This Code Shows How to Add Controls at Run Time

 private void Page_Load(object sender, System.EventArgs e)
{
    if (!IsPostBack)
        AddControls();
}

protected override void LoadViewState(object savedState)
{
    base.LoadViewState(savedState);
    if (ViewState["controsladded"] == null)
    AddControls();
}

private void AddControls()
{
    TextBox dynamictextbox = new TextBox();
    dynamictextbox.Text = "(Enter some text)";
    dynamictextbox.ID = "dynamictextbox";
    Button dynamicbutton = new Button();
    dynamicbutton.Click  = new System.EventHandler(dynamicbutton_Click);
    dynamicbutton.Text = "Dynamic Button";
    Panel1.Controls.Add(dynamictextbox);
    Panel1.Controls.Add(new LiteralControl("<BR>"));
    Panel1.Controls.Add(new LiteralControl("<BR>"));
    Panel1.Controls.Add(dynamicbutton);
    ViewState["controlsadded"] = true;
}

private void dynamicbutton_Click(Object sender, System.EventArgs e)
{
    TextBox tb = new TextBox();
    tb = (TextBox) (Panel1.FindControl("dynamictextbox"));
    Label1.Text = tb.Text;
}