C# 8 Code sample：Using declarations（ef-core）

Taking a VS2017 Windows Form and class project using Entity Framework Core to VS2019 .NET Core Windows forms.

using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
using System.Collections;
using System.Reflection;
using System.Reflection.Emit;
using System.Diagnostics;

namespace Equin.Applicationframework
{
    public class AggregateBindingListView : Component IBindingListView IList IRaiseItemChangedEvents ICancelAddNew ITypedList IEnumerable
    {
        #region Constructors

        public AggregateBindingListView（）
        {
            _sourceLists = new BindingList（）;
            （_sourceLists as IBindingList）.ListChanged += new ListChangedEventHandler（SourceListsChanged）;
            _savedSourceLists = new List（）;
            _sourceIndices = new MultiSourceIndexList（）;
            // Start with a filter that includes all items.
            _filter = IncludeAllItemFilter.Instance;
            // Start with no sorts applied.
            _sorts = new ListSortDescriptionCollection（）;
            _objectViewCache = new DictionaryjectView>（）;
        }

        public AggregateBindingListView（IContainer container）
            : this（）
        {
            container.Add（this）;

            if （Site is ISynchronizeInvoke）
            {
                Synchronizingobject = Site as ISynchronizeInvoke;
            }
        }

        #endregion

        #region Private Member Fields

        /// 

        /// The list of underlying list of items on which this view is based.
        /// 

        private IList _sourceLists;
        /// 

        /// The sorted filtered list of item indices in _sourceList.
        /// 

        private MultiSourceIndexList _sourceIndices;
        /// 

        /// The current filter applied to the view.
        /// 

        private IItemFilter _filter;
        /// 

        /// The current sorts applied to the view.
        /// 

        private ListSortDescriptionCollection _sorts;
        /// 

        /// The IComparer used to compare items when sorting.
        /// 

        private IComparer int>> _comparer;
        /// 

        /// The item in the process of being added to the view.
        /// 

        private objectView _newItem;
        /// 

        /// The IList we will add new items to.
        /// 

        private IList _newItemsList;
        /// 

        /// The object used to marshal event-handler calls that are invoked on a non-UI thread.
        /// 

        private ISynchronizeInvoke _synchronizingobject;
        /// 

        /// A copy of the source lists so when a list is removed from SourceLists
        /// we still have a reference to use for unhooking events etc.
        /// 

        private List _savedSourceLists;
        /// 

        /// The proper

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2020-11-14 19:47  ef-core-vs2019-winforms-master\
     文件        2518  2020-11-14 19:47  ef-core-vs2019-winforms-master\.gitattributes
     文件        5745  2020-11-14 19:47  ef-core-vs2019-winforms-master\.gitignore
     目录           0  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\
     文件       84956  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\AggregateBindingListView.cs
     文件        2913  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\BindingListView.cs
     文件        4008  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\BindingListView.csproj
     文件         999  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\BindingListView.nuspec
     文件         817  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\CompositeItemFilter.cs
     文件        4350  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\IItemFilter.cs
     文件        1034  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\INotifyingEditableobject.cs
     文件         646  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\InvalidSourceListException.cs
     文件        4597  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\MultiSourceIndexList.cs
     文件       13854  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\objectView.cs
     目录           0  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\Properties\
     文件        1344  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\Properties\AssemblyInfo.cs
     文件        8774  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\Properties\Resources.Designer.cs
     文件        7955  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\Properties\Resources.resx
     文件        1083  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\Properties\Settings.Designer.cs
     文件         242  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\Properties\Settings.settings
     文件        2167  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\ProvidedViewPropertyDescriptor.cs
     文件         501  2020-11-14 19:47  ef-core-vs2019-winforms-master\BindingListView\readme.md
     文件        5045  2020-11-14 19:47  ef-core-vs2019-winforms-master\EntityframeworkSamples.sln
     目录           0  2020-11-14 19:47  ef-core-vs2019-winforms-master\NorthEntityLibrary\
     文件         255  2020-11-14 19:47  ef-core-vs2019-winforms-master\NorthEntityLibrary\App.config
     目录           0  2020-11-14 19:47  ef-core-vs2019-winforms-master\NorthEntityLibrary\Classes\
     目录           0  2020-11-14 19:47  ef-core-vs2019-winforms-master\NorthEntityLibrary\Classes\Comparers\
     文件         803  2020-11-14 19:47  ef-core-vs2019-winforms-master\NorthEntityLibrary\Classes\Comparers\OrderedPredicateComparer.cs
     文件         251  2020-11-14 19:47  ef-core-vs2019-winforms-master\NorthEntityLibrary\Classes\Countries.cs
     文件        1142  2020-11-14 19:47  ef-core-vs2019-winforms-master\NorthEntityLibrary\Classes\CountryOperations.cs
     文件         922  2020-11-14 19:47  ef-core-vs2019-winforms-master\NorthEntityLibrary\Classes\Customer.cs
............此处省略75个文件信息