SKMC.API-v3/SKMC.API/Common/Types/ObservableCollectionEx.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SKMC.Api.Common.Types
{
    /// <summary>
    /// Expanded ObservableCollection to include some List<T> Methods
    /// </summary>
    [Serializable]
    public class ObservableCollectionEx<T> : ObservableCollection<T>
    {

        /// <summary>
        /// Constructors
        /// </summary>
        public ObservableCollectionEx() : base() { }
        public ObservableCollectionEx(List<T> l) : base(l) { }
        public ObservableCollectionEx(IEnumerable<T> l) : base(l) { }

        /// <summary>
        /// Sorts the items of the collection in multiply keys.
        /// </summary>
        /// <param name="sortExpressions"></param>
        public void Sort(params (Func<T, object> keySelector, bool ascending)[] sortExpressions)
        {
            if (sortExpressions == null || sortExpressions.Length == 0)
                return;

            // Get the sorted items as a list
            var sortedItems = this.ToList();

            IOrderedEnumerable<T> orderedEnumerable = null;
            for (int i = 0; i < sortExpressions.Length; i++)
            {
                var sortExpression = sortExpressions[i];
                if (i == 0)
                {
                    orderedEnumerable = sortExpression.ascending
                        ? sortedItems.OrderBy(sortExpression.keySelector)
                        : sortedItems.OrderByDescending(sortExpression.keySelector);
                }
                else
                {
                    orderedEnumerable = sortExpression.ascending
                        ? orderedEnumerable.ThenBy(sortExpression.keySelector)
                        : orderedEnumerable.ThenByDescending(sortExpression.keySelector);
                }
            }

            sortedItems = orderedEnumerable.ToList();

            // Reorder the collection using Move
            for (int i = 0; i < sortedItems.Count; i++)
            {
                var item = sortedItems[i];
                var currentIndex = IndexOf(item);
                if (currentIndex != i)
                {
                    Move(currentIndex, i);
                }
            }
        }
    }
}