Is there a shorthand way to return values that might be null?

Using null-coalescing operator ( ?? ):

get 
{ 
     _rows = _rows ?? new List<Row>(); 
     return _rows; 
}

OR (less readable):

get { return _rows ?? (_rows = new List<Row>()); }

The ?? operator is called the null-coalescing operator. It returns the
left-hand operand if the operand is not null; otherwise it returns the
right hand operand.