How to reverse a generic list without changing the same list?

Question

I have a generic list that is being used inside a method that's being called 4 times. This method writes a table in a PDF with the values of this generic list.

My problem is that I need to reverse this generic list inside the method, but I'm calling the method 4 times so the list is being reversed every time I call the method and I don't want that... what can I do? Is there a way to reverse the list without mutating the original?

This is inside the method:

t.List.Reverse();
foreach (string t1 in t.List)
{
    //Some code
}

Answer 1

The "easy" option would be to just iterate the list in reverse order without actually changing the list itself instead of trying to reverse it the first time and know to do nothing the other times:

foreach (string t1 in t.List.AsEnumerable().Reverse())
{
    //Some code
}

By using the LINQ Reverse method instead of the List Reverse, we can iterate it backwards without mutating the list. The AsEnumerable needs to be there to prevent the List Reverse method from being used.