How to group by multiple fields and get the count of another field
<p>So let's say I have a simple class like </p>

<pre><code>class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int Age { get; set; }
}
</code></pre>

<p>and I have an <code>IQueryable&lt;Person&gt;</code> called <code>persons</code>. What I'm trying to do is the equivalent of</p>

<pre><code>SELECT
   FirstName, 
   LastName,
   COUNT(Age) As AgeCount
FROM dbo.Persons
GROUP BY FirstName, LastName
</code></pre>

<p>if we were in SQL land. How do I write this in LINQ? </p>

<p>I've looked at posts like <a href="https://stackoverflow.com/questions/7285714/linq-with-groupby-and-count">linq with groupby and count</a> and none of them are exactly like my scenario.</p>