返回按钮事件代码

 protected void Page_Load(object sender, EventArgs e)
  {
    if (!IsPostBack)
    {
        if (Request.UrlReferrer != null)
          ViewState["UrlReferrer"] = Request.UrlReferrer.ToString();
            }
  }

protected void btnBack_Click(object sender, EventArgs e)
  {
    Response.Redirect(ViewState["UrlReferrer"].ToString());
  }