如何分区查询并只加载Linq到实体的几个属性？

Question

我有以下波苏斯：

public Ticket 
{ 
    public int Id { get; set; } 
    public int IdOwner { get; set; } 
    public int IdDependency { get; set; } 
    public string SerialNumber { get; set; } 

    public Owner Owner { get; set; } 
    public Dependency Dependency { get; set; } 
} 

public Owner 
{ 
    public int Id { get; set; } 
    public string Name { get; set; } 
    // Other attributes 
} 

public Dependency 
{ 
    public int Id { get; set; } 
    public string Name { get; set; } 
    // Other attributes 
} 

我想回程票的List仅具有Owner Name和Dependency Name。问题是，我会写where与Owner，如果在我的过滤器我通过OwnerId，并相同Dependency。看看我的过滤器：

public List<Ticket> SelectTickets(string SerialNumber, int IdOwner, int IdDependency) 
{ 
    IQueryble<Ticket> query = context.Tickets.Where(t => t.SerialNumber == SerialNumber); 

    if (IdOwner != 0) 
    { 
     query = query.Where(??); 
    } 

    if (IdDependency!= 0) 
    { 
     query = query.Where(??); 
    } 

    return query.ToList(); 
} 

Answer 1

这将是有道理的，如果我明白你的意思。

 public Ticket 
     { 
      public int Id { get; set; } 
      public int OwnerId{ get; set; } 
      public int DependencyId { get; set; } 
      public string SerialNumber { get; set; } 

      public Owner Owner { get; set; } 
      public Dependency Dependency { get; set; } 
     } 

     public Owner 
     { 
      public int Id { get; set; } 
      public string Name { get; set; } 
      public List<Ticket> Tickets {get;set;} 
     } 

     public Dependency 
     { 
      public int Id { get; set; } 
      public string Name { get; set; } 
      public List<Ticket> Tickets {get;set;} 
     } 
     public List<Ticket> SelectTickets(string serialNumber, int ownerId, int dependencyId) 
     { 
      return context.Tickets.Where(t => t.SerialNumber == serialNumber && t.OwnerId == ownerId && t.DependencyId == dependencyId).ToList(); 
     } 

Answer 2

使用select语句。

query = query.Select(t => new Ticket { 
    Owner = new Owner {Name = t.Owner.Name}, 
    Dependency = new Dependency {Name = t.Dependency.Name} 
}); 
return query.ToList(); 

然而，似乎在这种情况下，你不会想退票，但一些其他的对象，如TicketSummary

public class TicketSummary { 
    public OwnerName {get;set;} 
    public DependencyName {get;set;} 
} 

那么你将有

query = query.Select(t => new TicketSummary { 
    OwnerName = t.Owner.Name, 
    DependencyName = t.Dependency.Name 
}); 
return query.ToList(); 

Answer 3

你可以将结果查询投影到您在过滤后所需的任何格式。

用这个工作替换你的return语句还是你有更复杂的需求我没有完全理解？

return query.Select(t => new Ticket() { 
    Owner = t.Owner, 
    Dependency = t.Dependency; 
}.ToList();