Panel pnlTextBox;

protected void Page_PreInit(object sender, EventArgs e)

{

    //Create a Dynamic Panel

    pnlTextBox = new Panel();

    pnlTextBox.ID = "pnlTextBox";

    pnlTextBox.BorderWidth = 1;

    pnlTextBox.Width = 300;

    this.form1.Controls.Add(pnlTextBox);

    //Create a LinkDynamic Button to Add TextBoxes

    LinkButton btnAddtxt = new LinkButton();

    btnAddtxt.ID = "btnAddTxt";

    btnAddtxt.Text = "Add TextBox";

    btnAddtxt.Click += new System.EventHandler(btnAdd_Click);

    this.form1.Controls.Add(btnAddtxt);

    //Recreate Controls

    RecreateControls("txtDynamic", "TextBox");

}

Protected Sub Page_PreInit(ByVal sender As Object, ByVal e As EventArgs) Handles Me.PreInit

  'Create a Dynamic Panel

  pnlTextBox = New Panel()

  pnlTextBox.ID = "pnlTextBox"

  pnlTextBox.BorderWidth = 1

  pnlTextBox.Width = 300

  Me.form1.Controls.Add(pnlTextBox)

  'Create a LinkDynamic Button to Add TextBoxes

  Dim btnAddtxt As New LinkButton()

  btnAddtxt.ID = "btnAddtxt"

  btnAddtxt.Text = "Add TextBox"

  AddHandler btnAddtxt.Click, AddressOf btnAdd_Click

  Me.form1.Controls.Add(btnAddtxt)

  'Recreate Controls

  RecreateControls("txtDynamic", "TextBox")

End Sub

protected void btnAdd_Click(object sender, EventArgs e)

{

    int cnt = FindOccurence("txtDynamic");

    CreateTextBox("txtDynamic-" + Convert.ToString(cnt + 1));

}

Protected Sub btnAdd_Click(ByVal sender As Object, ByVal e As EventArgs)

    Dim cnt As Integer = FindOccurence("txtDynamic")

    CreateTextBox("txtDynamic-" & Convert.ToString(cnt + 1))

End Sub

private int FindOccurence(string substr)

{

    string reqstr = Request.Form.ToString();

    return ((reqstr.Length - reqstr.Replace(substr, "").Length)

                      / substr.Length);

}

Private Function FindOccurence(ByVal substr As String) As Integer

   Dim reqstr As String = Request.Form.ToString()

   Return ((reqstr.Length - reqstr.Replace(substr, "").Length) & _

                                           / substr.Length)

End Function

private void CreateTextBox(string ID)

{

    TextBox txt = new TextBox();

    txt.ID = ID;

    txt.AutoPostBack = true;

    txt.TextChanged += new EventHandler(OnTextChanged);

    pnlTextBox.Controls.Add(txt);

    Literal lt = new Literal();

    lt.Text = "<br />";

    pnlTextBox.Controls.Add(lt);

}

Private Sub CreateTextBox(ByVal ID As String)

    Dim txt As New TextBox()

    txt.ID = ID

    txt.AutoPostBack = True

    AddHandler txt.TextChanged, AddressOf OnTextChanged

    pnlTextBox.Controls.Add(txt)

    Dim lt As New Literal()

    lt.Text = "<br />"

    pnlTextBox.Controls.Add(lt)

End Sub

protected void OnTextChanged(object sender, EventArgs e)

{

    TextBox txt = (TextBox)sender;

    string ID = txt.ID;

    ClientScript.RegisterClientScriptBlock(this.GetType(), "Alert",

                 "<script type = 'text/javascript'>alert('" + ID  +

                  " fired OnTextChanged event');</script>");

    //Place the functionality here

}

Protected Sub OnTextChanged(ByVal sender As Object, ByVal e As EventArgs)

    Dim txt As TextBox = DirectCast(sender, TextBox)

    Dim ID As String = txt.ID

    'Place the functionality here

    ClientScript.RegisterClientScriptBlock(Me.GetType(), _

    "Alert", "<script type = 'text/javascript'>alert('" & ID _

    & " fired OnTextChanged event');</script>")

End Sub

private void RecreateControls(string ctrlPrefix, string ctrlType)

{

    string[] ctrls = Request.Form.ToString().Split('&');

    int cnt = FindOccurence(ctrlPrefix);

    if (cnt > 0)

    {

        for (int k = 1; k <= cnt; k++)

        {

            for (int i = 0; i < ctrls.Length; i++)

            {

                if (ctrls[i].Contains(ctrlPrefix + "-" + k.ToString())

                    && !ctrls[i].Contains("EVENTTARGET"))

                {

                    string ctrlID = ctrls[i].Split('=')[0];

                    if (ctrlType == "TextBox")

                    {

                        CreateTextBox(ctrlID);

                    }

                    break;

                }

            }

        }

    }

}

Private Sub RecreateControls(ByVal ctrlPrefix As String, ByVal ctrlType As String)

  Dim ctrls As String() = Request.Form.ToString().Split("&"c)

  Dim cnt As Integer = FindOccurence(ctrlPrefix)

  If cnt > 0 Then

      For k As Integer = 1 To cnt

         For i As Integer = 0 To ctrls.Length - 1

             If ctrls(i).Contains((ctrlPrefix & "-") + k.ToString()) _

                  AndAlso Not ctrls(i).Contains("EVENTTARGET") Then

                 Dim ctrlID As String = ctrls(i).Split("="c)(0)

                 If ctrlType = "TextBox" Then

                      CreateTextBox(ctrlID)

                 End If

                 Exit For

             End If

         Next

     Next

  End If

End Sub