I have a ConfigurationViewModel which inherits from BaseViewModel. BaseViewModel is placed in a separate project and has an INotifyPropertyChanged interface implemented. This separate project does not have Fody.PropertyChanged installed.
When I try to build solution I have exception:
Failed to execute weaver C:\Users\Rafal\.nuget\packages\propertychanged.fody\2.6.0\build\..\netclassicweaver\PropertyChanged.Fody.dll
Type:
System.Exception
StackTrace:
at InnerWeaver.ExecuteWeavers() in C:\projects\fody\FodyIsolated\InnerWeaver.cs:line 186
at InnerWeaver.Execute() in C:\projects\fody\FodyIsolated\InnerWeaver.cs:line 109
Source:
FodyIsolated
TargetSite:
Void ExecuteWeavers()
Could not inject EventInvoker method on type 'Designer.VVM.ConfigurationViewModel'. It is possible you are inheriting from a base class and have not correctly set 'EventInvokerNames' or you are using a explicit PropertyChanged event and the event field is not visible to this instance. Either correct 'EventInvokerNames' or implement your own EventInvoker on this class. If you want to suppress this place a [DoNotNotifyAttribute] on Designer.VVM.ConfigurationViewModel.
Type:
Fody.WeavingException
StackTrace:
at ModuleWeaver.InjectMethod(TypeDefinition targetType, InvokerTypes& invokerType)
at ModuleWeaver.AddOnPropertyChangedMethod(TypeDefinition targetType)
at ModuleWeaver.FindMethodsForNodes()
at ModuleWeaver.Execute()
at InnerWeaver.ExecuteWeavers() in C:\projects\fody\FodyIsolated\InnerWeaver.cs:line 182
Source:
PropertyChanged.Fody
TargetSite:
Mono.Cecil.MethodDefinition InjectMethod(Mono.Cecil.TypeDefinition, InvokerTypes ByRef)
When I move BaseViewModel to the same project as ConfigurationViewModel then everything is ok.
Is it standard behaviour? Is it a bug? Am I doing something wrong? How to use Fody.PropertyChanged having BaseViewModel in a separate project?
when the base View Model is in the same project, then the "OnPropertyChanged" method can be injected into that class. When referencing the base View Model from another project, then that project has to have an "OnPropertyChanged" that matches the convention or customise the method name using EventInvokerNames https://github.com/Fody/PropertyChanged/wiki/EventInvokerSelectionInjection
in summary, try adding this to your base view model
public virtual void OnPropertyChanged(string propertyName)
{
var propertyChanged = PropertyChanged;
if (propertyChanged != null)
{
propertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
Related
I have a UWP application which uses the Managed UWP Behavior SDK.
I wrote a custom behavior which has two dependency properties, one of which is a ObservableCollection.
Whenever I update an item in the collection, I make sure that PropertyChanged is called for the collection.
However, the Dependency property is not being updated.
My code:
<trigger:CustomBehavior ItemIndex="{x:Bind ItemIndex}"
Presences="{Binding ElementName=Box,
Path=DataContext.CustomCollection,
UpdateSourceTrigger=PropertyChanged, Converter={StaticResource TestConverter}}" />
My TestConverter shows me that when I update an item in the collection, the updatesource trigger is working. The dependency property in my behavior however, is not firing the Changed event. When I change the entire custom collection, the DP is updated, when I just change one item, it isn't.
Research so far says that DependencyObject.SetValue just checks to see if the object has changed and if one item changed, it will just think that the collection didn't change at all? Is this true, and if so, how can I overcome this?
Thanks
A collection-type dependency property should usually be declared as the most basic collection type, IEnumerable. This way you can assign a variety of actual collection types to the property, including those that implement INotifyCollectionChanged, like ObservableCollection<T>.
You would check at runtime if the collection type actually implements the interface, and possibly attach and detach a handler method for the CollectionChanged event.
public class CustomBehavior : ...
