private void Sample1_DialogHost_OnDialogClosing(object sender, DialogClosingEventArgs eventArgs) { if (!Equals(eventArgs.Parameter, true)) { return; } var computermodel = (ComputerViewModel)DataContext; if (!string.IsNullOrWhiteSpace(OperationBox.Text)) { computermodel.Operation.Add(new OperationDTO() { Name = OperationBox.Text.Trim(), FirmId = computermodel.FirmId }); OperationViewModel operation = new OperationViewModel(computermodel.FirmId); operation.Operation = computermodel.Operation; operation.SaveCommand(); } OperationBox.Text = ""; }