How to send data from C# to xaml file through TabbedPage

Issue

I have a Tabbedpage app that is supposed to send/pass "count" (number of clicks) variable in MianPage.xaml.cs to Page1.xaml. I need the label on Page1.xaml to show "count". Please let me your idea how I can fix it.

below is MainPage.xaml which is only a text and button :

<TabbedPage 
      xmlns:local="clr-namespace:bottomtest;assembly=bottomtest"
      x:Class="buttontest.MainPage">
        
      <ContentPage Title="MainPage" >
            <StackLayout>
                <Label Text="Welcome to MainPage1 !" 
               HorizontalOptions="Center"
               VerticalOptions="CenterAndExpand" />
   
               <Button Text="Push Me" Clicked="Button_Clicked" />
               
            </StackLayout>
                
        </ContentPage>
        <NavigationPage Title="Page1" >
            <x:Arguments>
                <local:Page1 />
            </x:Arguments>
        </NavigationPage>  
</TabbedPage>

and MainPage.xaml.cs and where I want to send "count" are below:

namespace buttontest
{
    public partial class MainPage : TabbedPage
    {
        public MainPage()
        {
            InitializeComponent();
        }

        int count = 0;
        void Button_Clicked(object sender, System.EventArgs e)
        {
            count++;
            ((Button)sender).Text = $"You Pushed {count} times.";
            // something here that send "count" to Page1.xaml 
            // like NI.Text = String.Format("${0:.##}", count);
        }        
    }
}

Page1.xaml is just a Lable to show "count":

<ContentPage 
             x:Class="bottomtest.Page1"
             Title="Page1">
 
        <StackLayout>
          
                <Label Text="PAGE 1 here"
               FontSize="Large"/>
        
            <Label Text="$0.0"
                   x:Name="NI"
                   HorizontalOptions="CenterAndExpand"></Label>
    </StackLayout>
</ContentPage>

Page1.xaml.cs is below

namespace buttontest
{
    public partial class Page1 : ContentPage
    {
        public Page1()
        {
            InitializeComponent();          
        }
    }
}

Solution

You can use MessageCenter to achieve value transfer.

Here is the TabbedPage1 code:

public partial class TabbedPage1: TabbedPage
 {    
     public TabbedPage1()
     {
         InitializeComponent();
     }
     public int count {get; set;}
     private void Button_Clicked(object sender, EventArgs e)
     {
         count++;
         ((Button)sender).Text = $"You Pushed {count} times.";
         MessagingCenter.Send<Object,int>(this, "Hi", count);
     }
 }

Here is the Page1 code:

public partial class Page1: ContentPage
 {
     public Page1()
     {
         InitializeComponent();
         MessagingCenter.Subscribe<object, int>(this, "Hi", (sender, res) =>
         {
             NI.Text = Convert.ToString(res);
         });
     }
 }

Here is a screenshot of the page:

Answered By - Wen xu Li - MSFT