Instance lifetime management - autofac

I am using Caliburn.Micro v2 along with Autofac and I am having some issues with the WindowManager.ShowDialog function.
I have the following which successfully displays a dialog:
windowManager.ShowDialog(dialogViewModel.Show(typeToShow));
If after closing the newly shown window via the cross button I recall the above expecting to see the dialog once again, I encounter the following exception:
Cannot set Visibility or call Show, ShowDialog, or WindowInteropHelper.EnsureHandle after a Window has closed.
It is my understanding that the error is due to ShowDialog only being usable once and that if I want to call ShowDialog again, I need to provide a new instance. I have proven this to some degree by using:
windowManager.ShowDialog(new DialogViewModel().Show(typeToShow));
This successfully results in a new dialog each time, however, I do not wish to call new here each time. How do I therefore tell Autofac to give me a new instance of DialogViewModel each time, rather than reusing the same instance?
EDIT 1 - DialogViewModel registration
var buider = new ContainerBuilder();
builder.Register(e => new DialogViewModel())
.AsSelf()
.InstancePerDependency();
I have previously been using .SingleInstance() and thought using .InstancePerDependency() might be what I was looking for, it appears not though.

Autofac has built-in factory support via Func<T> class. You just need to resolve Func<DialogViewModel> instead of DialogViewModel which means a factory that returns DialogViewModel. You don't need to change your existing registration. More info on wiki page.

Related

Object reference not set to an instance of an object. ( I can't edit design or create new form, class)

I got this error in my project. I cannot access the design for editing. while when I build, the program still runs normally. I also get error https://i.stack.imgur.com/8WBBy.jpg when creating new form or new class.Help me!!
how to solve this problem?

Attachments are not updated asynchronously in Fiori MyInbox app?

I use SAP standard library: Inbox.
in library class S3.controller by tap on attachments icon is onTabSelect event executed, witch makes
this.fnDelegateAttachmentsCreation();
this.fnFetchDataOnTabSelect("Attachments");
this.fnHandleAttachmentsCountText("Attachments");
this.fnHandleNoTextCreation("Attachments");
break;
fnFetchDataOnTabSelect makes an asynchronous call. During this call is fnHandleAttachmentsCountText already executed, so the update of attachments count occurs before the request for attachments is ready. As far the request for attachments is ready, there is no update for title executed.
On screenshot is AttachmentCountText „Attachnents (1/1)“, that comes from previously selected item.
It should be „Attachements (2/2)".
Also if response comes too quick, then view changes to loading view after it received the answer from request.
If list of attachments was updated from request callback, then it should not be updated second time.
Here it seems, that there is something on loading, but request is already finished.
How could be Inbox extended, to update the attachment header and content after request is ready?
used SAPUI5-Version: 1.71.4
You are using the standard bsp-application ca_fiori_inbox?
You didn't create an extension project of the application ca_fiori_inbox with custom coding?
If that's the case, it's a bug in an standard application delivered by the SAP. SAP releases so called notes to fix bugs in their standard applications.
You can import notes in your system via the transaction SNOTE. May ask a SAP Basis Administrator from your company for help.
The following notes exactly describe your problem
2873960
2823664
2916255
2901520
If you already extended the SAP standard application(MyInbox) without using ExtensionPoints codechanges in the standard application will not affect your custom extension.
When overriding a controller method, any functionality that was previously provided by it is no longer available. Likewise, any future changes made to the original controller method implementation will not be reflected in the custom controller.
In this case you could still implement the note and check the changes in the standard controller vs. your custom controller on your system and change the respective lines in your custom coding.
Don't fix SAP coding. Report it and get a fix.
The Note 2873960 corrects coding in an abap class, not in the bsp-application(ca_fiori_inbox). So definitly import the note and check if it's fixing your problem.
I actually do not know, how the app works, but I want to give it a try.
Since it is an asynchronous function, you can always also wait for the function until it is done. So in your case, you could try to set an await keyword in front of the function.
await fnFetchDataOnTabSelect("Attachments");
This will now wait on this position until it has finished the function call before it will call the next functions. In addition to that you also need to set the upper function onTabSelect to async. So in the end it should look something like this.
onTabSelect: async function() {
// ...
this.fnDelegateAttachmentsCreation();
await this.fnFetchDataOnTabSelect("Attachments");
this.fnHandleAttachmentsCountText("Attachments");
this.fnHandleNoTextCreation("Attachments");
// ...
}
Although the Web IDE maybe shows you errors, it does work, since it is an official JavaScript API.

