The variable 'className' is declared but never used

Dereference of a possibly null reference.

Converting null literal or possible null value to non-nullable type.

Dereference of a possibly null reference.

Converting null literal or possible null value to non-nullable type.

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

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

Possible null reference return.

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.

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.