Creating a Microsoft Teams Meeting using VB.NET and Microsoft Graph API - vb.net

Question

I have created a login authentication using the Microsoft Graph API which means after I sign in, as a result, I have the access token of the current user signed-in. My next step is to create a Microsoft Teams Meeting on behalf of the current user signed-in.
I have tried to follow the Microsoft documentation Application POST onlinemeetings, where It shows the required steps to achieve this scenario.
Unfortunately, they didn't provide an example of how it can be achieved in VB.Net (which is not a big deal because I have converted the code to VB).
Currently, I am stuck on sending a POST request to generate this meeting based on the hard coded values when the user clicks on the button.
Please have a look at the code below:
Imports System.IO
Imports System.Net
Imports System.Net.Http
Imports System.Net.Http.Headers
Imports System.Threading.Tasks
Imports Microsoft.Graph
Imports Microsoft.IdentityModel.Clients.ActiveDirectory
Imports Newtonsoft.Json
Imports Newtonsoft.Json.Linq
Public Class _Default
Inherits Page
Private Shared httpClient As HttpClient = New HttpClient()
Private Shared context As AuthenticationContext = Nothing
Private Shared credential As ClientCredential = Nothing
Private Shared graphClient As GraphServiceClient
Private Shared authprovider As IAuthenticationProvider
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
Dim code = HttpContext.Current.Request.QueryString("Code")
If Not Page.IsPostBack Then
If code <> "" Then
Dim url = "https://login.microsoftonline.com/common/oauth2/v2.0/token"
Dim myParameters = "grant_type=authorization_code&code=" & code & "&redirect_uri=https://localhost:4312/&client_id=CLIENTID&client_secret=CLIENTSECRET"
Dim wb = New WebClient
wb.Headers(HttpRequestHeader.ContentType) = "application/x-www-form-urlencoded"
Dim response = wb.UploadString(url, "POST", myParameters)
responseToken.Text = response
Success.Text = "O365 login successful. Below is the response token"
Dim SurroundingClass = JsonConvert.DeserializeObject(Of SurroundingClass)(response)
Dim rss As JObject = JObject.Parse(response)
Dim token = rss.SelectToken("access_token")
Dim res = GetUsers(token)
End If
End If
End Sub
Private Shared Async Function GetUsers(ByVal result As String) As Task(Of String)
Try
Dim users As String = Nothing
Dim querystring As String = "api-version=1.6"
Dim uri = "https://graph.microsoft.com/v1.0/me"
httpClient.DefaultRequestHeaders.Authorization = New AuthenticationHeaderValue("Bearer", result)
httpClient.DefaultRequestHeaders.Accept.Add(New MediaTypeWithQualityHeaderValue("application/json"))
Dim User = GetMeAsync().Result
Console.WriteLine($"Welcome {User.DisplayName}!\n")
Dim getResult = Await httpClient.GetAsync(uri)
If getResult.Content IsNot Nothing Then
users = Await getResult.Content.ReadAsStringAsync()
End If
Return users
Catch ex As Exception
Throw ex
End Try
End Function
Protected Sub tes_Click(sender As Object, e As EventArgs)
Try
'Dim fr As System.Net.HttpWebRequest
Dim client_id = ""// App Client ID'
Dim uri = "https://localhost:4312/"
Dim targetURI As String = "https://login.microsoftonline.com/common/oauth2/v2.0/authorize?client_id=" & client_id &
"&redirect_uri=" & uri & "&response_type=code&scope=openid+Mail.Read"
Response.Redirect(targetURI)
Catch ex As System.Net.WebException
'Error in accessing the resource, handle it
End Try
End Sub
Public Shared Async Function CreateMeeting() As Task(Of OnlineMeeting)
Try
graphClient = New GraphServiceClient(authprovider)
Dim onlineMeeting = New OnlineMeeting With {
.StartDateTime = DateTimeOffset.Parse("2020-04-23T21:33:30.8546353+00:00"),
.EndDateTime = DateTimeOffset.Parse("2020-04-23T22:03:30.8566356+00:00"),
.Subject = "Application Token Meeting",
.Participants = New MeetingParticipants With {
.Organizer = New MeetingParticipantInfo With {
.Identity = New IdentitySet With {
.User = New Identity With {
.Id = "MYID"
}
}
}
}
}
Dim encodings As New UTF8Encoding
Dim serializer As New JavaScriptSerializer()
Dim arrayJson As String = serializer.Serialize(onlineMeeting)
Dim result As String = Nothing
Dim postRequest As HttpWebRequest = DirectCast(WebRequest.Create("https://graph.microsoft.com/v1.0/me/onlineMeetings"), HttpWebRequest)
postRequest.Method = "POST"
postRequest.ContentType = "application/json"
httpClient.DefaultRequestHeaders.Authorization = New AuthenticationHeaderValue("Bearer", Token)
If postRequest.Method = "POST" Then
Dim parsedContent As String = JsonConvert.SerializeObject(onlineMeeting)
Dim encoding As ASCIIEncoding = New ASCIIEncoding()
Dim bytes As Byte() = encoding.GetBytes(parsedContent)
Dim newStream As Stream = postRequest.GetRequestStream()
newStream.Write(bytes, 0, bytes.Length)
newStream.Close()
End If
Dim createMeetings = Await graphClient.Communications.OnlineMeetings.Request().AddAsync(onlineMeeting)
Console.WriteLine("The meeting has been created")
Return createMeetings
Catch ex As ServiceException
Console.WriteLine($"Error while creating the meeting: {ex.Message}")
Return Nothing
End Try
End Function
Public Sub InvokeMeeting(sender As Object, e As EventArgs)
Try
Dim testing = CreateMeeting()
Catch ex As Exception
End Try
End Sub
PS: I have added the permission required to call this API to be able to create a Teams meeting.
Any suggestions on how to achieve the following scenario?
Any help will be greatly appreciated.
Thank you!