Umbraco-CMS/src/Umbraco.Core/Models/KeyValue.cs

using System;
using System.Runtime.Serialization;
using Umbraco.Cms.Core.Models.Entities;

namespace Umbraco.Cms.Core.Models
{
    /// <summary>
    /// Implements <see cref="IKeyValue"/>.
    /// </summary>
    [Serializable]
    [DataContract(IsReference = true)]
    public class KeyValue : EntityBase, IKeyValue, IEntity
    {
        private string _identifier = null!;
        private string? _value;

        /// <inheritdoc />
        public string Identifier
        {
            get => _identifier;
            set => SetPropertyValueAndDetectChanges(value, ref _identifier!, nameof(Identifier));
        }

        /// <inheritdoc />
        public string? Value
        {
            get => _value;
            set => SetPropertyValueAndDetectChanges(value, ref _value, nameof(Value));
        }

        bool IEntity.HasIdentity => !string.IsNullOrEmpty(Identifier);
    }
}