Question

我已经完成了研究，并且不明白为什么我的Linq查询不起作用。我试图从这个XML返回一个“Grant”元素列表：

<?xml version="1.0" encoding="utf-8"?>
<root>
  <ArrayOfMapItem>
    <MapItem>
      <Id xmlns="Private.CO.path.type">7D2B99FA-0000-0000-0000-000000000000</Id>
      <Map xmlns="Private.CO.path.type">6557A558-7ED9-4199-8585-6FD8610E4119</Map>
      <ServiceCollectionId xmlns="Private.CO.path.type">69DB37D4-8A29-4C4E-8671-6C054B9F62E5</ServiceCollectionId>
      <ServiceCollectionName xmlns="Private.CO.path.type">S-AVCL-CC-01-DF8_SC</ServiceCollectionName>
      <Services xmlns="Private.CO.path.type">S-AVCL-CC-01-DF8</Services>
      <Position xmlns="Private.CO.path.type">1350</Position>
    </MapItem>
    <MapItem>
      <Id xmlns="Private.CO.path.type">7D2B99FC-0000-0000-0000-000000000000</Id>
      <Map xmlns="Private.CO.path.type">80703716-4BCE-4465-902E-6B92A9BD41AC</Map>
      <ServiceCollectionId xmlns="Private.CO.path.type">A8266306-9384-4CAA-9746-DD9279F9A27E</ServiceCollectionId>
      <ServiceCollectionName xmlns="Private.CO.path.type">S-AVCL-CC-02-DF8_SC</ServiceCollectionName>
      <Services xmlns="Private.CO.path.type">S-AVCL-CC-02-DF8</Services>
      <Position xmlns="Private.CO.path.type">1351</Position>
    </MapItem>
  </ArrayOfMapItem>
  <GrantArrays>
    <GrantArray>
      <Grant ResourceId="6557a558-7ed9-4199-8585-6fd8610e4119" PrincipalExternalId="royce" PrincipalType="Group" ResType="Package" Right="Access">
        <Conditions xmlns="http://www.here.com/location/bss">
          <TimeExpiration Start="2014-05-01T07:00:00" End="9999-12-31T23:59:59.997" Type="TimeExpiration" Expiration="9999-12-31T23:59:59" />
        </Conditions>
      </Grant>
      <Grant ResourceId="6557a558-7ed9-4199-8585-6fd8610e4119" PrincipalExternalId="peter" PrincipalType="Group" ResType="Package" Right="Access">
        <Conditions xmlns="http://www.here.com/location/bss">
          <TimeExpiration Start="2014-04-04T19:18:04.963" End="9999-12-31T23:59:59.997" Type="TimeExpiration" Expiration="9999-12-31T23:59:59" />
        </Conditions>
      </Grant>
    </GrantArray>
    <GrantArray>
      <Grant ResourceId="80703716-4bce-4465-902e-6b92a9bd41ac" PrincipalExternalId="royce" PrincipalType="Group" ResType="Package" Right="Access">
        <Conditions xmlns="http://www.here.com/location/bss">
          <TimeExpiration Start="2014-05-01T07:00:00" End="9999-12-31T23:59:59.997" Type="TimeExpiration" Expiration="9999-12-31T23:59:59" />
        </Conditions>
      </Grant>
      <Grant ResourceId="80703716-4bce-4465-902e-6b92a9bd41ac" PrincipalExternalId="peter" PrincipalType="Group" ResType="Package" Right="Access">
        <Conditions xmlns="http://www.here.com/location/bss">
          <TimeExpiration Start="2014-04-04T19:18:05.2" End="9999-12-31T23:59:59.997" Type="TimeExpiration" Expiration="9999-12-31T23:59:59" />
        </Conditions>
      </Grant>
    </GrantArray>
  </GrantArrays>
</root>

我在此方法中应用Linq查询，将方法传递给已知存在的ResourceId的属性值：

        private static void CheckGrantChanges(string approvemapid) //, string checkmapid)
    {
        // approvemapid = "6557a558-7ed9-4199-8585-6fd8610e4119". value confirmed several times

        var docApproved = XDocument.Load(@"C:\Tools\WorkOnChannelChecker\Daily11ApprovedMapping.xml");

        var approveGrants = docApproved.Descendants("GrantArray");

        var queryApproved = from a in approveGrants.Elements("Grant")
                            where a.Attribute("ResourceId").Value == approvemapid
                            select a;
    }

我希望在“queryApproved”中返回两个Grant元素，但它会一直空着。请告诉我这是什么我在这个过程中误解了？提前谢谢你的帮助！

Answer 1

感谢Florian。问题是字符串比较。将查询更改为： ...

            var queryApproved = from a in approveGrants.Elements("Grant")
                            where a.Attribute("ResourceId").Value.Equals(approvemapid,StringComparison.OrdinalIgnoreCase)
                            select a;

... 解决了这个问题。

如何按属性值返回元素列表

1 个答案: