Part 2 Complete code (Windows Store apps using C#/VB and XAML)

Applies to Windows only

This topic provides the complete code sample used in the tutorial Part 2: Manage app lifecycle and state.

Important  This tutorial is intended for use with Microsoft Visual Studio 2013 and Windows 8.1. Parts of it will not work correctly with Microsoft Visual Studio 2012 and Windows 8.

This topic contains these sections:

Download location

This sample is not available for download.

Technologies

Programming languagesC#, Visual Basic .NET
Programming modelsWindows Runtime

Requirements

Minimum supported clientWindows 8.1
Minimum supported serverWindows Server 2012 R2
Minimum required SDKMicrosoft Visual Studio Express 2012 for Windows 8

View the code ()

App.xaml

App.xaml contains only generated code.

App.xaml.cs/vb


using System;
using Windows.ApplicationModel;
using Windows.ApplicationModel.Activation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

// The Blank Application template is documented at http://go.microsoft.com/fwlink/?LinkId=234227

namespace HelloWorld
{
    /// <summary>
    /// Provides application-specific behavior to supplement the default Application class.
    /// </summary>
    sealed partial class App : Application
    {
        /// <summary>
        /// Initializes the singleton application object.  This is the first line of authored code
        /// executed, and as such is the logical equivalent of main() or WinMain().
        /// </summary>
        public App()
        {
            this.InitializeComponent();
            this.Suspending += OnSuspending;
        }

        /// <summary>
        /// Invoked when the application is launched normally by the end user.  Other entry points
        /// will be used such as when the application is launched to open a specific file.
        /// </summary>
        /// <param name="e">Details about the launch request and process.</param>
        protected async override void OnLaunched(LaunchActivatedEventArgs e)
        {

#if DEBUG
            if (System.Diagnostics.Debugger.IsAttached)
            {
                this.DebugSettings.EnableFrameRateCounter = true;
            }
#endif

            Frame rootFrame = Window.Current.Content as Frame;

            // Do not repeat app initialization when the Window already has content,
            // just ensure that the window is active
            if (rootFrame == null)
            {
                // Create a Frame to act as the navigation context and navigate to the first page
                rootFrame = new Frame();
                HelloWorld.Common.SuspensionManager.RegisterFrame(rootFrame, "appFrame");

                if (e.PreviousExecutionState == ApplicationExecutionState.Terminated)
                {
                    //TODO: Load state from previously suspended application
                    await HelloWorld.Common.SuspensionManager.RestoreAsync();
                }

                // Place the frame in the current Window
                Window.Current.Content = rootFrame;
            }

            if (rootFrame.Content == null)
            {
                // When the navigation stack isn't restored navigate to the first page,
                // configuring the new page by passing required information as a navigation
                // parameter
                if (!rootFrame.Navigate(typeof(MainPage), e.Arguments))
                {
                    throw new Exception("Failed to create initial page");
                }
            }
            // Ensure the current window is active
            Window.Current.Activate();
        }

        /// <summary>
        /// Invoked when application execution is being suspended.  Application state is saved
        /// without knowing whether the application will be terminated or resumed with the contents
        /// of memory still intact.
        /// </summary>
        /// <param name="sender">The source of the suspend request.</param>
        /// <param name="e">Details about the suspend request.</param>
        private async void OnSuspending(object sender, SuspendingEventArgs e)
        {
            var deferral = e.SuspendingOperation.GetDeferral();
            //TODO: Save application state and stop any background activity
            await HelloWorld.Common.SuspensionManager.SaveAsync();
            deferral.Complete();
        }
    }
}


MainPage.xaml


<Page
    x:Name="pageRoot"
    x:Class="HelloWorld.MainPage"
    DataContext="{Binding DefaultViewModel, RelativeSource={RelativeSource Self}}"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:HelloWorld"
    xmlns:common="using:HelloWorld.Common"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Page.Resources>
        <common:BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
        <!-- TODO: Delete this line if the key AppName is declared in App.xaml -->
        <x:String x:Key="AppName">Hello, world!</x:String>
        <Style x:Key="BigGreenTextStyle" TargetType="TextBlock">
            <Setter Property="Foreground" Value="Green"/>
            <Setter Property="FontSize" Value="36"/>
            <Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}"/>
            <Setter Property="TextTrimming" Value="CharacterEllipsis"/>
            <Setter Property="TextWrapping" Value="Wrap"/>
            <Setter Property="Typography.StylisticSet20" Value="True"/>
            <Setter Property="Typography.DiscretionaryLigatures" Value="True"/>
            <Setter Property="Typography.CaseSensitiveForms" Value="True"/>
            <Setter Property="LineStackingStrategy" Value="BlockLineHeight"/>
            <Setter Property="TextLineBounds" Value="TrimToBaseline"/>
            <Setter Property="OpticalMarginAlignment" Value="TrimSideBearings"/>
        </Style>
    </Page.Resources>

