First of all, I'm using MVVM for this and I would like to continue using it and ofc using the best practices as well.
I have a Mainpage which will display a list of items. On another page you can add such items. The items will be saved in a database which came with the Mango update.
When a item is added I want to navigate back to the mainpage and I want the list to be updated automatically. Is this possible and what's the best way? I'm thinking of following scenario's:
Use the Refresh query string when you navigate. Check in the back end of your main if there is a refresh. Then send a message 2 the ViewModel that he needs to update his list. I have tried this and this works. But this doesn't really sound the right way for MVVM.
Can't this be done with the NotifyPropertyChanged event that you can raise on your Database Model ? Or doesn't it work over different pages?
Reload the whole ViewModel for the main page somehow.
Any other idea's?
Use MVVM-Lights Messenger. The MainViewMode can subscribe to a Refresh event and the ViewModel where the items are added can publish a Refresh event.
This is a good example of how messenger can be used.
Related
I have a subgrid on my form which I assign a dynamically generated fetchxml query using javascript. When the user clicks on the subgrid's "pop out" button, the query is lost and it displays the default view for that entity.
The user needs to be able to perform multi selection and bulk editing. As far as I know this is not possible for subgrids in CRM 2013 upwards. Is there a way to retain the query when it is popped out?
There's no supported way to interact with a popped out grid. If you started digging into the client side application code, you might be able to find a hook to the new window, but doing so would be unsupported, liable to break, and I wouldn't recommend it.
I was going to suggest hiding that pop-out button on your entity's sub-grid altogether before re-reading that your users need to use the popped out grid for bulk edit.
In that case your best option will be to do ditch the JS and move to a RetrieveMultiple plugin against the sub-entity. RetrieveMultiple plugins should be generally avoided, but from what it sounds like in your case, it's your only option.
And, just to be thorough, are you positive you need dynamic fetch for the sub-grid? Is there any way you could come up with a view that would get close enough to your requirement, even if it's not perfect?
Update:
Based on the additional information you provided in your comment, I can only think of two options:
Implement a custom grid--or modify one of the free ones out there--that allows multi-select and bulk edit
Your custom web app takes the user's criteria, creates a personal view (entity: userquery) for the user and saves it to the database, then your JS on the form sets the grid to that view.
You can do that liks this:
document.getElementById("someGridId").control.SetParameter("viewtype", "4230"); // 4230 is the objecttypecode for userquery
document.getElementById("someGridId").control.SetParameter("viewid", "{11310965-0306-E611-80E5-3863BB36DD08}");
Doing this actually does make the popped out grid load the personal view, but in my tests just now the grid gets upset if you try to refresh it.
This approach has obvious downsides: 1) You have to come up with a way to clean up the personal views that get generated 2) the grid might break on refresh 3) it's unsupported and liable to break on an update.
Still worth considering, I suppose.
A more supported way instead of using unsupported getElementById is to hook a plugin to multiple retrieve of the entity and amend the query in there
Chris
So, I am using ui-router for my app's routing. There is a scenario, I clicked like button on the item detail page. Then I hit back button, it goes back to the main page, it is a list of items. The item has a likes counter. But I found the counter did not increase because back button did not fire the controller for main page.
I want to understand how can I fire the controller while clicking back button.
You should isolate your data in a provider to manage the data sync between your views. If all of the data is contained in a service, you can update it from one view, and it will always be synced with the other.
In both of the controllers, require 'ItemRepository' which will provide the data to the views.
All, I am new to Windows 7 Phone. My situation is that I have a main page which contains a ScrollViewer which in turn houses a StackPanel. I want to populate this StackPanel with multiple sub-StackPanels (at runtime) which are to hold an Image Thumb nail a hyperlink and some basic information about the image.
This is all good when I do this from the main page, but I want to know how to update this control (which is on the main page), but from any page other than the main page. I would like to know what is considered best practice for updating a page's control (like that outlined above) from another page.
