Question

Lets say i have a class

    [Serializable()]
public class Car
{
    public string model;
    public int year;
}

I serialize that to disk named “car.xx”. Then i add a property to my Car class so it will be like this:

    [Serializable()]
public class Car
{
    public string model;
    public int year;
    public string colour;
}

Then i deserialize “car.xx” ( that contains 2 fields ) to my current car class that contains 3 fields, which will make the “colour” property of our Car class null.

How do i set that “new properties” dont get null values? Setting them in the constructor wont help.

I am using BinaryFormatter serializer

I want string values that are null to be replaced with “”

Answer 1

if you are not using XmlSerializer then consider using OnDeserializedAttribute, OnSerializingAttribute, OnSerializedAttribute, and OnDeserializingAttribute attributes

see this.

like:

[Serializable()]
public class Car
{
    public string colour;
    public string model;
    public int year;

    [OnDeserialized()]
    internal void OnDeserializedMethod(StreamingContext context)
    {
       if (colour == null)
       {
           colour = string.Empty;
       }
    }
}