DemoService/AddEditWindow.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="600"
        x:Class="DemoService.AddEditWindow"
        Title="AddEditWindow">
	<StackPanel>
		<TextBlock>
			<Run Text="ID:"/>
			<Run Name="ServiceID"/>
		</TextBlock>
		<TextBox Name="ServiceName"
				 Watermark="Название"/>
		<TextBox Name="Cost"
				 Watermark="Стоимость"/>
		<TextBox Name="DurationInSeconds"
				 Watermark="Длительность"/>
		<TextBox Name="Description"
				 Watermark="Описание"/>
		<TextBox Name="Discount"
				 Watermark="Скидка"/>
		<Button Name="AddPictureButton"
				Click="AddPictureButton_Click">
			Добавить картинку
		</Button>
		<Image/>
		<Button Name="AddServiceButton"
				Click="AddServiceButton_Click">
			Добавить услугу
		</Button>
		<Button Name="EditServiceButton"
				Click="EditServiceButton_Click">
			Изменить услугу
		</Button>
	</StackPanel>
</Window>