How to sort the list with duplicate keys?

Question

I have a set of elements/keys which I'm reading from two different config files. So the keys may be same but with different values associated with each of them.

I want to list them in the sorted order. What can I do ? I tried with SortedList class but it does not allow duplicate keys.

How can I do it?

e.g Lets say I have 3 elements with keys 1,2,3. Then i get one more element having key 2 (but different value). Then I want the new key to get inserted after existing key 2 but before 3. If I againg find an element with key 2, then it should go after most recently added key 2.

Please note than I'm using .NET 2.0

Answer 1

I prefer to use LINQ for this type of thing:

using System.Linq;

...

var mySortedList = myList.Orderby(l => l.Key)
                         .ThenBy(l => l.Value);

foreach (var sortedItem in mySortedList) {
    //You'd see each item in the order you specified in the loop here.
}

Note: you must be using .NET 3.5 or later to accomplish this.

Answer 2

what you need is a Sort function with a custom IComparer. What you have now is the default icomparer when you use sort. this will check on a field value.

When you create a custom IComparer (you do this in you class by implementing the Icomparable interface). what it does is: your object checks itself to every other object in the list you sort.

this is done by a function. (don't worry VS will implementd it when refering your interface

public class  ThisObjectCLass : IComparable{

    public int CompareTo(object obj) {
            ThisObjectCLass something = obj as ThisObjectCLass ;
            if (something!= null) 
                if(this.key.CompareTo(object.key) == 0){
                //then:
                   if .....
                }
                else if(this.value "is more important then(use some logic here)" something.value){
                 return 1
                }
                else return -1
            else
               throw new ArgumentException("I am a dumb little rabid, trying to compare different base classes");
        }
}

read on the links above for better information.

I know I had some troubles understanding this myself in the beginning, so for any extra help add a comment and I will elaborate