从Array

Question

VB.net编写XML我有一个简单的类

Public Class Employee 

     Public _id As Integer 
     Public _firstName As String 
     Public _lastName As String 
     Public _location As String 

     Public Sub New(ByVal id As Integer, ByVal firstName As String, ByVal lastName As String, location As String) 
      _id = id 
      _firstName = firstName 
      _lastName = lastName 
      _location = location 
     End Sub 

    End Class 

我已经定义了一些示例数据：

Dim Employees(2) As Employee 
     Employees(0) = New Employee(42, "John", "Smith", "NewYork") 
     Employees(1) = New Employee(64, "John2", "Smith2", "Budapest") 
     Employees(2) = New Employee(62, "John3", "Smith3", "NewYork") 

我想将其写入到XML文件如下：

<?xml version="1.0" encoding="utf-8"?> 
<Employees> 
    <NewYork> 
    <Employee> 
     <ID>42</ID> 
     <FirstName>John</FirstName> 
     <LastName>Smith</LastName> 
    </Employee> 
    <Employee> 
     <ID>62</ID> 
     <FirstName>John3</FirstName> 
     <LastName>Smith3</LastName> 
    </Employee> 
    </NewYork> 
    <Budapest> 
    <Employee> 
     <ID>64</ID> 
     <FirstName>Jonh2</FirstName> 
     <LastName>Smith2</LastName> 
    </Employee> 
    </Budapest> 
</Employees> 

对于编写XML，我有以下代码：

Sub XMLWrite() 

     Dim Employees(2) As Employee 
     Employees(0) = New Employee(42, "John", "Smith", "NewYork") 
     Employees(1) = New Employee(64, "John2", "Smith2", "Budapest") 
     Employees(2) = New Employee(62, "John3", "Smith3", "NewYork") 

     ' Create XmlWriterSettings. 
     Dim settings As XmlWriterSettings = New XmlWriterSettings() 
     settings.Indent = True 

     ' Create XmlWriter. 
     Using writer As XmlWriter = XmlWriter.Create("C:\employees.xml", settings) 
      ' Begin writing. 
      writer.WriteStartDocument() 
      writer.WriteStartElement("Employees") ' Root. 
      writer.WriteStartElement("NewYork") 
      Dim empl As Employee 
      For Each empl In Employees 

       If empl._location = "NewYork" Then 
        writer.WriteStartElement("Employee") 
        writer.WriteElementString("ID", empl._id.ToString) 
        writer.WriteElementString("FirstName", empl._firstName) 
        writer.WriteElementString("LastName", empl._lastName) 

        writer.WriteEndElement() 
       End If 
      Next 
      writer.WriteEndElement() 

      writer.WriteStartElement("Budapest") 



      Dim empl2 As Employee 
      For Each empl2 In Employees 
       If empl2._location = "Budapest" Then 
        writer.WriteStartElement("Employee") 
        writer.WriteElementString("ID", empl2._id.ToString) 
        writer.WriteElementString("FirstName", empl2._firstName) 
        writer.WriteElementString("LastName", empl2._lastName) 

        writer.WriteEndElement() 
       End If 

      Next 


      writer.WriteEndElement() 
      writer.WriteEndElement() 
      writer.WriteEndDocument() 


     End Using 


    End Sub 

我有超过1000个用户拥有30多个位置，我不想在代码中手动定义每个位置。我想转换它，代码应该确定位置，并在正确的位置父元素下创建xml元素。谢谢。

Answer 1

使用XML LINQ

Imports System.Xml 
Imports System.Xml.Linq 
Module Module1 

    Sub Main() 
     Dim Employees(2) As Employee 
     Employees(0) = New Employee(42, "John", "Smith", "NewYork") 
     Employees(1) = New Employee(64, "John2", "Smith2", "Budapest") 
     Employees(2) = New Employee(62, "John3", "Smith3", "NewYork") 


     Dim header As String = "<?xml version=""1.0"" encoding=""utf-8""?><Employees></Employees>" 

     Dim doc As XDocument = XDocument.Parse(header) 
     Dim root As XElement = doc.Root 
     Dim bornGroups = Employees.GroupBy(Function(x) x.born).ToList() 

     For Each group In bornGroups 
      Dim newCity As XElement = New XElement(group.Key) 
      root.Add(newCity) 

      For Each _employee In group 
       Dim newEmployee As XElement = New XElement("Employee", New List(Of XElement)({ _ 
        New XElement("ID", _employee.id), 
        New XElement("FirstName", _employee.firstName), 
        New XElement("LastName", _employee.lastName) 
        })) 
       newCity.Add(newEmployee) 
      Next _employee 

     Next group 
    End Sub 

End Module 


Public Class Employee 
    Public id As Integer 
    Public firstName As String 
    Public lastName As String 
    Public born As String 

    Sub New(id As Integer, firstName As String, lastName As String, born As String) 
     Me.id = id 
     Me.firstName = firstName 
     Me.lastName = lastName 
     Me.born = born 
    End Sub 


End Class