Cannot convert null literal to non-nullable reference type.

Cannot convert null literal to non-nullable reference type.

Nullability of reference types in type of parameter 'x' of 'int VnPayCompare.Compare(string x, string y)' doesn't match implicitly implemented member 'int IComparer<string>.Compare(string? x, string? y)' (possibly because of nullability attributes).

Nullability of reference types in type of parameter 'y' of 'int VnPayCompare.Compare(string x, string y)' doesn't match implicitly implemented member 'int IComparer<string>.Compare(string? x, string? y)' (possibly because of nullability attributes).

Nullability of type of parameter 'exception' doesn't match overridden member (possibly because of nullability attributes).

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

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

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

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