Question

I have this code below. Gets data and sets data property to the values gathered.

public struct TrblShootData
    {
       public List<string> Logins;
       public IEnumerable<Hieracrhy> Hierarchy;
       public IEnumerable<EmployeeTeam> EmpTeam; 
    }

  public TrblShootData TroubleShootData
   {
       get;
       private set;
   }

 class DataGetter
 { 
 public void GetData(string FirstName, string LastName, string Login, string Email, bool isFirstName, bool isLastName, bool isLogin, bool isEmail)
    {         
        List<string> logins = null;
        IEnumerable<Hieracrhy> hier = null;
        IEnumerable<EmployeeTeam> tmemp = null;

        TrblShootData tsData = new TrblShootData();

        queries q = BuildQuery(FirstName, LastName, Login, Email, isFirstName, isLastName, isLogin, isEmail);

        if (q.isValidQueries)
        {
            DataContext1 mscDB = new DataContext1 ();

            using (DataContext2 opsDB = new DataContext2 ())
            {                    
                tmemp = opsDB.ExecuteQuery<EmployeeTeam>(q.qryEmployeeTeam);

            }

            using (DataContext3 rptDB = new DataContext3 ())
            {                    
                hier = rptDB.ExecuteQuery<Hieracrhy>(q.qryHierarchy);

                if (hier != null)
                {
                    logins = hier.Select(s => s.SalesRepLogin).Distinct().ToList();
                }

            }

            tsData.EmpTeam = tmemp.Select(r=>r);
            tsData.Hierarchy = hier.Select(r => r);
            tsData.Logins = logins.Select(r => r).ToList();

            TroubleShootData = tsData;

        }//if                  
    }
  }

From another class I attempt to do this:

 tshtr.GetData(txtFirstName.Text, txtLastName.Text, txtLogin.Text, txtEmail.Text, chkFirstName.Checked, chkLastName.Checked, chkLogin.Checked, chkEmail.Checked);

        gvEmpTeams.DataSource = tshtr.TroubleShootData.EmpTeam;
        gvHierarchy.DataSource = tshtr.TroubleShootData.Hierarchy;

        gvEmpTeams.DataBind();
        gvHierarchy.DataBind();

But at the DataBind() I get an error saying that I cannot read from a closed reader.

I’m not seeing why it would throw this error when I’ve set my property as above after I’ve assigned the values in the usings. So I’m not seeing how this is trying to use a closed reader.

Thanks for any help!

Answer 1

Because of deferred execution, your query only executes when the data-binding engine enumerates its results, after you close the DataContext.

You need to call .ToList() before closing the DataContext to force it to be evaluated immediately.