create dragpanel in asp.net dynamically

Question

I want to create ajax dragpanel dynamically and add the controls and panel dynamically.I used the below code for create the control dynamically.But I can`t able to drag it.

 

    enter code here

    protected void Page_PreInit(object sender, EventArgs e)

    {

        DragPanelExtender drg = new DragPanelExtender();

        drg.ID = "drg_1";

        drg.DragHandleID = "pnl_1";

        drg.TargetControlID = "pnl_2";

        Panel p1 = new Panel();

        p1.ID = "pnl_1";

        Panel p2 = new Panel();

        p2.ID = "pnl_2";

        Label l1 = new Label();

        l1.Text = "First";

        TextBox t = new TextBox();

        t.Text = "Enter text";

        p2.Controls.Add(l1);

        p2.Controls.Add(t);

        p1.Controls.Add(p2);

        Page.Controls.Add(p1);

    }

How to I create drag controls inside the panel