Get timezone using asp.net

using System;
using System.Collections.ObjectModel;

protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
lblLocalTime.Text = DateTime.Now.ToString();
ReadOnlyCollection tzi;
tzi = TimeZoneInfo.GetSystemTimeZones();
foreach (TimeZoneInfo timeZone in tzi)
{
ddlTimeZone.Items.Add(new ListItem(timeZone.DisplayName, timeZone.Id));
}
}
}

protected void ddlTimeZone_SelectedIndexChanged(object sender, EventArgs e)
{
if (ddlTimeZone.SelectedIndex > 0)
{
DateTime dt = DateTime.Now;
lblTimeZone.Text = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(dt,
TimeZoneInfo.Local.Id, ddlTimeZone.SelectedValue).ToString();
}
}