{
public static readonly DependencyProperty PresencesProperty =
DependencyProperty.Register(
"Presences", typeof(IEnumerable), typeof(CustomBehavior),
new PropertyMetadata(null,
(o, e) => ((CustomBehavior)o).OnPresencesPropertyChanged(e)));
private void OnPresencesPropertyChanged(DependencyPropertyChangedEventArgs e)
{
var oldCollectionChanged = e.OldValue as INotifyCollectionChanged;
var newCollectionChanged = e.NewValue as INotifyCollectionChanged;
if (oldCollectionChanged != null)
{
oldCollectionChanged.CollectionChanged -= OnPresencesCollectionChanged;
}
if (newCollectionChanged != null)
{
newCollectionChanged.CollectionChanged += OnPresencesCollectionChanged;
// in addition to adding a CollectionChanged handler, any
// already existing collection elements should be processed here
}
}
private void OnPresencesCollectionChanged(
object sender, NotifyCollectionChangedEventArgs e)
{
// handle collection changes here
}
}
I have UI object that wraps JPA entity and in constructor of that UI object I do lazy loading of some properties. In that same constructor I need to know what JsonView is currently active so I dont lazy load some fields that are not needed if say its the List view.
Is there way to find out from constructor what is current active JsonView at runtime. Or is there any other way to achieve what I described above.
My current plan
create custom serializer that during serialization will call setJsonView(Class jsonView) of the object that it serializes. All my objects that serialized will have to support that method. Inside that metid I can do lazy loading based on now known json view. Something like this:
public class JsonViewSerializer extends JsonSerializer<BaseSerializableEntity> {
#Override
public void serialize(BaseSerializableEntity value, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonProcessingException {
value.setJsonView(provider.getSerializationView());
// need to pass serialization to base class...
}
}
Currently active view is accessible via context object (SerializerProvider or DeserializationContext), using method getActiveView().
I'm working on a Windows 8 Store App (using the Grid App Template) and while I'm loading data from a server I want to show a ProgressRing and hide the GridView or ListView (depends on if the app is snapped or not) that will display the data once it is fully loaded.
The issue is that when the ViewModel is loading data I need to be able to change the VisualState.
I found what I thought was a solution Here, but this code will not build.
public class StateManager : DependencyObject
{
public static string GetVisualStateProperty(DependencyObject obj)
{
return (string)obj.GetValue(VisualStatePropertyProperty);
}
public static void SetVisualStateProperty(DependencyObject obj, string value)
{
obj.SetValue(VisualStatePropertyProperty, value);
}
public static readonly DependencyProperty VisualStatePropertyProperty =
DependencyProperty.RegisterAttached(
"VisualStateProperty",
typeof(string),
typeof(StateManager),
new PropertyMetadata((s, e) => //this throws the error
{
var propertyName = (string)e.NewValue;
var ctrl = s as Control;
if (ctrl == null)
throw new InvalidOperationException("This attached property only supports types derived from Control.");
System.Windows.VisualStateManager.GoToState(ctrl, (string)e.NewValue, true);
}));
}
ERROR: Cannot convert lambda expression to type 'object' because it is
not a delegate type
Does anyone know how to get the linked solution to work? Or is there a simpler method that I am completely missing (I'm a XAML newbie!)?
I'm not even sure if the listed solution will work because the "Snapped" vs "Full" states are managed by the base LayoutAwarePage class included with the template.
why not simply use a datatrigger bind to a viewmodel property like IsBusy {get;set;} to enable your Progressring?
(or "Using LocationInterceptionAspect and IInstanceScopedAspect together")
Using Postsharp I'm trying to inject a property into a target class using 'IntroduceMember' and then using the 'OnGetValue' functionality of LocationInterceptionAspect dynamically give it a value on inspection.
Originally I thought that I'd need two separate aspects, one for the field injection and one for the location interception but managed to combine the two by implementing the IInstanceScopedAspect interface and inheriting from LocationInterceptionAspect.
The problem is that if I set a breakpoint I will see the property that's been injected, but if I set another breakpoint in the OnGetValue method (that gets fired for each property on the class) I can't see it...
Here's some sample code:
[Serializable]
class DALDecoratorWrapper : LocationInterceptionAspect, IInstanceScopedAspect
{
public override void OnGetValue(LocationInterceptionArgs args)
{
if (args.LocationName == "Type")
{
args.Value = "computed value here";
}
args.ProceedGetValue();
}
[IntroduceMember(OverrideAction = MemberOverrideAction.OverrideOrFail)]
public String Type { get; set; }
I was also hoping there was a better way of doing this than overriding OnGetValue as that's called for each getter where really I want to only target the getter of the property that's been injected
Cheers
here is my problem: I'm building a desktop application, with the following tools:
Caliburn
Ninject
NHibernate
All my view models and repositories are instanciated with Ninject. My repositories all need an ISession in their constructor.
