我正在尝试创建一个循环,为具有特定ID号的项读取XML文档,然后将该项的子节点存储为变量,然后用于填充页面上的标签。
Sub LinkButton_Click(sender As Object, e As CommandEventArgs)
Dim selected = Convert.ToInt32(e.CommandArgument)
System.Diagnostics.Debug.WriteLine("selected")
System.Diagnostics.Debug.WriteLine (selected)
Dim selectedXML = New XmlTextReader(MapPath("xml/questions.xml"))
selectedXML.ReadToFollowing("Question")
If selectedXML.HasAttributes Then
selectedXML.MoveToNextAttribute()
Do While selectedXML.MoveToNextAttribute()
Dim compareID = selectedXML.Value
System.Diagnostics.Debug.WriteLine("compareID:")
System.Diagnostics.Debug.WriteLine(compareID)
If compareID = selected Then
selectedXML.ReadToFollowing("A")
sA.Text = selectedXML.Value
System.Diagnostics.Debug.WriteLine("SA:")
System.Diagnostics.Debug.WriteLine(sA.Text)
selectedXML.ReadToFollowing("Q")
sQ.Text = selectedXML.Value
System.Diagnostics.Debug.WriteLine("SQ:")
System.Diagnostics.Debug.WriteLine(sQ.Text)
selectedXML.ReadToFollowing("Download")
sDL.Text = selectedXML.Value
System.Diagnostics.Debug.WriteLine("SDL:")
System.Diagnostics.Debug.WriteLine(sDL.Text)
selectedXML.Close()
Else
selectedXML.ReadToNextSibling("Question")
End If
Loop
Else
System.Diagnostics.Debug.WriteLine("error")
selectedXML.Close()
End If
End Sub
XML Document(冗余ID节点用于获取ID号,但最终会被删除。当前代码只查找“id”属性。这是可能的,因为它区分大小写)
<?xml version="1.0" encoding="utf-8" ?>
<Questions>
<Question id="1">
<ID>1</ID>
<Category>Troubleshooting</Category>
<Keywords>tags troubleshooting troubleshoot slow computer slowly</Keywords>
<Q>Why is my computer so slow?</Q>
<A>You have bad habits and your computer sucks</A>
<Download>None.</Download>
</Question>
<Question id="2">
<ID>2</ID>
<Category>Troubleshooting</Category>
<Keywords>tags troubleshooting troubleshoot slow computer slowly</Keywords>
<Q>Why is my computer so slow? (again)</Q>
<A>You have bad habits and your computer sucks</A>
<Download>None.</Download>
</Question>
<Question id="3">
<ID>3</ID>
<Category>Microsoft Office</Category>
<Keywords>tags microsoft office outlook calendar room rooms meeting schedule scheduling reserving reserve</Keywords>
<Q>How do I reserve rooms and set up meetings?</Q>
<A>View the following Document:</A>
<Download><![CDATA[<a href="doc/new_employee/new_employee_agreement.doc">New Employee Software and Hardware Agreement</a>]]></Download>
</Question>
</Questions>
linkbutton将变量“selected”作为命令参数传递。在我的控制台中,我可以看到这是正常的。即,单击第一个项目,将“selected”设置为1.我遇到问题的方法是读取XML并将id属性作为compareID
变量传递。无论我做什么,我似乎总是得到compareID=0
。
其次,循环似乎无限期地运行。如何找到没有匹配的读者在文档结束时停止编程。
答案 0 :(得分:0)
即使出现异常,也可以使用Using Statement自动关闭XmlReader。
不使用XmlTextReader类,不建议从.NET Framework 2.0开始。请改用XmlReader。
请注意,我们必须按照xml文档中排列的顺序转到节点Q
,A
和Download
。
简化代码:
Using selectedXML = XmlReader.Create(MapPath("xml/questions.xml"))
While selectedXML.ReadToFollowing("Question") ' Iterates through Question nodes.
Dim compareID = selectedXML.GetAttribute("id")
If compareID IsNot Nothing Then
Debug.WriteLine("compareID: " + compareID)
If compareID = selected Then
selectedXML.ReadToFollowing("Q")
sQ.Text = selectedXML.ReadElementContentAsString
Debug.WriteLine("SQ: " + sQ.Text)
selectedXML.ReadToFollowing("A")
sA.Text = selectedXML.ReadElementContentAsString
Debug.WriteLine("SA: " + sA.Text)
selectedXML.ReadToFollowing("Download")
sDL.Text = selectedXML.ReadElementContentAsString
Debug.WriteLine("SDL: " + sDL.Text)
Exit While
End If
Else
Debug.WriteLine("Error: attribute id not found")
End If
End While
End Using ' Close XmlReader