public partial class Testing : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

    // Add any controls that have been previously added dynamically

    for (int i = 0; i < TotalNumberAdded; ++i)

    {

        AddControls(i + 1);

    }

    // Attach the event handler to the button

    Button1.Click += new EventHandler(Button1_Click);

}

protected void Button1_Click(object sender, EventArgs e)

{

    // Increase the number added and add the new label and textbox

    TotalNumberAdded++;

    AddControls(TotalNumberAdded);

}

private void AddControls(int controlNumber)

    {

        var newPanel = new Panel();

        var newLabel = new Label();

        var newTextbox = new TextBox();

        // textbox needs a unique id to maintain state information

        newTextbox.ID = "TextBo" + controlNumber;

        newLabel.Text = "Nature Of Accident";

        // add the label and textbox to the panel, then add the panel to the form

        newPanel.Controls.Add(newLabel);

        newPanel.Controls.Add(newTextbox);

        form1.Controls.Add(newPanel);

    }

    protected int TotalNumberAdded

    {

        get { return (int)(ViewState["TotalNumberAdded"] ?? 0); }

        set { ViewState["TotalNumberAdded"] = value; }

    }

}