BaseDAL最牛数据层基类2

using System;
using System.Data.Entity;
using System.Linq;
using System.Threading.Tasks;
using System.Linq.Expressions;
using YunEdu.Model;

namespace DAL
{
    /// <summary>
    /// EF数据库操作基类
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public partial class BaseDAL<T> where T : class, new()
    {
        /// <summary>
        /// 数据库上下文
        /// </summary>
        private DbContext dbContext = DbContextFactory.Create();

        /*
         * 2017-03-22 重新封装的方法
         * 2017-03-26 更新方法添加异步
         */

        #region    Add    添加实体

        /// <summary>
        /// 添加
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>添加的记录数[isSave=true时有效]</returns>
        public virtual int Add(T entity, bool isSave = true)
        {
            dbContext.Set<T>().Add(entity);
            if (isSave) return dbContext.SaveChanges();
            else return ;
        }

        /// <summary>
        /// 添加(异步)
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>添加的记录数[isSave=true时有效]</returns>
        public virtual async Task<int> AddAsync(T entity, bool isSave = true)
        {
            dbContext.Set<T>().Add(entity);
            if (isSave) return await dbContext.SaveChangesAsync();
            else return ;
        }

        /// <summary>
        /// 添加[批量]
        /// </summary>
        /// <param name="entities">实体</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>添加的记录数[isSave=true时有效]</returns>
        public virtual int AddRange(T[] entities, bool isSave = true)
        {
            dbContext.Set<T>().AddRange(entities);
            if (isSave) return dbContext.SaveChanges();
            else return ;
        }

        /// <summary>
        /// 添加[批量](异步)
        /// </summary>
        /// <param name="entities">实体</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>添加的记录数[isSave=true时有效]</returns>
        public virtual async Task<int> AddRangeAsync(T[] entities, bool isSave = true)
        {
            dbContext.Set<T>().AddRange(entities);
            if (isSave) return await dbContext.SaveChangesAsync();
            else return ;
        }

        #endregion

        #region Delete 删除实体

        /// <summary>
        /// 删除
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>是否删除成功[isSave=true时有效]</returns>
        public virtual bool Remove(T entity, bool isSave = true)
        {
            dbContext.Set<T>().Remove(entity);
            if (isSave) return dbContext.SaveChanges() > ;
            else return false;
        }

        /// <summary>
        /// 删除(异步)
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>是否删除成功[isSave=true时有效]</returns>
        public virtual async Task<bool> RemoveAsync(T entity, bool isSave = true)
        {
            dbContext.Set<T>().Remove(entity);
            if (isSave) return await dbContext.SaveChangesAsync() > ;
            else return false;
        }

        /// <summary>
        /// 批量删除
        /// </summary>
        /// <param name="entities">实体数组</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>成功删除的记录数</returns>
        public virtual int RemoveRange(T[] entities, bool isSave = true)
        {
            dbContext.Set<T>().RemoveRange(entities);
            if (isSave) return dbContext.SaveChanges();
            else return ;
        }

        /// <summary>
        /// 批量删除(异步)
        /// </summary>
        /// <param name="entities">实体数组</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>成功删除的记录数[isSave=true时有效]</returns>
        public virtual async Task<int> RemoveRangeAsync(T[] entities, bool isSave = true)
        {
            dbContext.Set<T>().RemoveRange(entities);
            if (isSave) return await dbContext.SaveChangesAsync();
            else return ;
        }

        #endregion

        #region Update 更新实体

        /// <summary>
        /// 更新实体
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>在“isSave”为True时返回受影响的对象的数目，为False时直接返回0</returns>
        public virtual int Update(T entity, bool isSave)
        {
            dbContext.Set<T>().Attach(entity);
            dbContext.Entry<T>(entity).State = EntityState.Modified;//将所有属性标记为修改状态
            return isSave ? dbContext.SaveChanges() : ;
        }

        /// <summary>
        /// 更新实体(异步)
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="isSave">是否立即保存</param>
        /// <returns>在“isSave”为True时返回受影响的对象的数目，为False时直接返回0</returns>
        public async virtual Task<int> UpdateAsync(T entity, bool isSave)
        {
            dbContext.Set<T>().Attach(entity);
            dbContext.Entry<T>(entity).State = EntityState.Modified;//将所有属性标记为修改状态
            if (isSave) return await dbContext.SaveChangesAsync();
            return ;
        }

        #endregion

        #region Find   查询实体
        /// <summary>
        /// 查找最大实体
        /// </summary>
        /// <returns></returns>
        public virtual T Max()
        {
            return dbContext.Set<T>().Max();
        }

        /// <summary>
        /// 查找最大实体(异步)
        /// </summary>
        /// <returns></returns>
        public async virtual Task<T> MaxAsync()
        {
            return await dbContext.Set<T>().MaxAsync();
        }

