Demo_Examen_Gromov/Demo_Gromov/MainWindow.xaml

<Window x:Class="Demo_Gromov.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:Demo_Gromov"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="37*"/>
            <RowDefinition Height="348*"/>
            <RowDefinition Height="49*"/>
        </Grid.RowDefinitions>
        <StackPanel Grid.Row="0" Background="Azure">
            <Button Content="кнопка"/>
        </StackPanel>
        <TextBlock Grid.Row="1" Text="Проверка !" FontSize="100" HorizontalAlignment="Center" Margin="0,90,0,0"/>
        <StackPanel Grid.Row="2" Background="Azure"/>
    </Grid>
</Window>