private void buttonAdd_Click(object sender, EventArgs e)
 {
     if (textBoxSubject.Text == "")
     {
         ProcessInvalid(labelSubject);
         MessageBox.Show("Subject name can't be empty", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
     }
     else if (CheckSubjectExists(textBoxSubject.Text))
     {
         ProcessInvalid(labelSubject);
         MessageBox.Show("Subject already exists", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
     }
     else
     {
         var sub = new Subject
         {
             SubjectName = textBoxSubject.Text,
             IsActive    = checkBoxIsActive.Checked
         };
         if (_settingService.AddSubject(sub))
         {
             MessageBox.Show("Data Saved Successfully!", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information);
             ProcessValid(labelSubject);
             gridViewSelectedId = sub.SubjectId.ToString();
             LoadDataSubject(_settingService.GetSubjectList());
             dataGridViewSubject.Refresh();
         }
         else
         {
             MessageBox.Show("error", "ERROR", MessageBoxButtons.OK, MessageBoxIcon.Error);
         }
     }
 }