System throws exception during on click on the navigate Button in Xamarin.Forms App

Question

On click on the navigate button, system throws exception in my xamarin.Form app. I am trying to get the email text value and display in the Home page.

Exception: Unhandled Exception: System.InvalidOperationException: 
<Timeout exceeded getting exception details>`

MainPage.xaml.cs;

public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();
        var emailText = emailEntry.Text;
        var passwordText = passwordEntry.Text;
    }
    int count = 0;

    public void Button_Clicked(object sender, System.EventArgs e)
    {
        string text = emailEntry.Text;
    }

    public async void NavigateButton_OnClicked(object sender, EventArgs e)
    {
        await Navigation.PushAsync(new Home(emailEntry.Text));
    }
}

Following is my Home.xaml.cs where I need to display the text email value from the MainPage.xaml.cs;

public partial class Home : ContentPage
{
    public Home(string parameter1)
    {
        InitializeComponent();
        HomeLabel.Text = parameter1;
    }
}

App.xaml.cs details below;

public partial class App : Application
{
    string parameter1;
    public App()
    {
        InitializeComponent();
        var tabbedPage = new TabbedPage();
        tabbedPage.Children.Add(new Home(parameter1));
        tabbedPage.Children.Add(new Map());
        tabbedPage.Children.Add(new Settings());
        MainPage = new MainPage();
        //MainPage = new TabbedPage();
        //MainPage = tabbedPage;
    }

    protected override void OnStart()
    {
        // Handle when your app starts
    }

    protected override void OnSleep()
    {
        // Handle when your app sleeps
    }

    protected override void OnResume()
    {
        // Handle when your app resumes
    }
}

MainPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:local="clr-namespace:soccerapp"
    x:Class="soccerapp.MainPage">

    <StackLayout Spacing="20" Padding="50">
        <Entry x:Name="emailEntry" Placeholder="Email Id"></Entry>
        <Entry x:Name="passwordEntry" Placeholder="Password" IsPassword="True"></Entry>
        <Button Text="Log In"  Clicked="Button_Clicked" TextColor="White" BackgroundColor="#404751"></Button>
        <Button Text="Navigate to Home"  Clicked="NavigateButton_OnClicked" TextColor="White" BackgroundColor="ForestGreen"></Button>

        <!-- Place new controls here -->
        <Label Text="Welcome Mate!" HorizontalOptions="Center" VerticalOptions="CenterAndExpand" />
        </StackLayout>

</ContentPage>

Home.xaml:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
                 xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                 x:Class="soccerapp.Home" BackgroundColor="GreenYellow" Title="Home">
    <ContentPage.Content>
        <StackLayout>
            <Label x:Name="HomeLabel"  Text="Home Page is here" TextColor="White"
            VerticalOptions="CenterAndExpand" 
            HorizontalOptions="CenterAndExpand"></Label>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

InvalidOperationException seems weird here. Can you check the stack trace to see the source of the exception? — Jason
– Jason, Commented Apr 10, 2019 at 3:27
Why do you use Navigation.PushAsync(new Home(...)) if you already have this page in your TabbedPage? — Денис Чорный
– Денис Чорный, Commented Apr 10, 2019 at 3:27
@soccerway please see my answer, you use Navigation and TabbedPage in a wrong way. — Денис Чорный
– Денис Чорный, Commented Apr 10, 2019 at 3:50

Денис Чорный · Accepted Answer · 2019-04-10 05:33:44Z

1

Ok, first of all you have to create NavigationPage in you App.xaml.cs. Also, you need to move your TabbedPage initialization into separate xaml file or in NavigationsClicked event.

Edit your App.xaml.cs:

public App()
    {
        InitializeComponent();
        MainPage = new NavigationPage(new MainPage());
    }

There are 2 ways of doing it:

Create your TabbedPage in NavigationClicked event:

public async void NavigateButton_OnClicked(object sender, EventArgs e)
{
    var tabbedPage = new TabbedPage();
    tabbedPage.Children.Add(new Home(parameter1));
    tabbedPage.Children.Add(new Map());
    tabbedPage.Children.Add(new Settings());
    await Navigation.PushAsync(tabbedPage);
}

or create new XAML file for TabbedPage:

<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
            xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
            x:Class="MyTabbedPage">
  <!--Pages can be added as references or inline-->
    <ContentPage Title="HomeTitle">
  <!--Content for Home Page-->
    </ContentPage>

    <ContentPage Title="MapTitle">
  <!--Content for Map Page-->
    </ContentPage>

    <ContentPage Title="SettingsTitle">
  <!--Content for Settings Page-->
    </ContentPage>
</TabbedPage>

edited Apr 10, 2019 at 5:33

answered Apr 10, 2019 at 3:45

Денис Чорный

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9 Comments

soccerway Over a year ago

Sorry I didn't get that completely, where do I need add CurrentPage = Children[yourSpecificIndex];

Денис Чорный Over a year ago

@soccerway hmm, by the way, I'm wrong. You didn't use your tabbed page in an app. I'll edit my answer now, please wait.

soccerway Over a year ago

Thanks, I saw that, but what do you mean by CurrentPage, in my case it should be MainPage right ?

soccerway Over a year ago

I am confused now, why shouldn't i use the tabbed page ? Where do i make changes now ?

Денис Чорный Over a year ago

@soccerway Yes, you should. You should use TabbedPage, but in a proper way. You initialize it in App.xaml.cs, but never use. Please see my answer edit.

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