var list = BaseBizService.BOSCenterContent.ProductCategories.Where(p => p.ProductCategoryID.StartsWith(param.CategoryID)).ToList();
                    foreach (var item in list)
                    {
                       var cgModel = BaseBizService.BOSCenterContent.ProductCategories.Single(p => p.ProductCategoryID == item.ProductCategoryID);
                       cgModel.IsPublished = true;
                    }
                    
                    BaseBizService.BOSCenterContent.SaveChanges();

/// <summary>
        /// 更新满足条件的实体，返回更新实体的条数
        /// </summary>
        /// <typeparam name="T">更新的类型</typeparam>
        /// <param name="Entity">实体类</param>
        /// <param name="Predicate">更新的条件</param>
        /// <param name="Updater">更新的值</param>
        /// <returns>int</returns>
        public static int UpdateEntity<T>(this ObjectSet<T> Entity, Expression<Func<T, bool>> Predicate, Expression<Func<T, T>> Updater) where T : class
        {
            ConditionBuilder Builder = new ConditionBuilder();
            Builder.Build(Predicate.Body);
            string sqlCondition = Builder.Condition;
            //获取Update的赋值语句
            var updateMemberExpr = (MemberInitExpression)Updater.Body;
            var updateMemberCollection = updateMemberExpr.Bindings.Cast<MemberAssignment>().Select(c => new
            {
                Name = c.Member.Name,
                Value = ((ConstantExpression)c.Expression).Value
            });
            int i = Builder.Arguments.Length;
            string sqlUpdateBlock = string.Join(", ", updateMemberCollection.Select(c => string.Format("[{0}]={1}", c.Name, "{" + (i++) + "}")).ToArray());
            string commandText = string.Format("Update {0} Set {1} Where {2}", Entity.EntitySet.Name, sqlUpdateBlock, sqlCondition);
            //获取SQL参数数组 (包括查询参数和赋值参数)
            var args = Builder.Arguments.Union(updateMemberCollection.Select(c => c.Value)).ToArray();
            var Result = Entity.Context.ExecuteStoreCommand(commandText, args);
            return Result;
        }

------解决方案--------------------
是别人(好像是国外人)写的一个类,具体可以加我Q（252377274），我发给你完整的类