Question

我有Contact个查询，其中包含Communication子查询，其中包含CommunicationExtension子查询

static class Program
    {
        public class Contact
        {
            public int ContactID { get; set; }
            public List<Communication> Communications { get; set; }
            public DateTime? DeletionDate { get; set; }
        }

        public class Communication
        {
            public int CommuncationID { get; set; }
            public List<CommunicationExtension> CommunicationExtensions { get; set; }
            public DateTime? DeletionDate { get; set; }
        }

        public class CommunicationExtension
        {
            public int CommunicationExtensionID { get; set; }
            public int AreaCode { get; set; }
            public DateTime? DeletionDate { get; set; }
        }

        static void Main(string[] args)
        {
            IQueryable<Contact> q = GenerateData();
            IQueryable<Contact> result =
                q.Where(c => c.DeletionDate == null && 
                    c.Communications.Where(co => co.DeletionDate == null && 
                        co.CommunicationExtensions.Where(ce => ce.DeletionDate == null));
        }



        private static IQueryable<Contact> GenerateData()
        {
            return new List<Contact>
                       {
                           new Contact
                               {
                                   ContactID = 1,
                                   DeletionDate = DateTime.Now,
                                   Communications =
                                       new List<Communication>
                                           {
                                               new Communication
                                                   {
                                                       CommuncationID = 1,
                                                       DeletionDate = DateTime.Now,
                                                       CommunicationExtensions = 
                                                       new List<CommunicationExtension>
                                                           {
                                                               new CommunicationExtension
                                                                   {
                                                                       CommunicationExtensionID = 1,
                                                                       AreaCode = 5,
                                                                       DeletionDate = null
                                                                   }
                                                           }
                                                   },
                                               new Communication
                                                   {
                                                       CommuncationID = 2,
                                                       DeletionDate = null,
                                                       CommunicationExtensions = 
                                                       new List<CommunicationExtension>
                                                           {
                                                               new CommunicationExtension
                                                                   {
                                                                       CommunicationExtensionID = 2,
                                                                       AreaCode = 55,
                                                                       DeletionDate = DateTime.Now
                                                                   }
                                                           }
                                                   }
                                           }
                               },
                           new Contact
                               {
                                   ContactID = 2,
                                   DeletionDate = null,
                                   Communications =
                                       new List<Communication>
                                           {
                                               new Communication
                                                   {
                                                       CommuncationID = 1,
                                                       DeletionDate = null,
                                                       CommunicationExtensions = 
                                                       new List<CommunicationExtension>
                                                           {
                                                               new CommunicationExtension
                                                                   {
                                                                       CommunicationExtensionID = 3,
                                                                       AreaCode = 54,
                                                                       DeletionDate = null
                                                                   }
                                                           }
                                                   },
                                               new Communication
                                                   {
                                                       CommuncationID = 2,
                                                       DeletionDate = DateTime.Now,
                                                       CommunicationExtensions = 
                                                       new List<CommunicationExtension>
                                                           {
                                                               new CommunicationExtension
                                                                   {
                                                                       CommunicationExtensionID = 4,
                                                                       AreaCode = 5565,
                                                                       DeletionDate = null
                                                                   }
                                                           }
                                                   }
                                           }
                               }
                       }.AsQueryable();
        }
    }

当我尝试构建它时，我收到错误：

运营商'＆amp;＆amp;'不能应用于'bool'和'System.Collections.Generic.IEnumerable'类型的操作数

在线：

IQueryable<Contact> result =
                q.Where(c => c.DeletionDate == null && 
                    c.Communications.Where(co => co.DeletionDate == null && 
                        co.CommunicationExtensions.Where(ce => ce.DeletionDate == null)));

我需要过滤所有未删除的数据（DeletionDate == null）。在我的场景中，数据库中有大约200个表，每个表包含可空字段DeletionDate

Answer 1

问题在于：

c.Communications.Where(co => co.DeletionDate == null && 
    co.CommunicationExtensions.Where(ce => ce.DeletionDate == null)

这两行不返回布尔值，因此您的Where调用不知道如何处理它。您是否希望任何至少有一个未删除Communications和CommuincationExtensions的联系人？如果是，请将Where调用更改为Any，它应该有效。但请注意，在实际处理您的Contacts时，您仍需要过滤掉任何已删除的Communications / CommunicationExtensions，因为无论如何，关系都会为您提供相关记录。换句话说，contact.Communications将返回与Communications相关的所有Contact，而comm.CommunicationExtensions将返回所有CommunicationExtensions，因此您仍需要过滤掉任何处理过的记录都会被删除。

如何过滤IQueryable整棵树？

1 个答案: