如何使用Visual Basic从XML文件中提取数据？

I've not used XML too much and I need a little help.

我没有太多使用XML,我需要一些帮助。

My .NET application gets this XML response from the W3C's public validation server:

我的.NET应用程序从W3C的公共验证服务器获取此XML响应:

<?xml version="1.0" encoding="UTF-8" ?> 
<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">
    <env:Body>
        <m:markupvalidationresponse env:encodingStyle="http://www.w3.org/2003/05/soap-encoding" xmlns:m="http://www.w3.org/2005/10/markup-validator">
            <m:uri>upload://Form Submission</m:uri> 
            <m:checkedby>http://validator.w3.org/</m:checkedby> 
            <m:doctype>-//W3C//DTD XHTML 1.1//EN</m:doctype> 
            <m:charset>utf-8</m:charset> 
            <m:validity>true</m:validity> 
            <m:errors>
                <m:errorcount>0</m:errorcount> 
                <m:errorlist /> 
            </m:errors>
            <m:warnings>
                <m:warningcount>0</m:warningcount> 
                <m:warninglist /> 
            </m:warnings>
        </m:markupvalidationresponse>
    </env:Body>
</env:Envelope>

I want to extract from this the following values:

我想从中提取以下值:

Uri as String

Uri as String

Checkedby as String

Checkedby String

Doctype as String

Doctype as String

CharSet as String

CharSet as String

Validity as Boolean

有效性为布尔值

ErrorList as System.Collections.Generic.List(Of W3CError)

ErrorList as System.Collections.Generic.List(Of W3CError)

WarningList as System.Collections.Generic.List(Of W3CError)

WarningList as System.Collections.Generic.List(Of W3CError)

That type W3CError is a small class I created with the following properties:

那个类型W3CError是我用以下属性创建的一个小类:

Line as Integer

行为整数

Col as Integer

Col as Integer

Message as String

消息为字符串

MessageId as String

MessageId as String

Explanation as String

字符串解释

Source as String

来源为字符串

Here's what I've go so far. But, this doesn't work...

这就是我到目前为止所做的事情。但是,这不起作用......

Dim ResponseReader As Xml.XmlTextReader = New Xml.XmlTextReader(ResponseStream)
Dim ResponseDocument As New Xml.XPath.XPathDocument(ResponseReader)
Dim ResponseNavigator As Xml.XPath.XPathNavigator = ResponseDocument.CreateNavigator()
Dim ResponseIterator As Xml.XPath.XPathNodeIterator

'uri
ResponseIterator = ResponseNavigator.Select("uri")
ResponseIterator.MoveNext()
_Uri = ResponseIterator.Current.Value

'checked by
ResponseIterator = ResponseNavigator.Select("checkedby")
ResponseIterator.MoveNext()
_Checkedby = ResponseIterator.Current.Value

...etc...

How can I fix the broken code above? Or: Am I way off track with this? What's a better way?

我怎样才能修复上面破碎的代码?或者:我是否偏离了这个轨道?什么是更好的方法?

3 个解决方案

#1

Try this

'Import these Namespaces at the top of your file
Imports System.Linq
Imports System.Xml.Linq
Imports <xmlns:env="http://www.w3.org/2003/05/soap-envelope">
Imports <xmlns:m="http://www.w3.org/2005/10/markup-validator">

'in a procedure do this
Dim doc As XDocument = <?xml version="1.0" encoding="UTF-8" ?> 
<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">
    <env:Body>
        <m:markupvalidationresponse env:encodingStyle="http://www.w3.org/2003/05/soap-encoding" xmlns:m="http://www.w3.org/2005/10/markup-validator">
            <m:uri>upload://Form Submission</m:uri> 
            <m:checkedby>http://validator.w3.org/</m:checkedby> 
            <m:doctype>-//W3C//DTD XHTML 1.1//EN</m:doctype> 
            <m:charset>utf-8</m:charset> 
            <m:validity>true</m:validity> 
            <m:errors>
                <m:errorcount>0</m:errorcount> 
                <m:errorlist /> 
            </m:errors>
            <m:warnings>
                <m:warningcount>0</m:warningcount> 
                <m:warninglist /> 
            </m:warnings>
        </m:markupvalidationresponse>
    </env:Body>
</env:Envelope>

_Uri = doc.Root.<env:Body>.<m:markupvalidationresponse>.<m:uri>.Value
_Checkedby = doc.Root.<env:Body>.<m:markupvalidationresponse>.<m:checkedby>.Value
'note that the following code assumes you have a class named W3CError
_errorList = (From er in doc.Root...<m:errors> _
             Select New W3CError With {.Line = CInt(er.<m:line>.Value), .Col = CInt(er.<m:col>.Value), .Message = er.<m:message>.Value, .MessageId = er.<m:messageId>.Value, .Explanation = er.<m:explanation>.Value, .Source = er.<m:source>.Value}).ToList
'do the same for the _warningList as above
'now do what you want with it

#2

Have you heard about XPath?

你听说过XPath吗?

XmlDocument doc  = new XmlDocument()
doc.Load(xml)
// set the namspace manager, I don't remember exact syntax
....
XmlNode node = doc.SelectSingleNode("//m:checkedby", namespaceManagerThatDeclaresMNamespace);

You code probably don't work because you are ignoring the namespaces in xml

您的代码可能无法正常工作,因为您忽略了xml中的命名空间

#3

There is also linq2xml. It is located in System.Xml.Linq. It has a new XDocument class that is easier to work with than the older System.Xml.XmlDocument class.

还有linq2xml。它位于System.Xml.Linq中。它有一个新的XDocument类,比旧的System.Xml.XmlDocument类更容易使用。

#1