WPF Trigger animation when Visibility is changed? - wpf

Question

Well i have a custom control and when Visibility is changed to Visible I have a Trigger with a enter/exit action but the problem is that when the exit action fires the Visibility is no longer Visible so the animation can't be seen how would I fix this?
here is my Trigger:
<ControlTemplate.Triggers>
<Trigger Property="Visibility" Value="Visible">
<Trigger.ExitActions>
<BeginStoryboard Storyboard="{StaticResource Hide}"/>
</Trigger.ExitActions>
<Trigger.EnterActions>
<BeginStoryboard Storyboard="{StaticResource Show}"/>
</Trigger.EnterActions>
</Trigger>
</ControlTemplate.Triggers>

Answer 1

I tried this too and failed. I think it is not possible to accomplish this in a simple ControlTemplate with a Trigger on the Visibility property. What you can do is add an Opacity animation From 1 To 0 to a Trigger for a different property, for instance a DependencyProperty that you add in the code behind yourself.

Answer 2

You could also use ObjectAnimationUsingKeyFrames to set Visibility for animation period.
In such case there is no need in any codebehind.

Answer 3

There is a way to achieve it. Not 100 % pure, but works for me:
Don't use Visibility property, but use Opacity and Tag property.
<ListView.Resources>
<Style TargetType="{x:Type ListViewItem}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListViewItem}">
<Border CornerRadius="5"
BorderThickness="2"
BorderBrush="DodgerBlue"
Background="#CC4f9dea" >
<Grid>
<ContentPresenter HorizontalAlignment="Stretch" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="Stretch" />
<Button x:Name="btnClose" Opacity="0" Content="X" Style="{StaticResource RoundedButtonStyle}"/>
</Grid>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Tag" TargetName="btnClose" Value="Visible" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListView.Resources>
<Style x:Key="RoundedButtonStyle" TargetType="{x:Type Button}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Border CornerRadius="15" Background="White" BorderThickness="1" Padding="2" BorderBrush="Black">
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="Tag" Value="Visible">
<Trigger.EnterActions>
<BeginStoryboard>
<Storyboard>
<DoubleAnimation Storyboard.TargetProperty="Opacity"
From="0.0" To="0.5" Duration="0:0:0.5"/>
</Storyboard>
</BeginStoryboard>
</Trigger.EnterActions>
<Trigger.ExitActions>
<BeginStoryboard>
<Storyboard>
<DoubleAnimation Storyboard.TargetProperty="Opacity"
From="0.5" To="0.0" Duration="0:0:0.5"/>
</Storyboard>
</BeginStoryboard>
</Trigger.ExitActions>
</Trigger>
</Style.Triggers>
</Style>