XmlArrayItemAttribute.Type 屬性

定義

命名空間:

System.Xml.Serialization

組件:

netstandard.dll, System.Xml.XmlSerializer.dll

來源:

XmlArrayItemAttribute.cs

取得或設定陣列中允許的型別。

public:
 property Type ^ Type { Type ^ get(); void set(Type ^ value); };

public Type? Type { get; set; }

member this.Type : Type with get, set

Public Property Type As Type

屬性值

Type

Type A是陣列中允許的。

範例

以下範例序列化一組物件。 回傳陣列的欄位被賦予兩個 XmlArrayItemAttribute 實例。 每個實例都會指示 接受 XmlSerializer 陣列中指定的 Type 條件。

using System;
using System.IO;
using 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 = typeof(Manager)),
   XmlArrayItem(Type=typeof(Person))]
   public Person[]Staff;
}

public class Person
{
   public string Name;
}

public class Manager:Person
{
   public int Rank;
}

public class Run
{
   public static void Main()
   {
      Run test = new Run();
      test.SerializeOrder("TypeEx.xml");
   }

   public void SerializeOrder(string filename)
   {
      // Creates an XmlSerializer.
      XmlSerializer xSer =
      new XmlSerializer(typeof(Group));

      // Creates the Group object, and two array items.
      Group myGroup = new Group();

      Person p1 = new Person();
      p1.Name = "Jacki";
      Manager p2 = new Manager();

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

      Person [] myStaff = {p1,p2};
      myGroup.Staff = myStaff;

      // Serializes the object, and closes the StreamWriter.
      TextWriter writer = new StreamWriter(filename);
      xSer.Serialize(writer, myGroup);
   }
}

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


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

備註

利用該 Type 屬性指定一個覆蓋的公共欄位類型或公共讀寫屬性值。

如果某欄位或屬性回傳的陣列為 Object，則該欄位或屬性對該欄位或屬性套 XmlArrayItemAttribute 用多個實例。 對每個實例，將屬性設定 Type 為可插入陣列的物件類型。

如果陣列只包含原始型別，則不需要套用 XmlArrayItemAttribute。 預設情況下，會 XmlSerializer 為每個值產生一系列元素，每個元素名稱相同，但每個元素的型別設定為 XML Schema 資料型別。 例如，下列程式碼：

' 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};
}

結果如下：

<?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>

然而，如果你為每個原始型別指定 Type 屬性，每個值的元素名稱會用 .NET 型別名稱產生。 例如這段程式碼：

' 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};
}

結果如下：

<?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>