MainWindow.xaml

<Window x:Class="GeometryDash.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:GeometryDash"
        xmlns:views="clr-namespace:GeometryDash.Views"
        xmlns:viewmodels="clr-namespace:GeometryDash.ViewModels"
        mc:Ignorable="d"
        Title="Geometry Dash" Height="450" Width="700" ResizeMode="NoResize">
    <Window.Resources>
        <DataTemplate x:Key="TitleView" DataType="{x:Type viewmodels:SelectorViewModel}">
            <views:TitleView />
        </DataTemplate>

        <DataTemplate x:Key="GameView" DataType="{x:Type viewmodels:SelectorViewModel}">
            <views:GameView />
        </DataTemplate>

        <DataTemplate x:Key="GameOverView" DataType="{x:Type viewmodels:SelectorViewModel}">
            <views:GameOverView />
        </DataTemplate>
    </Window.Resources>
    <Grid>
        <ContentControl x:Name="PageContent" Content="{Binding}">
            <ContentControl.Style>
                <Style TargetType="{x:Type ContentControl}">
                    <Setter Property="ContentTemplate" Value="{StaticResource TitleView}"/>
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding SwitchView}" Value="1">
                            <Setter Property="ContentTemplate" Value="{StaticResource GameView}"/>
                        </DataTrigger>
                        <DataTrigger Binding="{Binding SwitchView}" Value="2">
                            <Setter Property="ContentTemplate" Value="{StaticResource GameOverView}"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </ContentControl.Style>
        </ContentControl>
    </Grid>
</Window>