Question

I have the following code in one of my methods:

foreach (var s in vars) {     foreach (var type in statusList)     {         if (type.Id == s)         {             Add(new NameValuePair(type.Id, type.Text));             break;         }     } } 

This seems sort of ineffective to me, and I was wondering if there was a way to substitute at least one of the foreaches wih a LINQ query. Any suggestions?

EDIT: vars is an array of strings and the Add method adds an item to a CSLA NameValueList.

Answer 1

EDIT: I hadn’t noticed the break; before

If there could be more than one type with the relevant ID, then you need to use FirstOrDefault as per Keith’s answer or my second code sample below.

EDIT: Removing ‘multi-from’ version as it’s unnecessarily inefficient assuming equality/hashcode works for whatever the type of type.Id is.

A join is probably more appropriate though:

var query = from s in vars             join type in statusList on s equals type.Id             select new NameValuePair(type.Id, type.Text);  foreach (var pair in query) {     Add(pair); } 

You might want to make an AddRange method which takes an IEnumerable<NameValuePair> at which point you could just call AddRange(query).

Alternatively, you can use a LookUp. This version makes sure it only adds one type per ‘s’.

var lookup = types.ToLookup(type => type.Id); foreach (var s in vars) {     var types = lookup[s];     if (types != null)     {         var type = types.First(); // Guaranteed to be at least one entry         Add(new NameValuePair(type.Id, type.Text));     } } 

The benefit of this is that it only goes through the list of types once to build up a dictionary, basically.