try this
private void Form1_Load(object sender, EventArgs e)
{
ReadOnlyCollection<timezoneinfo> tzCollection;
tzCollection = TimeZoneInfo.GetSystemTimeZones();
this.timeZoneList.DataSource = tzCollection;
}
private void OkButton_Click(object sender, EventArgs e)
{
TimeZoneInfo selectedTimeZone = (TimeZoneInfo) this.timeZoneList.SelectedItem;
MessageBox.Show("You selected the " + selectedTimeZone.ToString() + " time zone.");
}
</timezoneinfo>