Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim outlookvcs As New System.Text.StringBuilder
        Dim subject As String
        Dim content As String
        Dim startdate As DateTime
        Dim enddate As DateTime
 
        ' SET SUBJECT HEADER
        subject = "TESTING"
 
        ' SET CONTENT [use '=0D' to make outlook perform a line break]
        content = "There is some content here"
 
        ' SET DATES
        startdate = New DateTime(2007, 12, 25, 12, 0, 0)
        enddate = New DateTime(2007, 12, 25, 19, 30, 0)
 
        With outlookvcs
            .Append("BEGIN:VCALENDAR" & vbLf)
            .Append("PRODID:-//Microsoft Corporation//Outlook 10.0 MIMEDIR//EN" & vbLf)
            .Append("VERSION:1.0" & vbLf)
            .Append("BEGIN:VEVENT" & vbLf)
            .Append("DTSTART:" & str_outlookdate(startdate) & "T" & str_outlooktime(startdate) & "Z" & vbLf)
            .Append("DTEND:" & str_outlookdate(enddate) & "T" & str_outlooktime(enddate) & "Z" & vbLf)
            .Append("UID:1" & vbLf)
            .Append("DESCRIPTION;ENCODING=QUOTED-PRINTABLE:" & content & "=0A" & vbLf)
            .Append("SUMMARY;ENCODING=QUOTED-PRINTABLE:" & subject & vbLf)
            .Append("PRIORITY:3" & vbLf)
            .Append("END:VEVENT" & vbLf)
            .Append("END:VCALENDAR" & vbLf)
        End With
 
        Response.Clear()
        Response.ContentType = "text/calendar"
        Response.AddHeader("content-disposition", "attachment; filename=outlook_calendar_appointment.vcs")
        Response.Write(outlookvcs)
        Response.End()
    End Sub
 
    Private Function str_outlookdate(ByVal dat_date As Date) As String
        str_outlookdate = Format(dat_date, "yyyyMMdd")
    End Function
 
    Private Function str_outlooktime(ByVal dat_time As Date) As String
        str_outlooktime = Format(dat_time, "HHmmss")
    End Function