ASP.NET search form - dynamic Linq to SQL?

Question

I have a search form that allows users to search on several different fields in several different ways. Here is an example of my code.

var claims = from c in db.         


        

Answer 1

You could make a dictionary of your possible predicates:

Dictionary>>> map = new Dictionary>>>() {
    { "StartsWith", t => c => c.companyFileID.StartsWith(t) },
    { "Equals",     t => c => c.companyFileID == t },
    { "Contains",   t => c => c.companyFileID.Contains(t) }
};

Which could be used like this:

var search = ddlSearchField.Text;
var text = txtSearchBox.Text;

var claims = from c in db.Claims select c;

Func>> predicate = null;
if(dict.TryGetValue(search, out predicate))
    claims = claims.Where(predicate(text));