Ошибка в событии нажатия кнопки

 public partial class StudentTable : Window
    {
        public StudentTable()
        {
            InitializeComponent();
        }
        CourseWork.University0DataSetTableAdapters.StudentsTableAdapter university0DataSetStudentsTableAdapter;
        CourseWork.University0DataSet university0DataSet;
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
 
            university0DataSet = ((CourseWork.University0DataSet)(this.FindResource("university0DataSet")));
            CourseWork.University0DataSetTableAdapters.StudentsTableAdapter university0DataSetStudentsTableAdapter = new CourseWork.University0DataSetTableAdapters.StudentsTableAdapter();
            university0DataSetStudentsTableAdapter.Fill(university0DataSet.Students);
            System.Windows.Data.CollectionViewSource studentsViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("studentsViewSource")));
            studentsViewSource.View.MoveCurrentToFirst();
            university0DataSet.Students.StudentsRowChanged += new University0DataSet.StudentsRowChangeEventHandler(button2_Click);
            university0DataSet.Students.StudentsRowDeleted += new University0DataSet.StudentsRowChangeEventHandler(button2_Click);
        }
 
        private void button1_Click(object sender, RoutedEventArgs e)
        {
            AddStudentWindow x = new AddStudentWindow();
            x.Show();
        }
 
        private void button2_Click(object sender, University0DataSet.StudentsRowChangeEvent e)
        {
            university0DataSetStudentsTableAdapter.Update(university0DataSet.Students);
        }
    }