XmlArrayItemAttribute.Type Property

 

Gets or sets the type allowed in an array.

Namespace:   System.Xml.Serialization
Assembly:  System.Xml (in System.Xml.dll)

Public Property Type As Type

Property Value

Type: System.Type

A Type that is allowed in the array.

Use the Type property to specify an overridden type for a public field or public read/write property value.

If a field or property returns an array of type Object, apply multiple instances of the XmlArrayItemAttribute to the field or property. For each instance, set the Type property to a type of object that can be inserted into the array.

If an array contains only primitive types, you do not need to apply the XmlArrayItemAttribute. By default, the XmlSerializer generates a series of elements, each with the same element name, for each value, but the type of each element is set to the XML Schema data type. For example, the following code:

' Visual Basic code
Public Class Arrays
   Public XSDTypes ()As Object= New Object(){"one", 2, 3.0}
End Class
// C# code
public class MyArray{
   // No XmlArrayItemAttribute is applied.
   public object[] XSDTypes= new object[]{"one", 2, 3.2};
}

results in this XML:

<?xml version="1.0" encoding="utf-8"?>
<Arrays xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <XSDTypes>
    <Object xsi:type="xsd:string">one</Object>
    <Object xsi:type="xsd:int">2</Object>
    <Object xsi:type="xsd:double">3</Object>
  </XSDTypes>
</Arrays>

However, if you specify the Type property for each primitive type, the element name for each value is generated using the .NET type name. For example this code:

' Visual Basic code
Public Class Arrays
   <XmlArrayItem(GetType(String)), _
   XmlArrayItem(GetType(Integer)), _
   XmlArrayItem(GetType(Double))> _
   Public PrimitiveTypes () As Object = New Object(){"one", 2, 3.0}
End Class
// C# code
public class Arrays{
   [XmlArrayItem(typeof(string))]
   [XmlArrayItem(typeof(int))]
   [XmlArrayItem(typeof(double))]
   public object [] PrimitiveTypes = new object[]{"one", 2, 3.0};
}

results in this XML:

<?xml version="1.0" encoding="utf-8"?>
<Arrays xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <PrimitiveTypes>
    <string>one</string>
    <int>2</int>
    <double>3</double>
  </PrimitiveTypes>
</Arrays>

The following example serializes an array of objects. The field that returns the array is attributed with two XmlArrayItemAttribute instances. Each instance instructs the XmlSerializer to accept the specified Type in the array.

Imports System
Imports System.IO
Imports System.Xml.Serialization



Public Class Group
    ' The Type property instructs the XmlSerializer to accept both
    ' the Person and Manager types in the array. 
    <XmlArrayItem(Type := GetType(Manager)), _
     XmlArrayItem(Type := GetType(Person))> _
    Public Staff() As Person

End Class 'Group


Public Class Person
    Public Name As String
End Class 


Public Class Manager
    Inherits Person
    Public Rank As Integer
End Class 


Public Class Run

    Public Shared Sub Main()
        Dim test As New Run()
        test.SerializeOrder("TypeEx.xml")
    End Sub 


    Public Sub SerializeOrder(filename As String)
        ' Creates an XmlSerializer.
        Dim xSer As New XmlSerializer(GetType(Group))

        ' Creates the Group object, and two array items.
        Dim myGroup As New Group()

        Dim p1 As New Person()
        p1.Name = "Jacki"
        Dim p2 As New Manager()

        p2.Name = "Megan"
        p2.Rank = 2

        Dim myStaff() As Person =  {p1, p2}
        myGroup.Staff = myStaff

        ' Serializes the object, and closes the StreamWriter.
        Dim writer As New StreamWriter(filename)
        xSer.Serialize(writer, myGroup)
    End Sub 
End Class 'Run

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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