NonSerializedAttribute Class

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Source:

NonSerializedAttribute.cs

Indicates that a field of a serializable class should not be serialized. This class cannot be inherited.

public ref class NonSerializedAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Field, Inherited=false)]
public sealed class NonSerializedAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Field, Inherited=false)>]
type NonSerializedAttribute = class
    inherit Attribute

Public NotInheritable Class NonSerializedAttribute
Inherits Attribute

Inheritance

Object

Attribute

NonSerializedAttribute

Attributes

AttributeUsageAttribute

Examples

The following example demonstrates SOAP serialization of an object marked with the SerializableAttribute attribute, and the behavior of a field marked with the NonSerializedAttribute in the serialized object.

Note

The code uses the SoapFormatter class to serialize the object. The class is found in the system.runtime.serialization.formatters.soap.dll file, which is not loaded by default into a project. To run the code, you must add a reference to the DLL to your project.

#using <system.dll>
#using <system.messaging.dll>
#using <System.Runtime.Serialization.Formatters.Soap.dll>

using namespace System;
using namespace System::IO;
using namespace System::Runtime::Serialization::Formatters::Soap;

// A test object that needs to be serialized.

[Serializable]
ref class TestSimpleObject
{
private:
   int member1;
   String^ member2;
   String^ member3;
   double member4;

public:

   // A field that is not serialized.

   [NonSerialized]
   String^ member5;
   TestSimpleObject()
   {
      member1 = 11;
      member2 = "hello";
      member3 = "hello";
      member4 = 3.14159265;
      member5 = "hello world!";
   }

   void Print()
   {
      Console::WriteLine( "member1 = ' {0}'", member1 );
      Console::WriteLine( "member2 = ' {0}'", member2 );
      Console::WriteLine( "member3 = ' {0}'", member3 );
      Console::WriteLine( "member4 = ' {0}'", member4 );
      Console::WriteLine( "member5 = ' {0}'", member5 );
   }

};

int main()
{
   // Creates a new TestSimpleObject object.
   TestSimpleObject^ obj = gcnew TestSimpleObject;
   Console::WriteLine( "Before serialization the Object* contains: " );
   obj->Print();

   // Opens a file and serializes the object into it in binary format.
   Stream^ stream = File::Open( "data.xml", FileMode::Create );
   SoapFormatter^ formatter = gcnew SoapFormatter;

   formatter->Serialize( stream, obj );
   stream->Close();

   // Empties obj.
   obj = nullptr;

   // Opens file S"data.xml" and deserializes the object from it.
   stream = File::Open( "data.xml", FileMode::Open );
   formatter = gcnew SoapFormatter;

   obj = dynamic_cast<TestSimpleObject^>(formatter->Deserialize( stream ));
   stream->Close();
   Console::WriteLine( "" );
   Console::WriteLine( "After deserialization the object contains: " );
   obj->Print();
}

using System;
using System.IO;
using System.Runtime.Serialization.Formatters.Soap;

public class Test {
   public static void Main()  {

      // Creates a new TestSimpleObject object.
      TestSimpleObject obj = new TestSimpleObject();

      Console.WriteLine("Before serialization the object contains: ");
      obj.Print();

      // Opens a file and serializes the object into it in binary format.
      Stream stream = File.Open("data.xml", FileMode.Create);
      SoapFormatter formatter = new SoapFormatter();

      formatter.Serialize(stream, obj);
      stream.Close();

      // Empties obj.
      obj = null;

      // Opens file "data.xml" and deserializes the object from it.
      stream = File.Open("data.xml", FileMode.Open);
      formatter = new SoapFormatter();

      obj = (TestSimpleObject)formatter.Deserialize(stream);
      stream.Close();

      Console.WriteLine("");
      Console.WriteLine("After deserialization the object contains: ");
      obj.Print();
   }
}

// A test object that needs to be serialized.
[Serializable()]
public class TestSimpleObject  {

    public int member1;
    public string member2;
    public string member3;
    public double member4;

    // A field that is not serialized.
    [NonSerialized()] public string member5;

    public TestSimpleObject() {

        member1 = 11;
        member2 = "hello";
        member3 = "hello";
        member4 = 3.14159265;
        member5 = "hello world!";
    }

    public void Print() {

        Console.WriteLine("member1 = '{0}'", member1);
        Console.WriteLine("member2 = '{0}'", member2);
        Console.WriteLine("member3 = '{0}'", member3);
        Console.WriteLine("member4 = '{0}'", member4);
        Console.WriteLine("member5 = '{0}'", member5);
    }
}

open System
open System.IO
open System.Runtime.Serialization.Formatters.Soap

// A test object that needs to be serialized.
[<Serializable>]
type TestSimpleObject() =
    let member1 = 11
    let member2 = "hello"
    let member3 = "hello"
    let member4 = 3.14159265

