Storyboard targeting GridLength for WP8

Question

I want to make a storyboard for RowDefinition changing the Height, and I found this to help me. The only problem when I want to create the class GridLengthAnimation, I cannot make it a AnimationTimeline. Is this because windows phone 8 does not support this?

In this case is there another work around for making a storyboard for RowDefinition?

Answer 1

Easiest way may be that you put grids to the rows, and animate their Height-property like this.

Here is the xaml:

<Grid x:Name="LayoutRoot">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>

    <Grid Background="AliceBlue"
          Grid.Row="0"
          Height="100"
          Tap="Grid_Tap"
          CacheMode="BitmapCache" />
    <Grid Background="AntiqueWhite"
          Grid.Row="1"
          Height="100"
          Tap="Grid_Tap"
          CacheMode="BitmapCache" />
    <Grid Background="Aqua"
          Grid.Row="2"
          Height="100"
          Tap="Grid_Tap"
          CacheMode="BitmapCache" />
    <Grid Background="Aquamarine"
          Grid.Row="3"
          Height="100"
          Tap="Grid_Tap"
          CacheMode="BitmapCache" />

</Grid>

And the cs:

private void AnimateHeight(Grid grid)
{
    double newHeight = grid.ActualHeight == 100 ? 300 : 100; //select the height we want to animate

    Storyboard story = new Storyboard();
    DoubleAnimation animation = new DoubleAnimation();
    animation.To = newHeight;
    animation.Duration = TimeSpan.FromSeconds(0.5);

    Storyboard.SetTarget(animation, grid);
    Storyboard.SetTargetProperty(animation, new PropertyPath(Grid.HeightProperty));

    story.Children.Add(animation);
    story.Begin();
}

private void Grid_Tap(object sender, System.Windows.Input.GestureEventArgs e)
{
    Grid grid = sender as Grid; //select the grid we tapped
    AnimateHeight(grid);
}

Notice that I putted cachemode to bitmapcache all of the grids. That's not necessary, but gives more fluent animation, because static grids won't be redrawed again in each frame.