работа с БД с помощью ADO-компонентов

void __fastcall TMainForm::FormCreate(TObject *Sender)
{
 String filename = "Компьютерная база.mdb";
  if(!FileExists(ExtractFilePath(Application->ExeName)+filename))
{
   AnsiString ds = "В корневом каталоге отсутствует файл с именем \n\n\t" +filename;
 
     if (Application->MessageBox(ds.c_str(),"Предупреждение",MB_OK +MB_TOPMOST+ MB_ICONWARNING)==IDOK)
  {
     Application->Terminate();
  }
 
}
  
else
 {
   String WayToBase=ExtractFilePath(Application->ExeName)+filename;
  ADOConnection1->ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+WayToBase+";Persist Security Info=True";
   ADOConnection1->Connected = true;
  ADOQuery1->ConnectionString = ADOConnection1->ConnectionString;
  DBGrid1->Options = TDBGridOptions(DBGrid1->Options) >> dgIndicator >> dgTitles >> dgColLines >> dgRowLines >> dgColumnResize >>dgEditing;
  DataSource1->DataSet = ADOQuery1;
  DBGrid1->DataSource = DataSource1;
  DBNavigator1->DataSource = DataSource1;
  ADOQuery1->Active = false;

OpenDialog1->FileName;

 if (OpenDialog1->Execute())
{
 String WayToBase = OpenDialog1->FileName;
 ADOQuery1->ConnectionString ="Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+WayToBase+";Persist Security Info=True";
}

OpenDialog1->FileName