just started stydying Prism. Can someone explain what I am doing wrong here...
I have basically 2 regions. 1 region - left menu. 2 region - content. They are all in the shell.
Left menu view and the content views are all in the separate projects.
Now, I would like on some button clicks in the left menu switch the views in the content region.
What i have done:
- created NavigationCommand + added it to the composite command (not relevant right now)
public LeftMenuViewModel(IRegionManager regionManager)
{
_regionManager = regionManager;
NavigateCommand = new DelegateCommand<object>(Navigate);
AppCommands.NavigateCommand.RegisterCommand(NavigateCommand);
}
+
public void Navigate (object navigatePath)
{
if (navigatePath !=null)
{
_regionManager.RequestNavigate(RegionNames.ContentRegion, navigatePath.ToString());
}
}
in my leftmenu view i have next piece of code:
dc:ButtonDropDown Header=" Enter New Client"
Style="{DynamicResource AppMenuCommandButton}"
Command="{x:Static Infrastracture:AppCommands.NavigateCommand}"
CommandParameter="ClientNewView"
Now, the command works and hits Navigate method in LeftMenuViewModel, it just refuses to load the content views (from different project) into Content Region, instead it just gives 'System.Object' in the content region.
I assume the problem is in this line of code:
_regionManager.RequestNavigate(RegionNames.ContentRegion, navigatePath.ToString());
we can't just load the views from different project?
Do I have to register the views with the container in the Content Views project? Like this:
_container.RegisterType<object, ClientNewView>(typeof (ClientNewView).FullName);?
thanks for any help !
I'm not sure what container you use, but with MEF you have to either:
a. Register library with container in bootstrapper
OR
b. Create separate project as a PRISM Module and add it to catalog. Then PRISM will import this library automatically
Now, this will solve your problem I think.
But if it doesn't - you need to trap navigation error. RequestNavigate swallows exceptions and to see them you need to subscribe for it like shown here:
http://blogs.southworks.net/gmaliandi/2011/08/how-to-prevent-region-navigation-from-hiding-exceptions-in-prism/
Related
I need to implement the routing functionality in Xamarin.Forms application using the ReactiveUI framework.
The following transitions map needs to be implemented:

Above the black arrows show forward transitions (e.g. I go from the Menu to the Order page by clicking on the menu item button), while the red arrows are for Go Back functionality. Please note that Go back should work for both: (a) the "Go back" link in the top navigation bar (b) the hardware «Back» button on the Android devices.
How do I implement the transitions between sibling pages like these:
Menu - Order - Map - Back to the Menu
Menu - Order - Order details - Pin details page - Back to the Map - Back to the Menu
?
P.S. Here is the guide https://www.reactiveui.net/docs/handbook/routing/ I followed recently, so I used GoNext/GoBack commands to implement more simple transitions like Menu - Order - Order details - Back to the Order - Back to the Menu. It does not work well for the described case, as the Back buttons make transitions back to the previous page instead of their parent page in the navigation map.
The NavigateBack command implementation is quite simple in ReactiveUI's RoutingState, it just removes the last element from the RoutingState.NavigationStack, RoutingState.NavigationStack is an instance of ObservableCollection<IRoutableViewModel>.
So in your particular case, you could write your own NavigateBack command implementation that mutates the navigation stack as required by your application domain. You could use a switch block to figure out what page is currently shown in the screen, and then map that page into another page, either newly created or stored in a field or in a Locator.Current. Probably your command will require a more complex canExecute implementation as well.
ReactiveCommand<Unit, IRoutableViewModel> navigateBackDomainAware =
ReactiveCommand.CreateFromObservable(() => {
var currentViewModel = NavigationStack[NavigationStack.Count - 1];
if (currentViewModel is PinDetailsViewModel) {
var mapViewModel = GetMapViewModel();
NavigationStack.Add(mapViewModel); // The navigation.
return Observable.Return(mapViewModel);
} else {
// Handle other pages. You can also put some domain-specific code
// describing the navigation mappings in your application here.
