Linq to datatable or array (using EntityFramework)

See more:

C#

LINQ

DataTable

I've got this classes:

UserServices:

UserRepository usrrep=new UserRepository();
 public Object[] listaFeedbackUtilizatori()
        {
            return usrrep.listaFeedbackUtilizatori();
        }

UserRepository:

public Object[] listaFeedbackUtilizatori()
       {
           DataTable dt = new DataTable();
           dt.Columns.Add("IdFeedback", typeof(int));
           dt.Columns.Add("Username", typeof(string));
           dt.Columns.Add("DataFaeedback",typeof(DateTime));
           dt.Columns.Add("TextFeedback", typeof(string));
           var query = from utilizator in net.utilizator
                       join feedback in net.feedback
                       on utilizator.idutilizator equals feedback.idutilizator
                       select dt.LoadDataRow(
               new object[] { feedback.idfeedback,utilizator.username, feedback.data, feedback.text },
               false);

          Object []o = new Object[100];
          DataTable d = new DataTable();
           try
           {
               d = query.CopyToDataTable();

           }
           catch (Exception e)
           {
               Console.WriteLine(e.Message);
           }
           return o;

       }

And class:

AdministrareRetele

private void AdministrareBazadeDate_Load(object sender, EventArgs e)
        {
            o = usrsrv.listaFeedbackUtilizatori();   
            comboBox1.DataSource = listarticol;
            comboBox1.DisplayMember = "nume_articol";
            comboBox1.ValueMember = "nume_articol";
           
            comboBox4.DataSource = o;
            comboBox4.DisplayMember = "username";
           comboBox4.ValueMember = "username";
        }

In my database (mysql) I have this table:

Feedback:
idfeedback (int)
iduser (int)
date (datetime)
text (varchar)

and a foreign key which connects to another table USER through iduser

And in form a combobox:

http://img854.imageshack.us/img854/3994/45618197.png[^][]

I just want to populate my combobox4 option list with values containing USERNAMES

I tried like in the code above , but It gives me an error:
"LINQ to Entities does not recognize the method 'LoadDataRow' method, and this method cannot be translated into a store expression"

Any help, or idea will be highly appreciated