Question

I have a silverlight app using Prism practices; the current code does a search by first name or last name or gender. regaring the names, I would like to alter the code to somethng like 3 characters because now it is searching as long as one character is found the name will display so you can see the issue, can I adjust the code here to only select those with a 3 character match? lets leave alone the issue of a name with less than 3 but we can allow anything there then.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace PBM.Web.Classes
{
    public class Search
    {
        public static IQueryable<Patient> GetSearchQueryPatient(IQueryable<Patient> pSearchQuery, Patient pPatient)
        {
            if (!string.IsNullOrEmpty(pPatient.FirstName))
            {
                pSearchQuery = pSearchQuery.Where(item => item.FirstName.Contains(pPatient.FirstName));
            }

            if (!string.IsNullOrEmpty(pPatient.LastName))
            {
                pSearchQuery = pSearchQuery.Where(item => item.LastName.Contains(pPatient.LastName));
            }

            if (pPatient.Gender.HasValue && pPatient.Gender.Value > 0)
            {
                pSearchQuery = pSearchQuery.Where(item => item.Gender.Value == pPatient.Gender.Value);
            }

            pSearchQuery = pSearchQuery.OrderBy(item => item.FirstName).ThenBy(item => item.LastName);

            return pSearchQuery;
        }
    }
}

Answer 1

If I’ve read your requirement and sample code correctly, simply add a length check to your tests should work:

if (!string.IsNullOrEmpty(pPatient.FirstName) && pPatient.FirstName.Length > 2)
{
    pSearchQuery = pSearchQuery.Where(item => item.FirstName.Contains(pPatient.FirstName));
}

It does mean that if the name is less than 3 characters it won’t match at all, so what you want to do is then check if this search returned anything and if not do the simple any length search:

if (!string.IsNullOrEmpty(pPatient.FirstName))
{
    // First look for a 3 or more character match
    if (pPatient.FirstName.Length > 2)
    {
        pSearchQuery = pSearchQuery.Where(item => item.FirstName.Contains(pPatient.FirstName));
    }
    // If didn't find anything do the simple search
    if (!pSearchQuery.Any())
    {
        pSearchQuery = pSearchQuery.Where(item => item.FirstName.Contains(pPatient.FirstName));
    }
}