using System;
using System.Collections.Generic;

namespace IPLocationServerTool.Model
{
    /// <summary>
    /// Collection change event arguments, a definited type collection change args can inherit form it
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class CollectionChangedArgs<T> : EventArgs 
    {
        public IEnumerable<T> RemovedItems { get; }
        public IEnumerable<T> AddedItems { get; }

        public CollectionChangedArgs(IEnumerable<T> removed, IEnumerable<T> added)
        {
            RemovedItems = removed ?? new List<T>();

            AddedItems = added ?? new List<T>();
        }
    }

    /// <summary>
    /// a delegate declare for collection changed handler
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    public delegate void CollectionChangedEventHandler<T>(object sender, CollectionChangedArgs<T> e);
}