How to programmatically create a .ics file?

Question

How to create an icalendar file with minimal data, I try to do it as follows, but something is wrong, when I try to import it into my Google calendar, it says that the events were imported successfully, but I can not see this event in my calendar

    strResult.Append("BEGIN:VCALENDAR" & vbCrLf)           

    strResult.Append("VERSION:2.0" & vbCrLf)

    strResult.Append("METHOD:PUBLISH" & vbCrLf)

    While rst1.Read
        strResult.Append("BEGIN:VEVENT" & vbCrLf)

        strResult.Append("DTSTART: " & CDate(getLeave_date_start(CStr(rst1.getInteger("inq_id")), g_dom_id)).ToUniversalTime().ToString("yyyyMMddTHHmmssZ") & vbCrLf)    

        strResult.Append("DTEND: " & CDate(getLeave_date_end(CStr(rst1.getInteger("inq_id")), g_dom_id)).ToUniversalTime().ToString("yyyyMMddTHHmmssZ") & vbCrLf)

        strResult.Append("SUMMARY: " & rst1.getString("inq_name") & vbCrLf)

        strResult.Append("UID: " & rst1.getInteger("inq_id") & vbCrLf)

        strResult.Append("CLASS:PUBLIC" & vbCrLf)

        strResult.Append("END:VEVENT" & vbCrLf)

    End While
    strResult.Append("END:VCALENDAR" & vbCrLf)

    WriteCalendar(strResult)

I wrote the WriteCalendar function as follows

Private Sub WriteCalendar(ByVal data As String)
    Dim response As HttpResponse = Page.Response
    response.Clear()
    response.Buffer = True
    response.ContentType = "text/calendar"
    response.ContentEncoding = Encoding.UTF8
    response.Charset = "utf-8"
    response.AddHeader("Content-Disposition", "attachment;filename=""" & "icalendarTest" & ".ics""")
    response.Write(data)
    response.[End]()
End Sub

I upload a file and see my events, but when it comes to importing into Google Calendar, it says that 6 events were imported successfully, but I can’t see them in the calendar

Output icalendarTest.ics

BEGIN:VCALENDAR  
VERSION:2.0  
METHOD:PUBLISH  
BEGIN:VEVENT  
DTSTART: 20110107T060000Z  
DTEND: 20110109T080000Z  
SUMMARY: ayin yedisinden dokuzuna  
UID: 9  
CLASS:PUBLIC  
END:VEVENT  
BEGIN:VEVENT
DTSTART: 20110119T103000Z  
DTEND: 20110119T150000Z  
SUMMARY: tek gunluk ondokuz  
UID: 10  
CLASS:PUBLIC  
END:VEVENT  
BEGIN:VEVENT  
DTSTART: 20110213T080000Z  
DTEND: 20110213T160000Z  
SUMMARY: Mijn Event  
UID: 21  
CLASS:PUBLIC  
END:VEVENT  
BEGIN:VEVENT  
DTSTART: 20110301T083000Z  
DTEND: 20110302T110000Z  
SUMMARY: Mart kapidan baktirir  
UID: 26  
CLASS:PUBLIC  
END:VEVENT  
BEGIN:VEVENT  
DTSTART: 20110117T080000Z  
DTEND: 20110117T120000Z  
SUMMARY: Neyse bi oncesi olsun  
UID: 27  
CLASS:PUBLIC  
END:VEVENT  
BEGIN:VEVENT  
DTSTART: 20110121T130000Z  
DTEND: 20110121T180000Z  
SUMMARY: ocak 21i  
UID: 31  
CLASS:PUBLIC  
END:VEVENT  
END:VCALENDAR  

Answer 1

I did not include all tags in .ics, this is the reason for this error.

Google , . DTSTAMP , , unessessary, ,

    strResult.Append("BEGIN:VCALENDAR" & vbCrLf)
    strResult.Append("PRODID:-//Google Inc//Google Calendar 70.9054//EN" & vbCrLf)
    strResult.Append("VERSION:2.0" & vbCrLf)
    strResult.Append("METHOD:PUBLISH" & vbCrLf)

    While rst1.Read
        strResult.Append("BEGIN:VEVENT" & vbCrLf)
        strResult.Append("DTSTART:" & rst1.getDateTime("hly_startdate").ToUniversalTime().ToString("yyyyMMddTHHmmssZ") & vbCrLf)
        strResult.Append("DTEND:" & rst1.getDateTime("hly_enddate").ToUniversalTime().ToString("yyyyMMddTHHmmssZ") & vbCrLf)
        strResult.Append("DTSTAMP:" & rst1.getDateTime("hly_date_created").ToUniversalTime().ToString("yyyyMMddTHHmmssZ") & vbCrLf)
        strResult.Append("SEQUENCE:0" & vbCrLf)
        strResult.Append("STATUS:CONFIRMED" & vbCrLf)
        strResult.Append("SUMMARY:" & rst1.getString("hly_name") & vbCrLf)
        strResult.Append("UID:" & System.Guid.NewGuid.ToString() & vbCrLf)
        strResult.Append("CLASS:PUBLIC" & vbCrLf)
        strResult.Append("TRANSP:OPAQUE" & vbCrLf)
        strResult.Append("END:VEVENT" & vbCrLf)

    End While
    strResult.Append("END:VCALENDAR" & vbCrLf)