Q:

Reset style values through c# file in Click Event

I have a button style declared in Xaml, I did a Click Event in my C# file to, when clicked, change some style but now, when clicked again, I want to reset my styles to inicial style.
How I can manage the clicks and reset the style?
<flv:FlowListView FlowColumnCount="3" SeparatorVisibility="None" HasUnevenRows="true"
                    FlowItemTappedCommand="{Binding ItemTappedCommand}" FlowLastTappedItem="{Binding LastTappedItem}"
                    FlowItemsSource="{Binding MyCategories}" >

    <flv:FlowListView.FlowColumnTemplate>
      <DataTemplate>
         <Button Text="{Binding Name}"
         TextColor="White"
         x:Name="categoryButtons"
         Clicked="ButtonSelected"
         ContentLayout="Top"
         BackgroundColor="Transparent"
         BorderColor="White"
         BorderWidth="2"
         CornerRadius="6"
         Margin="5,5,5,10" />
      </DataTemplate>
   </flv:FlowListView.FlowColumnTemplate>
</flv:FlowListView>

public void ButtonSelected(object sender, EventArgs e)
        {
            var button = (Button)sender;
            button.BackgroundColor = Color.Blue;
        }

A:

So I did this to the style reset to default: 
public partial class CategoriesMenuDetail : ContentPage
    {
        public Dictionary<int, Btn> buttons { get; set; }

        public CategoriesMenuDetail()
        {
            InitializeComponent();
            buttons = new Dictionary<int, Btn>();
        }

        public void ButtonSelected(object sender, EventArgs e)
        {          
            var button = (Button)sender;

            if (!buttons.ContainsKey(button.GetHashCode()))
            {
                buttons.Add(button.GetHashCode(), new Btn(button));
            }

            bool state = buttons[button.GetHashCode()].Toogle();

            var bgColor = (state) ? Color.FromHex("#26047AD5") : Color.FromHex("#40000000");
            var borderColor = (state) ? Color.FromHex("#FF8A00") : Color.FromHex("#FFFFFF");

            button.BackgroundColor = bgColor;
            button.BorderColor = borderColor;
        }
    }

    public  class Btn
    {
        private Button _button { get; set; }

        private bool isToogle = false;

        public Btn(Button button)
        {
            _button = button;
        }

        public bool Toogle()
        {
            isToogle = !isToogle;
            return isToogle;
        }
    }

