protected void Page_Load(object sender, EventArgs e)
{
ImageButton objImg = new ImageButton();
objImg.ID = "imgNew";
objImg.Click += new EventHandler(objImg_Click);
  Page.Controls.Add(objImg);
}

void objImg_Click(object sender, EventArgs e)
{
    Response.Write("btnTest_Click: " + DateTime.Now.ToString());
}