Windows phone databinding issue

I have an auto-generated class A which looks like the following.

class A
{
    string name;
    int totalCount;
}

I query the database to get list of objects, which has the most update totalCount number.

On the client side, I store the last time at which the the database was queried, so for each Object A, I have the previous totalCount.

In a listBox template, I want to show the difference between the two totalCou开发者_开发问答nts, how can I achieve this easily using databinding?

class A
{
    string name;
    int totalCount;
}
class Differences
{
    string name;
    int oldCount;
    int newCount;
    int differenceInCount;
}
//this has been set somewhere
private List<A> previousValues;
//assume this is going to be set with the next call.
private List<A> updatedValues;

//A listbox can be bound to the result of this function.
private List<Differences> CalculateDifference(){
    List<Differences> retval = new List<Differences>;
    Differences temp;
    foreach(A updated in updatedValues)
    {
        foreach(A previous in previousValues){
            if(updated.name == previous.name){
                temp = new Differences;
                temp.name = updated.name;
                temp.oldCount = previous.totalCount;
                temp.newCount = updated.totalCount;
                temp.differenceInCount = temp.newCount - temp.oldCount;
                retval.Add(temp);
                break;
            }
        }
    }
    return retval();
}