    // A field that is not serialized.
    [<NonSerialized>]
    let member5 = "hello world!"

    member _.Print() =
        printfn $"member1 = '{member1}'"
        printfn $"member2 = '{member2}'"
        printfn $"member3 = '{member3}'"
        printfn $"member4 = '{member4}'"
        printfn $"member5 = '{member5}'"

[<EntryPoint>]
let main _ =
    // Creates a new TestSimpleObject object.
    let obj = TestSimpleObject()

    printfn "Before serialization the object contains: "
    obj.Print()

    // Opens a file and serializes the object into it in binary format.
    let stream = File.Open("data.xml", FileMode.Create)
    let formatter = SoapFormatter()

    formatter.Serialize(stream, obj)
    stream.Close()

    // Opens file "data.xml" and deserializes the object from it.
    let stream = File.Open("data.xml", FileMode.Open)
    let formatter = new SoapFormatter()

    let obj = formatter.Deserialize stream :?> TestSimpleObject
    stream.Close()

    printfn "\nAfter deserialization the object contains: "
    obj.Print()
    0

Imports System.IO
Imports System.Runtime.Serialization
Imports System.Runtime.Serialization.Formatters.Soap




Public Class Test
   
   Public Shared Sub Main()
      
      ' Creates a new TestSimpleObject object.
      Dim obj As New TestSimpleObject()
      
      Console.WriteLine("Before serialization the object contains: ")
      obj.Print()
      
      ' Opens a file and serializes the object into it in binary format.
      Dim stream As Stream = File.Open("data.xml", FileMode.Create)
      Dim formatter As New SoapFormatter()
      


      formatter.Serialize(stream, obj)
      stream.Close()
      
      ' Empties obj.
      obj = Nothing
      
      ' Opens file "data.xml" and deserializes the object from it.
      stream = File.Open("data.xml", FileMode.Open)
      formatter = New SoapFormatter()



      obj = CType(formatter.Deserialize(stream), TestSimpleObject)
      stream.Close()
      
      Console.WriteLine("")
      Console.WriteLine("After deserialization the object contains: ")
      obj.Print()

   End Sub

End Class


' A test object that needs to be serialized.
<Serializable()> Public Class TestSimpleObject
   
   Public member1 As Integer
   Public member2 As String
   Public member3 As String
   Public member4 As Double
   
   ' A member that is not serialized.
   <NonSerialized()> Public member5 As String  
  
   
   Public Sub New()     
      member1 = 11
      member2 = "hello"
      member3 = "hello"
      member4 = 3.14159265
      member5 = "hello world!"
   End Sub
      
   
   Public Sub Print()      
      Console.WriteLine("member1 = '{0}'", member1)
      Console.WriteLine("member2 = '{0}'", member2)
      Console.WriteLine("member3 = '{0}'", member3)
      Console.WriteLine("member4 = '{0}'", member4)
      Console.WriteLine("member5 = '{0}'", member5)
   End Sub

End Class

Remarks

When using the BinaryFormatter or SoapFormatter classes to serialize an object, use the NonSerializedAttribute attribute to prevent a field from being serialized. For example, you can use this attribute to prevent the serialization of sensitive data.

The target objects for the NonSerializedAttribute attribute are public and private fields of a serializable class. By default, classes are not serializable unless they are marked with SerializableAttribute. During the serialization process all the public and private fields of a class are serialized by default. Fields marked with NonSerializedAttribute are excluded during serialization. If you are using the XmlSerializer class to serialize an object, use the XmlIgnoreAttribute class to get the same functionality. Alternatively, implement the ISerializable interface to explicitly control the serialization process. Note that classes that implement ISerializable must still be marked with SerializableAttribute.

To apply the NonSerializedAttribute class to an event, set the attribute location to field, as shown in the following C# code.

[field:NonSerializedAttribute()]   
public event ChangedEventHandler Changed;  

If a field is not serialized, but it still requires a default value that must be supplied after deserialization, you can create a method that supplies the field with a value, then apply the OnDeserializedAttribute to the method.

For more information about using attributes, see Attributes.

Note

This attribute does not apply to JSON serialization using System.Text.Json.

Constructors

NonSerializedAttribute()

Initializes a new instance of the NonSerializedAttribute class.

Properties

TypeId

When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)

Methods

Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
GetHashCode()	Returns the hash code for this instance. (Inherited from Attribute)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
Match(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

See also

• SerializableAttribute
• Attribute
• ISerializable
• Extending Metadata Using Attributes
• XML and SOAP Serialization