无法获取特定的XML节点

我想更新xml节点并搜索该站点以在中查找示例。但是，我在对象引用未设置为对象实例时遇到错误。有人能告诉我如何获取节点吗。提前谢谢

这是我的vb代码：

Imports System.Xml
Imports System.IO

Partial Class test2
Inherits System.Web.UI.Page


Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load      

    Dim xmlFileNamae As String = "Vancouver.xml"
    Dim xmlFilePath As String = ConfigurationManager.AppSettings("XMLFolder") & xmlFileNamae
    If File.Exists(xmlFilePath) Then
        Dim docXML As XmlDocument = New XmlDocument
        docXML.Load(xmlFilePath)
        Dim ID As String = "1"
        Dim node As XmlNode = docXML.SelectSingleNode("/Orders/Order[@ID='" & ID & "']/Date")
        node.InnerText = Date.Now
        node = docXML.SelectSingleNode("/Orders/Order[@ID='" & ID & "']/Country")
        node.InnerText = "Vancouver"
        docXML.Save(xmlFilePath)
    End If
End Sub

End Class

这是我的xml文件：

<?xml version="1.0" encoding="utf-8"?>
  <Orders>
    <order ID="2">
      <item>Organ</item>
      <Date>7/24/2014 3:50:42 PM</Date>
      <Country>China</Country>
    </Order>
   <order ID="1">
     <item>Apple</item>
     <Date>7/24/2014 3:50:42 PM</Date>
     <Country>China</Country>
   </order>
</Orders>

---

首先，您的XML被破坏了——您用order关闭了第一个订单，这是错误的

第二，您的XPath也不好

这两个XPath的代码都更清晰

    Dim XmlDoc As New XmlDocument
    Dim Node As XmlNode
    XmlDoc.Load(//Your path)
    //This will give you the date of the first order item in orders
    //where the ID attribute equals 1.
    Node = XmlDoc.SelectSingleNode("/Orders/order[@ID="1"]/Date")
    //Do somehintg
    //This will give you the country of the first order item in orders
    //where the ID attribute equals 1.
    Node=XmlDoc.SelectSingleNode("/Orders/order[@ID="1"]/Country")
    //Do something else.

---

哪一行引发错误？您能详细说明抛出错误的行吗？乍一看，我认为xmlFilePath没有很好地初始化&xmlFileNamae，这可能是写错的，这将导致.Load抛出错误。@Nadeem_MK，它在这一行中抛出Dim node作为XmlNode=docXML.SelectSingleNode/Files/File[@ID='&ID&']/Date。节点是nothing@Fabio将节点设置为XmlNode=docXML。选择singlenode/Files/File[@ID='&ID&']/Date会导致错误，因为找不到该节点。谢谢