VB.NET
Outlook -- Get Number of Emails

Gets the number of emails in an Outlook folder. This uses the OData $count system query option. See OData System Query Option $count for general information.
This example first gets the combined total number of messages across all folders.
Note: This example requires Chilkat v9.5.0.68 or greater.
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Dim success As Boolean = False

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim http As New Chilkat.Http

' Use your previously obtained access token here:
' See the following examples for getting an access token:
'    Get Microsoft Graph OAuth2 Access Token (Azure AD v2.0 Endpoint).
'    Get Microsoft Graph OAuth2 Access Token (Azure AD Endpoint).
'    Refresh Access Token (Azure AD v2.0 Endpoint).
'    Refresh Access Token (Azure AD Endpoint).

http.AuthToken = "MICROSOFT_GRAPH_ACCESS_TOKEN"

Dim sbResponse As New Chilkat.StringBuilder

' This gets the combined total number of emails in all folders.
success = http.QuickGetSb("https://graph.microsoft.com/v1.0/me/messages/$count",sbResponse)
If ((success <> True) And (http.LastStatus = 0)) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


Dim json As New Chilkat.JsonObject
json.EmitCompact = False

' If the status code was not 200, then it failed and the response is likely JSON:
If (http.LastStatus <> 200) Then
    Debug.WriteLine("Status code = " & http.LastStatus)
    json.LoadSb(sbResponse)
    Debug.WriteLine(json.Emit())
    Debug.WriteLine("Failed.")
    Exit Sub
End If


' A success response payload contains just the integer value (it is not JSON)
Debug.WriteLine("Combined Total Number of Emails = " & sbResponse.GetAsString())
Debug.WriteLine("--")

' ---------------------------------------------------------------------------
' To get the number of emails in a particular folder, we need to use the folder id.
' 

' In this example, we'd like to get number of messages in the folder "/Inbox/abc",
' but we must specify the corresponding folder_id.  The best way to do this is to create
' a local map of folderPaths-to-folderIds.
' We'll use the map created by this example:  Create Outlook Folder Map)
Dim htFolderMap As New Chilkat.Hashtable
Dim sbMap As New Chilkat.StringBuilder
sbMap.LoadFile("qa_data/outlook/folderMap.xml","utf-8")
htFolderMap.AddFromXmlSb(sbMap)

' Get the ID for the "/Inbox/abc" folder:
Dim folderId As String = htFolderMap.LookupStr("/Inbox/abc")
If (htFolderMap.LastMethodSuccess <> True) Then
    Debug.WriteLine("Folder ID not found")
    Exit Sub
End If

http.SetUrlVar("folder_id",folderId)

' Send the request get the folder information.
' In this case we are NOT using the $count system query option.
success = http.QuickGetSb("https://graph.microsoft.com/v1.0/me/mailFolders/{$folder_id}",sbResponse)
If ((success <> True) And (http.LastStatus = 0)) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


json.LoadSb(sbResponse)
Debug.WriteLine(json.Emit())
Debug.WriteLine("--")

If (http.LastStatus <> 200) Then
    Debug.WriteLine("Status code = " & http.LastStatus)
    Debug.WriteLine("Failed.")
    Exit Sub
End If


' The successful JSON response looks like this;

' 	{
' 	  "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#users('me')/mailFolders/$entity",
' 	  "id": "AQMkADAwATM0MDAAMS1iNTcwLWI2NTEtMDACLTAwCgAuAAADsVyfxjDU406Ic4X7ill8xAEA5_vF7TKKdE6bGCRqXyl2PQAAAL8huv8AAAA=",
' 	  "displayName": "abc",
' 	  "parentFolderId": "AQMkADAwATM0MDAAMS1iNTcwLWI2NTEtMDACLTAwCgAuAAADsVyfxjDU406Ic4X7ill8xAEA5_vF7TKKdE6bGCRqXyl2PQAAAgEMAAAA",
' 	  "childFolderCount": 2,
' 	  "unreadItemCount": 0,
' 	  "totalItemCount": 3
' 	}
' 

' Get the integer value from the JSON like this:
Dim totalItemCount As Integer = json.IntOf("totalItemCount")
Debug.WriteLine("totalItemCount = " & totalItemCount)

Dim childFolderCount As Integer = json.IntOf("childFolderCount")
Debug.WriteLine("childFolderCount = " & childFolderCount)

' etc..