private void btnAdd_Click(object sender, EventArgs e) { bool errorFound = false; if (string.IsNullOrEmpty(txt_boxName.Text) || string.IsNullOrEmpty(txt_boxStudentID.Text) || string.IsNullOrEmpty(txt_boxSurname.Text) || string.IsNullOrEmpty(txt_boxMajorID.Text)) { errorFound = true; MessageBox.Show("Please fill in all the fields"); } if (!errorFound) { string studentID = txt_boxStudentID.Text; string surname = txt_boxSurname.Text; string name = txt_boxName.Text; string dob = datePickerDOB.Value.ToString(); string sex = comboboxSex.Text; string majorID = txt_boxMajorID.Text; StudentDAO studentDAO = new StudentDAO(); bool isCreated = studentDAO.AddNewStudent(studentID, surname, name, dob, sex, majorID); if (isCreated) { MessageBox.Show("Student Added", "Succeed"); loadDataGridView(); } else { MessageBox.Show("Student Adding Failed", "Error"); } } }