I am loading controls dynamically from the web server from separate XAP files. After creating an instance I want to show them in tab Pages. The controls can be MMVM controls using CM but also non MVVM standard controls.
Before trying the tab I tested to simply show a control dynamically on the page by using:
<ContentControl Name="TestControl" />
Test control is a property of Type UserControl which is set via creating a new Instance of a dynamically loaded control. Now this gives me an error that it can't find the view. In case of non MVVM controls there is of course no view, so how do I load a non MVVM control?
I tried to make the test control a MVVM control, but still get the cannot load view error. Makes sense as such instance is not created. If I create an instance of the dynamically loaded view besides the view model, how do I "Add" this so that CM finds it?
Last but not least, how do I bind this to a tab control in Silverlight? The idea is to have a collection of user controls (plugins) which each is rendered in its separate tab page.
Thanks for any help.
(I got this done in no time NOT using MVVM, still not sure if MVVM is worth all the complexity)
There's no such thing as "mvvm control". MVVM is just a pattern not a control type. Basically, in Caliburn you don't need to work vith UserControls or Views directly, but if you pick the ViewModel first approach, Caliburn framework should be able to find the matching view for you. In your case since you're loading XAP files dynamically, you need to add them to the list of assemblies Caliburn looks to find a View/ViewModel (and bind them together) and this is done through IAssemblySource interface. According to the documentation here:
So, what is AssemblySoure.Instance? This is the place that
Caliburn.Micro looks for Views. You can add assemblies to this at any
time during your application to make them available to the framework,
but there is also a special place to do it in the Bootstrapper.
Related
Is there any library / framework that could simplify Universal Windows Platform app development of the application that contains multiple Frames.
I mean, using MVVM Light or BezySoftware MVVM-Navigation the application is highly tied to the idea of navigating between different pages that are hosted by single frame.
The UI I try to develop consist of multiple content frames (main, left, right) which content varies. I need something that will let me navigate easily between different views (by placing these views into appropriate frame) and provide the same features I would have with BezySoftware MVVM-Navigation, so:
handling of the view model state persistence
the ability to activate / query deactivate view models
back button feature
Few different options:
Combination of a single navigation service injected into your view model AND user controls for areas that need to be repeated view to view (e.g. a tabs, status bars, etc). With this route, every time you create a new view you would paste in the common user controls that need to appear. You would also be able to expose bindable properties from said user controls.
Combination of ContentControl, DataTemplate, and DataTemplateSelector to load in either an entire view (Page) or fragments of XAML. As one person pointed out you cannot use DataType attribute, instead you use the DataTemplateSelector class to do the mapping for you. With this approach you can also use triggers to dynamically change the template (content) based on changes to properties on your view model and/or user interactions.
A mix between 1 and 2 above.
I might right the whole thing right here, but it too lengthy. I just recommend you see this article to get your answer.
MVVM patter in UWP
I would like to know. How I can dynamically choose view? I would like to make the PropertyGrid in my application. The PropertyGrid should must change when user selects object. As I understand for this task I have to use a DataTemplate but how I can dynamically create DataTemplate in code? The fact is that I use plug-ins and View and ViewModel for each plugin located in separate dll and so I can't directly write DataTemplate in PropertyesViewModel.
How can I make the edit properties for each plugin using the Propertygrid if I can't use a DataTemplate?
For Catel it doesn't matter in which assemblies the views / view models are located since it uses relative naming conventions. However, if you want to show a custom view based on logic that might reside inside a plugin, I think this is out of scope for Catel.
To solve this issue, you must implement a custom service that can communicate with the plugins and resolve the right view for a selected object. One solution might be naming conventions (if it's a PersonModel, you might want to show the PersonPropertiesView and PersonPropertiesViewModel). However, this must be a custom service.
Can anyone help.
We are working on an app which has a consistent header and footer and therefore ideally we'll use one viewmodel for the "home page" but we want the header and footer to remain.
Before we switched to starting using Prism, this was easy enough to navigate as we could control that in the Pages event and set the page.contentFrame.Navigate method to go where we wanted.
