You can use Visibility
instead of IsVisible
OR Visible
.And in your code, just like this:
private void Flag1_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
if(Flag1.Visibility == Visibility.Collapsed)
{
Flag1.Visibility = Visibility.Visible;
Flag2.Visibility = Visibility.Collapsed;
Flag3.Visibility = Visibility.Collapsed;
Flag4.Visibility = Visibility.Collapsed;
PhoneApp1.MainPage.winners.AFirstPlace= "Brazil";
}
else if (Flag1.Visibility == Visibility.Visible)
{
Flag1.Visibility = Visibility.Collapsed;
PhoneApp1.MainPage.winners.AFirstPlace = null;
}
}