private void frmBaoCaoDoanhThuThang_Load(object sender, EventArgs e)
 {
     dttBUS = new DTTBUS();
 }
 private void frmBaoCaoDoanhThuNam_Load(object sender, EventArgs e)
 {
     dttBUS = new DTTBUS();
     dtnBUS = new DTNBUS();
 }