C# `Type.GetEnumUnderlyingType()`: Determining the Underlying Type of Enumerations

Learn how to determine the underlying integral type (e.g., `int`, `byte`, `short`) used to store enum values in C# using the `Type.GetEnumUnderlyingType()` method. This tutorial explains its functionality, demonstrates its usage with code examples, and highlights its application in situations requiring runtime inspection of enumeration types.

Using C#'s `Type.GetEnumUnderlyingType()` Method

The C# `Type.GetEnumUnderlyingType()` method retrieves the integral type used to store the values of an enumeration (enum). Enums are custom data types that represent a set of named constants.

Understanding Enums and Underlying Types

When you define an enum in C#, its members (named constants) are actually stored as integer values (or other integral types like `byte`, `short`, etc.). The `GetEnumUnderlyingType()` method tells you what this underlying integral type is.

`Type.GetEnumUnderlyingType()` Syntax

public static Type GetEnumUnderlyingType(Type enumType);

This method takes the `Type` object of an enumeration as input and returns a `Type` object representing the underlying integral type. If the input type is not an enum, it returns `null`.

Example 1: Determining the Underlying Type

enum MyEnum : byte { A, B, C } // Underlying type is byte

Type underlyingType = Enum.GetUnderlyingType(typeof(MyEnum));
Console.WriteLine(underlyingType); //Output: System.Byte

Example 2: Handling Non-Enum Types

try {
    Type underlyingType = Enum.GetUnderlyingType(typeof(string)); // string is not an enum
    Console.WriteLine(underlyingType);
} catch (ArgumentException ex) {
    Console.WriteLine($"Error: {ex.Message}");
}

Example 3: Working with Enum Members

public enum Days { Mon, Tue, Wed, Thu, Fri, Sat, Sun }

public class EnumExample {
    public static void Main(string[] args) {
        // ... (code to get the underlying type and print enum members with their underlying values) ...
    }
}

Uses of `Type.GetEnumUnderlyingType()`

• Serialization/Deserialization: Handling enums during data serialization/deserialization.
• Bitwise Operations: Performing bitwise operations on enum values.
• Arithmetic Operations: Performing arithmetic operations with enum values.
• Type Checking: Verifying if a given type is an enum before performing enum-specific operations.