Nullability of reference types in type of parameter 'parameter' of 'bool RelayCommand.CanExecute(object parameter)' doesn't match implicitly implemented member 'bool ICommand.CanExecute(object? parameter)' (possibly because of nullability attributes).

Nullability of reference types in type of parameter 'parameter' of 'void RelayCommand.Execute(object parameter)' doesn't match implicitly implemented member 'void ICommand.Execute(object? parameter)' (possibly because of nullability attributes).

Nullability of reference types in type of 'event EventHandler RelayCommand.CanExecuteChanged' doesn't match implicitly implemented member 'event EventHandler? ICommand.CanExecuteChanged'.

Nullability of reference types in type of parameter 'parameter' of 'bool RelayCommandParams.CanExecute(object parameter)' doesn't match implicitly implemented member 'bool ICommand.CanExecute(object? parameter)' (possibly because of nullability attributes).

Nullability of reference types in type of parameter 'parameter' of 'void RelayCommandParams.Execute(object parameter)' doesn't match implicitly implemented member 'void ICommand.Execute(object? parameter)' (possibly because of nullability attributes).

Nullability of reference types in type of 'event EventHandler RelayCommandParams.CanExecuteChanged' doesn't match implicitly implemented member 'event EventHandler? ICommand.CanExecuteChanged'.

Non-nullable field '_viewModel' must contain a non-null value when exiting constructor. Consider declaring the field as nullable.

Non-nullable event 'CanExecuteChanged' must contain a non-null value when exiting constructor. Consider declaring the event as nullable.

Non-nullable event 'CanExecuteChanged' must contain a non-null value when exiting constructor. Consider declaring the event as nullable.