Obviously there are a number of ways to pass data between pages
PhoneApplicationService.Current.State["yourparam"] = param
NavigationService.Navigate(new Uri("/view/Page.xaml", UriKind.Relative));
then in other page simply
var k = PhoneApplicationService.Current.State["yourparam"];
and many others. But what is best practice for updating a generic control from a different page?
Note: There are many question about data access and passing between pages.
Passing data from page to page
How to pass the image value in one xaml page to another xaml page in windows phone 7?
Passing image from one page to another windows phone 7
and more. This is not what I am asking.
If I understand your question correctly, you are trying to update a control which is on for example MainPage.xaml from another page for example Page2.xaml.
As far as I know there is no way to reach a pages controls from another page, and that seems unnecessary for the cases that I can think of.
The method used to achieve what you are trying is usually done by triggering an action (like the press of a button ) and passing a parameter to the page you are trying to update the control. And on that page's onnavigatedto event (or viewmodel constructor if you are using the MVVM pattern), update your control based on the passed parameter.
If your update is based on data then the best practice is to bind an observable collection or an object that extends the INotifyPropertyChanged (basically any object that can signal that one of their property changed to the ui) and change the data based on the parameter that is passed.
If these two pages somehow are visible at the same time and there is no navigation needed between them( like a popup or sliding menu kind of ui) then you can make the page that you are showing in the popup a usercontrol, and reach to the parent's controls by this.Parent.
I can be more helpful if you give more specifics about your app's flow.
The MVVM pattern would be a good way to go. Saying MVVM is too complicated for small teams isn't exactly accurate - the purpose of MVVM is to decouple Silverlight or WPF code. Using the codebehind of a Silverlight page to directly access data creates coupling in your code and accrues technical debt. Whether you're one developer or 100, if your UI is coupled with your data classes, if you have to change your data classes, you will have to make changes to every UI element that uses those classes. This takes longer and makes your application more difficult to change.
MVVM makes it so your UI (the View) doesn't know anything about the data (your Model). The ViewModel is the code in between that the UI can bind to, and which manages events in the UI that need to be persisted to the Model, and also changes in the Model that need to be represented in the View. For this reason, it handles events, and that's what it sounds like you need in your code - an event that can exist off of the codebehind, that can update the Views bound to it when the data changes. If you have two pages, then an event on one of the pages will be sent to the ViewModel, which will make a change to the Model (data) if necessary, and pass it back to the ViewModel. The ViewModel would then update any of the UI elements (Views) bound to that piece of data.
There's a REALLY good demonstration of how to implement the MVVM design pattern here
. The guy goes through and takes a typical WPF application (just like Silverlight), where the UI codebehind implements event handlers that directly access data, and refactors it using the MVVM pattern.
I am writing a Grails app and I have a quick question about the best way to do something. My controller has 2 lists of data, both of which are displayed on the view in separate HTML tables. What I want to do is to have a button that will allow you to move an item from one list to the other. What is the best way to do this?
I have done some research and using some form of AJAX seems to be the general consensus on the best way to do this. Is there any other way? The heart of the problem is that I can't figure out how to update the data contained in the contoller based on the button the user presses in the view.
Thanks
I solved this by just updating the model to reflect the new lists and rerendering the page
ASP.NET MVC noob here
I was writing a quiz application where a user can select her preferences (e.g. difficulty, number of question etc.), and once she hit a submit button - she got a new page with questions.
The preferences are represented as a "Preferences" object, and the questions are IEnumerable of Question.
This all worked well.
Now I decide both parts should be in the same page - and I don't know how to accomplish that:
Should I have a new model class that is a composition of these two parts?
And also - How will I make the "questions" part appear only after the user completed filling up her preferences and clicked a button?
Should I use AJAX?
I also read a little about partial views and RenderSection.. But I really couldn't understand which approach is the most appropriate for my scenario.
So how should I draw two parts of a page, where the second is only displayed after the first is submitted?
Thanks.
How familiar are you with AJAX? If I had to guess I would think a good way to do what you want to do is to have an AJAX call which is linked to an action when the user submits their preferences. The action can then return a partial view which you can have appear on the page without a reload via AJAX.