test/QualTask/RegistrationWindow.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="QualTask.RegistrationWindow"
        Title="Регистрация">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        
        <TextBox x:Name="FNameTextBox" Grid.Row="0" Watermark="Имя"/>
        <TextBox x:Name="LNameTextBox" Grid.Row="1" Watermark="Фамилия"/>
        <TextBox x:Name="LoginTextBox" Grid.Row="2" Watermark="Логин"/>
        <TextBox x:Name="PasswordTextBox" Grid.Row="3" Watermark="Пароль" PasswordChar="#"/>
        <ComboBox x:Name="RoleComboBox" Grid.Row="4">
            <ComboBoxItem>Пользователь</ComboBoxItem>
            <ComboBoxItem>Администратор</ComboBoxItem>
        </ComboBox>
        <Button x:Name="RegistrationButton" Grid.Row="5" Content="Зарегистрироваться" Click="RegistrationButton_OnClick"/>
        <Button x:Name="BackButton" Grid.Row="6" Content="Назад" Click="BackButton_OnClick"/>
        <TextBlock Grid.Row="7" x:Name="ErrorTextBlock" IsVisible="False" Foreground="Red" FontSize="16" 
                   FontWeight="SemiBold" HorizontalAlignment="Center" VerticalAlignment="Center"/>
    </Grid>
</Window>