Question

I have the following action method that builds a drop down list which is used for searching records that have a specific country. In addition to showing a list of all countries, I have added a static value named –Any— which will return all the records regardless of their country, as shown below:

public PartialViewResult ManageVisitSearch()
        {   var CountryList = repository.FindAllCountry().ToList();
            CountryList.Insert(0, new Country { Description = "--Any--", CountryID = 0 });
//code goes here
        ViewBag.CountryID = new SelectList(CountryList, "CountryID", "Description", 0);
        return PartialView("_ManageVisitSearch"); }

On the repository method which will perform the search, I did the following to return all the records in case the –Any— was selected from the dropdown lists:

    public IEnumerable<VisitSearch> visitsearch(DateTime? datefrom, DateTime? dateto, int countryid, int genderid)
            {
 var vs = (from v in entities.Visits  where 
(v.Patient.NationalityID == countryid || countryid == 0) 

//code goes here

The above approach is working fine with me, but I think that it might not be the best approach to follow. Is there a more rational approach to follow to add the –Any— to my search dropdown lists, or does my approach sound good?

Answer 1

 public IEnumerable<VisitSearch> visitsearch(DateTime? datefrom, DateTime? dateto, int? countryid, int genderid)
 {
     var vs = entities.Visits;

     if(countryid.HasValue)
         vs = vs.Where(v.Patient.NationalityID == countryid.Value);

     return vs;
 }

You can build your query by adding where clauses based on some conditions.