WPF auto resize elements

When application window is resized I want that the elements in it would resize proportionally too. Is that possible? I tried googling but couldn't really find anyting related to this. My XAML code:

<Window x:Class="app.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" KeyDown="Window_KeyDown">
    <Grid>
        <TabControl Name="MyTabControl">
            <TabItem Name="pradzia" Header="Pradžia" IsSelected="True">
                <Button Content="Pradžia" Height="55" Name="button1" Width="125" Click="button1_Click" />
            </TabItem>
            <TabItem Header="Vykdyti" Name="vykdyti" IsEnabled="False">
                    <Grid Button.Click="Grid_Click">
                    <Button Content="1" Height="50" HorizontalAlignment="Left" Margin="6,0,0,6" Name="button2" VerticalAlignment="Bottom" Width="125" FontSize="20" />
                        <Button Content="2" Height="50" HorizontalAlignment="Center" Name="button3" VerticalAlign开发者_如何学编程ment="Bottom" Width="125" FontSize="20" Margin="184,0,184,6" />
                    <Button Content="3" Height="50" HorizontalAlignment="Right" Margin="362,0,0,6" Name="button4" VerticalAlignment="Bottom" Width="125" FontSize="20" />
                        <TextBlock Height="23" HorizontalAlignment="Center" Name="textBlock1" Margin="0,15,0,0" Text="Kiek gyvūnų paveiksliuke?" VerticalAlignment="Top" FontSize="16" />
                    <Image Height="150" HorizontalAlignment="Center" Margin="0,-25,0,0" Name="mainImage" Stretch="Uniform" VerticalAlignment="Center" Width="200" />
                </Grid>
            </TabItem>
        </TabControl>
    </Grid>
</Window>

You seem to use a grid without actually utilizing its prime functionality: Rows & Columns
Using them you can make the layout allocate space proportially by defining star-sized rows and columns.

e.g.

<Window
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="3*"/>
        <ColumnDefinition Width="2*"/>
        <ColumnDefinition Width="3*"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="3*"/>
        <RowDefinition Height="2*"/>
        <RowDefinition Height="3*"/>
    </Grid.RowDefinitions>
    <!-- Note that width and height are not set to make it size to the grid cell -->
    <Button Grid.Row="1" Grid.Column="1" Content="Lorem Ipsum"/>
  </Grid>
</Window>

If by resizing proportionally you actually mean size rather than allocated layout space then use a Viewbox.

Any controls you want to have resize (like your buttons) they should not have a width or a height defined in you XAML. If they need a minimum size, use MinWidth and MinHeight