exam_prepare/MainWindow.xaml

<Window x:Class="examPrepare.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:examPrepare"
        mc:Ignorable="d"
        Title="Главное окно" Height="450" Width="800">
    <Grid>
    <Grid.RowDefinitions>
      <RowDefinition Height="1*"></RowDefinition>
      <RowDefinition Height="5*"></RowDefinition>
    </Grid.RowDefinitions>
    <Grid/>
    <DockPanel Grid.Row="0" LastChildFill="False">
      <Button DockPanel.Dock="Left" x:Name="catalog_btn" Height="25" Width="80" Content="Каталог" Click="catalog_btn_Click"/>
      <Button DockPanel.Dock="Left" x:Name="cart_btn" Height="25" Width="80" Content="Корзина" Click="cart_btn_Click"/>
      <TextBlock DockPanel.Dock="Right" Height="30" Text="0" x:Name="products_count" />
      <TextBlock DockPanel.Dock="Right" Height="30" Text="колво добавленных товаров: " />
    </DockPanel>
    <Frame Grid.Row="1" x:Name="workspace" NavigationUIVisibility="Hidden"/>
  </Grid>
</Window>