LINQ查询SelectMany（）返回空值

Question

我有这些类。为了简化起见，我忽略了与这个问题无关的成员。我想查找包含具有WWPN给定字符串值的成员的所有区域。下面的LINQ工作，但结果也包含空的不匹配的区域。我的其他尝试要么给我区域成员本身，要么给我一个布尔。有没有办法做到这一点，而没有得到空值？我不需要使用ContainsMemberWWPN（）类成员。

public class Zone 
    { .... 
     public List<ZoneMember> MembersList = new List<ZoneMember>(); 
    } 

    public class ZoneMember 
    { 
    private string _WWPN = string.Empty; 
    public string MemberWWPN {get{return _WWPN;} set{_WWPN = value; } } 
    private bool _IsLoggedIn; 
    public bool IsLoggedIn { get { return _IsLoggedIn; } set { _IsLoggedIn = value; } } 

    } 

public class CiscoVSAN 
    { 
     .... 
    public List<Zone> ActiveZoneset = new List<Zone>(); 
      .... 
    } 

public Zone ContainsMemberWWPN(string wwpn) 
    { 
     var contained = 
      this.MembersList.FirstOrDefault(m => m.MemberWWPN.Contains(wwpn)); 

     if (contained != null) { return this } 
     else { return null; } 

    } 

//find all the zones that contain the input string 
// this returns the zones that match 
// but selection3 also has null values for zones that don't match 
var selection3 = VSANDictionary.SelectMany(vsan => vsan.Value.ActiveZoneset.ZoneList).Select(z => z.ContainsMemberWWPN(zonemember)); 

Answer 1

过滤器的空项指出：

var selection3 = VSANDictionary 
       .SelectMany(vsan => vsan.Value.ActiveZoneset.ZoneList) 
       .Select(z => z.ContainsMemberWWPN(zonemember)) 
       .Where(m=> m != null)