        /// <summary>
        /// 查找实体(根据主键值查找)
        /// </summary>
        /// <param name="ID">实体主键值</param>
        /// <returns></returns>
        public virtual T Find(int ID)
        {
            return dbContext.Set<T>().Find(ID);
        }

        /// <summary>
        /// 查找实体(根据主键值查找,异步)
        /// </summary>
        /// <param name="ID">实体主键值</param>
        /// <returns></returns>
        public async virtual Task<T> FindAsync(int ID)
        {
            return await dbContext.Set<T>().FindAsync(ID);
        }

        /// <summary>
        /// 查找(根据联合主键)
        /// </summary>
        /// <param name="keyValues">主键</param>
        /// <returns></returns>
        public virtual T Find(object[] keyValues)
        {
            return dbContext.Set<T>().Find(keyValues);
        }

        /// <summary>
        /// 查找(根据联合主键,异步)
        /// </summary>
        /// <param name="keyValues">主键</param>
        /// <returns></returns>
        public virtual async Task<T> FindAsync(object[] keyValues)
        {
            return await dbContext.Set<T>().FindAsync(keyValues);
        }

        /// <summary>
        /// 查找实体(根据Lambda表达式)
        /// </summary>
        /// <param name="where">查询Lambda表达式</param>
        /// <returns></returns>
        public virtual T FindSingle(Expression<Func<T, bool>> where)
        {
            return dbContext.Set<T>().SingleOrDefault(where);
        }

        /// <summary>
        /// 查找实体(根据Lambda表达式,异步)
        /// </summary>
        /// <param name="where">查询Lambda表达式</param>
        /// <returns></returns>
        public async virtual Task<T> FindSingleAsync(Expression<Func<T, bool>> where)
        {
            return await dbContext.Set<T>().SingleOrDefaultAsync(where);
        }
        #endregion

        #region List   查询列表

        /// <summary>
        /// 查询所有
        /// </summary>
        /// <returns></returns>
        public virtual IQueryable<T> FindList()
        {
            return dbContext.Set<T>();
        }

        /// <summary>
        /// 查询所有(异步)
        /// </summary>
        /// <returns>实体列表</returns>
        public virtual async Task<IQueryable<T>> FindListAsync()
        {
            IQueryable<T> result = dbContext.Set<T>();
            return await Task.FromResult(result);
        }

        /// <summary>
        /// 查询(根据查询条件)
        /// </summary>
        /// <param name="predicate">查询条件</param>
        /// <returns>实体列表</returns>
        public virtual IQueryable<T> FindList(Expression<Func<T, bool>> predicate)
        {
            return dbContext.Set<T>().Where(predicate);
        }

        /// <summary>
        /// 查询(根据查询条件,异步)
        /// </summary>
        /// <param name="predicate">查询条件</param>
        /// <returns>实体列表</returns>
        public virtual async Task<IQueryable<T>> FindListAsync(Expression<Func<T, bool>> predicate)
        {
            return await Task.FromResult(FindList(predicate));
        }

        /// <summary>
        /// 查询(前几条)数据(根据查询条件)
        /// </summary>
        /// <param name="number">返回记录数</param>
        /// <param name="predicate">查询条件</param>
        /// <returns>实体列表</returns>
        public virtual IQueryable<T> FindList(int number, Expression<Func<T, bool>> predicate)
        {
            var entityList = dbContext.Set<T>().Where(predicate);
            if (number > ) return entityList.Take(number);
            else return entityList;
        }

        /// <summary>
        /// 查询(前几条)数据(根据查询条件,异步)
        /// </summary>
        /// <param name="number">返回记录数</param>
        /// <param name="predicate">查询条件</param>
        /// <returns>实体列表</returns>
        public virtual async Task<IQueryable<T>> FindListAsync(int number, Expression<Func<T, bool>> predicate)
        {
            return await Task.FromResult(FindList(number, predicate));
        }

        /// <summary>
        /// 查询(前几条)数据(根据查询条件,带排序)
        /// </summary>
        /// <param name="number">显示数量[小于等于0-不启用]</param>
        /// <typeparam name="TKey">排序字段</typeparam>
        /// <param name="predicate">查询条件</param>
        /// <param name="keySelector">排序</param>
        /// <param name="isAsc">正序</param>
        /// <returns></returns>
        public virtual IQueryable<T> FindList<TKey>(int number, Expression<Func<T, bool>> predicate, Expression<Func<T, TKey>> keySelector, bool isAsc)
        {
            var entityList = dbContext.Set<T>().Where(predicate);
            if (isAsc) entityList = entityList.OrderBy(keySelector);
            else entityList.OrderByDescending(keySelector);
            if (number > ) return entityList.Take(number);
            else return entityList;
        }

