oap_labs/MainWindow.xaml

<Window x:Class="WpfApp2.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:WpfApp2"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid ShowGridLines="True">
        <Grid.RowDefinitions>
            <RowDefinition Height="auto"/>
            <RowDefinition />
            <RowDefinition Height="auto"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="200"/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>

        <!-- типа логотип компании -->
        <Image 
        Source="img/portrait.jpg" 
        Grid.RowSpan="2" HorizontalAlignment="Right"/>
        <DataGrid
    Grid.Row="1"
    Grid.Column="1"
    CanUserAddRows="False"
    AutoGenerateColumns="False"
    ItemsSource="{Binding HeroList}">
            <DataGrid.Columns>
                <DataGridTextColumn
Header="Имя"
Binding="{Binding name}"/>
                <DataGridTextColumn
Header="Возраст"
Binding="{Binding Age}"/>
                <DataGridTextColumn
Header="Мощь"
Binding="{Binding power}"/>
                <DataGridTextColumn
Header="Раса"
Binding="{Binding race}"/>
            </DataGrid.Columns>
        </DataGrid>
        <StackPanel 
        Orientation="Vertical"
        Grid.RowSpan="3"
        VerticalAlignment="Bottom">
            <Button 
            x:Name="ExitButton"
            Content="Выход" 
            Click="ExitButton_Click"
            Height="50"/>
        </StackPanel>

        <WrapPanel
        Orientation="Horizontal"
        Grid.Column="1"
        MinHeight="50">
            <Label 
    Content="Мощь:"
    VerticalAlignment="Center"/>

            <ComboBox
    Name="powerFilterComboBox"
    SelectionChanged="powerFilterComboBox_SelectionChanged_1"
    VerticalAlignment="Center"
    MinWidth="100"
    SelectedIndex="0"
    ItemsSource="{Binding HeroPowerList}">

                <ComboBox.ItemTemplate>
                    <DataTemplate>
                        <Label 
                Content="{Binding title}"/>
                    </DataTemplate>
                </ComboBox.ItemTemplate>
            </ComboBox>
            <Label 
Content="Возраст:"
VerticalAlignment="Center"/>
            <ComboBox
Name="AgeFilterComboBox"
SelectionChanged="AgeFilterComboBox_SelectionChanged_2"
VerticalAlignment="Center"
MinWidth="100"
SelectedIndex="0"
ItemsSource="{Binding HeroAgeList}">

                <ComboBox.ItemTemplate>
                    <DataTemplate>
                        <Label 
            Content="{Binding title}"/>
                    </DataTemplate>
                </ComboBox.ItemTemplate>
            </ComboBox>
            <Label 
Content="Раса:"
VerticalAlignment="Center"/>
            <ComboBox
Name="RaceFilterComboBox"
SelectionChanged="RaceFilterComboBox_SelectionChanged_3"
VerticalAlignment="Center"
MinWidth="100"
SelectedIndex="0"
ItemsSource="{Binding HeroRaceList}">

                <ComboBox.ItemTemplate>
                    <DataTemplate>
                        <Label 
            Content="{Binding title}"/>
                    </DataTemplate>
                </ComboBox.ItemTemplate>
            </ComboBox>
            <!-- минимальную высоту я тут поставил, чтобы верхнюю строку сетки было видно. В реальном приложении она не нужна -->
        </WrapPanel>
    </Grid>
</Window>