SurrogateSelector Class

Definition

Namespace:

System.Runtime.Serialization

Assembly:

System.Runtime.Serialization.Formatters.dll

Assembly:

mscorlib.dll

Assembly:

netstandard.dll

Assists formatters in selection of the serialization surrogate to delegate the serialization or deserialization process to.

public ref class SurrogateSelector : System::Runtime::Serialization::ISurrogateSelector

public class SurrogateSelector : System.Runtime.Serialization.ISurrogateSelector

[System.Runtime.InteropServices.ComVisible(true)]
public class SurrogateSelector : System.Runtime.Serialization.ISurrogateSelector

type SurrogateSelector = class
    interface ISurrogateSelector

[<System.Runtime.InteropServices.ComVisible(true)>]
type SurrogateSelector = class
    interface ISurrogateSelector

Public Class SurrogateSelector
Implements ISurrogateSelector

Inheritance

Object

SurrogateSelector

Derived

System.Workflow.ComponentModel.Serialization.ActivitySurrogateSelector

Attributes

ComVisibleAttribute

Implements

ISurrogateSelector

Examples

The following code example shows how to make a serialization surrogate class that knows how to properly serialize or deserialize a class that is not itself serializable. In addition, this example also shows how to recover from a SerializationException.

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

// This class is not serializable.
class Employee
    {
    public String name, address;

    public Employee(String name, String address)
    {
        this.name = name;
        this.address = address;
    }
}

// This class can manually serialize an Employee object.
sealed class EmployeeSerializationSurrogate : ISerializationSurrogate
{

    // Serialize the Employee object to save the object's name and address fields.
    public void GetObjectData(Object obj,
        SerializationInfo info, StreamingContext context)
    {

        var emp = (Employee) obj;
        info.AddValue("name", emp.name);
        info.AddValue("address", emp.address);
    }

    // Deserialize the Employee object to set the object's name and address fields.
    public Object SetObjectData(Object obj,
        SerializationInfo info, StreamingContext context,
        ISurrogateSelector selector)
    {

        var emp = (Employee) obj;
        emp.name = info.GetString("name");
        emp.address = info.GetString("address");
        return emp;
    }
}

public sealed class App
{
    static void Main()
    {
        // This sample uses the BinaryFormatter.
        IFormatter formatter = new BinaryFormatter();

        // Create a MemoryStream that the object will be serialized into and deserialized from.
        using (Stream stream = new MemoryStream())
        {
            // Create a SurrogateSelector.
            var ss = new SurrogateSelector();

            // Tell the SurrogateSelector that Employee objects are serialized and deserialized
            // using the EmployeeSerializationSurrogate object.
            ss.AddSurrogate(typeof(Employee),
            new StreamingContext(StreamingContextStates.All),
            new EmployeeSerializationSurrogate());

            // Associate the SurrogateSelector with the BinaryFormatter.
            formatter.SurrogateSelector = ss;

            try
            {
                // Serialize an Employee object into the memory stream.
                formatter.Serialize(stream, new Employee("Jeff", "1 Microsoft Way"));
            }
            catch (SerializationException e)
            {
                Console.WriteLine("Serialization failed: {0}", e.Message);
                throw;
            }

            // Rewind the MemoryStream.
            stream.Position = 0;

            try
            {
                // Deserialize the Employee object from the memory stream.
                var emp = (Employee) formatter.Deserialize(stream);

                // Verify that it all worked.
                Console.WriteLine("Name = {0}, Address = {1}", emp.name, emp.address);
            }
            catch (SerializationException e)
            {
                Console.WriteLine("Deserialization failed: {0}", e.Message);
                throw;
            }
        }
    }
}

// This code produces the following output.
//
// Name = Jeff, Address = 1 Microsoft Way

Remarks

A serialization surrogate gives the users an object that can handle the serialization requirements of a different object and can transform the serialized data if necessary.

Constructors

SurrogateSelector()

Initializes a new instance of the SurrogateSelector class.

Methods

AddSurrogate(Type, StreamingContext, ISerializationSurrogate)	Adds a surrogate to the list of checked surrogates.
ChainSelector(ISurrogateSelector)	Adds the specified ISurrogateSelector that can handle a particular object type to the list of surrogates.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetNextSelector()	Returns the next selector on the chain of selectors.
GetSurrogate(Type, StreamingContext, ISurrogateSelector)	Returns the surrogate for a particular type.
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
RemoveSurrogate(Type, StreamingContext)	Removes the surrogate associated with a given type.
ToString()	Returns a string that represents the current object. (Inherited from Object)