/// <summary>
/// Determines if the given value represents a valid state of this property.
/// </summary>
/// <param name="value">The state that should be used.</param>
/// <returns>True if the state is valid, otherwise false.</returns>
protected override Boolean IsValid(CSSValue value)
{
var position = value.ToListPosition();
if (position.HasValue)
{
_position = position.Value;
return(true);
}
return(false);
}