Intersoft Community - ClientUI - DelegateCommand CanExecute called after Navigation

DelegateCommand CanExecute called after Navigation

hoffmaster@aretechllc.com — Thu, 18 Jul 2013 09:23:26 GMT

Thank you so much. When the IsAutomaticRequeryDisabled property gets set to true the command gets disabled. I binding to the UXPage Unloaded Event with Interaction Triggers and set the IsAutomaticRequerDisabled to True there.

DelegateCommand CanExecute called after Navigation

yudi — Thu, 18 Jul 2013 02:53:12 GMT

You can try to enable IsAutomaticRequeryDisabled property of DelegateCommand. It specifies whether automatic require should be disabled.

Following snippet code shows how to enable IsAutomaticRequeryDisabled in the ViewModel.

class HomeViewModel : ViewModelBase
{
    public HomeViewModel()
    {
        this.Cmd1Action = new DelegateCommand(ExecuteCmd1, CanExecuteCmd1, true);
        this.Cmd2Action = new DelegateCommand(ExecuteCmd2, CanExecuteCmd2, true);
    }
    ...
}

Hope this helps.

DelegateCommand CanExecute called after Navigation

hoffmaster@aretechllc.com — Wed, 17 Jul 2013 16:56:35 GMT

I am currently developing a WPF application in the MVVM pattern that involves many pages of user navigation and some of the pages consist of many commands. What I have noticed is that after navigating from one page to another, the CanExecute from my DelegateCommand of the previous view model are still called. I use the UXNavigationButton to simply display a new page (<Intersoft:UXNavigationButton Content="Login" HorizontalAlignment="Center" Grid.Row="6" Grid.Column="1" VerticalAlignment="Top" Style="{StaticResource NavButtonStyle}" NavigateUri="/MainPage" /> ). My delegate commands are created in the view model and simply do a WriteLine every time a CanExecute event is triggered. Is there a way to dispose the DelegateCommand after the current view and ViewModel are navigated away from? I can foresee performance issues down the rode with a 10+ page application with many Commands.