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  • EF CRUD 操作

    1.Add 操作

            public bool Add(EFDataModels.User model)
            {
                try
                {
    	       int result=0;
                    using (DBEntities db = new DBEntities())
                    {
                        if (model != null)
                        {
                            db.User.Add(model); // 添加模型
                            result = db.SaveChanges();  //保存到数据库
                        }
                    }
                     return result > 0;  //返回结果
                }
                catch (Exception e)
                {
                    throw e;
                }
            }
    

     2.Update 操作

     public bool Update(User model)
            {
                try
                {
                    using (DBEntities db = new DBEntities())
                    {
    
    		db.Entry<User>(model).State = System.Data.Entity.EntityState.Modified; //设置模型的状态
    		int result = db.SaveChanges(); // 保存更新
    		return result > 0;
                       
                    }
                    return false;
                }
                catch (Exception e)
                {
                    throw e;
                }
            }
    

     3. Delete  操作

            public bool Delete(int id)
            {
                try
                {
                    using (DBEntities db = new DBEntities())
                    {
                        var model = (from p in db.User
                                     where p.ID == id
                                     select p).FirstOrDefault<User>();
                        if (model != null)
                        {
                            db.User.Attach(model);
                            db.User.Remove(model); // 从上下文中移除 模型
                            db.Entry<User>(model).State = System.Data.Entity.EntityState.Deleted;
                            int result = db.SaveChanges();
                            return result > 0;
                        }
                    }
                    return false;
                }
                catch (Exception e)
                {
                    throw e;
                
    

    4. Select 操作

            public User GetModel(int id)
            {
                try
                {
                    using (DBEntities db = new DBEntities())
                    {
                        var model = (from p in db.User
                                     where p.ID == id
                                     select p).FirstOrDefault<User>();
                        return model;
                    }
                }
                catch (Exception e)
                {
                    throw e;
                }
            }
    

    5. 分页

     public List<UserModel> GetData(int pageIndex, int pageSize,  out int totalPage)
            {
                try
                {
                    using (DBEntities db = new DBEntities())
                    {
    
                        IQueryable<UserModel> quaryable = 
    	            from c in  db.User
                        select c.ID !=0
                    ;
                       
                       int totalCount = quaryable.Count();
                       var mylist = quaryable.OrderBy(p=>p.ID).Skip((pageIndex - 1) * pageSize).Take(pageSize).ToList();
                       totalPage = (totalCount - 1) / pageSize + 1;
                        return mylist;
                    }
                }
                catch (Exception e)
                {
                    throw e;
                }
            }
    
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  • 原文地址:https://www.cnblogs.com/wisdo/p/4922138.html
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