Visibility fadeout and fade in infinite loop - wpf

Question

I have some Grid with some element inside and I want to add it some fade in fade out effect with Visibility property in infinite loop base on some bool property.
This is what I have tried:
<Grid.Style>
<Style TargetType="FrameworkElement">
<Setter Property="Visibility" Value="Visible"/>
<Setter Property="Opacity" Value="0"/>
<Style.Triggers>
<Trigger Property="Visibility" Value="Collapsed">
<Trigger.EnterActions>
<BeginStoryboard>
<Storyboard>
<DoubleAnimation Storyboard.TargetProperty="Opacity"
From="0.0"
To="1.0"
Duration="0:0:0.2"/>
</Storyboard>
</BeginStoryboard>
</Trigger.EnterActions>
</Trigger>
</Style.Triggers>
</Style>
</Grid.Style>
Currently I cannot see my Grid at all.

Answer 1

There are a few issues in your style:
You do not see the Grid, because you set the initial Opacity to 0.
You can remove both of your Setters, because those are the default values
Making the trigger dependent on Visibility does not work, because when it is set to Collapsed, the Grid is already invisible, so the animation is not even visible.
There is no exit action to make the Grid fade in again.
You could solve the issues by exposing a property (here MyAnimationTriggerProperty) that you use as trigger for the animation. Depending o your actual application this could also be the IsChecked state of another control. Then you can add an ObjectAnimationUsingKeyFrames to set the Visibility at the end of the animation.
<Style TargetType="FrameworkElement">
<Style.Triggers>
<DataTrigger Binding="{Binding MyAnimationTriggerProperty}" Value="False">
<DataTrigger.EnterActions>
<BeginStoryboard>
<Storyboard>
<DoubleAnimation Storyboard.TargetProperty="Opacity"
From="1.0"
To="0.0"
Duration="0:0:0.2"/>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0:0:0.2" Value="{x:Static Visibility.Collapsed}"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</BeginStoryboard>
</DataTrigger.EnterActions>
<DataTrigger.ExitActions>
<BeginStoryboard>
<Storyboard>
<DoubleAnimation Storyboard.TargetProperty="Opacity"
From="0.0"
To="1.0"
Duration="0:0:0.2"/>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0:0:0" Value="{x:Static Visibility.Visible}"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</BeginStoryboard>
</DataTrigger.ExitActions>
</DataTrigger>
</Style.Triggers>
</Style>