Десериализация BinaryFormatter. Key всегда равен null. Как считать ключ

BinaryFormatter binaryFormatter = new BinaryFormatter();
FileStream fileStream = new FileStream(LogicForm.path, FileMode.Create, FileAccess.Write);
binaryFormatter.Serialize((Stream) fileStream, (object) new LogicSerializationWrapper(this.logicList, this.lines)
{
   Key = this.currentKey
});

BinaryFormatter binaryFormatter = new BinaryFormatter();
FileStream fileStream = new FileStream(file, FileMode.Open);
LogicSerializationWrapper serializationWrapper = (LogicSerializationWrapper)binaryFormatter.Deserialize(fileStream);
fileStream.Close();

[Serializable()]
  public class LogicSerializationWrapper
  {
    private string key;
    private LogicObject[,] array;
    private List<LogicLine> list;
 
    public string Key
    {
      get
      {
        return this.key;
      }
      set
      {
        this.key = value;
      }
    }
 
    public LogicObject[,] Array
    {
      get
      {
        return this.array;
      }
      set
      {
        this.array = value;
      }
    }
 
    public List<LogicLine> List
    {
      get
      {
        return this.list;
      }
      set
      {
        this.list = value;
      }
    }
 
    protected LogicSerializationWrapper(LogicObject[,] array, List<LogicLine> list)
    {
        this.array = array;
        this.list = list;
    }
  }