BinaryFormatter Class

Definition

Serializes and deserializes an object, or an entire graph of connected objects, in binary format.

[System.Runtime.InteropServices.ComVisible(true)]
public sealed class BinaryFormatter : System.Runtime.Remoting.Messaging.IRemotingFormatter
Inheritance
BinaryFormatter
Attributes
Implements

Inherited Members

System.Object

Examples

using namespace System;
using namespace System::IO;
using namespace System::Collections;
using namespace System::Runtime::Serialization::Formatters::Binary;
using namespace System::Runtime::Serialization;
ref class App
{
public:
   static void Serialize()
   {
      
      // Create a hashtable of values that will eventually be serialized.
      Hashtable^ addresses = gcnew Hashtable;
      addresses->Add( "Jeff", "123 Main Street, Redmond, WA 98052" );
      addresses->Add( "Fred", "987 Pine Road, Phila., PA 19116" );
      addresses->Add( "Mary", "PO Box 112233, Palo Alto, CA 94301" );
      
      // To serialize the hashtable (and its keys/values),  
      // you must first open a stream for writing. 
      // In this case we will use a file stream.
      FileStream^ fs = gcnew FileStream( "DataFile.dat",FileMode::Create );
      
      // Construct a BinaryFormatter and use it to serialize the data to the stream.
      BinaryFormatter^ formatter = gcnew BinaryFormatter;
      try
      {
         formatter->Serialize( fs, addresses );
      }
      catch ( SerializationException^ e ) 
      {
         Console::WriteLine( "Failed to serialize. Reason: {0}", e->Message );
         throw;
      }
      finally
      {
         fs->Close();
      }

   }

   static void Deserialize()
   {
      
      // Declare the hashtable reference.
      Hashtable^ addresses = nullptr;
      
      // Open the file containing the data that we want to deserialize.
      FileStream^ fs = gcnew FileStream( "DataFile.dat",FileMode::Open );
      try
      {
         BinaryFormatter^ formatter = gcnew BinaryFormatter;
         
         // Deserialize the hashtable from the file and 
         // assign the reference to our local variable.
         addresses = dynamic_cast<Hashtable^>(formatter->Deserialize( fs ));
      }
      catch ( SerializationException^ e ) 
      {
         Console::WriteLine( "Failed to deserialize. Reason: {0}", e->Message );
         throw;
      }
      finally
      {
         fs->Close();
      }

      
      // To prove that the table deserialized correctly, display the keys/values.
      IEnumerator^ myEnum = addresses->GetEnumerator();
      while ( myEnum->MoveNext() )
      {
         DictionaryEntry ^ de = safe_cast<DictionaryEntry ^>(myEnum->Current);
         Console::WriteLine( " {0} lives at {1}.", de->Key, de->Value );
      }
   }

};


[STAThread]
int main()
{
   App::Serialize();
   App::Deserialize();
   return 0;
}

using System;
using System.IO;
using System.Collections;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization;

public class App 
{
    [STAThread]
    static void Main() 
    {
        Serialize();
        Deserialize();
    }

    static void Serialize() 
    {
        // Create a hashtable of values that will eventually be serialized.
        Hashtable addresses = new Hashtable();
        addresses.Add("Jeff", "123 Main Street, Redmond, WA 98052");
        addresses.Add("Fred", "987 Pine Road, Phila., PA 19116");
        addresses.Add("Mary", "PO Box 112233, Palo Alto, CA 94301");

        // To serialize the hashtable and its key/value pairs,  
        // you must first open a stream for writing. 
        // In this case, use a file stream.
        FileStream fs = new FileStream("DataFile.dat", FileMode.Create);

        // Construct a BinaryFormatter and use it to serialize the data to the stream.
        BinaryFormatter formatter = new BinaryFormatter();
        try 
        {
            formatter.Serialize(fs, addresses);
        }
        catch (SerializationException e) 
        {
            Console.WriteLine("Failed to serialize. Reason: " + e.Message);
            throw;
        }
        finally 
        {
            fs.Close();
        }
    }

   
    static void Deserialize() 
    {
        // Declare the hashtable reference.
        Hashtable addresses  = null;

        // Open the file containing the data that you want to deserialize.
        FileStream fs = new FileStream("DataFile.dat", FileMode.Open);
        try 
        {
            BinaryFormatter formatter = new BinaryFormatter();

            // Deserialize the hashtable from the file and 
            // assign the reference to the local variable.
            addresses = (Hashtable) formatter.Deserialize(fs);
        }
        catch (SerializationException e) 
        {
            Console.WriteLine("Failed to deserialize. Reason: " + e.Message);
            throw;
        }
        finally 
        {
            fs.Close();
        }

        // To prove that the table deserialized correctly, 
        // display the key/value pairs.
        foreach (DictionaryEntry de in addresses) 
        {
            Console.WriteLine("{0} lives at {1}.", de.Key, de.Value);
        }
    }
}
Imports System.IO
Imports System.Collections
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization


Module App

    Sub Main()
        Serialize()
        Deserialize()
    End Sub

    Sub Serialize()

        ' Create a hashtable of values that will eventually be serialized.
        Dim addresses As New Hashtable
        addresses.Add("Jeff", "123 Main Street, Redmond, WA 98052")
        addresses.Add("Fred", "987 Pine Road, Phila., PA 19116")
        addresses.Add("Mary", "PO Box 112233, Palo Alto, CA 94301")

