at the same time, or are they mutually exclusive? — Mark Byers, Apr 10 '10 at 19:37

score 5 · Answer 1 · answered Apr 10 '10 at 19:29

5

Use an enum:

  enum ColorSortQualities
  {
       None,
       DistinguishColor,
       DistinguishNumberOfColors,
       DistinguishColorPattern
  };

answered Apr 10 '10 at 19:29

n535

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unecessarily explicitly declaring the type of an enum as other than int32 is a bad move in my opinion. Are you trying to save a few bytes on a static type? – Sky Sanders Apr 10 '10 at 19:30
Well, actually i don't know whether it is considered to be a good or bad practice, so thanks. – n535 Apr 10 '10 at 19:32
After reading http://stackoverflow.com/questions/746812/best-practices-for-using-and-persisting-enums things seem clear, thank you once again. – n535 Apr 10 '10 at 19:39
Virtually every enum in the CLR is the default int32. Explicit declaration otherwise, unless the enum is being repurposed in an edge case, for use in an api call requiring a byte for instance, just adds noise. I am measuring best practice from what I have seen, that's all. – Sky Sanders Apr 10 '10 at 19:39

score 4 · Accepted Answer · answered Apr 10 '10 at 19:29

4

It's called an enumeration and in C# you use the keyword enum.

answered Apr 10 '10 at 19:29

Mark Byers

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Matthew Flaschen · Answer 3 · 2010-04-10T19:45:19.157

I think you want a enumeration with the [Flags] attribute.

[Flags]
enum ColorSortQualities
{
    None = 0x0,
    DistinguishColor = 0x1,
    DistinguishNumberOfColors = 0x2,
    DistinguishColorPattern = 0x4
}

This will let the caller specify any combination of those, each of which will be implemented as a bit flag. Note that this will allow 32 options, because int is a 32-bit quantity.

Your condition code would look like:

if((searchOptions & ColorSortQualities.DistinguishColor) == ColorSortQualities.DistinguishColor)

If that isn't what you mean by "series of Boolean variables", please clarify.

Custom Data Types

3 Answers3