TObjects = _Objects.Split(';');    //имена полей
            i = 0;
            foreach (string TObject in TObjects)
            {
                string[] TAttrs = TObject.Split(':');
                Qtd = TAttrs[0].Substring(3, 1);
                clss = TAttrs[0].Substring(1, 2);
                Enabled = TAttrs[0].Substring(0, 1);
                if (clss == "TB")
                {
                    tb = new TextBox();
                    tb.AutoSize = true;
                    tb.Location = new Point(MaxWidth + 10, Y);
                    if (Enabled == "+") tb.Enabled = true;
                    else tb.Enabled = false;
                    tb.Name = TAttrs[1];
                    tb.Text = "";
                    tb.Size = new Size(200, 13);
                    this.Controls.Add(tb);
                    tb.Show();
                    AObjects.Add(tb);
                }
                if (clss == "CB")
                {
                    try
                    {
                        clientSocket.Connect("127.0.0.1", 8888);
                    }
                    catch (Exception ex)
                    {
                        // MessageBox.Show("Ошибка!\n\n" + ex.Message, "Ошибка SQL", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    }
                    SendCmd(_CMD_LIST + ";SprBanks");
                    NetworkStream Stream = clientSocket.GetStream();
                    int size = (int)clientSocket.ReceiveBufferSize;
                    byte[] ReceivedBytes = new byte[size];
                    Stream.Read(ReceivedBytes, 0, size);
                    data = DeserializeData(ReceivedBytes);
                    data.WriteXml(@"baa.xml");
                    cb = new ComboBox();
                    cb.AutoSize = true;
                    cb.Location = new Point(MaxWidth + 10, Y);
                    if (Enabled == "+") cb.Enabled = true;
                    else cb.Enabled = false;
                    cb.Name = TAttrs[1];
                    cb.Text = "";
                    cb.Size = new Size(200, 13);
                    this.Controls.Add(cb);
                    cb.Show();
                    cb.DataSource = data.Tables[0].DefaultView;
                    cb.DisplayMember = "Name";
                    cb.ValueMember = "Id";
                    cb.SelectedIndex = 0;
                    AObjects.Add(cb);
                }
                Labs[i].Left = 6 + MaxWidth - Labs[i].Width;
                i++;
                Y += 24;
            }
        }

как вариант

private void button1_Click(object sender, EventArgs e)
        {
            Func<Point> location = () =>
                {
                    var controls = this.Controls.Find("labelnew", false);
                    if (controls.Any())
                    {
                        var lastControl = controls.Last();
                        return new Point(lastControl.Location.X, lastControl.Location.Y + 40);
                    }
                    else
                    {
                        return new Point(button1.Location.X, button1.Location.Y + 40); 
                    }
                };
            this.Controls.Add(new Label()
                {
                    Name = "labelnew",
                    Text = "New Label",
                    Location = location()
                });
        }

             Object ob = AObjects[i];
             _fSQL_Update += (ob as TextBox).Text;

             Object ob = AObjects[i];
             _fSQL_Update += (ob as TextBox).Text;

             Object ob = AObjects[i];
             _fSQL_Update += (ob as TextBox).Text;

_fSQL_Update += ((TextBox)ob).Text;

var res = AObjects.OfType<System.Windows.Forms.Control>()
                .Select(n => n.Text)
                .Aggregate((a, b) => a + b);