Btukfyl

In my MainWindow.xaml.cs, I open a new Page (PkmnSelect) using this:

PkmnSelect pkmnSelect = new PkmnSelect(); 

Content = pkmnSelect;

Then, once the user has chosen their team of Pokémon in this page (PkmnSelect), they can click Start. The Start button has this as code:

Battle battle = new Battle(userPokemon, opponentPokemon);

Content = battle;

Battle is a page that I want to take as input two Pokémon, so I've created an additional constructor in Battle that looks like this:

public Battle(Pokemon userPkmn, Pokemon opponentPkmn) : this()

{

    userPokemon = userPkmn;

    opponentPokemon = opponentPkmn;

}

This gives me the error "Page can only have Window or Frame as parent."

My question is, what is the right way to send values from one page to another?
I have looked everywhere and nothing I've tried has worked.

EDIT: The beginning of Battle.xaml.cs:

public partial class Battle : Page

{

    Pokemon userPokemon;

    Pokemon opponentPokemon;



    public Battle()

    {

        InitializeComponent();

        //Some code to hide some xaml stuff and start some music

    }



    public Battle(Pokemon userPkmn, Pokemon opponentPkmn) : this()

    {

        userPokemon = userPkmn;

        opponentPokemon = opponentPkmn;

    }

You can't have a Page inside a Page.

Instead you should let their common parent component handles the transition using events:

Pokemon:

public class Pokemon

{

    public string Name { get; set; }

}

PkmnSelect

<Page x:Class="WpfApp1.PkmnSelect"

      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

      xmlns:system="clr-namespace:System;assembly=mscorlib"

      Title="PkmnSelect">

    <Grid>

        <Grid.RowDefinitions>

            <RowDefinition Height="*"></RowDefinition>

            <RowDefinition Height="Auto"></RowDefinition>

        </Grid.RowDefinitions>

        <Grid.ColumnDefinitions>

            <ColumnDefinition Width="*"></ColumnDefinition>

            <ColumnDefinition Width="Auto"></ColumnDefinition>

            <ColumnDefinition Width="*"></ColumnDefinition>

        </Grid.ColumnDefinitions>

        <ListBox Name="FirstPokemonList">

            <system:String>Pikachu</system:String>

            <system:String>Raichu</system:String>

            <system:String>Rattata</system:String>

        </ListBox>

        <Label Grid.Column="1" VerticalContentAlignment="Center" FontSize="20" FontWeight="ExtraBold">VS</Label>

        <ListBox Name="SecondPokemonList" Grid.Column="2" Margin="0,1,0,19" Grid.RowSpan="2">

            <system:String>Pikachu</system:String>

            <system:String>Raichu</system:String>

            <system:String>Rattata</system:String>

        </ListBox>

        <Button Click="Button_Click" Grid.Row="1" Grid.ColumnSpan="3">FIGHT!</Button>

    </Grid>

</Page>



public class PokemonsSelectedEventArgs : EventArgs

{

    public Pokemon FirstPokemon { get; set; }

    public Pokemon SecondPokemon { get; set; }

}



public partial class PkmnSelect : Page

{

    public event EventHandler<PokemonsSelectedEventArgs> PokemonsSelected = delegate { };



    public PkmnSelect()

    {

        InitializeComponent();

    }



    private void Button_Click(object sender, RoutedEventArgs e)

    {

        PokemonsSelected(this, new PokemonsSelectedEventArgs

        {

            FirstPokemon = new Pokemon { Name = (string)FirstPokemonList.SelectedValue },

            SecondPokemon = new Pokemon { Name = (string)SecondPokemonList.SelectedValue }

        });

    }

}

Battle:

<Page x:Class="WpfApp1.Battle"

      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

      Title="Battle">

    <Grid>

        <Grid.ColumnDefinitions>

            <ColumnDefinition Width="*"></ColumnDefinition>

            <ColumnDefinition Width="Auto"></ColumnDefinition>

            <ColumnDefinition Width="*"></ColumnDefinition>

        </Grid.ColumnDefinitions>

        <Label HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Content="{Binding UserPokemon.Name}" FontSize="40" FontWeight="ExtraBold"></Label>

        <Label VerticalContentAlignment="Center" FontSize="20" FontWeight="ExtraBold" Grid.Column="1">VS</Label>

        <Label HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Content="{Binding OpponentPokemon.Name}" FontSize="40" FontWeight="ExtraBold" Grid.Column="2"></Label>

    </Grid>

</Page>



public partial class Battle : Page

{

    public Pokemon UserPokemon { get; set; }

    public Pokemon OpponentPokemon { get; set; }



    public Battle()

    {

        InitializeComponent();



        DataContext = this;

    }



    public Battle(Pokemon userPkmn, Pokemon opponentPkmn) : this()

    {

        UserPokemon = userPkmn;

        OpponentPokemon = opponentPkmn;

    }

}

MainWindow:

<Window x:Class="WpfApp1.MainWindow"

        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

        xmlns:local="clr-namespace:WpfApp1"

        Title="MainWindow" Height="450" Width="800">

    <local:PkmnSelect PokemonsSelected="PkmnSelect_PokemonsSelected"></local:PkmnSelect>

</Window>



public partial class MainWindow : Window

{

    public MainWindow()

    {

        InitializeComponent();

    }



    private void PkmnSelect_PokemonsSelected(object sender, PokemonsSelectedEventArgs e)

    {

        Content = new Battle(e.FirstPokemon, e.SecondPokemon);

    }

}