Agents/MainWindow.axaml

<Window xmlns="https://github.com/avaloniaui"
        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"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="Agents.MainWindow"
        Title="Агенты"
	    xmlns:vm="using:Agents.Models">
	<DockPanel Background="Blue">
		<ScrollViewer>
			<StackPanel>
				
				<Border
				Background="Red"
				CornerRadius="10"
				Padding="20"
				Margin="20"
				Width="750"
				Height="300"
					>
					<ScrollViewer>
						<StackPanel>
							<TextBlock Text="Список компаний" HorizontalAlignment="Center" Foreground="Blue"/>
							<ListBox Name="ListAgents" SelectionChanged="ListBox_SelectionChanged">
								<ListBox.ItemTemplate>
									<DataTemplate x:DataType="vm:Agent">
										<StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="Название компании: "/>
												<TextBlock Text="{Binding Title}"/>
											</StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="ИНН: "/>
												<TextBlock Text="{Binding Inn}"/>
											</StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="КПП: "/>
												<TextBlock Text="{Binding Kpp}"/>
											</StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="Имя директора: "/>
												<TextBlock Text="{Binding Directorname}"/>
											</StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="Телефон компании: "/>
												<TextBlock Text="{Binding Phone}"/>
											</StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="Адрес: "/>
												<TextBlock Text="{Binding Address}"/>
											</StackPanel>

										</StackPanel>
									</DataTemplate>
								</ListBox.ItemTemplate>
							</ListBox>
						</StackPanel>
					</ScrollViewer>
				</Border>

				<TextBlock Text="Веберите сортировку списка продуктов компании" HorizontalAlignment="Center"/>
				<ComboBox Name="SortListAgents" HorizontalAlignment="Center">
					<ComboBoxItem>
						без. сорт.
					</ComboBoxItem>
					<ComboBoxItem>
						убыв.
					</ComboBoxItem>
					<ComboBoxItem>
						возраст.
					</ComboBoxItem>
				</ComboBox>

				<Border
				Background="Red"
				CornerRadius="10"
				Padding="20"
				Margin="20"
				Width="750"
				Height="300"
					>
				<ScrollViewer>
					<StackPanel>
						<TextBlock Text="Товары продавца" HorizontalAlignment="Center" Foreground="Blue"/>
							<ListBox Name="ListProducts" SelectionChanged="ListBox_SelectionChanged1">
								<ListBox.ItemTemplate>
									<DataTemplate x:DataType="vm:Product">
										<StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="Название продукта: "/>
												<TextBlock Text="{Binding Title}"/>
											</StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="Описание товара: "/>
												<TextBlock Text="{Binding Description}"/>
											</StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="Название продукта: "/>
												<TextBlock Text="{Binding Productionpersoncount}"/>
											</StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="Артикул: "/>
												<TextBlock Text="{Binding Articlenumber}"/>
											</StackPanel>

											<StackPanel Orientation="Horizontal">
												<TextBlock Text="Минимальная цена для агента: "/>
												<TextBlock Text="{Binding Mincostforagent}"/>
												<TextBlock Text=" Руб."/>
											</StackPanel>

										</StackPanel>
									</DataTemplate>
								</ListBox.ItemTemplate>
							</ListBox>
						</StackPanel>
					</ScrollViewer>
				</Border>

				<Border
				Background="Red"
				CornerRadius="10"
				Padding="20"
				Margin="20"
				Height="80"
					>
					<StackPanel HorizontalAlignment="Center">
						<TextBlock Text="Доступные функции" HorizontalAlignment="Center" Foreground="Blue"/>
						<StackPanel Orientation="Horizontal" Background="Red" HorizontalAlignment="Center">
							<Button Content="Обновить продукт" Click="ButtonProductEidtor" Background="Green"/>
							<Button Content="Изменить агентов" Click="ButtonAgentEidtor"  Background="Green"/>
							<Button Content="Добавление и удаление продукта" Click="ButtonAddProduct"  Background="Green"/>
							<Button Content="Редактированть данные продуктов" Click="ButtonProductEidtor"  Background="Green"/>
						</StackPanel>
					</StackPanel>
				</Border>
				
			</StackPanel>
		</ScrollViewer>
	</DockPanel>
</Window>