使用Prism框架隐藏Xamarin.Forms中的选项卡

Question

I am working on a Xamarin Forms project that uses an MVVM pattern and Prism.

My issue is, I need to be able to hide a tab on a tab page based off of a bool. There is a bindable property in the XAML called "IsVisible", which I assumed would hide the tab from the user, but instead the tab still shows but displays a blank page when selected.

Currently my XAML looks like this

<?xml version="1.0" encoding="utf-8"?>
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
        xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
        xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms"
        xmlns:local="clr-namespace:com.XXXXXXX"
        prism:ViewModelLocator.AutowireViewModel="True"

        BackgroundColor="White"
        x:Class="com.XXXXXXXXXX.EditChargePage"
        Title="{Binding Title}">

<local:EditChargeDetailsPage Title="Details" />
<local:EditChargeTrackingPage Title="Tracking" IsVisible="{Binding TabContext.HasTracking}" IsEnabled="{Binding TabContext.HasTracking}"/>
<local:EditChargeNotesPage Title="Notes" />


</TabbedPage>

Originally to solve the problem I just used "IsVisible", when that didn't work as expected I added "IsEnabled" which didn't seem to do anything.

Is there a way to hide the Tab from the UI using a boolean value in Xamarin (or Prism for Xamarin) without breaking MVVM?

Answer 1

You might want to check out the Prism Samples . The TabbedNavigation sample demonstrates how to initialize your tabbed children with INavigatingAware or the IEventAggregator , as well as dynamically adding the tabs at run time. If you need even finer control, such as a value in a ViewModel of one of your Child Pages that determines whether some other page should be shown, then you could use this to publish an event with the IEventAggregator and subscribe to that event in your TabbedPage to handle adding or removing the page.

Unfortunately IsVisible and IsEnabled do not actually work within a TabbedPage the way you were hoping. So the only way you can accomplish this is to actually manipulate the Children of the TabbedPage directly pushing or popping them from the collection.