this.ultraTimeZoneEditor1.DataFilter = new TimeZoneDataFilter( this.ultraTimeZoneEditor1 );

private class TimeZoneDataFilter : IEditorDataFilter
{
    private UltraTimeZoneEditor control = null;

    public TimeZoneDataFilter( UltraTimeZoneEditor control )
    {
        this.control = control;
    }

    #region IEditorDataFilter Members

    public object Convert(EditorDataFilterConvertArgs conversionArgs)
    {
        if ( conversionArgs.Direction == ConversionDirection.EditorToDisplay )
        {
            TimeZoneInfo tzi = this.control.Value as TimeZoneInfo;
            if ( tzi != null )
            {
                conversionArgs.Handled = true;
                return tzi.StandardName;
            }
        }

        return conversionArgs.Value;
    }

    #endregion
}