Prism Navigation

Navigation

Eyal Vardi
CEO E4D Solutions LTD
Microsoft MVP Visual C#
blog: www.eVardi.com

Agenda
 Interaction Request

 State-Based Navigation

 View-Based Navigation

© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

Interaction Request


View Model Codes Sample
InteractionRequest<Confirmation> action { get; set; }

action.Raise(
new Confirmation { Title = "Test II", Content = DateTime.Now },
x => Date = x.Content.ToString()
);

<ei:Interaction.Triggers>
<prism:InteractionRequestTrigger
SourceObject="{Binding action}">
<prism:PopupChildWindowAction
ContentTemplate="{StaticResource NT}"/>
</ei:Interaction.Triggers>


Interaction in ViewModel


Interaction in View


State-Based Navigation


State-Based Navigation

View
Binding
Model


Data State Behavior
<i:Interaction.Behaviors>
<ei:DataStateBehavior Binding="{Binding ShowDetails}" Value="True"
TrueState="ShowDetails"
FalseState="ShowContacts"/>
</i:Interaction.Behaviors>

<VisualStateManager.VisualStateGroups>

<VisualStateGroup x:Name="DetailStates">

<VisualStateGroup.Transitions />

<VisualState x:Name="ShowContacts" />
<VisualState x:Name="ShowContacts" />

</VisualStateGroup>

</VisualStateManager.VisualStateGroups>


Data State Behavior


View-Based Navigation


Basic Region Navigation
 The view to be displayed is identified via a URI
regionManager.RequestNavigate(
"MainRegion",
new Uri("InboxView", UriKind.Relative) );

 View Registration
// Unity
container.RegisterType<object, InboxView>("InboxView");

// MEF
[Export("InboxView")]
public partial class InboxView : UserControl


RequestNavigate Method
 The RequestNavigate method also allows you
to specify a callback method, or a delegate,
which will be called when navigation is
complete.

private void SelectedEmployeeChanged(object sender, EventArgs e)
{
...
regionManager.RequestNavigate(
RegionNames.TabRegion, "EmployeeDetails", NavigationCompleted);
}

private void NavigationCompleted(NavigationResult result) { ... }


INavigationAware Interface
 By implementing this interface, your view or
view model can opt-in to participate in the
navigation process.

public interface INavigationAware
{
bool IsNavigationTarget( NavigationContext navigationContext );
void OnNavigatedTo ( NavigationContext navigationContext );
void OnNavigatedFrom ( NavigationContext navigationContext );
}

IsNavigationTarget
View I View II
( Form ) OnNavigatedFrom OnNavigatedTo ( To )


Basic Navigation


IRegionMemberLifetime
 Sometimes you will want the deactivated view
to be removed from the region.

public class EmployeeDetailsViewModel : IRegionMemberLifetime
{
public bool KeepAlive { get { return true; } }
}


Passing Parameters During
Navigation
Employee employee = Employees.CurrentItem as Employee;

if (employee != null)
{
UriQuery query = new UriQuery();
query.Add("ID", employee.Id);

_regionManager.RequestNavigate( RegionNames.TabRegion,
new Uri("EmployeeDetailsView" + query.ToString(),
UriKind.Relative) );
}

public void OnNavigatedTo( NavigationContext navigationContext )
{
string id = navigationContext.Parameters["ID"];
}


IRegionNavigationContentLoader


Confirming or Cancelling Nav


IConfirmNavigationRequest
 The implementation of this method invokes
the interaction request defined earlier so that
the user can confirm or cancel the navigation
operation.

void IConfirmNavigationRequest.ConfirmNavigationRequest(
NavigationContext navContext, Action<bool> callback)
{
this.confirmExitInteractionRequest.Raise (
new Confirmation { Content = "...", Title = "..." },
c => callback(c.Confirmed)
);
}


Confirming or Cancelling
Navigation


Using the Navigation Journal
 The NavigationContext class provides access
to the region navigation service.
 The region navigation service implements the
IRegionNavigationService.

public interface IRegionNavigationService : INavigateAsync
{
IRegion Region {get; set;}
IRegionNavigationJournal Journal {get;}
event EventHandler<RegionNavigationEventArgs> Navigating;
event EventHandler<RegionNavigationEventArgs> Navigated;
event EventHandler<RegionNavigationFailedEventArgs> NavigationFailed;
}


IRegionNavigationJournal
 The Journal property provides access to the
navigation journal associated with the region.

public interface IRegionNavigationJournal
{
bool CanGoBack { get; }
bool CanGoForward { get; }
IRegionNavigationJournalEntry CurrentEntry { get; }
INavigateAsync NavigationTarget { get; set; }
void Clear();
void GoBack();
void GoForward();
void RecordNavigation(IRegionNavigationJournalEntry entry);
}


The Region
Navigation
Sequence


Navigation


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