title: Getting Error "Value Cannot Be NULL" when running a LINQ query
body: <p>I am running this LINQ to Entities query below, it crashes with error saying <code>{"Value cannot be null.\r\nParameter name: outer"}</code></p>
  
  <pre><code>    foreach (ProviderAddresses pa in providerAddresseses)
      {
          var eaAddrs = (from addrs in this.Context.EaAddresseses
              join ea in this.Context.EntityAssignments
                  on addrs.Ea_K equals ea.Ea_K
              where addrs.ProviderAddress_K == pa.ProviderAddress_K
              select new
              {
                  EAAddress = addrs,
                  AssignmentRTK = ea.Assignment_RTK
              });
  </code></pre>
  
  <p>But the parameter I am passing is NOT really null, so what is causing this? Is it because I am passing a List object and joining with real tables in LINQ to Entities? and they don't work together? </p>