private void NStaffHomeBtn_Click(object sender, EventArgs e)
        {
            LibraryAddBook add = new LibraryAddBook();

            this.Hide();
            add.ShowDialog();
        }
        private void Add_Click(object sender, EventArgs e)
        {
            LibraryAddBook libraryAddBook = new LibraryAddBook();

            this.Hide();
            libraryAddBook.ShowDialog();
        }