Search code examples
c#sortingcompareicomparable

Comparing for sorting in different ways

I have a class that implements IComparable. It works but the comparison is static, i.e. it's always the same ordering it achieves. What would be a good method to introduce comparison by a parameter, i.e. if we have:

class Poo : IComparable { 
  public int A { ... };
  public int B { ... };
  ... 
}
IEnumerable<Foo> list = ...;
list = list.Sort(???);

I' d like to order the list with respect to A or B depending on the parameter passed to Sort at the question marks. What's the most efficient way to do that?

At the moment, the best method I've came up with is to declare a couple of methods that I pass to Sort as delegates.

private static int CompareWrtA(Foo foo1, Foo foo2) { ... }
private static int CompareWrtB(Foo foo1, Foo foo2) { ... }

if(withRespectToA)
  list = list.Sort(CompareWrtA);
else
  list = list.Sort(CompareWrtB);

But it doesn't feel really as the best way. Criticism is welcome.

Solution

  • If you want to simplify that statement you can write it like this:

    list.Sort((x,y) => withRespectToA ? CompareWrtA(x,y) : CompareWrtB(x,y));

    BTW, Sort method is modifying your list, it doesn't return anything.So you don't need to assign it back to your list.