Question

我有这些课程。为了保持简单，我遗漏了与问题无关的成员。我想找到包含具有WWPN的给定字符串值的成员的所有区域。下面的LINQ可以工作，但对于不匹配的区域，结果也包含null。我的其他尝试要么给了我自己的区域成员，要么给了布尔。有没有办法在不获取空值的情况下执行此操作？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

过滤掉空项：

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

LINQ Query SelectMany（）返回空值

1 个答案: