• EF简单增删改查与分页


     1 /// <summary>
     2 /// 分页查询
     3  /// </summary>
     4 /// <typeparam name="T">要操作的数据类型</typeparam>
     5 /// <param name="whereLambda">Where条件语句</param>
     6 /// <param name="orderLambda">按什么条件排序</param>
     7  /// <param name="pageSize">每页都少条数据</param>
     8 /// <param name="pageIndex">要查询第几页</param>
     9   /// <returns>返回一个泛型集合</returns>
    10  static List<T> GetPageList<T>(Func<T, bool> whereLambda, Func<T, object> orderLambda, int pageSize,
    11   int pageIndex) where T : class
    12    {
    13          MyDBEntities context = new MyDBEntities();  
    14          var list =  context.Set<T>().Where(whereLambda).OrderBy(orderLambda).Skip((pageIndex - 1) * pageSize).Take(pageSize);
    15          return list.ToList();
    16  }
    View Code
    public class BaseRepository<T> where T : class
        {
            //实例化EF框架
            DataModelContainer db = new DataModelContainer();
    
            //添加
            public T AddEntities(T entity)
            {
                db.Entry<T>(entity).State = EntityState.Added;
                db.SaveChanges();
                return entity;
            }
    
            //修改
            public bool UpdateEntities(T entity)
            {
                db.Set<T>().Attach(entity);
                db.Entry<T>(entity).State = EntityState.Modified;
                return db.SaveChanges() > 0;
            }
    
            //删除
            public bool DeleteEntities(T entity)
            {
                db.Set<T>().Attach(entity);
                db.Entry<T>(entity).State = EntityState.Deleted;
                return db.SaveChanges() > 0;
            }
    
            //查询
            public IQueryable<T> LoadEntities(Func<T, bool> wherelambda)
            {
                return db.Set<T>().Where<T>(wherelambda).AsQueryable();
            }
    
            //分页
            public IQueryable<T> LoadPagerEntities<S>(int pageSize, int pageIndex, out int total,
                Func<T, bool> whereLambda, bool isAsc, Func<T, S> orderByLambda)
            {
                var tempData = db.Set<T>().Where<T>(whereLambda);
    
                total = tempData.Count();
    
                //排序获取当前页的数据
                if (isAsc)
                {
                    tempData = tempData.OrderBy<T, S>(orderByLambda).
                          Skip<T>(pageSize * (pageIndex - 1)).
                          Take<T>(pageSize).AsQueryable();
                }
                else
                {
                    tempData = tempData.OrderByDescending<T, S>(orderByLambda).
                         Skip<T>(pageSize * (pageIndex - 1)).
                         Take<T>(pageSize).AsQueryable();
                }
                return tempData.AsQueryable();
            }
        }
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  • 原文地址:https://www.cnblogs.com/wuzhenglong/p/6474814.html
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