Deserialization of an array always gives an array of nulls
Array deserializes first. Then all inner deserialization is done. So when you try to access items, they are null.
And idea to use [OnDeserialized] Attribute on some method, that builds up all other properies. And here is example:
[Serializable]public class TestClass : ISerializable{ private Trade[] _innerList; public ObservableCollection<Trade> List { get; set; } public TestClass() { } [OnDeserialized] private void SetValuesOnDeserialized(StreamingContext context) { this.List = new ObservableCollection<Trade>(_innerList); this._innerList = null; } protected TestClass(SerializationInfo info, StreamingContext context) { var value = info.GetValue("inner", typeof(Trade[])); this._innerList = (Trade[])value; } public void GetObjectData(SerializationInfo info, StreamingContext context) { info.AddValue("inner", this.List.ToArray()); }}