Right now, I am using Xamarin.Forms PLC project.
I have a label[x] on Page[x], then I will press button and go to Page[xx] ,then I will go back to Page[x] but I need to update Label[x] Text upon some Choices selected on Page[xx].
Which Event should i use to update Label.Text?
I was overriding OnResuem()Function on Xamarin.android, but it is not working on Xamarin.forms, I have no idea which is the best solution.
Some quick solution for this is:
-overriding the OnAppearing() method of the page and change the label.Text property once you change it on the other page
-Change the property to be public and change it on the other page
-Send the property to the next page as a parameter
but what you should do! is bind your property to a ViewModel and use OnPropertyChange() (Xamarin.Forms way and MVVM architecture) Events: a couple of tutorials how to understand this better:
https://blog.xamarin.com/advanced-data-binding-for-ios-android-and-windows/
https://developer.xamarin.com/guides/xamarin-forms/user-interface/xaml-basics/data_bindings_to_mvvm/
https://developer.xamarin.com/guides/xamarin-forms/user-interface/xaml-basics/data_binding_basics/
I'm not sure how youre code works because you havent said. So I'm not sure how Page[x] knows about Page[xx] but it sounds to me like you want to use the OnAppearing() override.
Which from the Xamarin.Forms Page API documentation states:
When overridden, allows application developers to
customize behavior immediately prior to the Page becoming visible.
You could do this by adding the following to your Page[x].xaml.cs file
protected override void OnAppearing()
{
//Your code here
}
Related
I'm currently trying to extend my Xamarin.Forms app with search bars in the navigation bar by this guide: https://codetraveler.io/2019/10/05/adding-a-search-bar-to-xamarin-forms-navigationpage/
So far it works great. But now I also want to add custom action to the keyboard based on what is available on this page. But it seems like the InputAccessoryView has no available setter for the UISearchController. So how can I set those custom actions and a Done button to it? Is there some other way to add this? Or is it maybe a bug by Xamarin that the InputAccessoryView is not setable?
nvm sometimes a bit of sleep helps a lot. The InputAccessoryView needs to be set on the SearchBar within the UISearchController of course and not directly on the UISearchController...
In my Xamarin.Forms Prism app, I am using a MasterDetailPage for navigation.
While I am on one detail page, I would like to navigate to another detail page, as if I had selected it from the master page.
Initial navigation in App.xaml.cs:
protected override void OnInitialized()
{
...
NavigationService.NavigateAsync("MainPage/RootNavigation/MyFirstPage");
}
When I click a shortcut button on MyFirstPage, I would like to go to MainPage/RootNavigation/MySecondPage. The closest that I have been able to achieve has been using an absolute Uri.
private async void OnShortcutTapped(MyModel sender)
{
...
await _navigationService.NavigateAsync(new Uri("http://myapp.com/MainPage/RootNavigation/MySecondPage", UriKind.Absolute), navigationParams, null, false);
}
This basically gets me what I want, but after navigating in this manner, if I make the Master visible and select the menu item for MySecondPage, it refreshes the detail page as if it is navigating to the page.
Is there a better way to maintain this navigation, so that the master page knows that MySecondPage is already being displayed and it doesn't try to reload it?
While your navigation pattern doesn't make a lot of sense to me, you can achieve what you want by invoking a navigate command in the MasterDetailPageViewModel. You have a number of ways to do this. You could use the IEventAggregator to send a message to the MasterDetailPageViewModel to navigate, or you can use a CompositeCommand that invokes a DelegateCommand that exists on the MasterDetailPageViewModel.
You can see a sample of using a CompositeCommand here: https://github.com/PrismLibrary/Prism-Samples-Forms/tree/master/UsingCompositeCommands
You can also see how to send messages in this sample that I gave at the Xamarin Evolve conference: https://github.com/brianlagunas/Evolve2016SamplesAndSlides
Another option would be to just call a navigate command off the App.Current.MainPage ViewModel from with your MyFirstPage code behind.
I programming a WPF GUI that uses multiple Views. I am using the MVVM Light Toolkit to implement the MVVM pattern.
For Navigating i use this mechanism by changing my main frame to a NavigationWindow and all my views to Pages.
I injected the navigation service in the ViewModel constructor and now I can navigate between the views.