}
});
I have a Content View in Xamarin forms with 2 StackLayout horizontally aligned in it. I want to change the Content of the 2nd Stacklayout dynamically, but I don't want to use Master details page in that case. Please find an attachment to see what my UI looks like. I want to load different pages in StackLayout 2 on button clicks in StackLayout 1.
Update: I want to achieve above using MVVM.
You specifically said you want to load different pages inside Stacklayout2.
Out of the box, this is not possible. A Page can not be nested inside another view in Xamarin.Forms*
However, you most likely don't need to nest a whole page either, which is good news.
You can create custom xaml views as separate xaml files, and then reference them like regular controls. For example you would create a xaml file MyDataView, inside you could use a and fill it out with your different labels, entries and what nots, then instantiate and add that MyDataView inside your page like you would any other control.
For your host page, I would recommend you change your StackLayout2 to a ContentView, as it will only ever contain one view, which in case of something like your custom "MyDataView" from above, would actually contain the stack layout and all the details.
From the point of view of your page, it has the left layout with all the buttons, and it has the "container" on the right to host different complex views. So it does not need a stacklayout there.
There is also an important decision that you need to make on when and how you want to instantiate all the views that you will host inside the right pane.
You might choose to instantiate them all at once, when loading the page, if there aren't too many. Then switchig to each one during page use should be quite quick. Something like this:
public partial class MainPage
{
private MyDataView myDataView = new myDataView();
private OtherView otherView = new OtherView();
private ThirdView thirdView = new ThirdView();
public void OnSomeButtonClick(object sender, EventArgs e)
{
Container.View = myDataView; //Container would be the x:Name you gave to your ContentView control on the right side of the page that will host the different views
}
}
Or you might prefer to "lazy" instantiate the views, which would only instantiate the view the first time it is navigated to. This is useful if some views will never actually be accessed, and you can save some cpu cycles and ram by not loading the view until it's needed. The downside of course is when you do load it for the first time, it will load slower. Like this:
public partial class MainPage
{
private MyDataView myDataView;
private OtherView otherView;
private ThirdView thirdView;
public void OnSomeButtonClick(object sender, EventArgs e)
{
if (myDataView == null) myDataView = new MyDataView();
Container.View = myDataView; //Container would be the x:Name you gave to your ContentView control on the right side of the page that will host the different views
}
}
And finally you can instantiate the view everytime it is needed. I would not go with this route in most cases. Unless you really specifically need to recreate the entire view each time (like if you are dynamically changing it during use, and you need to reset it when it's shown again)
*I have seen a custom renderer implementation that nested a whole page inside a view on github. I did not test it as it was not completely implemented at the time.
Cant you do something like this:
button1.OnClick += (sender, args) =>{
StackLayout2.Children.Remove(currentview);
StackLayout2.Children.Add(newview);
}
Not sure if its called onclick or clicked.
I have one main page with one button that directs my application to another page. When I click the button, the directed page should have gone to the address that I want on the Bing map. But I only see the world map. Here is the code of the second page:
public BingMapPage()
{
InitializeComponent();
BingMap.Mode = new RoadMode();
BingMapsTask bmt = new BingMapsTask();
bmt.SearchTerm = "Paris";
bmt.Show();
}
The code above only show the world map. However, if I write the same code in the constructor of the main page, it works as it is supposed to. Moreover, I tried to create a method in the second page as below:
public void StartSearch()
{
BingMapsTask bmt = new BingMapsTask();
bmt.SearchTerm = "Paris";
bmt.Show();
}
And then created an instance of my second page in the main page and called this method. It worked again.
My question is that is there a way of get these codes
bmt.SearchTerm = "Paris";
bmt.Show();
working outside of mainpage of an Windows Phone 7 application.
You cannot set the Searchterm to Paris. Searchterms are general terms like shops, businesses, hospitals etc. You may try an alternative approach. Create a webBrowser control and run the following line of code:
webBrowser.Navigate(new Uri("maps:<your address>"));
This will open the native maps app on the WP7 phone pointing to <your address>. I hope this was what you were looking for.
How do I unload a view from a Prism Region?
