如何以编程方式取消使用asp.net VB的Outlook会议？

我可以以编程方式创建会议请求，该会议请求通过代码发送给用户，并显示在Outlook邮件中，用户可以在其中接受请求，如果接受，约会将显示在其Outlook日历上。但在弄清楚如何以编程方式取消同一事件时遇到了麻烦。

以下代码是我用来发送会议邀请的代码。它可以正常工作，并将请求发送给收件人，他们可以接受或拒绝。如果接受，约会将在他们的日历上进行。

 Dim smtpServer As String = ConfigurationManager.AppSettings("MailServer").ToString()
 Dim credentials As New NetworkCredential(ConfigurationManager.AppSettings("SMTPUser").ToString(), ConfigurationManager.AppSettings("SMTPPassword").ToString())

 Dim startTime1 As String = Convert.ToDateTime("10/30/2015 11:00 AM").ToString("yyyyMMddTHHmmss")
 Dim endTime1 As String = Convert.ToDateTime("10/30/2015 01:00 PM").ToString("yyyyMMddTHHmmss")
 Dim smtp As New SmtpClient(smtpServer)
 smtp.Credentials = credentials

 Dim msg As New MailMessage()
 Dim emailFrom As String = ConfigurationManager.AppSettings("EmailFrom").ToString()
 Dim emailTo As String = "[email protected]"
 msg.From = New MailAddress(emailFrom, "Scheduling System")
 msg.[To].Add(New MailAddress(emailTo))
 msg.Subject = "JD"

 Dim strBody As New StringBuilder()
 strBody.AppendLine("Appointment Confirmation")
 strBody.AppendLine("Subject: JD")
 strBody.AppendLine("1599")
 strBody.AppendLine("Location: Exam 1")
 strBody.AppendLine("Date: 10/30/2015")
 strBody.AppendLine("Time: 11:00AM - 1:00PM")

 msg.Body = strBody.ToString()

 Dim str As New StringBuilder()
 str.AppendLine("BEGIN:VCALENDAR")

 'PRODID: identifier for the product that created the Calendar object
 str.AppendLine("PRODID:-//CARS//Outlook MIMEDIR//EN")
 str.AppendLine("VERSION:2.0")
 str.AppendLine("METHOD:REQUEST")

 str.AppendLine("BEGIN:VEVENT")

 str.AppendLine(String.Format("DTSTART:{0:yyyyMMddTHHmmss}", startTime1))
 'TimeZoneInfo.ConvertTimeToUtc("BeginTime").ToString("yyyyMMddTHHmmssZ")));
 str.AppendLine(String.Format("DTSTAMP:{0:yyyyMMddTHHmmss}", DateTime.Now))
 str.AppendLine(String.Format("DTEND:{0:yyyyMMddTHHmmss}", endTime1))       
 'TimeZoneInfo.ConvertTimeToUtc("EndTime").ToString("yyyyMMddTHHmmssZ")));
 str.AppendLine(String.Format("LOCATION:{0}", "Exam 1"))

 ' UID should be unique.
 str.AppendLine(String.Format("UID:{0}", "jd101"))
 str.AppendLine(String.Format("DESCRIPTION:{0}", msg.Body))
 str.AppendLine(String.Format("X-ALT-DESC;FMTTYPE=text/html:{0}", msg.Body))
 str.AppendLine(String.Format("SUMMARY:{0}", msg.Subject))

 str.AppendLine("STATUS:CONFIRMED")
 str.AppendLine("BEGIN:VALARM")
 str.AppendLine("TRIGGER:-PT15M")
 str.AppendLine("ACTION:Accept")
 str.AppendLine("DESCRIPTION:Reminder")
 str.AppendLine("X-MICROSOFT-CDO-BUSYSTATUS:BUSY")
 str.AppendLine("END:VALARM")
 str.AppendLine("END:VEVENT")

 str.AppendLine(String.Format("ORGANIZER:MAILTO:{0}", msg.From.Address))
 str.AppendLine(String.Format("ATTENDEE;CN=""{0}"";RSVP=TRUE:mailto:{1}", msg.[To](0).DisplayName, msg.[To](0).Address))

 str.AppendLine("END:VCALENDAR")
 Dim ct As New System.Net.Mime.ContentType("text/calendar")
 ct.Parameters.Add("method", "REQUEST")
 ct.Parameters.Add("name", "meeting.ics")
 Dim avCal As AlternateView = AlternateView.CreateAlternateViewFromString(str.ToString(), ct)
 msg.AlternateViews.Add(avCal)
 smtp.Send(msg)

