How to build a CAML query with several nested OR's using a loop

Question

I'm new to SharePoint development and I need your help to solve this issue.I've created a CAMLQuery builder class.

public class CAMLQueryBuilder
{
    #region Builder part

public static string QueryBody(string clause1)
{
    return "<Where>" + clause1 + "</Where>";
}

public static string QueryAnd(string clause1, string clause2)
{
    return "<And>" + clause1 + clause2 + "</And>";
}
public static string QueryOr(string clause1, string clause2)
{
    return "<Or>" + clause1 + clause2 + "</Or>";
}

public static string QueryEq(string fieldName, string fieldType, string fieldValue)
{
    return string.Format("<Eq><FieldRef Name='{0}'/><Value Type='{1}'>{2}</Value></Eq>", fieldName, fieldType, fieldValue);
}
#endregion
}

Now I have List<string>positions which may contain more than one string, and for each position Employee can see some info regarding some rules(if he is office director , he can see everything from his office, if he is delivery manager everything from his department).Now I need idea how can I build multiple OR query after going through the for loop. I want a query that will have as many nested OR's as there are positions at the and of for loop.

This is the basic structure of the code, I need your help to make it work. I've created generic recursive method in case there will be more than one positions to generate nested OR's.

public static string RecursiveNestedOr(int count, List<string> query) 
{
//please if you have another idea for naming this method
   if (count == 1)
   {
       return query[0];
   }
    else
    {
      return CAMLQueryBuilder.QueryOr(query[count-1], RecursiveNestedOr(--count, query));
    }
  }

Then I make a query string for each of the position and add it to Listqueries.After that I use recursive method and send list of queries as a parameter to it.

for (int i = 0; i < positions.Count - 1; i++)
{
  switch (positions[i])
  {
    case ("OfficeDirector"): query = CAMLQueryBuilder.QueryEq("Office", "Choice", emp.Offices[i]);
       break;
    case ("DeliveryManager"): query = CAMLQueryBuilder.QueryEq("Department", "Choice", emp.Departments[i]);
       break;
    default:query = "";
       break;
  }
   queries.Add(query);

}
   query = CAMLQueryBuilder.QueryBody(CAMLQueryBuilder.RecursiveCAMLOr(queries.Count, queries));
//this is only basic idea 

Is there any other solution ? More elegant ? Thank you!

Answer 1

You don't need to pass count as a parameter as you can get it from queries Inside the method RecursiveNestedOr itself (also, rename parameter query as queries).

Otherwise, your recursion looks fine to me. Here's how I'd "simplified" it, using LINQ (add using System.Linq):

public static string RecursiveNestedOr(IEnumerable<string> queries)
{
    if (queries == null || queries.Count() == 0)
        return "";

   if (queries.Count() == 1)
       return queries.First();

    // Now queries.Count is at least 2
    return CAMLQueryBuilder.QueryOr(queries.Last(), RecursiveNestedOr(queries.Take(queries.Count() - 1)));
}

EDIT:
Here's how to do it without recursion (code not tested):

public static string NestedOr(IEnumerable<string> queries)
{
    if (queries == null || queries.Count() == 0)
        return "";

   if (queries.Count() == 1)
       return queries.First();

   string result = queries.First();

   // Now queries.Count is at least 2

   foreach(string query in queries.Skip(1))
   {
      result = QueryOr(result, query);
   }

    return result;
}