        ' To serialize the hashtable (and its key/value pairs),  
        ' you must first open a stream for writing. 
        ' In this case, use a file stream.
        Dim fs As New FileStream("DataFile.dat", FileMode.Create)

        ' Construct a BinaryFormatter and use it to serialize the data to the stream.
        Dim formatter As New BinaryFormatter
        Try
            formatter.Serialize(fs, addresses)
        Catch e As SerializationException
            Console.WriteLine("Failed to serialize. Reason: " & e.Message)
            Throw
        Finally
            fs.Close()
        End Try
    End Sub



    Sub Deserialize()
        ' Declare the hashtable reference.
        Dim addresses As Hashtable = Nothing

        ' Open the file containing the data that you want to deserialize.
        Dim fs As New FileStream("DataFile.dat", FileMode.Open)
        Try
            Dim formatter As New BinaryFormatter

            ' Deserialize the hashtable from the file and 
            ' assign the reference to the local variable.
            addresses = DirectCast(formatter.Deserialize(fs), Hashtable)
        Catch e As SerializationException
            Console.WriteLine("Failed to deserialize. Reason: " & e.Message)
            Throw
        Finally
            fs.Close()
        End Try

        ' To prove that the table deserialized correctly, 
        ' display the key/value pairs.
        Dim de As DictionaryEntry
        For Each de In addresses
            Console.WriteLine("{0} lives at {1}.", de.Key, de.Value)
        Next
    End Sub
End Module

Remarks

The SoapFormatter and BinaryFormatter classes implement the IRemotingFormatter interface to support remote procedure calls (RPCs), and the IFormatter interface (inherited by the IRemotingFormatter) to support serialization of a graph of objects. The SoapFormatter class also supports RPCs with ISoapMessage objects, without using the IRemotingFormatter functionality.

During RPCs, the IRemotingFormatter interface allows the specification of two separate object graphs: the graph of objects to serialize, and an additional graph that contains an array of header objects that convey information about the remote function call (for example, transaction ID or a method signature).

RPCs that use the BinaryFormatter separate into two distinct parts: method calls, which are sent to the server with the remote object that contains the method called, and method responses, which are sent from the server to the client with the status and response information from the called method.

During serialization of a method call the first object of the object graph must support the IMethodCallMessage interface. To deserialize a method call, use the Deserialize method with the HeaderHandler parameter. The remoting infrastructure uses the HeaderHandler delegate to produce an object that supports the ISerializable interface. When the BinaryFormatter invokes the HeaderHandler delegate, it returns the URI of the remote object with the method that is being called. The first object in the graph returned supports the IMethodCallMessage interface.

The serialization procedure for a method response is identical to that of a method call, except the first object of the object graph must support the IMethodReturnMessage interface. To deserialize a method response, use the DeserializeMethodResponse method. To save time, details about the caller object are not sent to the remote object during the method call. These details are instead obtained from the original method call, which is passed to the DeserializeMethodResponse method in the IMethodCallMessage parameter. The first object in the graph returned by the DeserializeMethodResponse method supports the IMethodReturnMessage interface.

Important

Using binary serialization to deserialize untrusted data can lead to security risks. For more information, see Untrusted Data Security Risks.

Unpaired Surrogates

Any unpaired surrogate characters are lost in binary serialization. For example, the following string contains a high surrogate Unicode character (\ud800) in between the two Test words:

Test\ud800Test

Before serialization, the byte array of the string is as follows:

Byte Array Value Character
84 T
101 e
115 s
116 t
55296 \ud800
84 T
101 e
115 s
116 t

After deserialization, the high surrogate Unicode character is lost:

Byte Array Value Character
84 T
101 e
115 s
116 t
84 T
101 e
115 s
116 t

Constructors

BinaryFormatter()

Initializes a new instance of the BinaryFormatter class with default values.

BinaryFormatter(ISurrogateSelector, StreamingContext)

Initializes a new instance of the BinaryFormatter class with a given surrogate selector and streaming context.

Properties

AssemblyFormat

Gets or sets the behavior of the deserializer with regards to finding and loading assemblies.

Binder

Gets or sets an object of type SerializationBinder that controls the binding of a serialized object to a type.

Context

Gets or sets the StreamingContext for this formatter.

FilterLevel

Gets or sets the TypeFilterLevel of automatic deserialization the BinaryFormatter performs.

SurrogateSelector

Gets or sets a ISurrogateSelector that controls type substitution during serialization and deserialization.

TypeFormat

Gets or sets the format in which type descriptions are laid out in the serialized stream.

Methods

Deserialize(Stream)

Deserializes the specified stream into an object graph.

Deserialize(Stream, HeaderHandler)

Deserializes the specified stream into an object graph. The provided HeaderHandler handles any headers in that stream.

DeserializeMethodResponse(Stream, HeaderHandler, IMethodCallMessage)

Deserializes a response to a remote method call from the provided Stream.

Serialize(Stream, Object)

Serializes the object, or graph of objects with the specified top (root), to the given stream.

Serialize(Stream, Object, Header[])

Serializes the object, or graph of objects with the specified top (root), to the given stream attaching the provided headers.

UnsafeDeserialize(Stream, HeaderHandler)

Deserializes the specified stream into an object graph. The provided HeaderHandler handles any headers in that stream.

UnsafeDeserializeMethodResponse(Stream, HeaderHandler, IMethodCallMessage)

Deserializes a response to a remote method call from the provided Stream.