NullReferenceException when fetching messages using GraphClient

Aspose.Email Product Family
,
1

Hi

I am using the following code to fetch Messages:

List<stcListEnvelope> AllEnvelopes = new List<stcListEnvelope>();
TotalCount = 0;
using (var client = GetGraphClient(apiUrl, settings, mailbox))
{
    var inbox = client.ListFolders().First(fi => fi.DisplayName.Equals("Inbox", StringComparison.OrdinalIgnoreCase));
    var messages = client.ListMessages(inbox.ItemId);
    AllEnvelopes.AddRange(
        messages.Select(msg => new stcListEnvelope
        {
            Subject = msg.Subject,
            Date = msg.Date,
            From = msg.Sender.DisplayName,
            UniqueId = msg.MessageId,
            Unreaded = (bool)msg.Properties.First(p => p.Key == MAPIProperties.PR_Read).Value.GetValue()
        })
    );
}

and I am getting the following exception:

  Source=Aspose.Email
  StackTrace:
   at #=zC0EK0mxGaSQl5ecHrJnB5AmXXQ_wlgcwyBAG6EnAl$8v.#=zALAch_8=(StringBuilder #=zB9r_l87X1eEz, Exception #=zKh$_crA=)
   at #=zC0EK0mxGaSQl5ecHrJnB5AmXXQ_wlgcwyBAG6EnAl$8v.#=zfYYo7FY=()
   at #=zutMTYZlMABHSeVZqIVGf5PzfHFEhmr2TX1hqYQqXfGsA.#=zfYYo7FY=()
   at #=zMOKgog8JiUYhYbEPJVAYafntCIe6lof_jw==.ListMessages(String #=zlnk_NoE=, PageInfo #=zs5IpTPI=, MailQuery #=zSqzj60o=)
   at HelpSTAR.HsCommon.Outlook365Helper.GetInboxEnvelopes(String apiUrl, EmailOAUTHSettings settings, String mailbox, stcFetchEmailOptions fetchOptions, Boolean bNeedCount, Int32& TotalCount) in D:\repos\servicepro\Common\HS Temp\Outlook365Helper.cs:line 26

This exception was originally thrown at this call stack:
[External Code]

Inner Exception 1:

NullReferenceException: Object reference not set to an instance of an object.

Can you please review and update?

Thanks,
Vennila

2

@Vennila

It appears you are encountering a NullReferenceException when attempting to fetch messages using the GraphClient. This error typically occurs when you try to access a property or method on an object that is null. Here are some steps to troubleshoot and resolve the issue:

  1. Check Inbox Retrieval: Ensure that the inbox folder is being retrieved correctly. If the folder does not exist or the ListFolders() method returns an empty list, the inbox variable will be null.

    var inbox = client.ListFolders().FirstOrDefault(fi => fi.DisplayName.Equals("Inbox", StringComparison.OrdinalIgnoreCase));
if (inbox == null)
{
    throw new Exception("Inbox folder not found.");
}

  2. Validate Messages: After retrieving messages, check if the messages collection is null or empty before trying to access its properties.

    var messages = client.ListMessages(inbox.ItemId);
if (messages == null || !messages.Any())
{
    throw new Exception("No messages found in the inbox.");
}

  3. Check Message Properties: When accessing properties such as msg.Sender or msg.Properties, ensure they are not null before accessing their values.

    AllEnvelopes.AddRange(
    messages.Select(msg => new stcListEnvelope
    {
        Subject = msg.Subject,
        Date = msg.Date,
        From = msg.Sender?.DisplayName ?? "Unknown",
        UniqueId = msg.MessageId,
        Unreaded = msg.Properties.FirstOrDefault(p => p.Key == MAPIProperties.PR_Read)?.Value?.GetValue() as bool? ?? false
    })
);

By implementing these checks, you can prevent the NullReferenceException and handle scenarios where the expected data is not available.

If the issue persists, consider logging the details of the inbox and messages to further diagnose the problem.

Please let me know if you need any further assistance!

3

Yes I need further assistance, how do you want me to fix the root cause from the following line:

at #=zMOKgog8JiUYhYbEPJVAYafntCIe6lof_jw==.ListMessages(String #=zlnk_NoE=, PageInfo #=zs5IpTPI=, MailQuery #=zSqzj60o=)

Above is the method throwing null exception, can you please check the method and publish a nuget package with the fix?

Thanks,

4

Hello @Vennila,

Thank you for sharing the details.
We’ve logged a ticket to investigate this issue. The team is looking into it, and we’ll notify you once a fix is available.
Issue ID(s): EMAILNET-41645