Question

我正在构建一个VB.net控制台应用程序，该应用程序读取SQL并构建XML。我正在使用Visual Studio 2013和.Net Framework 4.5。我的代码如下：

Private _namespaceDefault as String = ""AAIS_Homeowners_Premium""

Dim writer As XmlWriter = XmlWriter.Create(policyDir & "\Policy.xml", settings)
writer.WriteStartDocument()
writer.WriteStartElement("ROOT")
writer.WriteAttributeString("xmlns", "", Nothing, _namespaceDefault)

我也尝试过：

writer.WriteAttributeString("xmlns", _namespaceDefault)

当我运行程序时，出现以下错误：“前缀”不能在同一开始元素标记中从”重新定义为“ AAIS_Homeowners_Premium”。” xmlns值不是URL，而是用于验证的Schema文件的名称。

如何将xmlns属性值添加到开始元素？ XML应该如下所示：

<?xml version="1.0"?>
<ROOT xmlns="AAIS_Homeowners_Premium">
    <Company>12345</Company>
    <LOB>ABCDEFG</LOB>
    <Policies>
        <Policy>
            <PolicyNumber>6789</PolicyNumber>
            <Date>01/24/2018</Date>
        </Policy>
        <Policy>
            <PolicyNumber>2345</PolicyNumber>
            <Date>03/17/2018</Date>
        </Policy>
    </Policies>
</ROOT>

谢谢。

Answer 1

这是一些代码和输出。应该是您要寻找的：

代码：

        Dim _namespaceDefault As String = "AAIS_Homeowners_Premium"

        Dim doc As System.Xml.XmlDocument
        Dim elm As System.Xml.XmlNode
        Dim elmSub As System.Xml.XmlNode
        Dim elmMain As Xml.XmlNode

        doc = New Xml.XmlDocument

        elmMain = doc.CreateElement("ROOT")
        elmSub = elmMain.Attributes.Append(doc.CreateAttribute("xmlns"))
        elmSub.Value = _namespaceDefault

        elm = elmMain.AppendChild(doc.CreateElement("FirstNode"))
        elm.InnerText = "12345"

        elm = elmMain.AppendChild(doc.CreateElement("SecondNode"))
        elm.InnerText = "ABCDEFG"

        doc.AppendChild(doc.CreateXmlDeclaration("1.0", "UTF-8", "no"))
        doc.AppendChild(elmMain)
        doc.Save("Policy.xml")

和结果：

    <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    <ROOT xmlns="AAIS_Homeowners_Premium">
      <FirstNode>12345</FirstNode>
      <SecondNode>ABCDEFG</SecondNode>
    </ROOT>

Answer 2

这是使用代码进行操作的方式（尽管两者都很有用）：

        Dim _namespaceDefault As String = "AAIS_Homeowners_Premium"

        Dim writer As Xml.XmlWriter = Xml.XmlWriter.Create("Policy.xml", settings)
        writer.WriteStartDocument()
        writer.WriteStartElement("ROOT", _namespaceDefault)
        writer.WriteElementString("Company", "12345")
        writer.WriteElementString("LOB", "ABCDEFG")
        writer.WriteStartElement("Policies")
        writer.WriteStartElement("Policy")
        writer.WriteElementString("PolicyNumber", "6789")
        writer.WriteElementString("Date", "01/24/2018")
        writer.WriteEndElement()  'Policy
        writer.WriteStartElement("Policy")
        writer.WriteElementString("PolicyNumber", "2345")
        writer.WriteElementString("Date", "03/17/2018")
        writer.WriteEndElement()  'Policy
        writer.WriteEndElement()  'Policies
        writer.WriteEndElement()  'ROOT
        writer.WriteEndDocument()

        writer.Close()

        writer = Nothing

，输出为

    <?xml version="1.0" encoding="utf-8"?>
    <ROOT xmlns="AAIS_Homeowners_Premium">
      <Company>12345</Company>
      <LOB>ABCDEFG</LOB>
      <Policies>
        <Policy>
          <PolicyNumber>6789</PolicyNumber>
          <Date>01/24/2018</Date>
        </Policy>
        <Policy>
          <PolicyNumber>2345</PolicyNumber>
          <Date>03/17/2018</Date>
        </Policy>
      </Policies>
    </ROOT>

将xmlns属性添加到开始元素VB.Net

2 个答案: