本系列原创博客代码已在EntityFramework6.0.0测试通过，转载请标明出处
有时候我们要通过IQueryable获取所在的DbContext信息，这是完全可以的。
以下代码从个人开源框架中抽取而出
using System;using System.Data.Entity;using System.Data.Entity.Core.Objects;using System.Data.Entity.Infrastructure;using System.Data.Entity.Infrastructure.Interception;using System.Linq;using System.Reflection;/** CopyRight © All Rights Reserved* 作者:Rex Sheng*/namespace SuperNet.EntityFramework.Extensions{public static class IQueryableExtensions{public static DbContext GetDbContext<TEntity>(this IQueryable<TEntity> query) where TEntity : class{ObjectQuery<TEntity> objectQuery = null;DbQuery<TEntity> dbQuery = null;if(query is ObjectQuery<TEntity>){objectQuery = (ObjectQuery<TEntity>)query;}else{if(query is DbQuery<TEntity>){dbQuery = (DbQuery<TEntity>)query;var propers = dbQuery.GetType().GetProperty("InternalQuery", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);if (propers == null){throw new Exception("未能从IQueryable表达式找到DbContext。您确定此表达式来自Ef DbContext吗?");}var obj = propers.GetValue(dbQuery, null);propers = obj.GetType().GetProperty("ObjectQuery", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);if (propers == null){throw new Exception("未能从IQueryable表达式找到DbContext。您确定此表达式来自Ef DbContext吗?");}objectQuery = propers.GetValue(obj, null) as ObjectQuery<TEntity>;if (objectQuery == null){throw new Exception("未能从IQueryable表达式找到DbContext。您确定此表达式来自Ef DbContext吗?");}}else{throw new Exception("未能从IQueryable表达式找到DbContext。您确定此表达式来自Ef DbContext吗?");}}return objectQuery.Context.GetDbContext();}}}
