Dynamically create datatable that allows population multiple times - asp.net

Question

I'm trying to dynamically create a datatable that will allow me to populate single records multiple times when a procedure is executed. I know how to create the datatable with the columns I need but my problem is that every time I execute the sub routine to add a record it re-initializes the datatable and wipes out the previously populated record. How do I create the datatable so that it initializes only once? I've tried initializing during the Page_Load event with a 'Not IsPostback' condition but that doesn't work. Any other ideas?
Partial Public Class ContactLookup
Inherits System.Web.UI.Page
Dim dtContacts As New DataTable
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
dtContacts = New DataTable
dtContacts.Columns.Add("Email", GetType(String))
dtContacts.Columns.Add("AccountNum", GetType(String))
End If
End Sub
Protected Sub btnAddContact_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnAddContact.Click
Dim AcctNum As String = txtLocAcct.Text
Dim Email As String = txtEmail.Text
Dim drContacts As DataRow = dtContacts.NewRow
drContacts("Email") = Email
drContacts("AccountNum") = AcctNum
dtContacts.Rows.Add(drContacts)
End Sub
End Class

Answer 1

If I am correct than you need the table returned by the query as datatable. If its so then you can try this. Change your SqlCommand like this,
var dt =new DataTable(); // a new table to populate dynamically.
var reader = cmd.ExecuterReader(CommandBehaviour.SequentialAccess");
dt.Load(reader);
return dt; // now your dt will be query dependent.
Sorry the answer is in C#. You can convert it to VB at http://converter.telerik.com
Updated Answer
In your case i would suggest create a class instead of datatables and datacolumns. See a sample below:
public class Student
{
public string Name{get;set;}
public int Roll{get;set;}
}
In your code behind
private Student _stud = new Student();
private void FillObjects(){
_stud.Name= txtName.Text;
_stud.Roll=Convert.ToInt32(txtRoll.Text);
}
private void ButtonClick{
FillObjects();
YourClass.SaveMethod(_stud);
}