I'm building a create survey / questionnaire app, where each question has the exact same format bound to a model.
Is it possible to do this with one controller + view and simply manipulate the binding context/path?
I've created a single view for this in SAP WEB IDE. When I go click on the "Add New question" button, (to display the input for Question 2) how exactly do I setup the new binding path/context to accept data for it?
Related
I have "PageMain" with "PageMainViewModel" binded, there is a "Edit" button in "PageMain", What is the best practice in MVVM for Blazor to pass the values(example:ProductInfo) to the new opened edit form window ("EditFormWindow") when the "Edit" button is clicked?
I used to use the massagers to communicate between each viewmodel, but in this case, the "EditFormWindow" is new opened, Even I added a register of messager in the constructor of "EditFormWindowViewModel", when sending message (passing data) from "PageMainViewModel", the "EditFormWindowViewModel" is not initialized yet so "EditFormWindowViewModel" cannot receive the message(passed data) from "EditFormWindow".
What I am doing now is to pass the values from View (Balzor file) to Viewmodel, but I am wondering if there is a better solution that I don't have to write any codes in View(Blazor file).
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
In my application I have a menu which open a SelectionDialog, this dialog is used to choose an object.
When this object is selected I have to display it in the view.
What is the best way to update my view?
Currently, I call myview.update(object) after the dialog is closed (in the handler of the menu). But I think this solution is not well design.
I have read about update my model and notify my view but my model does not change (no data are changed, I only display different Data ).
Does anyone has some ideas for a well design solution ?
Define model listener ( dataPopulated(Event e))
Make your view implement model listener and register it with the Model.
Define a Model class that can contain the objects that you want to populate in the view
When Model.setInput(Object input) is invoked fire dataPopulated() event on all registered model listeners.
Above steps works properly when you have view activated. You need to consider cases like when if view is deactivated or not visible ( make sure you refresh view is visible else you will have unnecessary overhead of refreshing view though it is notvisible)
Try adding a selection listener in the view and register this selection in the dialog.
In the listener action, add the code to show the selected object.
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.
I have a plugin which contains class A that brings up a view defined in class B via the following line of code:
(VideoLogView) PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().showView("Videolog.VideoLogView");
What I need to do in the createPartControl() method of the view (class B object) is access a method in the class A object.
How can this be done?
Thanks.
Look like you are facing the classic issue of "how do I pass arguments to my view" ?
This thread illustrates it best:
I was facing the same problem at the beggining of my RCP project. I was getting weird about the fact that there was no way to pass an argument to a view as the viewed model.
Why? Because (emphasis mine):
You are on an opened, pluggable platform.
You contribute to existing developments, others should be able to contribute to yours.
Therefore you will not "pass" arguments to a view, this would lock the whole thing into a non-opened design.
Instead, your view will ask the platform (or will listen to the platform) to determine which information to manage.
Other views (from other plugins that don't yet exist) might also want to manage the same information on the same event.
What you should do then is to ask the workbench for the current selection. I guess your view is opening on a double click action or simple selection so the object you want to manage in your view will be currently selected.
This is how you could retrieve the workbench selection from your view :
ISelection s = this.getSite().getWorkbenchWindow().getSelectionService().getSelection();
where "this" is a ViewPart.
Then you have to make your initial view (the one initiating the view creation from a given event like DoubleClick) a selection provider. A JFace viewer is a selection provider, so you can use it if you're using jface, or you can implement the ISelectionProvider interface when you're using custom SWT controls (that was my case).
The article "Eclipse Workbench: Using the Selection Service" can also give you some pointers.