Now we're using the MVVM structure (which is superb and wish I'd done it ages ago) the NavigationService class only navigates the entire page (the VisualStateAware page).
How can I set this up so that when calling the Navigate method on the interface in the viewmodel that only the main content frame is ever navigated? or is there a better approach to this?
Any help would be greatly appreciated.
thank you
The question title seems to, pre-empt the details of the question slightly as a solution. But to share a common view model and visual parts across all pages, within a frame, using the navigation service to navigate between pages here is an overview..
Create a shared ViewModel, say "HeaderViewModel" of type say IHeaderViewModel to be shared between the different pages' view models. Inject this into the constructor of each page's ViewModel.
Then expose this as a property of each page's ViewModel. This property could also be called HeaderViewModel too. You can then reference the properties of this common HeaderViewModel in the bindings in the View, using binding '.' notation.
If you are using Unity with Prism, you can create this shared instance HeaderViewModel in the OnInitialize override of the App.
Create a shared part for each Page/View as a UserControl, which can be positioned on each page in the same place. This enables you to bind to the same properties on your HeaderViewModel.
My application is designed to load up an XML file and display an error(s) (if any).
The problem I have is how to display both (the XML and Errors) on screen without coupling (my application does currently work).
My application currently looks like (no laughing or comments about me going on a Photoshop\UI course please):
The brown colour is a different view called XmlView.
The red box is where I want errors to be displayed.
So, the user clicks File->Open, selects the file and the .XML content is displayed in my XmlView (brown) and my error messages are shown in red. This works but, I have a horrible feeling my design is poor as I have totally coupled my MainWindow and XmlView.
The way I have this working is, when the user selects a valid XML file (from File->Open), I create an instance of my XmlView and bind it to my Views property of my MainWindow class. My XmlView takes 1 parameter which is the MainWindow type.
So, within my XmlView, to update my ErrorList, I would write code similar to
_mainWindow.ErrorList.Add(//newError)
But this now means my XmlView knows about my MainWindow which I thought was undesired.
So, finally, my question! Is my design poor or is this OK?
You should consider using an MVVM framework if you are doing MVVM.
It would depend on whose responsibility it was to load the XML, but I would suggest the XmlViewModel, not the MainViewModel.
In that case the MainViewModel should just be a conductor of other view models. In your first case, it would instantiate the XmlViewModel, passing the file path and set it as its current view.
The XmlViewModel would be responsible for loading and validating the XML. It too could have a child view model which displays the validation errors. It should load the XML asynchronously, with some form of busy notification.
The MainViewModel is likely to want to conduct many view models, so if you were going to use a framework such as Caliburn.Micro, this would be a conductor type.
I want to implement navigating a tree structure like it is done in e.g. the WinRT file picker. I then want to be able to drop this behavior as part of any page.
My current attempt, is to try and register a secondary FrameAdapter/INavigationService in the container and use that for a frame that is different from the app root frame. So far, I could not get it to work.
My motivation behind that, is, that I do not want to reimplement sth. that the INavigationService already provides.
Basic structure:
ShellView that represents the general app layout (header, footer, navigation) and is currently an OneActive conductor.
Frame control (x:Name="ActiveItem") on the ShellView inside which the hierarchical navigation should occur
The chosen conductor has no relevance yet, since I'll probably have to nest the FrameControl inside another view later to really set up a MDI interface. I'll will want to have multiple screens that should be able to hierarchically navigate
I could not find a CM WP7 example of such a scenario
Can you help me out here?
My problems so far:
How do I access the container from a view code-behind without resorting to using the Application.Current. I figured, it is in the code-behind where I would want to setup the secondary FrameAdapter, since it is here that I have access to the FrameControl
How do I setup the INavigationService so that the initial loading by CM (populating the ActiveItem) is registered with it. There does not seem to be a navigation event for this initial display of the ActiveItem.
Many thanks in advance,
Tobias
PS: I have cross-posted to the Caliburn Micro discussions (Discussion over at CodePlex CM)