Responsive interfaces

The interfaces used in all the examples so far used short-running commands that have no significant impact on the user interface.

If an event handler in the user interface carries out a longer-running activity, the entire interface will freeze. This problem is simulated by using Start-Sleep in the following example:

$xaml = '<?xml version="1.0" encoding="utf-8"?>
<Window
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 Width="350" Height="350">
    <Button Name="Button" Content="Start" />
</Window>'
$ui = Import-Xaml $xaml
$ui.Controls['Button'].add_Click({
    param ( $sender, $eventArgs )
    Start-Sleep -Seconds 60
})
$ui.MainWindow.ShowDialog()

Once the button is clicked, the user interface will freeze. It is not possible to move or close the window...