试图序列化一个没有命名空间或声明的类

Question

我一直在关注How can I make the xmlserializer only serialize plain xml? 上的解决方案，试图仅序列化纯文本，但是在 VB.net 端执行此操作时遇到了一些问题

目的是防止显示行<?xml version="1.0" encoding="utf-16"?>和属性xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

我有一个子如下：

  Private Sub writeXMLContent()
        For Each dataItem As dataClass In dataSet            
            Dim emptyNameSpace As XmlSerializerNamespaces = New XmlSerializerNamespaces({XmlQualifiedName.Empty})
            Dim serializer As New XmlSerializer(GetType(dataClass))
            Dim settings As New XmlWriterSettings
            settings.Indent = True
            settings.OmitXmlDeclaration = True

            Using stream As New StringWriter
                Using writer = XmlWriter.Create(stream, settings)
                    serializer.Serialize(writer, serializer, emptyNameSpace)
                    'will write each line to a file here
                End Using
            End Using
        Next
    End Sub

但是我一直遇到同样的两个错误：

1. Using writer = XmlWriter.Create(stream, settings) 行使用 object 类型的操作数时抛出错误必须实现 system.iDisposable
2. serializer.Serialize(writer, serializer, emptyNameSpace) 行似乎不像我的第二个参数，因为它需要一个对象？我不太确定我会在这里传递什么对象？

Answer 1

1. XmlWriter 没有实现IDisposable，即它没有Using statement 可以调用的Dispose 方法。只需不使用 Using 语句来修复它。

   Dim writer = XmlWriter.Create(stream, settings)
   

2. 第二个参数必须是你想要serialize的对象，即在这种情况下可能是dataItem。

   serializer.Serialize(writer, dataItem)
   

至于删除命名空间和注释，这里有一个解决方案：

Sub Test()
    Dim dataItem = New DataClass With {.Id = 5, .Name = "Test"}

    ' Serialize.
    Dim serializer As New XmlSerializer(GetType(DataClass))
    Dim sb As New StringBuilder()
    Using writer As New StringWriter(sb)
        serializer.Serialize(writer, dataItem)
    End Using

    Dim xml = RemoveNamespaces(sb.ToString())

    Console.WriteLine(xml)
End Sub

Private Function RemoveNamespaces(ByVal xml As String) As String
    Dim doc = New XmlDocument()
    doc.LoadXml(xml)

    ' This assumes that we have only a namespace attribute on the root element.
    doc.DocumentElement.Attributes.RemoveAll()

    Dim settings As New XmlWriterSettings With {.Indent = True, .OmitXmlDeclaration = True}
    Dim sb As New StringBuilder()
    Using stringWriter As New StringWriter(sb)
        Using writer = XmlWriter.Create(stringWriter, settings)
            doc.WriteTo(writer)
        End Using
    End Using
    Return sb.ToString()
End Function

它正在使用这个测试类

Public Class DataClass
    Public Property Id As Integer
    Public Property Name As String
End Class