xml 到 linq，如何修复后期绑定(bind)？

Question

我正在 xml 文件中搜索特定元素，我想出了一个不错的解决方案，它将找到我需要的元素，但是，如果我要打开 Option Strict，编译器会告诉我它没有不允许后期绑定(bind)。在互联网上的快速搜索使我发现绑定(bind)需要在执行之前初始化为类型，只是不确定如何进行。

我可以简单地关闭该选项，但为了更好地编码，我想保留它并看看如何避免后期绑定(bind)。老实说，我不确定从哪里开始，我是否需要一个具有自己属性的类？

Dim xmlDocument As String = "C:\***\comp.xml"  ' Path '
Dim xelement As XDocument = XDocument.Load(xmlDocument)
Console.WriteLine("What company are you searching for? ")
searchCompData = Console.ReadLine()

Dim results As IEnumerable(Of Object) = From c In xelement.Descendants("COMPANYINFO").Descendants("Office")
                                        Where CType(c.Parent.Parent.Element("compId"), String) = searchCompData
                                        Select New With
                                        {
                                            .reg = c.Parent.Element("Region"),
                                            .city = c.Parent.Element("City"),
                                            .ceo = c.Parent.Element("CEO"),
                                            .office = c
                                        }

For Each res As Object In results
    Console.WriteLine(res.reg)
    Console.WriteLine(res.city)
    Console.WriteLine(res.ceo)
    Console.WriteLine(res.office)
Next
Console.ReadLine()

我的示例 xml 文件

<?xml version="1.0" encoding="utf-8"?>
<CompType xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <CompanyRegion>
    <compId>1</compId>
    <compRegionId>654</compRegionId>
    <compTransPort>Van</compTransPort>
    <COMPANYINFO>
      <compInfoId>545</compInfoId>
      <City>London</City>
      <Zip>3214</Zip>
      <Zone>535</Zone>
      <Region>London Region</Region>
      <LocalNumber>54687874</LocalNumber>
      <CEO>Alice Goldsmith</CEO>
      <CompanyStreet>BongoBingo St</CompanyStreet>
      <Office>
        <Name>IT</Name>
        <Place>2nd Floor</Place>
        <Manager>
          <Name>Steven Smith</Name>
          <Address>Robo Street</Address>
          <Phonenumber>12345</Phonenumber>
        </Manager>
      </Office>
      <Office>
        <Name>Accountants</Name>
        <Place>3d Floor</Place>
        <Manager>
          <Name>Joana Petersen</Name>
          <Address>Lamba Street</Address>
          <Phonenumber>54321</Phonenumber>
        </Manager>
      </Office>
    </COMPANYINFO>
  </CompanyRegion>
  <CompanyRegion>
    <compId>2</compId>
    <compRegionId>785</compRegionId>
    <compTransPort>Truck</compTransPort>
    <COMPANYINFO>
      <compInfoId>321</compInfoId>
      <City>Oslo</City>
      <Zip>4598</Zip>
      <Zone />
      <Region>Oslo Region</Region>
      <LocalNumber>458754121</LocalNumber>
      <CEO>Michael Jonson</CEO>
      <CompanyStreet>BingoBango St</CompanyStreet>
      <Office>
        <Name>Sales</Name>
        <Place>4th Floor</Place>
        <Manager>
          <Name>Rachel Laurensen</Name>
          <Address>Albo Street</Address>
          <Phonenumber>55555</Phonenumber>
        </Manager>
      </Office>
      <Office>
        <Name>Accountants</Name>
        <Place>1st Floor</Place>
        <Manager>
          <Name>Peter Carlsen</Name>
          <Address>Lobo Street</Address>
          <Phonenumber>455656</Phonenumber>
        </Manager>
      </Office>
    </COMPANYINFO>
  </CompanyRegion>
</CompType>

Answer 1

可以删除

As IEnumerable(Of Object) 来推断匿名类型，并且需要 .Value 来获取元素值。另外，VB.Net XML axis properties可用于简化查询:

Dim results = From c In xelement...<CompanyRegion> 
              Where c.<compId>.Value = searchCompData
              Select New With {
                  .reg = c...<Region>.Value,
                  .city = c...<City>.Value,
                  .ceo = c...<CEO>.Value,
                  .office = c...<Office>
              }