Changing the color of a Grid BackGround

Question

In the CollectionView I would like the GestureRecognizer event to change the background color when the user presses a button. However, when the user presses on yet another button, I would like the previous one to return to its original color.

<CollectionView.ItemTemplate>
   <DataTemplate>
        <Grid>
          <Grid.RowDefinitions>
           <RowDefinition Height="12"/>
           <RowDefinition Height="24"/>
          </Grid.RowDefinitions>
        <Grid.GestureRecognizers>
        <TapGestureRecognizer Tapped="SelectedDate_Tapped"/>
        </Grid.GestureRecognizers>
          <Label Grid.Row="0" HorizontalTextAlignment="Center" Text="{Binding Giorno}" TextColor="White" FontSize="10"/> 
     </Grid>
    </DataTemplate>
  </CollectionView.ItemTemplate>


private void SelectedDate_Tapped(object sender, EventArgs e)
        {
            var model = (Grid)sender;
            model.BackgroundColor = Color.Blue;
        }

With my code it changes color, but it can never go back to the original color

Answer 1

track the last selected Grid

Grid last = null;

private void SelectedDate_Tapped(object sender, EventArgs e)
{
   var model = (Grid)sender;
   model.BackgroundColor = Color.Blue;

   if (last != null) last.BackgroundColor = myDefaultColor;

   last = model;
}