private void addStaffBtn_Click(object sender, EventArgs e)
 {
     add_Staff = new add_staff();
     add_Staff.Show();
     FillGrid();
     this.Close();
 }
 private void editBtn_Click(object sender, EventArgs e)
 {
     add_Staff                  = new add_staff();
     add_Staff._ID              = Convert.ToInt32(dgvStaff.CurrentRow.Cells[0].Value.ToString());
     add_Staff.btnSave.Text     = "Update";
     add_Staff.btnSave.ImageKey = "update.png";
     add_Staff.Text             = "Update Staff";
     add_Staff.Show();
     FillGrid();
     this.Close();
 }