Locking considerations for populating ConcurrentDictionary with database values ​​in C #

Do I need to use lock (lockObj) {} when I populate my ConcurrentDictionary here? For a little background this will be used in an MVC application, although I suspect the scripting question is relevant to any multithreaded application.

Searching stackoverflow, I didn't find this exact scenario. The first time a value is requested from the GetOptionById value, it can be called by two separate threads.

1) Would it be considered best practice to have List objects evaluate to a private static object that you have locked, in the hopes of not calling the database multiple times before filling the ConcurrentDictionary?

2) Is this (# 1 above) even necessary, or is the ConcurrentDictionary smart enough to handle this on its own? Thanks in advance for any input.

public class MyOptions
{
    static string GetOptionById(int id)
    {
        if (options == null || options.Count <= 0)
            FillOptionList();
        return options[id];
    }

    static void FillOptionList()
    {
        List<MyBusinessObject> objects = DataAccessLayer.GetList();
        foreach (MyBusinessObject obj in objects)
            options.TryAdd(obj.Id, obj.Name);
    }

    private static ConcurrentDictionary<int, string> options = new ConcurrentDictionary<int, string>();
}

      

        
        
        
      

    

EDIT: Thanks everyone for your input, would this be a safer approach?

    public static string OptionById(int id)
    {
        if (!options.ContainsKey(id))
        {
            //perhaps this is a new option and we need to reload the list
            FillOptionsOrReturn(true /*force the fill*/);
            return (!options.ContainsKey(id)) ? "Option not found" : options[id];
        }
        else
            return options[id];
    }

    private static void FillOptionsOrReturn(bool forceFill = false)
    {
        List<MyBusinessClass> objectsFromDb = null;
        lock (lockObj)
        {
            if (forceFill || options == null || options.Keys.Count <= 0)
                reasons = DataAccessLayer.GetList();
        }
        if (objectsFromDb != null)
        {
            foreach (MyBusinessClass myObj in objectsFromDb)
                options.TryAdd(myObj.id, myObj.name);
        }
    }

    private static ConcurrentDictionary<int, string> options = new ConcurrentDictionary<int, string>();
    private static object lockObj = new object();