search contacts by phone number, filter using a 3 digit prefix - windows-phone-7

Question

I want to get all the phone numbers in my contacts that start with a specific 3 digits, eg "012" when i hit a button.
I've been working on it using the following code:
private void ButtonContacts_Click(object sender, RoutedEventArgs e)
{
Contacts cons = new Contacts();
//Identify the method that runs after the asynchronous search completes.
cons.SearchCompleted += new EventHandler<ContactsSearchEventArgs>(Contacts_SearchCompleted);
//Start the asynchronous search.
cons.SearchAsync("0109", FilterKind.PhoneNumber, "State String 5");
}
void Contacts_SearchCompleted(object sender, ContactsSearchEventArgs e)
{
try
{
//Bind the results to the user interface.
ContactResultsData.DataContext = e.Results;
}
catch (System.Exception)
{
//No results
}
if (ContactResultsData.Items.Any())
{
ContactResultsLabel.Text = "results";
}
else
{
ContactResultsLabel.Text = "no results";
}
}
but the FilterKind.PhoneNumber only works when it has at least the last 6 digits matched of a phone number.
Any idea how to achieve this?
BTW I'm a total beginner.

Answer 1

As you say, the filter of the contacts api only match if the last six digits are the same, you can see it in the documentation, so you can't do it using it.
In my opinion the best way to do it is receive the all contact list and after that use LINQ to find the contact that you want.
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
var contacts = new Contacts();
contacts.SearchCompleted += Contacts_SearchCompleted;
contacts.SearchAsync(null, FilterKind.None, null);
}
void Contacts_SearchCompleted(object sender, ContactsSearchEventArgs e)
{
var results = e.Results.ToArray();
var myContacts = results.Where(c => c.PhoneNumbers.Any(p => p.PhoneNumber.StartsWith("66"))).ToArray();
}
You can see in the last line the query to find the contacts that some of their numbers start with 66. You can change this query as you want to match the numbers that you want.