Flutter Mobx - Passing store state between pages in PageView

How can i pass or preserve the state of my store between pages using PageView?
By example, I'm trying to upload an image at the first page to edit, and pass to a second page where i want to show the image with a form. Im using MVC, and the image is set via controller (store), but it's not working. I've been made some tests and sometimes, at debugging runtime, the image is shown at the second page. But, sometimes even debugging it isn't shown and its value is null.
I tried with AutomaticKeepAliveClientMixin also, but the behavior is the same.
Someone can tell me what i'm doing wrong or what i'm missing?
I think using singleton can solve your problem, actually I think I had this problem in two apps I made.
I used get_it plugin, this package creates singletons easily for you and it's simple to retrieve anywhere in the app without using context.
First, register your MobX as Singleton, I do it on main:
getIt.I.registerSingleton<YourStore>(YourStore());
Retrieve the same instance of your Store, if you have observables in the first page and call an action on the second page, it will trigger the observables in the first page or wherever you used any observable from this instance of Store.
GetIt.I<YourStore>().changeImageFromFirstPage();
You can call GetIt.I().youraction() anywhere in your app, it will trigger the observables you created on this Store.
final list = Provider.of<TodoList>(context);
in the MobX document, there is a provider that can be used as the above code.
I use GetIt too, it is really awesome.
there is a sample for this in the following URL for the MobX:
https://mobx.netlify.app/examples/todos

Stopping Ember.js Controller

My question is very basic on one hand but on the other hand the general situation is more complex, plus I cannot really get any working sample.
I'm developing/maintaing a web-application which is currently in transition from GWT code base into Ember.js.
Most of the newer code already relies on Ember.js and I think it's really awesome.
The problem is we cannot use Ember Router as all the request are being handled by the GWT.
In order to enabled the application run in this unusual configuration we have special JavaScript files that create our Ember main objects (Controllers & Models) for us.
As you can imagine navigation between tabs is cumbersome and is handled by GWT who creates Ember objects when needed. We are in transit toward a brave new world Ember Router and all.
But in the meantime, this is the problem I'm facing right now.
The user clicks a link which opens a page that contains some Ember based table.
The data is retrieved form the server using some Ajax code. Upon success it spawns a forEach loop which tries to pushObject all the received date into our Ember based components.
My problem happens when the user quickly switches between tabs. In this case the first list of object has not finished rendering yet and suddenly there's a new set of objects to handle. This causes Ember to throw errors like:
"Uncaught Error: Cannot perform operations on a Metamorph that is not in the DOM. "
and
"Uncaught NotFoundError: An attempt was made to reference a Node in a context where it does not exist."
Is it possible to prevent the loop from trying to render?
I've tried checking if the controller in question is already inDOM and it is, is there a way to notify Ember this object is no longer valid?
Sorry for a lengthy question and lack of running sample.
I'd probably modify the switch tab code to only execute afterRender has completed, that way you aren't mucking with ember objects while they are being used.
Ember.run.scheduleOnce('afterRender', this, function(){
// call GWT switch tab routine
});
Thank you Daniel and Márcio Rodrigues Correa Júnior. eventually what I did is to add a patch that would check the current context of the application (in my case the currently selected tab). If upon receiving the AJAX response the application is in the correct context (meaning the user haven't change the tab) go on. Otherwise just ignore the response and do not try to render it.
Now it seems to be working

Plugin and dialog together

If I use a dialog to create an instance of an entity, will it fire the plugin registered to that message (i.e. Create on EntityA)?
If not, how can I link that plugin to that message?
Yes, the plugin will always fire regardless of the source of the message.
You're safe to use the plugin. It will catch the dispatched message as long as you've registered it correctly.
The plugin will, in fact, react to the following events.
Creation of an instance (a record) by the user from the GUI.
Creation of an instance by a workflow.
Creation of an instance by a dialog.
Creation of an instance by a code from an extern program.
Creation of an instance by... anything.