How to make a Custom Sort Function

You can create your won custome IComparer implementation to control sort order. While IComparable.CompareTo method controls the default sort order for a class, IComparer.Compare can be used to provide custom sort order.

For e.g. following class which implements IComapere, provides custom reverse sort

public class reverseSort : IComparer
{
int IComparer.Compare(Object y, Object x)
{
return ((new CaseInsensitiveComparer()).Compare(x, y));
}
}


//test class
ArrayList al = new ArrayList();
al.AddRange(new String[] {"This", "is", "a", "Amazing", "world", "of", "Collections" });

//default sort order ascending
al.Sort();

foreach (object o in al)
{
Console.WriteLine(o.ToString());
}

//custom sort order


al.Sort(new reverseSort());

foreach (object o in al)
{
Console.WriteLine(o.ToString());
}