I have a TabControl region, where i am adding new tabs throw RequestNavigate method. Everything's working fine. But problem is, that new tabs are placed on the last position to the right. But i need to add them right next to active tab. So when i have 10 open tabs, but active is first tab - i want to add new opened tab to second place and move other tabs to right. Thx a lot
Ok, thanks to Sam's solution https://stackoverflow.com/a/4285764/1027262 I figured out that there is a SortComparison property of IRegion class that is responsible for sorting views inside region.
So my View classes implements ISortableView interface, that contains
public int SortIndex {get;set;}
This SortIndex is then used for sorting Views in region. SortComparison method looks like this:
private static int CompareViews(object x, object y)
{
return ((ISortableView)x).SortIndex.CompareTo(((ISortableView)y).SortIndex);
}
this._regionManager.Regions["MyRegion"].SortComparison = CompareViews;
Then I had to make service class, that is responsible for managing Views index. Index of parent view i am sending throw OnNavigatedFrom method of INavigationAware interface. But be aware of setting SortIndex in OnNavigatedTo method. This method is called AFTER region sort its views.
Related
I am creating a WPF application. Naturally my entry point is MainWindow.xaml, which is opened up by App.xaml
var mainWindow = container.Resolve<MainWindow>();
Application.Current.MainWindow = mainWindow;
Application.Current.MainWindow.Show();
I am using Dependency Injection and so far all the dependencies are passed as parameters in the ctor of the MainWindow's View Model.
i.e. my Main Window is
public partial class MainWindow : MetroWindow
{
private readonly MainWindowModel mainViewModel;
public MainWindow(MainWindowModel mainViewModel)
{
and its View model is:
public MainWindowModel(IDataRepository dataRepo, ICommand command1, ICommand command2, etc ...)
{
However, I am now starting to realize this might be a problem. Given that the MainWindow is the entry point to the entire app, it seems like any dependency, anywhere in the application will have to first pass through the MainWindow View Model constructor. This seems crazy.
I am coming from the background of ASP.NET MVC and there we have Controllers, which receive only the dependencies that they need. i.e. the concept of a main entry point there is missing and this makes things easier and more manageable.
Here is an example in my WPF app. A control, on the Main View needs to open up a dialog. This dialog is another Window and of course that window receives its ViewModel in its ctor. To me, it seems like to be able to resolve the dialog properly, I need to pass it through the Main Window View Model ctor first, keep it as private readonly field of the Main Window View Model and launch it when necessary. Ok, but what if I have 100 dialogs. That's just one of the examples. I have such issue with the ICommand implementations too.
To sum up my question:
How do I manage the dependencies in WPF properly, without using the Service Locator anti-pattern and without passing every single abstraction through the ctor of the main window view model? I could very easily pass a Container around and let, e.g., the create ABC command solve the ABCDialog before opening it, but I feel this will cause more issues than it would solve.
I am probably doing something wrong. Please advise me what is the best practice.
I have problem of thinking ideal solution for creating and showing window in WPF MVVM application. Some part of application needs to show some window with some data. I create VM, set its properties, create View, assign its VM (in constructor), then display window. This is done using class that I named ViewController and this class have methods with parameters for every window in my application. I think there can be better solution than this, but not overengineered.
The normal solution is you have a class that wraps and instantiates a View ViewModel pair. This is often called screen. it would look something like this.
public class Screen<TView> where TView : Window
{
public Screen(TView view, object viewModel){
//store view and viewModel props
//display view
//set viewModel as DataContext of view
}
}
This is a very rough example, there are lots of ways you can do it.
In the last I created implementation of IWindowManager, which have methods for showing required windows and these methods have parameters if needed. Methods create view model, set its properties and inject it to window. Only drawback of this solution is when new window is needed, new method must be added to interface and implementation of WindowManager.
I was going through the Caliburn Micro documenation here. Simultaneously, I was trying to put up some rough code for experiment. I am a little confused about how to activate item using a container and how to pass an object to the ViewModel that we are activating.
Lets consider a master/detail scenario. The master contains a list (say datagrid) and the details contain specific row from the master for update(say tab item inside tab control). In the documentation (for ease of understanding), I believe the detail ViewModel was directly instantiated using code like this
public class ShellViewModel : Conductor<IScreen>.Collection.OneActive {
int count = 1;
public void OpenTab() {
ActivateItem(new TabViewModel {
DisplayName = "Tab " + count++
});
}
}
So, to apply the above fundamental concept in real world app, we need to instantiate the DetailViewModel (TabViewModel above) using container(say MEF). The challenge then is to know whether the particular DetailViewModel is already opened in the TAB Control. The immediate crude thing that came to my mind was maintaining a List of the Opened Tabs (DetailViewModels). But then we are again referencing DetailViewModel in the MasterViewModel defeating the purpose. Is there any options available to solve this issue.
The second thing that is troubling me is how to pass the Objects from MasterViewModel (Selected Detail Item) to the DetailViewModel. If we use the EventAggregator here then each of the opened DetailViewModels will receive the event which I am not sure how to handle.
If anyone can throw some light on the above two issues, I would be grateful
Update:
The Master is Conductor like this
public class MainViewModel : Conductor<IScreen>.Collection.OneActive, IShell {
....
}
And the detail is defined like this
public class TabViewModel : Screen {
....
}
Both are in the same Window.
I'm not sure exactly what the issue is. In your conductor of many, you have an Items collection provided by Caliburn.Micro. When you come to display a detail view, you can check this collection for the existence of that detail view (using the primary key which you have from the master view).
