XmlRootAttribute.IsNullable 属性

定义

命名空间:

System.Xml.Serialization

程序集:

netstandard.dll, System.Xml.ReaderWriter.dll

Source:

XmlRootAttribute.cs

获取或设置一个值，该值指示必须XmlSerializer序列化设置为属性nullxsi:nil集的成员true。

public:
 property bool IsNullable { bool get(); void set(bool value); };

public bool IsNullable { get; set; }

member this.IsNullable : bool with get, set

Public Property IsNullable As Boolean

属性值

Boolean

如果生成属性，则为 ;否则为 。

示例

下面的示例序列化名为 Group.. 该示例将应用于 XmlRootAttribute 类，并将属性设置为 IsNullablefalse.

using System;
using System.IO;
using System.Xml.Serialization;
using System.Xml;

// Apply the XmlRootAttribute and set the IsNullable property to false.
[XmlRoot(IsNullable = false)]
public class Group
{
   public string Name;
}

public class Run
{
   public static void Main()
   {
   Console.WriteLine("Running");
      Run test = new Run();
      test.SerializeObject("NullDoc.xml");
   }

   public void SerializeObject(string filename)
   {
      XmlSerializer s = new XmlSerializer(typeof(Group));

      // Writing the file requires a TextWriter.
      TextWriter writer = new StreamWriter(filename);

      // Create the object to serialize.
      Group mygroup = null;

      // Serialize the object, and close the TextWriter.
      s.Serialize(writer, mygroup);
      writer.Close();
   }
}

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


' Apply the XmlRootAttribute and set the IsNullable property to false.
<XmlRoot(IsNullable := False)> _
Public Class Group
    Public Name As String
End Class


Public Class Run
    
    Public Shared Sub Main()
        Console.WriteLine("Running")
        Dim test As New Run()
        test.SerializeObject("NullDoc.xml")
    End Sub     
    
    Public Sub SerializeObject(ByVal filename As String)
        Dim s As New XmlSerializer(GetType(Group))
        
        ' Writing the file requires a TextWriter.
        Dim writer As New StreamWriter(filename)
        
        ' Create the object to serialize.
        Dim mygroup As Group = Nothing
        
        ' Serialize the object, and close the TextWriter.
        s.Serialize(writer, mygroup)
        writer.Close()
    End Sub
End Class

注解

结构的 XML 架构规范允许 XML 文档显式指示元素的内容缺失。 此类元素包含设置为 true.xsi:nil. 有关详细信息，请参阅 XML 架构第 1 部分：结构第二版。

IsNullable如果该属性设置为true，则会xsi:nil生成属性，如以下 XML 中所示：

<?xml version="1.0" encoding="utf-8"?>
<Group xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema" xsi:nil="true" />

IsNullable如果该属性是false，则会创建一个空元素，如以下代码所示：

<?xml version="1.0" encoding="utf-8"?>
<Group xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema" />