private void btnAlterar_Click(object sender, EventArgs e)
{
p.Id = id;
p.Nome = txtNome.Text;
p.Descricao = txtDescricao.Text;
p.Preco = float.Parse(txtPreco.Text);
pDAO.Alterar(p);
this.pizzaTableAdapter.Fill(this.pizzaBdDataSet1.Pizza);
txtNome.Text = "";
txtDescricao.Text = "";
txtPreco.Text = "";
}