        /// <summary>
        /// 查询(前几条)数据(根据查询条件,带排序,异步)
        /// </summary>
        /// <param name="number">显示数量[小于等于0-不启用]</param>
        /// <typeparam name="TKey">排序字段</typeparam>
        /// <param name="predicate">查询条件</param>
        /// <param name="keySelector">排序</param>
        /// <param name="isAsc">正序</param>
        /// <returns></returns>
        public virtual async Task<IQueryable<T>> FindListAsync<TKey>(int number, Expression<Func<T, bool>> predicate, Expression<Func<T, TKey>> keySelector, bool isAsc)
        {
            var entityList = dbContext.Set<T>().Where(predicate);
            if (isAsc) entityList = entityList.OrderBy(keySelector);
            else entityList.OrderByDescending(keySelector);
            if (number > ) entityList = entityList.Take(number);
            return await Task.FromResult(entityList);
        }

        #endregion

        #region Count  查询总数

        /// <summary>
        /// 查询记录数
        /// </summary>
        /// <param name="predicate">查询条件表达式</param>
        /// <returns>记录数</returns>
        public virtual int Count(Expression<Func<T, bool>> predicate)
        {
            return dbContext.Set<T>().Count(predicate);
        }

        /// <summary>
        /// 查询记录数(异步)
        /// </summary>
        /// <param name="predicate">查询条件表达式</param>
        /// <returns>记录数</returns>
        public virtual async Task<int> CountAsync(Expression<Func<T, bool>> predicate)
        {
            return await dbContext.Set<T>().CountAsync(predicate);
        }

        #endregion

        #region Exist  是否存在

        /// <summary>
        /// 查询是否存在
        /// </summary>
        /// <param name="predicate">查询条件表达式</param>
        /// <returns>是否存在</returns>
        public virtual bool Exists(Expression<Func<T, bool>> predicate)
        {
            return dbContext.Set<T>().Any(predicate);
        }

        /// <summary>
        /// 查询是否存在(异步)
        /// </summary>
        /// <param name="predicate">查询条件表达式</param>
        /// <returns>是否存在</returns>
        public virtual async Task<bool> ExistsAsync(Expression<Func<T, bool>> predicate)
        {
            return await dbContext.Set<T>().AnyAsync(predicate);
        }

        #endregion

        #region Page   分页查询

        /// <summary>
        /// 查找分页列表(无条件,无排序)
        /// </summary>
        /// <param name="pageSize">每页记录数。必须大于1</param>
        /// <param name="pageIndex">页码。首页从1开始，页码必须大于1</param>
        /// <param name="totalNumber">总记录数</param>
        /// <returns></returns>
        public virtual IQueryable<T> FindPageList(int pageSize, int pageIndex, out int totalNumber)
        {
            OrderParam _orderParam = null;
            return FindPageList(pageSize, pageIndex, out totalNumber, _orderParam);
        }

        /// <summary>
        /// 查找分页列表(无条件,带排序)
        /// </summary>
        /// <param name="pageSize">每页记录数。必须大于1</param>
        /// <param name="pageIndex">页码。首页从1开始，页码必须大于1</param>
        /// <param name="totalNumber">总记录数</param>
        /// <param name="order">排序键</param>
        /// <param name="asc">是否正序</param>
        /// <returns></returns>
        public virtual IQueryable<T> FindPageList(int pageSize, int pageIndex, out int totalNumber, OrderParam orderParam)
        {
            return FindPageList(pageSize, pageIndex, out totalNumber, (T) => true, orderParam);
        }

        /// <summary>
        /// 查找分页列表(带条件,无排序)
        /// </summary>
        /// <param name="pageSize">每页记录数。必须大于1</param>
        /// <param name="pageIndex">页码。首页从1开始，页码必须大于1</param>
        /// <param name="totalNumber">总记录数</param>
        /// <param name="where">查询表达式</param>
        public virtual IQueryable<T> FindPageList(int pageSize, int pageIndex, out int totalNumber, Expression<Func<T, bool>> where)
        {
            OrderParam _param = null;
            return FindPageList(pageSize, pageIndex, out totalNumber, where, _param);
        }

        /// <summary>
        /// 查找分页列表(无条件,单字段排序)
        /// </summary>
        /// <param name="pageSize">每页记录数。</param>
        /// <param name="pageIndex">页码。首页从1开始</param>
        /// <param name="totalNumber">总记录数</param>
        /// <param name="where">查询表达式</param>
        /// <param name="orderParam">排序【null-不设置】</param>
        /// <returns></returns>
        public virtual IQueryable<T> FindPageList(int pageSize, int pageIndex, out int totalNumber, Expression<Func<T, bool>> where, OrderParam orderParam)
        {
            OrderParam[] _orderParams = null;
            if (orderParam != null) _orderParams = new OrderParam[] { orderParam };
            return FindPageList(pageSize, pageIndex, out totalNumber, where, _orderParams);
        }

