hope everyone is safe. Your assistance the question below would be very much appreciated.
I am currently using the Levelspace extension in conjunction with the extrawidget extension in Netlogo. Using Levelspace I'm attempting to have the parent model call a child model whose primary tab is an extrawidget GUI tab, which is tab 2. Levelspace always and only calls the interface tab which is tab 1.
Is there any way Levelspace can have the parent model call tab 2 instead of tab 1 when calling and loading a child model?
Thanks
Rudy
Related
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.
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 been using the MVVM Light Toolkit to help learn the MVVM pattern. However, I have not been able to solve the problem of usercontrols within controls scenario.
For example, in a Timesheet application, lets say we have a control called NewUnitOfWork. When it first loads, a panel with a ListBox with a list of projects is loaded as the Content of the NewUnitOfWork. The user clicks on one. A new panel is swapped in with a ListBox containing the possible tasks for that project. A task is selected and a new panel is loaded which will contain controls to input data for the chosen task of the chosen project.
So, we have the selected item in one usercontrol being passed to the other two user controls, which are, in turn swapped in as the Content of the NewUnitOfWork control (or window).
If each control has its own ViewModel, we need to pass the selected value from one ViewModel to the next etc.
I have got it working in a single user situation using global variables (via a "service"). However, there are concurrency issues with that and it is not a good solution. It's sub-par.
I have seen many times the suggestion on this forum to have on ViewModel as a member of another ViewModel. Whilst this solves the problem at hand, I believe it is a violation of the MVVM pattern. Another ViewModel is not UI-related functionality that the ViewModel shoule be directly.
So. Has anyone found a clean MVVM-complying way to do this sort of thing?
Cheers
Please always keep in mind that MVVM is just a pattern and it is designed to help you separate your UI and logic. Do not be afraid to “violate the pattern” if it helps to increase testability or maintainability of the application.
Having a master ViewModel with several child ViewModels is very handy if you have a complex UI. The main ViewModel may be responsible for handling the top level UI controls and for coordination of the child VMs, while other ViewModels are responsible for communication with the sub regions of your UI.
Moreover, if you have a really complex UI with the multiple nesting UI layers, you can implement an infrastructure to automatically cascade all the events from master to child VMs.
And of cause, you may try to use one of the more advanced MVVM frameworks. For example Catel implements pretty comprehensive model to resolve such situations with nested VMs.
I don't see a problem with ViewModels referencing other ViewModels (based on my experience with TreeViews). Have a look at any article about TreeView and MVVM. You will see that each node is a ViewModel, that references a collection of child nodes, which are ViewModels. Trying to do that without VM-VM references would be a nightmare.
Josh Smith
http://www.codeproject.com/KB/WPF/TreeViewWithViewModel.aspx
I have been using the following setup:
A 'master' VM with a 'collection' VM and a 'details' VM as nested properties.
The master VM is tied to a View that is used as a master-detail form. This master-detail View is composed from two other Views.
I find it a very neat setup because it allows me to put search criteria in the master View(Model) and keeps the other View(Model)s clean.
I can't see how this would break the pattern.
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.