Sharing state/changes across ViewModels

Posted by joshperry on Stack Overflow See other posts from Stack Overflow or by joshperry
Published on 2010-06-10T20:39:06Z Indexed on 2010/06/10 20:42 UTC
Read the original article Hit count: 208

Filed under:

wpf

|

xaml

|

mvvm

I have an App which has a Tasks tab and a Projects tab. I decided to make a separate ViewModel for each of the tabs, TasksViewModel and ProjectsViewModel.

The Tasks tab has a new task area with an associated project pulldown and the Projects tab (obviously) has a list of projects.

What I'd like is for the pulldown on the Tasks tab to share the same collection as the Projects tab list so that any time I add or remove a project on the Projects tab the list on the Tasks tab is up to date automatically. This worked well with a single ViewModel but it was beginning to become quite unruly.

Should I not have split into two ViewModels? Is there a common method of sharing data like this? Perhaps pass the same ObservableCollection<Project> into each of the ViewModels? Perhaps some type of notification back to the TasksViewModel along the lines of ICollectionChanged.

Appreciate any insight/input!

© Stack Overflow or respective owner

Related posts about wpf

C#/WPF - RoutedEvent in WPF class that isn't a UIElement

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a class that needs to notify that something significant has occured. The class is in a WPF-project, even though this specific class, is lookless (and doesn't inherit from UIElement, neither directly or indirectly). Normally, I just register a RoutedEvent to get this functionality but as this… >>> More
How to pass value from wpf form to wpf user control

as seen on Stack Overflow - Search for 'Stack Overflow'
Hai am having a WPF user control in my WPF Form, when i click my button in my form , i just want to pass some value to the textbox which is in the usercontrol, tell me how to do this. >>> More
WPF opening up exe program within WPF window

as seen on Stack Overflow - Search for 'Stack Overflow'
Not sure if this is possible but is there a way to open up another program like notepad within the container of a WPF window? similiar to that of being able to open a web page using the webbrowser control? Basically I would like to open notepad or other exe but keep it constrained within the WPF… >>> More
Silverlight Commands Hacks: Passing EventArgs as CommandParameter to DelegateCommand triggered by Ev

as seen on ASP.net Weblogs - Search for 'ASP.net Weblogs'
Today I've tried to find a way how to pass EventArgs as CommandParameter to DelegateCommand triggered by EventTrigger. By reverse engineering of default InvokeCommandAction I find that blend team just ignores event args.To resolve this issue I have created my own action for triggering delegate commands… >>> More
Building applications with WPF, MVVM and Prism(aka CAG)

as seen on ASP.net Weblogs - Search for 'ASP.net Weblogs'
In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab). The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen… >>> More

Related posts about xaml

Getting Started Building Windows 8 Store Apps with XAML/C#

as seen on ASP.net Weblogs - Search for 'ASP.net Weblogs'
Technology is fun isn’t it? As soon as you think you’ve figured out where things are heading a new technology comes onto the scene, changes things up, and offers new opportunities. One of the new technologies I’ve been spending quite a bit of time with lately is Windows 8 store applications. I posted… >>> More
XAML and WPF - Passing Variables to XAML Windows

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I'm pretty new to WPF and i'm trying to load a XAML window and pass a variable to this XAML in its constructor or so, because i need it to load some items from this passed variable. Could anyone point me to the direction of how to go about this please? How does one start up a XAML window and… >>> More
WPF: Xaml, create an observable collection<object> in xaml in Dot Net 4.0

as seen on Stack Overflow - Search for 'Stack Overflow'
the web site says you can in dot net 4.0 I cant seem to do it though, what assesmbly references and xmlns' do i need the following does not work xmlns:coll="clr-namespace:System.Collections.ObjectModel;assembly=mscorlib" <coll:ObservableCollection x:TypeArguments="x:Object"> <MenuItem… >>> More
Silverlight insert XAML inside other XAML

as seen on Stack Overflow - Search for 'Stack Overflow'
I am using WPF and Silverlight BookControls by Mitsu http://www.codeplex.com/wpfbookcontrol The WPF example alows that every page in the book to be a XAML file, but the Silverlight example dont. Is there a way load a XAML in every book page in the Silverlight example ? >>> More
WPF: Xaml, create an observable collection<object> in xaml in .NET 4.0

as seen on Stack Overflow - Search for 'Stack Overflow'
the web site says you can in .NET 4.0 I cant seem to do it though, what assesmbly references and xmlns' do i need the following does not work xmlns:coll="clr-namespace:System.Collections.ObjectModel;assembly=mscorlib" <coll:ObservableCollection x:TypeArguments="x:Object"> <MenuItem… >>> More