MvvMAva/AvaloniaApplication4/Views/Page2.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"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
			   xmlns:vm="using:AvaloniaApplication4.ViewModels"
	         x:DataType="vm:MainWindowViewModel"
             x:Class="AvaloniaApplication4.Page2">
	<StackPanel  HorizontalAlignment="Center" VerticalAlignment="Center">
		<TextBlock Text="Выберите арифметическую операцию" />
	
		<ComboBox Name="cm" ItemsSource="{Binding Page2VM.funclis}" SelectedItem="{Binding Page2VM.Selectedfunc}" Width="260"/>


		<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="10">
			<TextBox Width="70" Text="{Binding Page2VM.Num1}"> </TextBox>
			<TextBlock FontSize="25" Margin="20 0 20 0" Text="{Binding Page2VM.Symb}"></TextBlock>
			<TextBox Width="70" Text="{Binding Page2VM.Num2}"> </TextBox>
		</StackPanel>
		
		
		

		<Button Width="250" Command="{Binding Page2VM.Calculate}">
			<TextBlock VerticalAlignment="Center" HorizontalAlignment="Center">
				Рассчитать
			</TextBlock>
		</Button>
		<TextBlock>Результат:</TextBlock>
		<TextBlock Text="{Binding Page2VM.Result}" > </TextBlock>

	</StackPanel>
</UserControl>