I am writing a WPF Prism app with a Ribbon control in the Shell. The Ribbon's Home tab contains a region, RibbonHomeTabRegion, into which one of my modules (call it ModuleA) loads a RibbonGroup. That works fine.
When the user navigates away from ModuleA, the RibbonGroup needs to be unloaded from the RibbonHomeTabRegion. I am not replacing the RibbonGroup with another view--the region should be empty.
EDIT: I have rewritten this part of the question:
When I try to remove the view, I get an error message that "The region does not contain the specified view." So, I wrote the following code to delete whatever view is in the region:
// Get the regions views
var regionManager = ServiceLocator.Current.GetInstance<IRegionManager>();
var ribbonHomeTabRegion = regionManager.Regions["RibbonHomeTabRegion"];
var views = ribbonHomeTabRegion.Views;
// Unload the views
foreach (var view in views)
{
ribbonHomeTabRegion.Remove(view);
}
I am still getting the same error, which tells me there is something pretty basic that I am doing incorrectly.
Can anyone point me in the right direction? Thanks for your help.
I found my answer, although I can't say I fully understand it. I had used IRegionManager.RequestNavigate() to inject the RibbonGroup into the Ribbon's Home tab, like this:
// Load RibbonGroup into Navigator pane
var noteListNavigator = new Uri("NoteListRibbonGroup", UriKind.Relative);
regionManager.RequestNavigate("RibbonHomeTabRegion", noteListNavigator);
I changed the code to inject the view by Registering it with the region, like this:
// Load Ribbon Group into Home tab
regionManager.RegisterViewWithRegion("RibbonHomeTabRegion", typeof(NoteListRibbonGroup));
Now I can remove the RibbonGroup using this code:
if(ribbonHomeTabRegion.Views.Contains(this))
{
ribbonHomeTabRegion.Remove(this);
}
So, how you inject the view apparently matters. If you want to be able to remove the view, inject by registration with the Region Manager
StockTraderRI Example Project by Microsoft contains the following example of removing views from region in ViewModel.
private void RemoveOrdersView()
{
IRegion region = this._regionManager.Regions[RegionNames.ActionRegion];
object ordersView = region.GetView("OrdersView");
if (ordersView != null)
{
region.Remove(ordersView);
}
}
Is it possible you have a RegionAdapter that is wrapping the view inside another view before adding it? The ribbonHomeTabRegion should have a property with the collection of views - is there anything inside it?
This should be quite a common problem, but I couldn't find anything helpful on the topic.
We are developing an application with Eclipse RCP. The application shows data in an editor of which usually multiple instances are open. In an additional view you can edit the editor-values. When the values are changed in the view they are updated in the editor and it's dirty flag is set.
So far it works fine. What we're missing is: When another editor instance gets the focus, our view should show the data of this editor.
I managed to do that for two views. The second view is sucessfully updated using a TableViewer as selection Provider and registering a SelectionListener in the other view. I tried the same thing for the editor using a Viewer I subclassed from ContentViewer, but it didn't work.
Can this approach be working?
Or do I need a different approach on the problem?
May be you can subclass your view from PageBookView and then provide special adapter for your editor. Outline View is implemented using this approach.
Thank you cerealk, that was exactly what I needed. :-)
Update the View when another Editor is selected
public class myView {
// Create an IPartListener2
IPartListener2 pl = new IPartListener2() {
// If the Editor I'm interested in was updated ...
public void partActivated(IWorkbenchPartReference ref) {
IWorkbenchPart part = ref.getPart(true);
if (part instanceof DetailEditor) {
// ... update the view
Contact contactFromSelectedEditor = ((DetailEditor) part).detailComposite.contact;
detailComposite.update(contactFromSelectedEditor);
}
}
...
}
// Add the IPartListener2 to the page
IWorkbenchPage page = this.getSite().getPage();
page.addPartListener(pl);
}
Why use an IPartListener2 instead of an IPartListener
The IPartListener2 replaces IPartListener with 3.5.
As explained in this this answer:
You should always use IPartListener2 as it can handle part-change events on parts that have not yet been
created because they are hidden in a stack behind another part.
This
listener will also tell you when a part is made visible or hidden or
when an editor's input is changed.