在Windows Phone上使用HubTiles，PRISM和MVVM进行页面导航

Question

I'm trying to use the HubTile control from the WPToolkit, PRISM, and MVVM design. My problem is navigating pages.

MainPageModel

private string _navigationUri;
        public string NavigationUri
        {
            get { return _navigationUri; }
            set
            {
                if (_navigationUri != value)
                {
                    NotifyPropertyChanging();
                    _navigationUri = value;
                    NotifyPropertyChanged();
                }
            }
        }

MainPageViewModel

        private void Navigate(string s)
    {
        (Application.Current.RootVisual as PhoneApplicationFrame).Navigate(new Uri(s, UriKind.RelativeOrAbsolute));
    }

        private DelegateCommand<string> _hubTileTap;
    public DelegateCommand<string> HubTileTap
    {
        get { return _hubTileTap; }
    }

_hubTileTap = new DelegateCommand<string>(Navigate);

XAML

<DataTemplate>
                        <toolkit:HubTile 
                            Margin="10"
                            Size="Default"
                            Title="{Binding Title}">
                            <i:Interaction.Triggers>
                                <i:EventTrigger EventName="Tap">
                                    <i:InvokeCommandAction 
                                        Command="{Binding DataContext.HubTileTap}"
                                        CommandParameter="{Binding NavigationUri}"></i:InvokeCommandAction>
                                </i:EventTrigger>
                            </i:Interaction.Triggers>
                        </toolkit:HubTile>
                    </DataTemplate>

Putting in a breakpoint, I can see that my method never actually fires. Also, honestly, I'm not 100% certain that I set things up the right way to pass the string from the HubTile object to the DelegateCommand and then to the Method.

I'm very new to MVVM, PRISM, and still a noob at programming. Thanks for any help!

Answer 1

What does data template live in? Do you have a collection of tiles? The context of the template is the item usually. So, where Title lives is where the command will fire.

edit: what you added, DataContext.HubTileTap won't work, inside the template, DataContext is the item.

One possible way to do this in with prism is to put an action on the item class. Then when you create the items, set the action of each item to your tap method.

public class EmptyClass
    {
        public ObservableCollection<HubTileItem> HubTiles { get; set; }

        public EmptyClass()
        {
            HubTiles = new ObservableCollection<HubTileItem>();
            HubTiles.Add(new HubTileItem { Title = "Tile1", HubTileTap = () => HubTileTap() };);
        }

        public void HubTileTap()
        {
        }
    }

    public class HubTileItem
    {
        public string Title { get; set; }

        public Action HubTileTap { get; set; }
    }