If the item is already in the Items collection then just activate it (using the ActivateItem method). If the item isn't in the collection, then instantiate it (presumably using a factory if you're using MEF), and add it to the Items collection, and then activate it.
I'm trying to create an application similar to Visual Studio in that we have a main content area (i.e. where documents are displayed in a TabControl, not a true MDI interface), with a menu on the side.
So far, I have everything working, except the content. My goal is that when a user double clicks on an item in the navigation menu on the side, it opens the document in the Content region. This works, but every time I double click it spawns a new instance of that same view. There's a chance that I could have multiple views of the same type (but different "names") in the TabControl content container.
Right now, my code looks something like this...
IRegion contentRegion = IRegionManager.Regions[RegionNames.ContentRegion];
object view = IUnityContainer.Resolve(viewModel.ViewType, viewModel.UniqueName);
if (!IUnityContainer.IsRegistered(viewModel.ViewType, viewModel.UniqueName))
{
IUnityContainer.RegisterInstance(viewModel.UniqueName, view);
contentRegion.Add(view);
}
contentRegion.Activate(view);
However, it appears that the view is never registered, even though I register it... I imagine I'm probably doing this wrong -- is there another way to do this? (re: the right way)
So, the problem was trying to do it this entire way. The smart method (for anyone else trying to do this) is to make use of Prism the correct way.
What I ended up doing was instead Navigating by:
1. In the Navigation Menu, constructing a UriQuery (included in Prism) with the UniqueID of the view I want to display (which is guaranteed to be unique) and adding that to the View I wanted to navigate to, i.e.:
IRegionManager.RequestNavigate(RegionNames.ContentRegion, new Uri(ViewNames.MyViewName + query.ToString(), UriKind.Relative));
where query is the UriQuery object.
2. Register the View and ViewName in the Module via:
IUnityContainer container = ServiceLocator.Current.GetInstance<IUnityContainer>();
container.RegisterType<object, MyView>(Infrastructure.ViewNames.MyViewName);
3. In the View, make sure the ViewModel is a parameter on the constructor. Let Prism inject this manually for us. Inside the constructor, make sure you set the DataContext to the incoming ViewModel.
4. Finally, make sure your ViewModel implements INavigationAware interface... This is a very simple implementation of it (UniqueID is a property on the ViewModel):
public virtual bool IsNavigationTarget(NavigationContext navigationContext)
{
if (navigationContext.Parameters != null)
return (navigationContext.Parameters["UniqueID"] == UniqueID);
return false;
}
public virtual void OnNavigatedFrom(NavigationContext navigationContext)
{
}
public virtual void OnNavigatedTo(NavigationContext navigationContext)
{
if (navigationContext.Parameters != null)
UniqueID = navigationContext.Parameters["UniqueID"];
}
From here, Prism will ensure that only one view of your "UniqueID" will exists, while allowing for others of the same view, but different ViewModel (or data for that ViewModel, i.e. viewing two users in different tabs, but both use the same templated view).
I am working on a project using PRISM where I have left navigation implemented as Tree View and any click event happens raise event using event aggergation to Enrolment Module which has multiple view model for multiple views (like Wizard Applicaiton where you can go through many views to collect data). I want to have a common or shared or singleton model which can be passed across this view models and save at the end.... users can click on any link any navigation at any time and it should save data in to this singleton model expsosed through different view model. Do you have any samples which are doing something like this... or can you type up a quick one on how to do it? OR it is not possible to do it at all. I am following all patterns from Brian Lagunas's Pluralsight Video for PRISM so try to use that way....
I would have a MasterViewModel which controls the "wizard" pages and current state
It would contain the following properties:
List<ViewModelBase> Pages
int CurrentPageIndex
ViewModelBase CurrentPage, which returns Pages[CurrentPageIndex]
MyClass DataObject
The MasterView that goes with the MasterViewModel would be nothing more than a ContentControl with it's Content bound to CurrentPage. I would probably also define DataTemplates in the MasterView which tells WPF which View to draw with which Page
Your MasterViewModel would be in charge of handling the pages, and passing each page a reference to the data it needs. For example in the constructor it might say,
public MasterViewModel(MyClass dataObject)
{
DataObject = dataObject;
Pages.Add(new InfoPage(DataObject));
Pages.Add(new AddressPage(DataObject.Addresses));
Pages.Add(new PhonePage(DataObject.Phones));
Pages.Add(new SaveMyClassPage(DataObject));
CurrentPageIndex = 0;
}
I have an example here if you're interested
I don't know, is it prism way, or something another, when I build something like wizard, first of all I create instance of all data which wizard collect.
public WizardData wd = new WizardData();
Then, every page of wizard are initialized by this wd instance, i.e.
public FirstWizardPage(WizardData wd)
{
this.wizardData = wd;
}
So, this way allow you to have button Finish on every page, for example. You can initialize your ViewModel with wd, or its properties.
This way is not the best. Its hust one of the possible way.
Another - is to create singleton and use it without reference passing from page-to-page.
When you use Prism you also have a Dependency Injection Container, usually Unity or MEF. To solve your problem you can register your model as singleton to those DI containers. Every view model that asks the DI container to resolve their dependecy, in our special case the model, will get the singleton instance back from the DI container.
Unity example: You register your model as singleton instance:
public void Initialize( )
{
container.RegisterInstance<Model>(new Model(), new ContainerControlledLifetimeManager( ));
}
Now you can resolve your dependencies in your view model:
public ViewModel(IUnityContainer container)
{
Model model = container.Resolve<Model>();
}