c# - 如何检查包含多个值的 CONTAINS

Question

我正在尝试查找包含 2 个或更多区域成员的所有区域，其中搜索词是字符串值。这是我的代码。在 FindCommmonZones 方法中，当我尝试将 Intersect 的结果转换为 ObservableCollection 时，我得到了一个无效转换的运行时。问题是，有没有更好的方法来做到这一点？作为 FindCommonZones() 参数的字符串数组可以是任意数量的字符串。 StackOverflow 有一些其他类似的帖子，但没有一个真正回答我的问题 - 看起来它们都更多地与 SQL 相关。

部分代码:

public class Zone
{ 
    public List<ZoneMember> MembersList = new List<ZoneMember>();
    private string _ZoneName;
    public string zoneName{ get{return _ZoneName;}  set{_ZoneName=value;} }
        public Zone ContainsMember(string member)
    {
      var contained = this.MembersList.FirstOrDefault(m => m.MemberWWPN.
             Contains(member) || m.MemberAlias.Contains(member));

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

    }

}

 public class ZoneMember
    // a zone member is a member of a zone
    // zones have ports, WWPNs, aliases or all 3
{
    private string _Alias = string.Empty;
    public string MemberAlias {get{return _Alias;} set{_Alias = value; } }
    private FCPort _Port = null;
    public FCPort MemberPort { get { return _Port; } set { _Port = value; } }
    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; } }
    private string _FCID;
    public string FCID {get{return _FCID;} set{ _FCID=value; } }
}


private ObservableCollection<ZoneResult> FindCommonZones(string[] searchterms)
    {

        ObservableCollection<ZoneResult> tempcollection = 
          new ObservableCollection<ZoneResult>();
        //find the zones for the first search term
        tempcollection = this.FindZones(searchterms[0]);

        //now search for the rest of the search terms and compare 
         //them to existing result
        for (int i = 1; i < searchterms.Count(); i++ )
        {  
           // this line gives an exception trying to cast
           tempcollection = (ObservableCollection<ZoneResult>)tempcollection.
             Intersect(this.FindZones(searchterms[i]));

        }

        return tempcollection;
    }
    private ObservableCollection<ZoneResult> FindZones(string searchterm)
    // we need to track the vsan where the zone member is found
    // so use a foreach to keep track
    {
        ObservableCollection<ZoneResult> zonecollection = new ObservableCollection<ZoneResult>();
        foreach (KeyValuePair<int, Dictionary<int, CiscoVSAN>> fabricpair in this.FabricDictionary)
        {
            foreach (KeyValuePair<int, CiscoVSAN> vsanpair in fabricpair.Value)
            {
                var selection = vsanpair.Value.ActiveZoneset.
                           ZoneList.Select(z => z.ContainsMember(searchterm)).
                               Where(m => m != null).OrderBy(z => z.zoneName);
                if (selection.Count() > 0)
                {

                    foreach (Zone zone in selection)
                    {
                        foreach (ZoneMember zm in zone.MembersList)
                        {
                            ZoneResult zr = new ZoneResult(zone.zoneName, 
                            zm.MemberWWPN, zm.MemberAlias, vsanpair.Key.ToString());
                            zonecollection.Add(zr);
                        }

                    }

                }
            }

        }
        return zonecollection;
    }

Answer 1

Intersect实际上是 Enumerable.Intersect并返回 IEnumerable<ZoneResult> .这不是 ObservableCollection 的可转换，因为它不是一个 - 它是两个集合中相交元素的枚举。

不过，您可以从枚举中创建一个新 ObservableCollection:

tempcollection = new ObservableCollection<ZoneResult>(tempcollection
    .Intersect(this.FindZones(searchterms[i]));

取决于你有多少元素，如何ZoneResult.Equals已实现，以及您期望有多少搜索词，此实现可能可行也可能不可行(乍一看，FindZones 确实似乎有点过于复杂，复杂度为 O(n^4))。如果它看起来是资源消耗或瓶颈，那么就该进行优化了；否则，如果它有效，我就不会管它。

---

一个建议的优化可能如下(结合@Keith 将 ContainsMember 更改为 bool 的建议)——尽管它未经测试，但我的 SelectManys 可能有误，而且它实际上在很大程度上是相同的，你希望得到想法:

private ObservableCollection<ZoneResult> FindCommonZones(string[] searchterms)
{

    var query = this.FabricDictionary.SelectMany(fabricpair => 
        fabricpair.Value.SelectMany(vsanpair => 
            vsanpair.Value.ActiveZoneSet.ZoneList
            .Where(z=>searchterms.Any(term=>z.ContainsMember(term)))
            .SelectMany(zone => 
                zone.MembersList.Select(zm=>new ZoneResult(zone.zoneName, zm.MemberWWPN, zm.MemberAlias, vsanpair.Key.ToString()))
        )
    )
    .Distinct()
    .OrderBy(zr=>zr.zoneName);

    return new ObservableCollection<ZoneResult>(query);
}