xaml于c#代码混编

<Window x:Class="xaml混编后台.Window1"
    xmlns=" http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x=" http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Grid>
        <Button Name="btn1" Click="btn_Click" Height="40" Width="80">Click Me!</Button>
            <x:Code >
        <![CDATA[
           void btn_Click(object sender,RoutedEventArgs e)
           {
                btn1.Content="hello Button!!";     
           }  
           
       
        ]]>
        </x:Code>
    </Grid>
</Window>