public AddStudentsWindow(StuListControl slc, string[] existingNumbers, string grade, string @class)
        {
            if (existingNumbers == null)
            {
                throw new ArgumentNullException(nameof(existingNumbers));
            }

            InitializeComponent();

            mStuList         = slc;
            mGrade           = grade;
            mClass           = @class;
            mExistingNumbers = existingNumbers;
        }
        public EditStudentsWindow(StuListControl slc, string[] existingNumbers, string grade, string @class, DataRow rowToEdit, int rowIndexToEdit)
        {
            if (existingNumbers == null)
            {
                throw new ArgumentNullException(nameof(existingNumbers));
            }

            if (rowToEdit == null)
            {
                throw new ArgumentNullException(nameof(rowToEdit));
            }

            InitializeComponent();

            mStuList         = slc;
            mGrade           = grade;
            mClass           = @class;
            mExistingNumbers = existingNumbers;
            mRowToEdit       = rowToEdit;
            mRowIndexToEdit  = rowIndexToEdit;
        }