Xamarin - TabbedPage with childreen content page MVVM

Question

Hi everybody!

I have a tabbed page with its respective viewmodel where a rest service is called from that viewmodel. The moment that rest service is called and returns a response, I need to pass that response to the viewmodels of the children of the tabbed. What is the best way to do this?

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

You could also use Delegate to achieve the function. Create the delegate in the TabbedPage's ViewModel class and then subscribe the event in child page's ViewModel class.

   //the viewModel class of the tabbedPage  
   public delegate void TestEventHandler();  
   namespace TestApplication  
   {  
       public class ViewModel_TabbedPge  
       {  
           public event TestEventHandler TestEvent;  
           public async Task TestMethod()  
           {  
               var response = await getResponseMethod();  
               if (TestEvent != null)  
               {  
                   TestEvent();  
               }  
           }  
       }  
   }  
         
   //the child page  
   public class ViewModel_Page1  
   {  
       ViewModel_Page1 viewModel;  
       ViewModel_TabbedPge viewModel_TabbedPge;  
     
       public ViewModel_Page1(ViewModel_TabbedPge viewModel_TabbedPge)  
       {  
           InitializeComponent();  
     
           viewModel = new ViewModel_Page1();  
           BindingContext = viewModel;  
     
           viewModel_TabbedPge = App.viewModel_TabbedPge;//create a global static instance of the ViewModel_TabbedPge class in the App.cs  
           viewModel_TabbedPge.TestEvent += TheTestEvent;  
       }  
     
       private void TheTestEvent()  
       {  
           //perform the work  
       }  
   }  

Best Regards,

Jarvan Zhang

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