        /// <summary>
        /// 查找分页列表(带条件,带多字段排序)
        /// </summary>
        /// <param name="pageSize">每页记录数。</param>
        /// <param name="pageIndex">页码。首页从1开始</param>
        /// <param name="totalNumber">总记录数</param>
        /// <param name="where">查询表达式</param>
        /// <param name="orderParams">排序【null-不设置】</param>
        public virtual IQueryable<T> FindPageList(int pageSize, int pageIndex, out int totalNumber, Expression<Func<T, bool>> where, OrderParam[] orderParams)
        {
            //条件过滤
            IQueryable<T> query = where == null ? dbContext.Set<T>() : dbContext.Set<T>().Where(where);

            //创建表达式变量参数
            var parameter = Expression.Parameter(typeof(T), "o");

            if (orderParams != null && orderParams.Length > )
            {
                for (int i = ; i < orderParams.Length; i++)
                {
                    //根据属性名获取属性
                    var property = typeof(T).GetProperty(orderParams[i].PropertyName);
                    //创建一个访问属性的表达式
                    var propertyAccess = Expression.MakeMemberAccess(parameter, property);
                    var orderByExp = Expression.Lambda(propertyAccess, parameter);

                    string OrderName = "";
                    if (i > )
                    {
                        OrderName = orderParams[i].IsDesc ? "ThenByDescending" : "ThenBy";
                    }
                    else
                        OrderName = orderParams[i].IsDesc ? "OrderByDescending" : "OrderBy";

                    MethodCallExpression resultExp = Expression.Call(typeof(Queryable), OrderName, new Type[] { typeof(T), property.PropertyType }, query.Expression, Expression.Quote(orderByExp));

                    query = query.Provider.CreateQuery<T>(resultExp);
                }
            }

            totalNumber = query.Count();
            return query.Skip((pageIndex - ) * pageSize).Take(pageSize);
        }

        /// <summary>
        /// 查找分页列表(带条件,单字段lambda表达式排序)
        /// </summary>
        /// <typeparam name="type">排序字段类型</typeparam>
        /// <param name="pageSize">每页记录数</param>
        /// <param name="pageIndex">页码,首页从1开始</param>
        /// <param name="totalNumber">输出总数</param>
        /// <param name="isAsc">是否升序</param>
        /// <param name="OrderByLambda">排序条件</param>
        /// <param name="WhereLambda">查询条件</param>
        /// <returns></returns>
        public virtual IQueryable<T> FindPageList<type>(int pageSize, int pageIndex, out int totalNumber, bool isAsc,
            Expression<Func<T, type>> OrderByLambda, Expression<Func<T, bool>> WhereLambda)
        {
            //输出记录总数
            totalNumber = dbContext.Set<T>().Where(WhereLambda).Count();
            //是否升序
            if (isAsc)
            {
                return dbContext.Set<T>().Where(WhereLambda).OrderBy(OrderByLambda).Skip((pageIndex - ) * pageSize).Take(pageSize);
            }
            else
            {
                return dbContext.Set<T>().Where(WhereLambda).OrderByDescending(OrderByLambda).Skip((pageIndex - ) * pageSize).Take(pageSize);
            }
        }
        #endregion

        #region Save   保存数据
        /// <summary>
        ///  保存数据【在Add、Upate、Delete未立即保存的情况下使用】
        /// </summary>
        /// <returns>更改的记录数</returns>
        public virtual int SaveChanges()
        {
            return dbContext.SaveChanges();
        }

        /// <summary>
        ///  保存数据【在Add、Upate、Delete未立即保存的情况下使用】(异步)
        /// </summary>
        /// <returns>更改的记录数</returns>
        public virtual async Task<int> SaveChangesAsync()
        {
            return await dbContext.SaveChangesAsync();
        }
        #endregion

        #region  扩展用 私有方法

        /// <summary>
        /// 私有方法,用于更新指定列
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="properties">要修改的属性名称</param>
        private void UpdateRe(T entity, string[] properties = null)
        {
            var entry = dbContext.Entry(entity);
            if (properties == null)
            {
                entry.State = EntityState.Modified;//将所有属性标记为修改状态
            }
            else
            {
                //Detached 对象存在，但未由对象服务跟踪。在创建实体之后、但将其添加到对象上下文之前，该实体处于此状态；
                if (entry.State == EntityState.Detached) entry.State = EntityState.Unchanged;//先将所有属性状态标记为未修改
                foreach (var property in properties)
                {
                    entry.Property(property).IsModified = true;//将要修改的属性状态标记为修改
                }
            }
        }

        #endregion

    }
}