Databinding during Navigation in UWP - mvvm

I'm using Windows Template Studio to create a simple UWP app. I'm using the built-in MVVM template for Multiple Pages.
I have 2 Pages on the app. Both the pages contain the few textboxes where the user can enter some values. Data binding is working perfectly on both the pages individually. My problem is:
When I navigate to Page 2 and return back on Page 1, the value in the Textboxes return to the original initialization values and do not remain the last updated values.
I am expecting that when I return to Page 1 from Page 2, the values on Page 1 should be the last updated values.
I've followed a lot of tutorials but could not find a comprehensive solution to it.
I am just getting started with UWP and MVVM so it may be hard for me to wrap my head around some of the basic concepts.
Any help in this regard is appreciated.

You need to think about saving these TextBox values in the ApplicationData. For example, the ApplicationData.LocalSettings.
When you navigate from page1 to page2, you could save the value in localSettings.
var localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
localSettings.Values["exampleSetting"] = "Hello Windows";
When you get back from page2 to page1. You could get the value from LocalSettings.
Object value = localSettings.Values["exampleSetting"];
Please see the Application data sample for more details.

Have a look at NavigationCacheMode
https://learn.microsoft.com/en-us/uwp/api/windows.ui.xaml.controls.page.navigationcachemode
This should allow you to Cache the data you've entered and will persist whilst navigating to different frames

Related

Ionic UI Router issue: 2nd level state views not loading

I can't wrap my head around this issue I've been experiencing, or perhaps I'm missing some crucial point here. I jotted down this sample app on ionic playground, it is of course a simplified version of my app.
Basically I have a tabbed layout with two views which share a common datasource of items (in my app it's a sqlite db table); the first view displays items in a certain state whereas the other tab display the remaining items (in my example I've used the TODO list metaphor).
Each tab has a child state which I refer to as 2nd-level state (assuming level 0 is the abstract tab state. These two 2nd-level states are defined separately but share a common controller and template.
I cannot for the life of me understand why these two states aren't being navigated to when I click on a list item from either of the two lists (1st-level state views).
NOTE: In the ionic playground no error is thrown in the console, but I can't quite tell what is going on in terms of state URLs. But when I test my actual app (where the problem is the same) in a browser I can see the URL changing to #/tab/tasks/xxxx or #/tab/completed/xxxx but template is not loading. Upon googling I came across several SO questions:
Ui-router URL changes, nested view not loading
In Angular ui-router nested state url changes,but template is not loading
UI-Router: URL changes, but view is not loaded
Angular Router - Url changes but view does not load
URL changes but view does not hcange
Angular UI-Router : URL changed but view isn't loaded
but the answers provided therein haven't worked for me (tried, as per the last one I listed, to add the # sign after the view name in the child states, but to no avail).
Kinda stuck, would really appreciate some input! Cheers.
Managed to get it working following this answer; I had previously tried simply appending the # character after the view name in nested states but it turns out the trick was to append #tab, where tab is the name of the top-level abstract state. I updated my fiddle on ionic playground. Cheers to you all.

Which approach to use MVVM or Static

Im pretty new in using the MVVM architecture and looking for some advice on the "correct" to approach this task.
2 page app.
Page 1 displays the alphabet.
Page 2 displays the selected character's details.
Example - Select "A" and screen 2 displays apple, Apricot, Aprium. Select "B" screen 2 displays Banana, Blackberry, Blackcurrant, Blueberry.
Data is being retrieved from a web service everytime the user selects an alphabet character.
Would the correct approach be to create a static menu for screen 1 (as you would never have anything else other than the alphabet characters) and on the click event load the second screen with the items as above using the MVVM approach (i.e. pass in the selected character to the LoadItems method). Or is there a simpler way to do this using a MVVM structure?
Ive read around and its not very clear on when to use which approach but then again as i say im new with MVVM too and would like to learn the correct/preferred way so i can get a better understanding.
Another approach which maybe more in-keeping with the Windows Phone experience would be to have a single page containing a LongListSelector. Fruit bound to this view could then be grouped by letter. Implementing a JumpList would allow users to quickly navigate this list by jumping between groups. You can find a sample implementation here- http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj244365(v=vs.105).aspx
Microsoft actually prefers that when you use a list in windows phone it is always better to display it in another page. So you should populate the list in another page. And if you are selecting some thing to show then pass them as parameters using the NavigationService.Navigate or store the data in Phone Application State if you have to use app wide. Phone.Application.Resources . Its good that you are going through Mvvm You'll know Xaml, WP7,8, Get Metro Application Idea also Silverlight.
Heres a toolkit that might help you. It also displays the same way in a new Windows Not a popup
Long List Selector

MultiPage Form Identify VBA

it might be the silliest question anyone ever asked, but I have been looking for a long time and I could not find an answer.
I have a form with a multipage with 2 pages, and I want to know which page is the one the user is filling up when he presses the ComandButton (which page is the user viewing at that moment). I want that because depends on which page the data will be inserted in diferent place.
If more info is needed, just let me know.
Thanks.
For a control called MultiPage1 you could return the page as below
For example
`1st tab
Me.MultiPage1.Value = 0
`3rd tab
Me.MultiPage1.Value = 2

overriding setResponsePage() to build breadcrumb

I 'm trying to build my own simple breadcrumb component that pushes a PageRefence onto a List for each and every Link in the application.
Unfortunately, setResponsePage() is final (I use wicket 6).
The only other option that comes to my mind is to add a parameter to my base page constructor. But this would require me to change every link in the app..
Are there any other options?
Since you already have a base page, it's easier to override onBeforeRender() in your base page to update the breadcrumbs list that you'd store in your Session object.
Or am I missing something?
To answer my own question:
In the end I realized, that I do not want to have the breadcrumb updated on each new page.
Therefore I created an object that holds a List of Pagereferences. When I navigate to a new Page, I take the list of the current page, make a copy of it an add the current page. The resulting list is pased onto the new page.
All this is handeld in the base page.
Keeping it in the page, avoids problems with multiple tabs / windows.
Thanks for the help.

Creating reusable widgets

I`m using asp.net mvc 2.0 and trying to create reusable web site parts, that can be added at any page dynamically.
The problem I have is how to load a partial view with all related js and data? Ive tried the following ways to do that:
Use partial view and put all the js into it. In main view use render partial. But to initialize partial view I need to add model to current action method model to be able to make RenderPartial("MyPartialView", Model.PartialViewModel).
Also I do not have a place to put additional data I need to fill my form(like drop down lists values, some predefined values etc).
Use RenderAction, but it seems it have same problems as RenderPartial, except for I do not need to add anything to any other model.
Any other oprions are greatly appreciated.
As I understand it, RenderAction performs the full pipeline on the action, then renders the result - so what is rendered is the same as what you'd see if you'd browsed to the action.
I've used RenderAction to render 'widgets' throughout a site, but in my view they should be independent of the page rendering them, otherwise they're not really widgets and should be part of the rendering page's code instead. For instance, if there's a log in form, you will always take the user to a page that can process the information, no matter what page they are currently on, so this makes for a good widget. Other ways I've used it is to show a shopping basket or advertising. Neither of which are dependent on the page being shown.
Hope this helps a little!