C# Programming - Enumerations - Discussion

Each enum type has a corresponding integral type called the underlying type of the enum type. This underlying type can represent all the enumerator values defined in the enumeration. An enum declaration may explicitly declare an underlying type of byte, sbyte, short, ushort, int, uint, long or ulong. Note that char cannot be used as an underlying type.

Not only char but also float, double, decimal and even bool value types are not accepted by Enum. Because enumerations are user defined integer data types. This is the answer.