Get DisplayName attribute's value from a property.

Extensioins.cs

using System.ComponentModel;
using System.Reflection;

namespace YourApp.Extensions;

public class ReflectionHelpers
{
    /// <summary>
    /// Get's the string value of the DisplayName attribute of a property.
    /// </summary>
    /// <typeparam name="T">The type of the object the property is part of</typeparam>
    /// <param name="propertyName">The property name We are looking for.</param>
    /// <returns>The value of the property's DisplayName attribute.</returns>
    /// <exception cref="ArgumentException">Throws this exception if the property does not exists, the parameter is null or does not have a DisplayName attribute.</exception>
    public static string GetDisplayName<T>(string propertyName)
    {
        if (string.IsNullOrEmpty(propertyName))
            throw new ArgumentException("Property name should not be empty");

        Type type = typeof(T);
        PropertyInfo? propertyInfo = type.GetProperty(propertyName);

        if (propertyInfo == null)
            throw new ArgumentException($"The property {propertyName} does not exists");

        Attribute? attribute = propertyInfo
            .GetCustomAttributes(typeof(DisplayNameAttribute)).SingleOrDefault();

        if (attribute == null)
            throw new ArgumentException($"The property {propertyName} does not have display name attribute");

        return ((DisplayNameAttribute)attribute).DisplayName;
    }
}