I'd like to follow ayende's advice concerning the ViewModels: each ViewModel opens a new session.
Is it possible to configure Ninject to open a new session when a ViewModel is created, and use this session inside the repositories used by this view model?
I had a look to the InScope function of Ninject, as well as the ICurrentSessionContext interface in NHibernate, but I don't know how to model all of that to get what I want...
Did someone make something like that before?
Thanks in advance
Mike
I solved a similar scenario leveraging the ViewModel lifecycle: I created an ISessionAware interface (with a SetSession method) to be implemented by repositories, then I initialized the repositories through ISessionAware in the OnInitialize method of the ViewModel (which is enforced by Caliburn when the VM is managed by a ScreenConductor).
Using reflection to inspect the properties holding the repositories, I could put all the infrastructure on a BaseDataVM class.
Using a scope in the container would be more elegant, I think, but I don't know Ninject.
I have a very similar project (except I'm not using Caliburn) and have been trying to figure out how to do this as well. I did come up with one method that works well for constructor injection using Ninject's InScope() method.
I have a static class called IoC that wraps access to Ninject's kernel. Since the dependencies are all injected into the constructor, the context is only relevant when the object is being created. So it doesn't matter what is supplied for context, but a Guid feels like the safe choice. Program.OpenSession() is a static method to open a new ISession.
public static class Ioc
{
private static readonly IKernel _kernel;
static IoC()
{
_kernel = new StandardKernel();
_kernel.Load(new ContextModule());
}
private static object _context;
public static T ResolveInContext<T>(object context)
{
_context = context;
var result = _kernel.Get<T>();
_context = null;
return result;
}
private class ContextModule : NinjectModule
{
public override void Load()
{
Bind<ISession>().ToMethod(x => Program.OpenSession()).InScope(x => _context);
Bind<frmCompanyViewer>().ToSelf().InScope(x => _context);
}
}
}
Usage is:
var frm = IoC.ResolveInContext<frmCompanyViewer>(Guid.NewGuid());
The form's constructor signature is:
public frmCompanyViewer(ISession session, ICompanyRepository companyRepository)
I verified that with InScope on the bindings, the same ISession that is used to construct frmCompanyViewer is also used to construct companyRepository. If I remove InScope then two ISessions are used.
Edited to add: This would also work, see comments. This should be made thread safe for a real application. I changed the method name to ConstructInContext to clarify that the context only applies during object construction.
public static T ConstructInContext<T>()
{
_context = Guid.NewGuid();
var result = _kernel.Get<T>();
_context = null;
return result;
}
We have this with AOP, in unhaddins.
Is called "Conversation per Business Transaction".
search in google
here you have ;)
http://groups.google.com/group/unhaddins/browse_thread/thread/29eca74a83df5faf/d9fab4062d4cb4c4?lnk=gst&q=ninject#d9fab4062d4cb4c4
Well, I've found a solution thanks to the ninject group.
The solution here is to use the function InScope when I bind ISession, and browse in the IContext variable to inspect the services. If one service in the request hierarchy is assignable to the base class of my view models, I use the context as scope.
So the first time an ISession will be injected in the constructor of my ViewModel, a new scope is used. And all subsequent calls to ISession inside the constructor of the ViewModel will be resolved with the same scope. And then only one session is created for my ViewModel.
Here is the code:
Bind<ISession>().ToMethod(ctx =>
{
var session = ctx.Kernel.Get<INHibernateSessionFactoryBuilder>()
.GetSessionFactory()
.OpenSession();
session.FlushMode = FlushMode.Commit;
return session;
})
.InScope(ctx =>
{
var request = ctx.Request;
if (request.Service is IScreen)
return request;
while ((request = request.ParentRequest) != null)
if (typeof(IScreen).IsAssignableFrom(request.Service))
return request;
return new object();
});
And the constructor of the viewmodel must contains all the injected dependencies which rely on the ISession:
[Inject]
public PlayersManagementViewModel(ISession session, IPlayersRepository playersRepository)
{
}
Hope that helps