string GetPropertyName(Expression e)
{
  var lambdaExpression = e as LambdaExpression;
  if (lambdaExpression != null)
  {
    return GetPropertyName(lambdaExpression.Body);
  }

  var unaryExpression = e as UnaryExpression;
  if (unaryExpression != null)
  {
    return GetPropertyName(unaryExpression.Operand);
  }

  var memberExpression = e as MemberExpression;
  if (memberExpression != null)
  {
    return memberExpression.Member.Name;
  }

  throw new NotSupportedException(String.Format("Invalid Expression: {0}.", e.ToString()));
}