以下代码是我必须取消现有会议的代码。就像上面的代码一样，它发出通知，但不会取消/删除/删除会议。有人可以指出我正确的方向。我希望在运行这部分代码后将事件从Outlook日历中删除。谢谢你的帮助。

Dim smtpServer As String = ConfigurationManager.AppSettings("MailServer").ToString()
Dim credentials As New NetworkCredential(ConfigurationManager.AppSettings("SMTPUser").ToString(), ConfigurationManager.AppSettings("SMTPPassword").ToString())

Dim startTime1 As String = Convert.ToDateTime("10/30/2015 11:00 AM").ToString("yyyyMMddTHHmmss")
Dim endTime1 As String = Convert.ToDateTime("10/30/2015 01:00 PM").ToString("yyyyMMddTHHmmss")
Dim smtp As New SmtpClient(smtpServer)
smtp.Credentials = credentials

Dim msg As New MailMessage()
Dim emailFrom As String = ConfigurationManager.AppSettings("EmailFrom").ToString()
Dim emailTo As String = "[email protected]"
msg.From = New MailAddress(emailFrom, "Scheduling System")
msg.[To].Add(New MailAddress(emailTo))
msg.Subject = "JD"

Dim strBody As New StringBuilder()
strBody.AppendLine("Appointment Confirmation")
strBody.AppendLine("Subject: JD")
strBody.AppendLine("HRPO#: 1599")
strBody.AppendLine("Location: Exam 1")
strBody.AppendLine("Date: 10/30/2015")
strBody.AppendLine("Time: 11:00AM - 1:00PM")

msg.Body = strBody.ToString()

Dim str As New StringBuilder()
str.AppendLine("BEGIN:VCALENDAR")

'PRODID: identifier for the product that created the Calendar object
str.AppendLine("PRODID:-//CARS//Outlook MIMEDIR//EN")
str.AppendLine("VERSION:2.0")
str.AppendLine("METHOD:REQUEST")

str.AppendLine("BEGIN:VEVENT")

str.AppendLine(String.Format("DTSTART:{0:yyyyMMddTHHmmss}", startTime1))
'TimeZoneInfo.ConvertTimeToUtc("BeginTime").ToString("yyyyMMddTHHmmssZ")));
str.AppendLine(String.Format("DTSTAMP:{0:yyyyMMddTHHmmss}", DateTime.Now))
str.AppendLine(String.Format("DTEND:{0:yyyyMMddTHHmmss}", endTime1))
'TimeZoneInfo.ConvertTimeToUtc("EndTime").ToString("yyyyMMddTHHmmssZ")));
str.AppendLine(String.Format("LOCATION:{0}", "Exam 1"))

' UID should be unique.
str.AppendLine(String.Format("UID:{0}", "jd101"))
str.AppendLine(String.Format("DESCRIPTION:{0}", msg.Body))
str.AppendLine(String.Format("X-ALT-DESC;FMTTYPE=text/html:{0}", msg.Body))
str.AppendLine(String.Format("SUMMARY:{0}", msg.Subject))

str.AppendLine("STATUS:CANCELLED")
str.AppendLine("BEGIN:VALARM")
str.AppendLine("TRIGGER:-PT15M")
str.AppendLine("ACTION:Accept")
str.AppendLine("DESCRIPTION:Reminder")
str.AppendLine("X-MICROSOFT-CDO-BUSYSTATUS:BUSY")
str.AppendLine("END:VALARM")
str.AppendLine("END:VEVENT")

str.AppendLine(String.Format("ORGANIZER:MAILTO:{0}", msg.From.Address))
str.AppendLine(String.Format("ATTENDEE;CN=""{0}"";RSVP=TRUE:mailto:{1}", msg.[To](0).DisplayName, msg.[To](0).Address))

str.AppendLine("END:VCALENDAR")
Dim ct As New System.Net.Mime.ContentType("text/calendar")
ct.Parameters.Add("method", "CANCEL")
ct.Parameters.Add("name", "meeting.ics")
Dim avCal As AlternateView = AlternateView.CreateAlternateViewFromString(str.ToString(), ct)
msg.AlternateViews.Add(avCal)
smtp.Send(msg)