private async void Authenticate(Client tentativeClient) { ErrorMessage.Text = ""; Client authClient = await ClientAPI.Auth(tentativeClient); if (authClient != null) { // set as active client and change panel ActiveClient = authClient; ChangeActivePanel(MainForm.Panel.Home); } else { ErrorMessage.Text = "Informations de connexion erronées."; UserTextBox.Text = ""; PasswordTextBox.Text = ""; UserTextBox.Focus(); } }