private void AtualizaGrid()
{
ClienteNegocios clienteNegocios = new ClienteNegocios();
ClienteCollection clienteCollection = clienteNegocios.ConsultaPorNome(txbPesquisa.Text);
dataGridViewPrincipal.DataSource = null;
dataGridViewPrincipal.DataSource = clienteCollection;
dataGridViewPrincipal.Update();
dataGridViewPrincipal.Refresh();
}