Всплывающее окно открыто закрыто wpf
<Button Name="CloseThisPopUp" VerticalAlignment="Top" HorizontalAlignment="Right" Content="X">
<Button.Triggers>
<EventTrigger RoutedEvent="Button.Click">
<EventTrigger.Actions>
<BeginStoryboard>
<Storyboard>
<BooleanAnimationUsingKeyFrames Storyboard.TargetName="CloseThisPopUp" Storyboard.TargetProperty="IsOpen">
<DiscreteBooleanKeyFrame KeyTime="0:0:0" Value="False" />
</BooleanAnimationUsingKeyFrames>
</Storyboard>
</BeginStoryboard>
</EventTrigger.Actions>
</EventTrigger>
</Button.Triggers>
</Button>
Worrisome Weasel