如何使用 DataContractSerializer 从 XMLDocument 的单个节点进行反序列化？

发布于 2024-10-11 15:31:06 字数 722 浏览 7 评论 0原文

DataContractSerializer 在 ReadObject 中使用的读取器似乎是基于流的。我已经有一个 XMLDocument，并且我想反序列化该文档的一部分。

在此代码片段中，我从文件流反序列化 MyItem 对象：

Dim fs As New FileStream("c:\myinputfile.xml", FileMode.Open)
Dim reader As XmlDictionaryReader = XmlDictionaryReader.CreateTextReader(fs, New XmlDictionaryReaderQuotas())
Dim ser As New DataContractSerializer(GetType(MyItemClass))
Dim deserializedMyItem As ClassTemplate = CType(ser.ReadObject(reader, True), MyItemClass)

但是如果我只想反序列化文档的一部分，该怎么办？

Dim MyItemNode as Xml.XmlNode = parentDoc.selectSingleNode("MyItemElementName")
Dim deserializedMyItem As MyItemClass = getMyItemFromNode(MyItemNode)

getMyItemFromNode 是什么样子的？

原文

The readers that DataContractSerializer uses in ReadObject seem to be stream-based. I already have an XMLDocument, and I would like to deserialize one part of that document.

In this code snippet, I am deserializing a MyItem object from a filestream:

Dim fs As New FileStream("c:\myinputfile.xml", FileMode.Open)
Dim reader As XmlDictionaryReader = XmlDictionaryReader.CreateTextReader(fs, New XmlDictionaryReaderQuotas())
Dim ser As New DataContractSerializer(GetType(MyItemClass))
Dim deserializedMyItem As ClassTemplate = CType(ser.ReadObject(reader, True), MyItemClass)

but what if instead I want to deserialize just a part of a document.

Dim MyItemNode as Xml.XmlNode = parentDoc.selectSingleNode("MyItemElementName")
Dim deserializedMyItem As MyItemClass = getMyItemFromNode(MyItemNode)

What does getMyItemFromNode look like?

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无敌元气妹 2024-10-18 15:31:06

除非有更好的方法来流式传输它，否则这是使用内存流的解决方案：

Function getMyItemFromNode(ByVal itemNode as Xml.XmlNode) as MyItemClass
    Dim stm As New MemoryStream()
    Dim stw  As New StreamWriter(stm)
    stw.Write(itemNode.OuterXml)
    stw.Flush()
    stm.Position = 0
    Dim reader As XmlDictionaryReader = XmlDictionaryReader.CreateTextReader(stm, New XmlDictionaryReaderQuotas())
    Dim ser As New DataContractSerializer(GetType(MyItemClass))
    Return CType(ser.ReadObject(reader, True), MyItemClass)

End Function

将其推送到流的代码来自此回复相关问题。

Unless there is a better way that streaming it, here's a solution using the memorystream:

Function getMyItemFromNode(ByVal itemNode as Xml.XmlNode) as MyItemClass
    Dim stm As New MemoryStream()
    Dim stw  As New StreamWriter(stm)
    stw.Write(itemNode.OuterXml)
    stw.Flush()
    stm.Position = 0
    Dim reader As XmlDictionaryReader = XmlDictionaryReader.CreateTextReader(stm, New XmlDictionaryReaderQuotas())
    Dim ser As New DataContractSerializer(GetType(MyItemClass))
    Return CType(ser.ReadObject(reader, True), MyItemClass)

End Function

Code for pushing it to a stream came from this response to a related question.

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玉环 2024-10-18 15:31:06

使用 [CreateDictionaryReader](http://msdn.microsoft.com/en-us/library/system.xml.xmldictionaryreader.createdictionaryreader.aspx) 以及指向所需节点的XmlReader`：

Dim doc As XmlDocument = new XmlDocument()
' fill it

Dim nav as XPathNavigator = doc.CreateNavigator()
Dim docReader As XmlReader = nav.ReadSubTree()
Dim reader As XmlDictionaryReader = _
    XmlDictionaryReader.CreateDictionaryReader(docReader)
Dim ser As New DataContractSerializer(GetType(MyItemClass))

Use [CreateDictionaryReader](http://msdn.microsoft.com/en-us/library/system.xml.xmldictionaryreader.createdictionaryreader.aspx) with anXmlReader` pointing to the node you want:

Dim doc As XmlDocument = new XmlDocument()
' fill it

Dim nav as XPathNavigator = doc.CreateNavigator()
Dim docReader As XmlReader = nav.ReadSubTree()
Dim reader As XmlDictionaryReader = _
    XmlDictionaryReader.CreateDictionaryReader(docReader)
Dim ser As New DataContractSerializer(GetType(MyItemClass))

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