C# - Get Display Attribute Value from Enum

Every now and then, I have a use case where decorating an Enum’s values with Attributes comes in handy. Things such as… Adding Display Names, Descriptions, etc.

Well, every time I have this use-case, I have to go google how I did it the previous time… and in most cases, StackOverflow is less then helpful. Then, I remember a few personal projects where I previously did this, and I find the code and reuse it.

Well, for the others who have this issue, I am going to share the solution I came up with many moons ago.

The Code

public static class AttributeHelper
{
    /// <summary>
    /// If <paramref name="Enum"/> has <see cref="DisplayAttribute"/> defined, this will return <see cref="DisplayAttribute.Name"/>. Otherwise, <see langword="null" /> will be returned.
    /// </summary>
    /// <returns><see cref="string"/> containing <see cref="DisplayAttribute.Name"/> if defined. Otherwise, will return <see langword="null" /></returns>
    public static string GetDisplayName<T>(this T Enum) where T : System.Enum
        => Enum.GetEnumAttribute<T, DisplayAttribute>()?.Name;
    /// <summary>
    /// If <paramref name="Enum"/> has <see cref="DisplayAttribute"/> defined, this will return <see cref="DisplayAttribute.Description"/>. Otherwise, <see langword="null" /> will be returned.
    /// </summary>
    /// <returns><see cref="string"/> containing <see cref="DisplayAttribute.Description"/> if defined. Otherwise, will return <see langword="null" /></returns>
    public static string GetDescription<T>(this T Enum) where T : System.Enum
        => Enum.GetEnumAttribute<T, DisplayAttribute>()?.Description;
    /// <summary>
    /// Returns <see cref="DisplayAttribute"/> from <paramref name="Enum"/> if defined. Otherwise will return <see langword="null" />.
    /// </summary>
    public static DisplayAttribute GetDisplayAttribute<T>(this T Enum) where T : System.Enum
        => Enum.GetEnumAttribute<T, DisplayAttribute>();
    public static TAttribute GetEnumAttribute<TEnum, TAttribute>(this TEnum Enum)
        where TEnum : System.Enum
        where TAttribute : System.Attribute
    {
        var MemberInfo = typeof(TEnum).GetMember(Enum.ToString());
        return MemberInfo[0].GetCustomAttribute<TAttribute>();
    }
}

How do you use it?

Simple. Since the helpers are defined as an extension method, just make sure you are using the proper namespace, and… that is it.

public enum TestEnum
{
    [Display(Name = "Value 1", Description = "This is a description for value 1.")]
    VALUE_1,

    VALUE_2,

    [Display(Name = null, Description = null)]
    VALUE_3
}


public void TestDisplayName()
{
    TestEnum.VALUE_1.GetDisplayName(); //Returns "Value 1"
    TestEnum.VALUE_2.GetDescription(); //Returns "This is a description for value 1."
    TestEnum.VALUE_1.GetDisplayAttribute().Name; //Returns "Value 1"

    TestEnum.VALUE_2.GetDisplayName(); //Returns null
    TestEnum.VALUE_2.GetDescription(); //Returns null
    TestEnum.VALUE_2.GetDisplayAttribute(); //Returns null
}

Unit Tests

Nothing is complete without proper unit testing! Here are some simple tests to get you started.

[TestCase(TestEnum.VALUE_1, "Value 1", "This is a description for value 1.")]
[TestCase(TestEnum.VALUE_2, null, null)]
[TestCase(TestEnum.VALUE_3, null, null)]
public void TestDisplayName(TestEnum Enum, string DisplayName, string Description)
{
    Assert.DoesNotThrow(() =>
    {
      Assert.AreEqual(DisplayName, Enum.GetDisplayName());
      Assert.AreEqual(Description, Enum.GetDescription());
    });
}