private void btnAlter_Click(object sender, EventArgs e) { if (txtId.Text.Trim().Equals(String.Empty)) { MessageBox.Show("A caixa de Id não deve estar vazia, selecione um pet antes de alterar."); return; } else if (allFullfilled()) { var ownerId = Convert.ToInt64(cbOwner.SelectedValue); Owner petOwner = (Owner)ownerService.GetById(ownerId); Pet newPet = new Pet(txtName.Text, dtBirthday.Value, petOwner.OwnerId, txtSpecies.Text) { PetId = Convert.ToInt64(txtId.Text) }; Composition.AddSlice <Owner, Pet>(petOwner, newPet); petService.Alter(newPet); refreshDataGridView(petOwner); resetForm(); } }