使用Linq优化WMI查询

时间:2013-01-04 20:04:19

标签: c# linq optimization query-optimization wmi

首先,我应该首先承认我真的不太了解使用WMI或LINQ。因此,我确信任何人都不会感到惊讶,因为我有这么艰难的时刻!

麻烦的是我正在尝试从同一个WMI对象查询或返回多个值。通常情况下这不会很糟糕,但由于需要仅返回与特定数据集匹配的元素,因此我发现难以解决这个问题。问题是,我必须首先查询WMI以获取特定元素或值,然后重新启动查询,按所述元素或值过滤以返回所需的数据集。

我确信我可以遍历WMI对象中的所有元素并将它们附加到集合中。然后遍历集合直到我得到我正在寻找的东西,但后来我仍然有过滤掉所有额外不必要元素的问题。

所以我想我的问题是,对于WMI对象进行高级搜索的最佳方法是什么?如何优化流程以便检索我正在寻找的信息不需要这么长时间?

在我的多次搜索中,我发现了几个使用LINQ的人的引用,但我对LINQ的有限接触意味着我不确定如何在这个实例中使用它,所以任何帮助或见解都将非常感激。

这是我到目前为止所提出的:

        ManagementObjectSearcher searcher = new ManagementObjectSearcher
            ("SELECT * FROM Win32_NetworkAdapterConfiguration where IPEnabled=true");
        IEnumerable<ManagementObject> objects = searcher.Get().Cast<ManagementObject>();
        string description = (from o in objects orderby o["IPConnectionMetric"] 
                              select o["Description"].ToString()).FirstOrDefault();

        _NICINDEX = (from o in objects orderby o["IPConnectionMetric"]
                     select o["Index"].ToString()).FirstOrDefault();

        _MACADDRESS = (from o in objects orderby o["IPConnectionMetric"]
                       select o["MACAddress"].ToString()).FirstOrDefault();

        _IPADDRESS = (from o in objects orderby o["IPConnectionMetric"]
                      select o["IPAddress"].ToString()).FirstOrDefault();

        _IPV6ADDRESS = (from o in objects orderby o["IPConnectionMetric"]
                        select o["IPAddress"].ToString()).FirstOrDefault();

        _SUBNETMASK = (from o in objects orderby o["IPConnectionMetric"]
                       select o["IPSubnet"].ToString()).FirstOrDefault();

        _GATEWAY = (from o in objects orderby o["IPConnectionMetric"]
                    select o["DefaultIPGateway"].ToString()).FirstOrDefault();

        _DNSSERVER = (from o in objects orderby o["IPConnectionMetric"]
                      select o["DNSServerSearchOrder"].ToString()).FirstOrDefault();

        _DNSSECSVR = (from o in objects orderby o["IPConnectionMetric"]
                      select o["DNSServerSearchOrder"].ToString()).FirstOrDefault();

        return description;

2 个答案:

答案 0 :(得分:2)

所以我不熟悉您的特定数据库提供程序,但您的主要问题是您正在迭代IEnumerable 10次,这意味着对数据库进行了10次不同的查询。你当然不需要这样做,而且它真的会扼杀你的表现。您还要对返回的数据进行10次不同的排序;你应该只做一次。

以下是代码的重构,用于获取项目一次,然后从中获取10个不同的值:

ManagementObjectSearcher searcher = new ManagementObjectSearcher
            ("SELECT * FROM Win32_NetworkAdapterConfiguration where IPEnabled=true");
ManagementObject managementObject = searcher.Get()
    .Cast<ManagementObject>()
    .OrderBy(obj => obj["IPConnectionMetric"])
    .FirstOrDefault();

string description = managementObject["Description"];
_NICINDEX  = managementObject["Index"];
//repeat for the other 8 values following the above pattern
return description;

请注意,如果可能的话,您应该在数据库端进行排序,并将输出限制为数据库端的1个值。在不知道您正在使用的查询提供程序的细节的情况下,我无法说明这样做的最佳方式是什么。

答案 1 :(得分:1)

创建WMI查询以获取所需数据,将其转换为LINQ to Objects查询,然后遍历结果,获取所需的数据将更容易。

var queryStr =
    "SELECT * " +
    "FROM Win32_NetworkAdapterConfiguration " +
    "WHERE IPEnabled = true";
using (var searcher = new ManagementObjectSearcher(queryStr))
using (var managementQuery = searcher.Get())
{
    // convert to LINQ to Objects query
    var query =
        from ManagementObject mo in managementQuery
        orderby Convert.ToUInt32(mo["IPConnectionMetric"])
        select new
        {
            Description          = Convert.ToString(mo["Description"]),
            Index                = Convert.ToString(mo["Index"]),
            MACAddress           = Convert.ToString(mo["MACAddress"]),
            IPAddress            = String.Join(", ", (string[])mo["IPAddress"] ?? new string[0]),
            IPSubnet             = String.Join(", ", (string[])mo["IPSubnet"] ?? new string[0]),
            DefaultIPGateway     = String.Join(", ", (string[])mo["DefaultIPGateway"] ?? new string[0]),
            DNSServerSearchOrder = String.Join(", ", (string[])mo["DNSServerSearchOrder"] ?? new string[0]),
        };

    // grab the fields
    String description = null;
    foreach (var item in query)
    {
        description  = description  ?? item.Description;
        _NICINDEX    = _NICINDEX    ?? item.Index;
        _MACADDRESS  = _MACADDRESS  ?? item.MACAddress;
        _IPADDRESS   = _IPADDRESS   ?? item.IPAddress;
        _IPV6ADDRESS = _IPV6ADDRESS ?? item.IPAddress;
        _SUBNETMASK  = _SUBNETMASK  ?? item.IPSubnet;
        _GATEWAY     = _GATEWAY     ?? item.DefaultIPGateway;
        _DNSSERVER   = _DNSSERVER   ?? item.DNSServerSearchOrder;
        _DNSSECSVR   = _DNSSECSVR   ?? item.DNSServerSearchOrder;
        // check if all fields are set so we can stop
        if (new[] { description, _NICINDEX, _MACADDRESS, _IPADDRESS, _IPV6ADDRESS, _SUBNETMASK, _GATEWAY, _DNSSERVER, _DNSSECSVR }.All(x => x != null))
            break;
    }
}

虽然我不清楚为什么你想要单独获得每个领域的第一个。我希望你会想要第一个适配器的字段作为一个整体。所以最后,我认为它应该只是:

var first = query.FirstOrDefault();
if (first != null)
{
    description  = first.Description;
    _NICINDEX    = first.Index;
    _MACADDRESS  = first.MACAddress;
    _IPADDRESS   = first.IPAddress;
    _IPV6ADDRESS = first.IPAddress;
    _SUBNETMASK  = first.IPSubnet;
    _GATEWAY     = first.DefaultIPGateway;
    _DNSSERVER   = first.DNSServerSearchOrder;
    _DNSSECSVR   = first.DNSServerSearchOrder;
}