Enum Storage should be Int32

Cause

The underlying type of a public enumeration is not System.Int32.

Rule Description

An enumeration is a value type that defines a set of related named constants. By default, the System.Int32 data type is used to store the constant value. Even though you can change this underlying type, it is not necessary or recommended for most scenarios. Note that there is no significant performance gain in using a data type smaller than Int32. If you cannot use the default data type, you should use one of the CLS-compliant integral types, Byte, Int16, Int32, or Int64, to ensure that all of the enumeration's values are representable in CLS-compliant programming languages.

How to Fix Violations

To fix a violation of this rule, unless there are size or compatibility issues, use Int32. For situations where Int32 is not large enough to hold the values, use Int64. If backward compatibility requires a smaller data type, use Byte or Int16.

When to Exclude Warnings

Exclude a warning from this rule only if backward compatibility issues require it. In applications, failure to comply with this rule usually does not cause problems. In libraries, where language interoperability is required, failure to comply with this rule might negatively affect your users.

Example

The following example shows two enumerations that do not use the recommended underlying data type.

using System;

namespace DesignLibrary
{
   [Flags]
   public enum Days : uint
   {
      None        = 0,
      Monday      = 1,
      Tuesday     = 2,
      Wednesday   = 4,
      Thursday    = 8,
      Friday      = 16,
      All         = Monday| Tuesday | Wednesday | Thursday | Friday
   }

   public enum Color :sbyte
   {
      None        = 0,
      Red         = 1,
      Orange      = 3,
      Yellow      = 4
   }
}

Related Rules

Enums should have zero value

Mark enums with FlagsAttribute

Do not mark enums with FlagsAttribute

Do not name enum values 'Reserved'

Do not prefix enum values with type name

See Also

Reference

System.Byte
System.Int16
System.Int32
System.Int64