Sending meeting requests using ical through outlook - vb.net

Question

Here is my dilemma. I have a vb.net application for requesting time using an asset. The user submits a request (can contain required and optional users), then an approver has to approve it. When it is approved, I want to send a meeting request. I can't do it using outlook code since it won't let me change the organizer. If I try to send it using outlook.application > outlook.olitemtype.olappointmentitem or whatever it is, it will default the organizer to the person sending the meeting request, which in this case is the approver, which I don't want. So I think I am left with trying to send an ical. This is where I am having issues. I can't use smtpclient to create the email and send it using the proper content-type, etc. I have to send it using outlook. So I create an ics file and add it as an attachment. I am not sure the difference between METHOD:PUBLISH and METHOD:REQUEST. All the searches I've have done say I should use method:request, but when i open the ICS file, it doesn't give me the options to accept, etc. It doesn't add to my calendar. I want the ability to be able to update and cancel the meeting as well, which I think I know how to do with uid, sequence, etc. I've done searches and just can't get to where I need to be. It looks like the best option is to use smtpclient to create the mail message where you add the headers and ical stuff, but I can't do that, is there a way to it using outlook?
If someone can help point me in the right direction, I would greatly appreciate it.
Here is my current code:
Dim msg As MailMessage = New MailMessage
msg.From = New MailAddress(br.requesting_user_email)
msg.To.Add(New MailAddress(br.requesting_user_email))
msg.Subject = variables.UserInfo.last_name & ", " + variables.UserInfo.first_name & " has approved your request through the Bench Scheduler."
Dim bodytxt As String = "User: " & variables.UserInfo.last_name & ", " + variables.UserInfo.first_name & vbLf & "5+2: " + variables.UserInfo.username & vbLf & vbLf
bodytxt += "Has approved your bench request for " & br.program_name & " - " & br.project_name & "." & vbLf & vbLf
bodytxt += "Start: " & br.start_time & vbLf & "End: " & br.end_time & vbLf
bodytxt += "Bench: " & br.bench_name & vbLf & "Priority: " & br.priority & vbLf & "Purpose: " & br.objective & vbLf & vbLf
bodytxt += "Request Notes: " & br.notes & vbLf & vbLf
bodytxt += vbLf & vbLf & vbLf & "This email was automatically generated by Bench Scheduler. You may respond to this email."
msg.Body = bodytxt
Dim str As StringBuilder = New StringBuilder
str.AppendLine("BEGIN:VCALENDAR")
str.AppendLine("PRODID:-//Microsoft Corporation//Outlook 15.0 MIMEDIR//EN")
str.AppendLine("VERSION:2.0")
If cancel Then
str.AppendLine("METHOD:CANCEL")
Else
str.AppendLine("METHOD:REQUEST")
End If
str.AppendLine("BEGIN:VEVENT")
str.AppendLine("X-MS-OLK-FORCEINSPECTOROPEN:TRUE")
str.AppendLine("BEGIN:VTIMEZONE")
str.AppendLine("TZID:Eastern Standard Time")
str.AppendLine("BEGIN:STANDARD")
str.AppendLine("DTSTART:16011104T020000")
str.AppendLine("RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11")
str.AppendLine("TZOFFSETFROM:-0400")
str.AppendLine("TZOFFSETTO:-0500")
str.AppendLine("END:STANDARD")
str.AppendLine("BEGIN:DAYLIGHT")
str.AppendLine("DTSTART:16010311T020000")
str.AppendLine("RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3")
str.AppendLine("TZOFFSETFROM:-0500")
str.AppendLine("TZOFFSETTO:-0400")
str.AppendLine("END:DAYLIGHT")
str.AppendLine("END:VTIMEZONE")
Dim dt As New DataTable
Dim ta As New BSDataSetTableAdapters.getUserRequestTableAdapter
dt = ta.GetData(br.request_id, "T")
For Each row As DataRow In dt.Rows
If row("type") = "Required" Then
str.AppendLine(String.Format("ATTENDEE;CN='{0}';RSVP=TRUE:mailto:{1}", row("username"), row("email")))
ElseIf row("type") = "Optional" Then
str.AppendLine(String.Format("ATTENDEE;CN='{0}';ROLE=OPT-PARTICIPANT;RSVP=TRUE:mailto:{1}", row("username"), row("email")))
End If
Next
str.AppendLine("CLASS:PUBLIC")
str.AppendLine("CREATED:" & Format(Date.Now, "yyyyMMddTHHmmssZ"))
str.AppendLine(String.Format("DESCRIPTION:{0}", br.objective))
str.AppendLine("DTEND;TZID=" & """" & "Eastern Standard Time" & """" & ":" & Format(CDate(br.end_time), "yyyyMMddTHHmmss"))
str.AppendLine("DTSTAMP:" & Format(Date.Now, "yyyyMMddTHHmmssZ"))
str.AppendLine("DTSTART;TZID=" & """" & "Eastern Standard Time" & """" & ":" & Format(CDate(br.start_time), "yyyyMMddTHHmmss"))
str.AppendLine(String.Format("LOCATION:{0}", br.bench_name))
str.AppendLine(String.Format("ORGANIZER;CN='" & br.requesting_username & "':mailto:" & br.requesting_user_email))
str.AppendLine("PRIORITY:5")
str.AppendLine("SEQUENCE:0")
str.AppendLine(String.Format("SUMMARY;LANGUAGE=en-us:{0}", "Approved Bench Request (ID-" & br.request_id & "): " & br.program_name & "-" & br.project_name & "-" & br.activity))
str.AppendLine("TRANSP:OPAQUE")
str.AppendLine(String.Format("UID:{0}", br.uid))
str.AppendLine(String.Format("X-ALT-DESC;FMTTYPE=text/html:{0}", br.objective))
str.AppendLine("X-MICROSOFT-CDO-BUSYSTATUS:BUSY")
str.AppendLine("X-MICROSOFT-CDO-IMPORTANCE:1")
str.AppendLine("X-MICROSOFT-CDO-INTENDEDSTATUS:BUSY")
str.AppendLine("X-MICROSOFT-DISALLOW-COUNTER:FALSE")
str.AppendLine("X-MS-OLK-AUTOFILLLOCATION:FALSE")
str.AppendLine("X-MS-OLK-CONFTYPE:0")
str.AppendLine("BEGIN:VALARM")
str.AppendLine("TRIGGER:-PT30M")
str.AppendLine("ACTION:DISPLAY")
str.AppendLine("DESCRIPTION:Reminder")
str.AppendLine("END:VALARM")
str.AppendLine("END:VEVENT")
str.AppendLine("END:VCALENDAR")
Dim smtpclient As SmtpClient = New SmtpClient
smtpclient.Host = "replaced for privacy"
smtpclient.Credentials = System.Net.CredentialCache.DefaultNetworkCredentials
Dim contype As System.Net.Mime.ContentType = New System.Net.Mime.ContentType("text/calendar")
contype.Parameters.Add("method", "REQUEST")
contype.Parameters.Add("name", "Meeting.ics")
Dim avcal As AlternateView = AlternateView.CreateAlternateViewFromString(str.ToString, contype)
msg.AlternateViews.Add(avcal)
smtpclient.Send(msg)