双语:与学习有关的成语的英文表达

2019-08-31 07:13 来源:未知

图片 1与学习有关的成语的英文表达

Introduction

A Unit of Work is a combination of several actions that will be grouped into a transaction. This means that all actions inside a unit of work are committed or rolled back. The advantage of using a unit of work is that multiple save actions to multiple repositories can be grouped as a unit.

图片 2

The image above shows that the Unit of Work is the top-level component to be used. Each Unit Of  Work contains its own DbContext instance.

写作文的时候,为了显示自己的语言水平,不少同学都喜欢引用几个成语。在英语写作中,老师也会建议我们偶尔引用一些经典词句来起到画龙点睛的作用。今天,我们就跟大家一起学习是个与学习有关的汉语成语英译,下次写作文的时候说不定就用上了呢。

Road Map

Part1:Follow me to learn how to use mvc template

Part2:Follow me to learn what is repository pattern

Part3:Follow me to learn what is Unit of Work pattern

业精于勤 Excellence in work is possible only with diligence

How to implement Unit Of Work

Now, let us to start to implement unit of work

Step1: Create interface IUnitOfWork

public  interface IUnitOfWork:IDisposable
    {
        bool IsCommitted { get; set; }
        int Commit();
        void Rollback();
    }

Step 2: Concrete Implementation of IUnitOfWork

public class UnitOfWorkBase : IUnitOfWork
    {
        public UnitOfWorkBase()
        {

        }
        private Dictionary<Type, object> _repositories;
        private ObjectContext _context=null;
        internal ObjectContext Context
        {
            get { return _context; }
        }
        public bool IsCommitted { get; set; }
        public RepositoryBase<TSet> GetRepository<TSet>() where TSet : class, new()
        {
            if (null == _repositories) _repositories = new Dictionary<Type, object>();
            if (_repositories.Keys.Contains(typeof(TSet)))
                return _repositories[typeof(TSet)] as RepositoryBase<TSet>;

            var repository = new RepositoryBase<TSet>(true,this.Context);

            _repositories.Add(typeof(TSet), repository);
            if (null == _context) _context = repository.Repository.Context;
            return repository;
        }

        public int Commit()
        {
            if (IsCommitted) return 0;
            return this.Context.SaveChanges();
        }
        public void Rollback()
        {
            this.IsCommitted = true;
            this.Context.Dispose();
        }
        public void Dispose()
        {
            if (!this.IsCommitted)
            {
                this.Context.SaveChanges();
            }           
            this.Context.Dispose();
        }

    }

Let’s take a look at our IRepository GetRepository<TSet>()  method here in our UnitOfWork implementation. Here we are storing all the activated instances of repositories for each and every requests. One there is a request for a given repository we will first check to see if our Container  has been created, if not, will go ahead and create our container. Next, we’ll scan our container to see if the requested repository instance has already been created, if it has, then will return it, if it hasn’t, we will activate the requested repository instance, store it in our container, and then return it. If it helps, you can think of this as lazy loading our repository instances, meaning we are only creating repository instances on demand, this allows us to only create the repository instances needed for a given web request.

学以致用 One should make use of what one has leaned

How to use?

图片 3

Demo

public ObjectModel.RoleAction DeleteAndInsertRoleAction(ObjectModel.RoleAction model, ObjectModel.TreeViewModel TreeView)
        {
            using (var dao = new UnitOfWorkBase())
            {
                var repositoryNew = dao.GetRepository<RoleAction>();
                var oldRecords = repositoryNew.Query(p => p.IsActive && p.RoleInfoId == model.RoleInfoId).ToList();
                int roleid = model.RoleInfoId;
                List<string> newActionIds = TreeView.NodeItems.Where(item => item.Checked)
                                                        .SelectMany(item => item.Items.Where(a => a.Checked))
                                                        .Select(a => a.Value)
                                                        .ToList();
                var deleteRecords = oldRecords.Where(p => !newActionIds.Contains(p.ActionInfoId.ToString())).ToList();
                var insertRecords = newActionIds.Where(p => !oldRecords.Select(q => q.ActionInfoId.ToString()).Contains(p)).ToList();
                try
                {

                    foreach (var item in deleteRecords)
                    {
                        repositoryNew.Delete(item);
                    }
                    for (int i = 0; i < insertRecords.Count; i  )
                    {
                        RoleAction roleAction = new RoleAction();
                        roleAction.RoleInfoId = roleid;
                        roleAction.ActionInfoId = Convert.ToInt32(insertRecords[i]);
                        repositoryNew.Insert(roleAction);
                    }
                }
                catch (Exception ex)
                {
                    dao.Rollback();
                    throw ex;
                }
            }
            return model;
        }

Note:

        refer to http://blog.catenalogic.com/post/2013/02/27/Entity-Framework-Unit-of-Work-and-repositories.aspx

学而不厌 Have s thirst for learning

学而后知不足 One discovers one’s ignorance only through learning

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