Dereference of a possibly null reference.

Non-nullable property 'Nav' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Id' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.

Non-nullable property 'Nav' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Cannot convert null literal to non-nullable reference type.

Cannot convert null literal to non-nullable reference type.

Cannot convert null literal to non-nullable reference type.

Cannot convert null literal to non-nullable reference type.