I've got a View containing a TabControl bound to a region "CustomerRegion".
I've got a few View/ViewModels which are marked as [ViewExport(RegionName = "CustomerRegion")].
These items are loaded successfully into the TabControl.
But now I need these TabItems to share some data in this TabControl (can't be global since there might be two or more of these open at one time).
Any ideas how these TabItems can share data without leaving MVVM/MEF?
Prism has the concept of "Region Context" that you might be able to use, depending on your scenario.
Check out the Prism Region documentation and look for the section entitled "Sharing Data Between Multiple Regions" (though this title is a little misleading...).
If you find this doesn't work for you, I would suggest writing a custom inheriting attached property that you can bind to from subviews and modify from the parent view.
Related
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)
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.
GWT's Editor framework is really handy and it can not only be used for editing POJOs but also for read-only display.
However I am not entirely sure what the best practice is for doing inline edits.
Let's assume I have a PersonProxy and I have one Presenter-View pair for displaying and editing the PersonProxy. This Presenter-View should by default display the PersonProxy in read-only mode and if the user presses on a edit button it should allow the user to edit the PersonProxy object.
The solution I came up with was to create two Editors (PersonEditEditor and PersonDisplayEditor) that both added via UiBinder to the View. The PersonEditEditor contains
ValueBoxEditorDecorators and the PersonDisplayEditor contains normal Labels.
Initially I display the PersonDisplayEditor and hide PersonEditEditor.
In the View I create two RequestFactoryEditorDriver for each Editor and make it accessable from the Presenter via the View interface. I also define a setState() method in the View interface.
When the Presenter is displayed for the first time I call PersonDisplayDriver.display() and setState(DISPLAYING).
When the user clicks on the Edit button I call PersonEditDriver.edit() and setState(EDITING) from my Presenter.
setState(EDITING) will hide the PersonDisplayEditor and make the PersonEditEditor visible.
I am not sure if this is the best approach. If not what's the recommended approach for doing inline edits? What's the best way to do unit-testing on the Editors?
If you can afford developing 2 distinct views, then go with it, it gives you the most flexibility.
What we did in our app, where we couldn't afford the cost of developing and maintaining two views, was to bake the two states down into our editors, e.g. a custom component that can be either a label or a text box (in most cases, we simply set the text box to read-only and applied some styling to hide the box borders).
To detect which mode we're in, because we use RequestFactoryEditorDriver (like you do), we have our editors implement HasRequestContext: receiving a null value here means the driver's display() method was used, so we're in read-only mode. An alternative would be to use an EditorVisitor along with some HasReadOnly interface (which BTW is exactly what RequestFactoryEditorDriver does to pass the RequestContext down to HasRequestContext editors).
Yes,Presenter-View pair should be. But Here two ways to achieve this feature if you like to go with:
1) Integrate Edit/View code design in one ui.xml i.e.Edit code in EDitHorizonatlPanel and View code in ViewHorizontalPanel.The panel has different id. By using id, show/hide panel with display method. if getView().setState() ==Displaying then show ViewHorizontalPanel and if getView().setState()==Editing then show EditHorizontalPanel.
2) Instead of using labels, Use textboxes only. set Enable property is false when you need it in view mode otherwise true
You have created two Presenter/view but I think if Edit/View function has similar code so no need to rewrite similar code again and again for view purpose.
If a big project has so many Edit/View function and you will create such type of multiple View/Presenter than your project size become so huge unnecessary.
I think that whatever I have suggest that might be not good approach but a way should be find out which help to avoid code replication.
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've been working on a Cook Book App and I've been making each page individually which takes a really long time to do, I asked a question similar to this and it was brought to my attention that you can setup a way to automate the design process so all you need to do is input your data.
Can someone please explain in as much detail as possible how you setup your xcode files/code to automate such a process
So for example I would just enter the page text and it would automatically put my standard background picture in and add a scroll view and appropriate buttons etc.
Thanks
You could make one master view that contains all the controls that you need: standard background picture, scroll view, appropriate buttons, etc, and make any subsequent views that you create inherit from this view, so that they all contain those controls.
You could also use just one view and work with multiple instances of it, one instance per page. Just make sure to have a Text property on it, or a constructor that takes in your text string, so that you could set it to a different text on each page.
Xcode project templates and file templates are pretty easy to make, with a few caveats.
Check the answers to these questions:
Add new templates in Xcode
Change templates in XCode
Also take a gander at these handy tutorials:
Custom Xcode Templates
Xcode: How to customize the existing project templates
It sounds to me like your putting your data into your views (pages). That's a big design error. You need to employ the Model-View-Controller design pattern and separate your data from your views. That will make it easy to create one view (template) that you can reload with data to display each individual recipe.
The first thing to do is to separate your data from the view. You need to have the recipes stored in an array, dictionary, Core Data etc and then wrap that data in a dedicated object. The second thing to do is to create a dedicated view to display all the recipes. As the user moves from recipe to recipe the app will simply remove and add information to the same view as needed.
I would recommend Cocoa Recipes for Mac OS X: The Vermont Recipes, Second Edition because it addresses these issues and it uses a recipe type app as its example. It's for Cocoa but the basic principles apply to iPhone apps as well.