使用linq查询XML并比较两个变量

Question

Trying to write a select that will let me select a specific office element

Here is my XML

<?xml version="1.0"> 
<regions>
    <region>
        <office>
            <name>Office One</name>
        </office>

        <office>
            <name>Office Two</name>
        </office>
        <settings>
            <name>Main Regional Name</name>
        </settings>
    </region>
    <region>
        <office>
            <name>Office Three</name>
        </office>

        <office>
            <name>Office Four</name>
        </office>
        <settings>
            <name>Secondary Regional Name</name>
        </settings>
    </region>

Here is my code

    Dim clfWizardXml As XElement
    Dim selectRegion = lstRegions.SelectedItem
    Dim selectOffice = lstOffices.SelectedItem


    Console.WriteLine(selectRegion + " " + selectOffice)


    Dim officeList As IEnumerable(Of XElement) = _
        From region In clfWizardXml.Elements("region"), _
             office In clfWizardXml.Elements("region").Elements("office") _
        Where region.Element("settings").Element("name").Value = selectRegion _
        And office.Element("name").Value = selectOffice
        Select office

I think my issue is somewhere around here: And office.Element("name").Value = selectOffice

Thanks for your help everyone, the issue was I had an office element at the wrong level in the second region.

Answer 1

It looks like your issue is that clfWizardXml.Elements("region") doesn't return anything, since region is not directly under the document. Instead you need clfWizardXml.Root.Elements("region") , or clfWizardXml.Descendants("region") :

Dim officeList As IEnumerable(Of XElement) = _
    From region In clfWizardXml.Root.Elements("region"), _
         office In clfWizardXml.Root.Elements("region").Elements("office") _
    Where region.Element("settings").Element("name").Value = selectRegion _
    And office.Element("name").Value = selectOffice
    Select office

Also, since VB.NET supports XML literals, you can make it look a little nicer (to me anyway, you may disagree):

Dim officeList As IEnumerable(Of XElement) =
    From region In clfWizardXml...<region>,
         office In region.<office>
    Where region.<settings>.<name>.Value = selectRegion _
        AndAlso office.<name>.Value = selectOffice
    Select office