However, i would like to transmit data between the views while navigating. There is a method from Navigation Window that makes this possible through event handlers. I already implemented a method into my Interface but I'm having problems calling the event handler on the navigated View Model.
Can anyone tell me how to call the event handler inside my ViewModel?
Thanks!!
Edit: I tried calling:
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
}
But i get an error saying:
OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs)': no
suitable method found to override
I already cleaned my solution and tried a rebuild...
Any ideas?
Edit2:
So i found out that in WPF .Net 4.5 the OnNavigatedTo event is gone. What i couldnt find out why and how i could call something similiar.
I haven't gotten an answer to my question so I will attempt an answer...
Don't over think this...if one needs to transfer information either create a static link to the VM(s) in question, or set aside a static drop on the app class. Either way when a view is shown, subscribe to one of the initialization/load events and pick up the information at the predetermined location.
I'd like to write some code that fires when the layout details screen is opened. Is there an event, some sort of API or some way to hijack Sitecore UI to allow me to do this? There's nothing in the Sitecore.config events sectiont hat looks relevant.
What I want to do is capture the ID of the item for which I'm currently updating so that I can use it in custom controls later on.
I'm using Sitecore 6.6.
Marek Musielak's answer is great. An alternative would be to change the command fired from the 'Details' Button - Look for item:setlayoutdetails in the commands.config.
You could create your own class that does your work then instantiates Sitecore.Shell.Framework.Commands.SetLayoutDetails afterwards.
You can override the \sitecore\shell\Applications\Content Manager\Dialogs\LayoutDetails\LayoutDetails.xml and change its code beside:
<CodeBeside
Type="Sitecore.Shell.Applications.ContentManager.Dialogs.LayoutDetails.LayoutDetailsForm,Sitecore.Client"/>
to inherit from your custom class that will simply inherits from LayoutDetailsForm and overrides e.g. OnLoad method.
In my MainPage.xaml, I created a Pivot Control: <controls:Pivot Title="Powder God" Name="PivotControl">.
My first pivot view is a HubTile that summarize all other individual pages. So my application bar will be different between the first pivot view and all other ones.
That's why I put my application bar in App.xaml's resource section, then load based on selected index of my pivot.
My question is:
In the application bar I will be using for all individual pages, I want to have a delete option, where I will remove that specific item (a view model) from my data context.
I know I can use PhoneApplicationFrame root = Application.Current.RootVisual as PhoneApplicationFrame; to access navigation services, but I don't know how can I reference to my pivot, so that I can get the selected index and proceed forward.
Thanks!
Using MVVM you SHOULDN'T do this:
((PageType)Application.Current.RootVisual).PivotControl. //Blah
PageType is whatever type PhoneApplicationFrame is that contains your PivotControl. If this doesn't work you need a Property in the RootVisual
PAGE
public Pivot MyPivot
{
get
{
return PivotControl;
}
}
APP
((PageType)RootVisual).MyPivot. //Blah
On one level Microsoft's suggestion of putting the ApplicationBar in App.xaml is great as it can be referenced from everywhere and would appear to encourage code reuse: however this question highlights the limit to this approach. An application bar is typically used to provide actions which are specific to the current page (or pivot item) and just because the buttons are the same you may not want the exact same code to run in each case.
In this case I think it would better to create a factory method that creates your common ApplicationBar with the click handlers you specify specific to your page/pivot item. For bonus points put the method in a new class (not App) so it doesn't get lost in all the boilerplate code there. Call this factory method in your page constructor and remember your ApplicationBar in your class. For multiple app bars, create them all up front and you can then easily switch between these app bars in your Pivot SelectionChanged code.
The alternative of creating the ApplicationBar in App.xaml and then retrieving this from the App.xaml.cs "Resources" ResourceDictionary in code, modifying the click callbacks, is more complicated in my opinion.
I wish they'd done a better job of implementing the ApplicationBar so people wouldn't want to do this. I've found that using the ApplicationBar forces you to add code to your Page.xaml.cs even if you use a framework like MVVM Light. This is still OK in MVVM as it's UI specific code that belongs in the View, but it makes things inconsistent if you're using ICommand everywhere else. Last time I decided it was better to create the entire ApplicationBar in code rather than hack this kind of thing via App.xaml.cs.
Update: There is a UserVoice request for a data bindable ApplicationBar.