Help with Dynamically creating controls

This is for the web using C#.

What i'm trying to do:
I would like everytime the user clicks a button a table with 3 rows and 2 columns are created. And 3 labels and 3 textboxes are created inside the table. The user can click on the button once, enter the info, then save the document. Reopen the document later and click the button again to add even more information. So if the user does this 4 times, there will be four tables with all of the information they entered.

I'm able to do this only once. When the i click the button it creates everything, but when i click it again it wipes it away and creates the same table over it..

I'll be working on this in the meantime, but any help with be greatly apprecaited.

I used the table control in the toolbox.
I tried:
Table tblInvoice = new Table() ;
but i get an error: "_Default.Table' does not contain a definition for 'Rows' ".
I'd like to create the table dynamically rather then dropping the control on the aspx page

here is my code.  

// -----INVOICE-----
           TableRow tRow = new TableRow();
           tblInvoice.Rows.Add(tRow);
           TableCell tCell = new TableCell();
           tRow.Cells.Add(tCell);
// add cell One content
            Label lblInvoice = new Label();
            lblInvoice.ID = "lblInvoice";
            lblInvoice.Text = "Invoice #:";
            tCell.Controls.Add(lblInvoice);
// add the cell to the Cells collection
            tRow.Cells.Add(tCell);
// add cell Two
            TableCell tCell2 = new TableCell();
            tRow.Cells.Add(tCell2);
// add cell Two content
            TextBox txtInvoice = new TextBox();
            txtInvoice.ID = "txtInvoice:";
            txtInvoice.Text = "";
            txtInvoice.Height = 18;
            tCell2.Controls.Add(txtInvoice);
// add the cell to the Cells collection
            tRow.Cells.Add(tCell2);
// -----AMOUNT-----
// add row Two
            TableRow tRow2 = new TableRow();
            tblInvoice.Rows.Add(tRow2);
// add cell Three
            TableCell tCell3 = new TableCell();
             tRow2.Cells.Add(tCell3);
// add cell Three content
             Label lblAmount = new Label();
             lblAmount.ID = "lblAmount";
             lblAmount.Text = "Amount:";
             tCell3.Controls.Add(lblAmount);
// add the cell to the Cells collection
              tRow2.Cells.Add(tCell3);
// add cell Four
              TableCell tCell4 = new TableCell();
              tRow2.Cells.Add(tCell4);
// add cell Four content
               TextBox txtAmount = new TextBox();
               txtAmount.ID = "txtAmount";
               txtAmount.Text = "";
               txtAmount.Height = 18;
               tCell4.Controls.Add(txtAmount);
// add the cell to the Cells collection
               tRow2.Cells.Add(tCell4);

// -----DATE-----
// add row Three
            TableRow tRow3 = new TableRow();
            tblInvoice.Rows.Add(tRow3);
// add cell Five
             TableCell tCell5 = new TableCell();
             tRow3.Cells.Add(tCell5);
// add cell Five content
             Label lblDateRecieved = new Label();
             lblDateRecieved.ID = "lblDateRecieved";
             lblDateRecieved.Text = "Date:";
             tCell5.Controls.Add(lblDateRecieved);
// add the cell to the Cells collection
             tRow3.Cells.Add(tCell5);
// add cell Six
             TableCell tCell6 = new TableCell();
             tRow3.Cells.Add(tCell6);
// add cell Six content
             TextBox txtDateRecieved = new TextBox();
             txtDateRecieved.ID = "txtDateRecieved";
             txtDateRecieved.Text = "";
             txtDateRecieved.Height = 18;
             Button btnCalendar = new Button();
             btnCalendar.BackColor = System.Drawing.Color.White;
             btnCalendar.CssClass = "calendarImage";
             btnCalendar.Width = 27;
             tCell6.Controls.Add(txtDateRecieved);
             tCell6.Controls.Add(btnCalendar);
// add the cell to the Cells collection
              tRow3.Cells.Add(tCell6);

Thanks a lot in advance.