public class MsgBoxShow
{
    public MsgBoxShow()
    {
        //
        //TODO: 在此处添加构造函数逻辑
        //
    }
    /// <summary>
    /// 显示“确定”，点击后转到预设的网址
    /// </summary>
    /// <param name="strMsg">提示信息</param>
    /// <param name="URL">转跳网址</param>
    public static void MsgBoxShowInfoAndRedirct(System.Web.UI.Page page, string strMsg, string URL)
    {
        StringBuilder builder = new StringBuilder();
        builder.Append("<language='javascript' defer>");
        builder.AppendFormat("alert('{0}');",strMsg);
        builder.AppendFormat("top.location.href='{0}';", URL);
        builder.Append("</script>");
        page.RegisterStartupScript("message", builder.ToString());
    }
}

protected void btnSubmit_Click(object sender, EventArgs e)
    {
        SqlConnection conn = new SqlConnection();
        conn.ConnectionString = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = conn;
        cmd.CommandText = "select * from users where username='" + txtUserName.Text.Trim() + "'";
        conn.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        if (dr.Read())
        {
            if (dr[2].ToString() == txtPwd.Text.Trim())
            {
                MsgBoxShow.MsgBoxShowInfoAndRedirct(this,"登陆成功！", "ManageNews.aspx");
                //Session["UserName"] = txtUserName.Text.Trim();
                //Response.Redirect("NewsManage.aspx");
            }
            else
            {
                MsgBoxShow.MsgBoxShowInfoAndRedirct(this, "密码错误！请重新输入", "login.aspx");
            }
        }
        else
        {
            MsgBoxShow.MsgBoxShowInfoAndRedirct(this, "查无此用户！请重新输入", "login.aspx");
        }
    }