Combine multiple Linq Where statements

Question

I've created a function to filter and sort the content of a list.

It's seems a bit 'bitty', however Linq isn't strong point. I'm wondering if the function can be streamlined, either from a performance perspective or even asthetic perspective.

Here's the code:

// Deserialise the XML to create a class of active rows

    var agents = XmlHelper
        .Deserialise<AgentConfigs>("~/Pingtree.xml")
        .Agents
        .Where(x => x.IsActive == true);

// First - get 'direct' agents and order them

    var direct = agents
        .Where(x => x.IsDirect)
        .OrderByDescending(x => x.MinPrice);

// Second - get indirect agents and order them

    var agency = agents
        .Where(x => !x.IsDirect)
        .OrderBy(x => x.Priority);

// Bolt the 2 sublists together, retaining the order

    Agents = direct.Concat(agency).ToList();

Any thoughts on how this could be improved?

Answer 1

You could use GroupBy or ToLookup to split both, i prefer ToLookup in this case:

var activeAgentDirectLookup = XmlHelper
    .Deserialise<AgentConfigs>("~/Pingtree.xml")
    .Agents
    .Where(x => x.IsActive == true)
    .ToLookup(a => a.IsDirect);

Agents = activeAgentDirectLookup[true].OrderByDescending(x => x.MinPrice)
    .Concat(activeAgentDirectLookup[false].OrderBy(x => x.Priority))
    .ToList();

A lookup is similar to a dictionary with a bool as key in this case(so two possible groups). The values are IEnumerable<Agents>, so all agents which are either IsDirect or !IsDirect. The benefit here is that you only need to evaluate it once.