Page 157 - CSharp/C#

Then you need to let your IFormatter know about the surrogates by defining and initializing a
SurrogateSelector and assigning it to your IFormatter

var surrogateSelector = new SurrogateSelector();
surrogateSelector.AddSurrogate(typeof(Item), new StreamingContext(StreamingContextStates.All),
new ItemSurrogate());
var binaryFormatter = new BinaryFormatter
{
SurrogateSelector = surrogateSelector
};

Even if the class is not marked serializable.

//this class is not serializable
public class Item
{
private string _name;

public string Name
{
get { return _name; }
set { _name = value; }
}
}

The complete solution

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

namespace BinarySerializationExample
{
class Item
{
private string _name;

public string Name
{
get { return _name; }
set { _name = value; }
}
}

class ItemSurrogate : ISerializationSurrogate
{
public void GetObjectData(object obj, SerializationInfo info, StreamingContext
context)
{
var item = (Item)obj;
info.AddValue("_name", item.Name);
}

public object SetObjectData(object obj, SerializationInfo info, StreamingContext
context, ISurrogateSelector selector)
{
var item = (Item)obj;

https://riptutorial.com/ 103