ScalarCollection

ScalarCollection.cs

using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Reflection;

namespace System.Collections.Specialized
{
  /// <summary>
  /// If you add read/write properties, don't forget to attribute with NotMapped, unless you want it in the database.
  /// </summary>
  /// <typeparam name="T"></typeparam>
#if NET462
  [ComplexType]
#endif
  public abstract class ScalarCollectionBase<T> :
#if NET462
    Collection<T>
#else
    ObservableCollection<T>
#endif
  {
    public static readonly string DefaultSeparator = Environment.NewLine;
    public virtual string Replacement { get; } = "\u23ce";
    public virtual IEqualityComparer<T> Comparer { get; } = EqualityComparer<T>.Default;

    protected ScalarCollectionBase(params T[] values)
      : base(values.Where(v => v != null).Distinct().ToList() ?? new List<T>())
    { }

    protected virtual string Separator { get; } = DefaultSeparator.ToString();
    protected virtual bool AllowDuplicates { get; } = false;

    /// <summary>
    /// Gets or sets a linebreak-separated collection of the column content.
    /// </summary>
#if NET462
    [Browsable(false)]
#endif
    [EditorBrowsable(EditorBrowsableState.Never)]
    [Obsolete("Not to be used directly by user, use Items property instead.")]
    public string Data
    {
      get
      {
        var data = Items.Select(item => Serialize(item).Replace(Separator, Replacement));
        return string.Join(Separator, data.Where(s => s?.Length > 0));
      }
      set
      {
        Items.Clear();
        if (string.IsNullOrWhiteSpace(value))
          return;

        foreach (var item in value.Split(new[] { Separator }, StringSplitOptions.RemoveEmptyEntries).Select(item => Deserialize(item)))
          Items.Add(item);
      }
    }

    public void AddRange(params T[] items)
    {
      if (items != null)
        foreach (var item in items)
          Add(item);
    }

    protected abstract string Serialize(T item);
    protected abstract T Deserialize(string item);
    protected override void SetItem(int index, T item)
    {
      if (AllowDuplicates || !Items.Contains(item, Comparer))
        base.SetItem(index, item);
    }

    protected override void InsertItem(int index, T item)
    {
      if (AllowDuplicates || !Items.Contains(item, Comparer))
        base.InsertItem(index, item);
    }
  }

  public class ScalarStringCollection : ScalarCollectionBase<string>
  {
    public ScalarStringCollection() : this(null) { }
    public ScalarStringCollection(params string[] values) : base(values)
    {
    }

    protected virtual bool IsCaseInsensitive { get; } = false;
    public override IEqualityComparer<string> Comparer => IsCaseInsensitive ? StringComparer.Ordinal : StringComparer.OrdinalIgnoreCase;

    protected override string Serialize(string item) => item;
    protected override string Deserialize(string item) => item;
  }
}