AvaloniaTaskFive/Auth/Views/Calc.axaml

<UserControl 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"
             x:DataType="vm:MainWindowViewModel"
             xmlns:vm="using:Auth.ViewModels"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="Auth.Calc">

	<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center" Width="350">
		<TextBlock>Выберите арифметическую операцию</TextBlock>
		<ComboBox x:Name="cm1" ItemsSource="{Binding Calc_VM.Operation}" SelectedItem="{Binding Calc_VM.SelectedOperation}" Width="260">
		</ComboBox>
		<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="10" Width="425">
			<NumericUpDown Width="150" Value="{Binding Calc_VM.Chislo1}" Increment="1" HorizontalAlignment="Stretch"/>
			<TextBlock FontSize="24" Margin="20 0 20 0" Text="{Binding Calc_VM.Znaki}"></TextBlock>
			<NumericUpDown Width="150" Value="{Binding Calc_VM.Chislo2}" Increment="1" HorizontalAlignment="Stretch"/>
		</StackPanel>
		<Button Width="260" Command="{Binding Calc_VM.Resultat}">
			<TextBlock VerticalAlignment="Center" HorizontalAlignment="Center">Вычислить</TextBlock>
		</Button>
		<TextBlock>Результат:</TextBlock>
		<TextBlock Text="{Binding Calc_VM.Result}"> </TextBlock>
	</StackPanel>
</UserControl>