private void btnSearchPeople_Click(object sender, EventArgs e)
 {
     txtName.Text = "";
     lvSearch.Columns.Clear();
     lvSearch.Items.Clear();
     if (radMaDG.Checked == true)
     {
         SearchByMaDG(txtSearchPeople.Text);
         DocGiaDAO dg     = new DocGiaDAO();
         DocGia    docgia = dg.GetNameDG(txtSearchPeople.Text);
         txtName.Text = docgia.HoTen;
     }
     if (rabMaSV.Checked == true)
     {
         DocGiaDAO dg     = new DocGiaDAO();
         DocGia    docgia = dg.GetNameDGByMsv(txtSearchPeople.Text);
         txtName.Text = docgia.HoTen;
         SearchByMaSV(txtSearchPeople.Text);
     }
 }