    <!--
        This grid acts as a root panel for the page that defines two rows:
        * Row 0 contains the back button and page title
        * Row 1 contains the rest of the page layout
    -->
    <Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
        <Grid.ChildrenTransitions>
            <TransitionCollection>
                <EntranceThemeTransition/>
            </TransitionCollection>
        </Grid.ChildrenTransitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="140"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <!-- Back button and page title -->
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="120"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
            <AppBarButton x:Name="backButton" Icon="Back" Height="95" Margin="10,46,10,0"
                          Command="{Binding NavigationHelper.GoBackCommand, ElementName=pageRoot}" 
                          Visibility="{Binding IsEnabled, Converter={StaticResource BooleanToVisibilityConverter}, RelativeSource={RelativeSource Mode=Self}}"
                          AutomationProperties.Name="Back"
                          AutomationProperties.AutomationId="BackButton"
                          AutomationProperties.ItemType="Navigation Button"/>
            <TextBlock x:Name="pageTitle" Text="{StaticResource AppName}" 
                       Style="{StaticResource HeaderTextBlockStyle}" Grid.Column="1" 
                       IsHitTestVisible="false" TextWrapping="NoWrap" VerticalAlignment="Bottom" Margin="0,0,30,40"/>
        </Grid>

        <StackPanel Grid.Row="1" Margin="120,30,0,0">
            <TextBlock Text="What's your name?" Style="{ThemeResource BaseTextBlockStyle}"/>
            <StackPanel Orientation="Horizontal" Margin="0,20,0,20">
                <TextBox x:Name="nameInput" Width="300" HorizontalAlignment="Left" TextChanged="NameInput_TextChanged"/>
                <Button Content="Say &quot;Hello&quot;" Click="Button_Click"/>
            </StackPanel>
            <TextBlock x:Name="greetingOutput" Style="{StaticResource BigGreenTextStyle}"/>
        </StackPanel>
    </Grid>
</Page>


MainPage.xaml.cs/vb


using HelloWorld.Common;
using System;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

// The Basic Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234237

namespace HelloWorld
{
    /// <summary>
    /// A basic page that provides characteristics common to most applications.
    /// </summary>
    public sealed partial class MainPage : Page
    {

        private NavigationHelper navigationHelper;
        private ObservableDictionary defaultViewModel = new ObservableDictionary();

        /// <summary>
        /// This can be changed to a strongly typed view model.
        /// </summary>
        public ObservableDictionary DefaultViewModel
        {
            get { return this.defaultViewModel; }
        }

        /// <summary>
        /// NavigationHelper is used on each page to aid in navigation and 
        /// process lifetime management
        /// </summary>
        public NavigationHelper NavigationHelper
        {
            get { return this.navigationHelper; }
        }


        public MainPage()
        {
            this.InitializeComponent();
            this.navigationHelper = new NavigationHelper(this);
            this.navigationHelper.LoadState += navigationHelper_LoadState;
            this.navigationHelper.SaveState += navigationHelper_SaveState;
        }

        /// <summary>
        /// Populates the page with content passed during navigation.  Any saved state is also
        /// provided when recreating a page from a prior session.
        /// </summary>
        /// <param name="navigationParameter">The parameter value passed to
        /// <see cref="Frame.Navigate(Type, Object)"/> when this page was initially requested.
        /// </param>
        /// <param name="pageState">A dictionary of state preserved by this page during an earlier
        /// session.  This will be null the first time a page is visited.</param>
        private void navigationHelper_LoadState(object sender, LoadStateEventArgs e)
        {
            // Restore values stored in session state.
            if (e.PageState != null && e.PageState.ContainsKey("greetingOutputText"))
            {
                greetingOutput.Text = e.PageState["greetingOutputText"].ToString();
            }


            // Restore values stored in app data.
            Windows.Storage.ApplicationDataContainer roamingSettings =
                Windows.Storage.ApplicationData.Current.RoamingSettings;
            if (roamingSettings.Values.ContainsKey("userName"))
            {
                nameInput.Text = roamingSettings.Values["userName"].ToString();
            }
        }

        /// <summary>
        /// Preserves state associated with this page in case the application is suspended or the
        /// page is discarded from the navigation cache.  Values must conform to the serialization
        /// requirements of <see cref="SuspensionManager.SessionState"/>.
        /// </summary>
        /// <param name="pageState">An empty dictionary to be populated with serializable state.</param>
        private void navigationHelper_SaveState(object sender, SaveStateEventArgs e)
        {
            e.PageState["greetingOutputText"] = greetingOutput.Text;

        }

        #region NavigationHelper registration

        /// The methods provided in this section are simply used to allow
        /// NavigationHelper to respond to the page's navigation methods.
        /// 
        /// Page specific logic should be placed in event handlers for the  
        /// <see cref="GridCS.Common.NavigationHelper.LoadState"/>
        /// and <see cref="GridCS.Common.NavigationHelper.SaveState"/>.
        /// The navigation parameter is available in the LoadState method 
        /// in addition to page state preserved during an earlier session.

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            navigationHelper.OnNavigatedTo(e);
        }

        protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
            navigationHelper.OnNavigatedFrom(e);
        }

        #endregion

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            greetingOutput.Text = "Hello, " + nameInput.Text + "!";
        }

        private void NameInput_TextChanged(object sender, TextChangedEventArgs e)
        {
            Windows.Storage.ApplicationDataContainer roamingSettings =
                Windows.Storage.ApplicationData.Current.RoamingSettings;
            roamingSettings.Values["userName"] = nameInput.Text;
        }
    }
}


 

 

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