如何过滤IQueryable整棵树？

Question

我已经Contact查询包含Communication子查询中包含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，我得到的错误：

操作“& &”不能应用于类型 '布尔' 和 'System.Collections.Generic.IEnumerable'

的上线操作数：

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）。在我的方案有数据库〜200个表，每个表都包含可空场DeletionDate

Answer 1

这里的问题：

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

这两行不返回布尔值，因此您的通话Where不知道如何处理它。您是否想要至少有一个未删除的联系人Communications和CommuincationExtensions？如果是这样，那么将Where调用更改为Any，它应该工作。但是，请注意，在实际处理您的Contacts时，您仍然需要过滤掉任何已删除的Communications/CommunicationExtensions，因为无论如何，关系只会为您提供相关记录。换句话说，contact.Communications将返回与Contact相关的所有Communications，而comm.CommunicationExtensions将返回所有CommunicationExtensions，因此，无论何时处理它们，您仍然需要过滤掉任何已删除的记录。