// -------------------------------- Button de validation ----------------------------------------- private void btnValider_Click(object sender, EventArgs e) { if (txtNom.Text == "" || txtDate.Text == "" || txtMontant.Text == "" || txtCodePostal.Text == "") { MessageBox.Show("Il faut remplir tout les champs!"); txtNom.Focus(); return; } Facture MaFactur = new Facture(txtNom.Text, DateTime.Parse(txtDate.Text), Convert.ToDouble(txtMontant.Text), Convert.ToInt32(txtCodePostal.Text)); if (MaFactur.DateIsValid()) { MessageBox.Show("Nom : " + txtNom.Text + "\n" + "Date : " + txtDate.Text + "\n" + "Montant : " + txtMontant.Text + "\n" + "Code Postal : " + txtCodePostal.Text, "Récapitulatif"); } else { MessageBox.Show("La date n'est pas Valid"); txtDate.Focus(); } }