public NewItemsViewModel()
{
//NB: You could do validation with this default reactive ui method, OR Use a better way
//this.ValidationRule(vm => vm.ItemDescription, desc => !string.IsNullOrEmpty(desc), "Description should not be empty");
ItemDescription = new ValidatableObject <string>();
ItemDescription.Validations.Add(new IsNotNullOrEmptyRule("Description should not be empty"));
ItemTitle = new ValidatableObject <string>();
ItemTitle.Validations.Add(new IsNotNullOrEmptyRule("Title should not be empty"));
//Create an observable stating if we can save this item or not.
var canSaveObservable = this.WhenAnyValue(vm => vm.ItemDescription.Value, vm => vm.ItemTitle.Value, (desc, title) =>
{
return(ItemDescription.TryValidate(desc) && ItemTitle.TryValidate(title));
});
CancelCommand = ReactiveCommand.Create(OnCancelCommand);
SaveCommand = ReactiveCommand.Create(OnSave, canSaveObservable);
}