How to fix the meeting invite cancelation popup issue ? (meeting invite and mail invite cancilation is working diffrently )

Question

How to fix the meeting invite cancelation popup issue ? (meeting invite and mail invite cancilation is working diffrently )

vamsi Sai Venkat, Matta 0

when we cancle the mail invite with in the code on the onsend event we are able to suppress the cancelation pop-up

But when we try to do the same with the meeting invite its not behaving the same way as mail invite cancelation popup is not geeting closed and user is being persented with the warning popup to clancle , draft or send . pop-up

this inconsistently in behaviour is causing lots of issues for our opetration.

Please respond AS soon as poosible

0 comments

1 answer

Your answer

Answer 1

Dora-T 715 Independent Advisor

Hi @vamsi Sai Venkat, Matta

Based on your description, it seems that you may be using the legacy On-send feature (ItemSend). Could you confirm whether this is the feature your add-in is using, or if you are using the newer Smart Alerts events (OnMessageSend / OnAppointmentSend)? Could you also provide your Outlook version and build number?

I have researched the available documentation and community discussions, but I couldn't find any specific information that matches the behavior you are experiencing.

Please note that this is a user-to-user forum, so I don't have access to Microsoft's internal information. I can provide guidance based on publicly available documentation.

For more accurate and hands-on assistance, I recommend opening a new thread on the Microsoft Community Hub or on GitHub, where experienced developers and contributors can provide more targeted assistance.

Thank you for your understanding.

vamsi Sai Venkat, Matta 0 Reputation points

2026-09-09T07:42:56.9566667+00:00

Yes, I am using the newer Smart Alerts events. The exact behavior is as follows:

When a mail item is in the draft state and we cancels or deletes it using c# code , we are able to do so without any warning dialog appearing. We can successfully suppress the warning popup and delete the item.

However, when performing the same action on a meeting item in the draft state, a warning popup still appears when attempting to delete the item. Despite trying multiple approaches, we have not been able to suppress this dialog.

Do you know if there is any supported solution or workaround for this scenario? We have tried everything we could think of, but the warning popup continues to appear when deleting a draft meeting item using the modern Outlook add-in.
Dora-T 715 Reputation points Independent Advisor

2026-09-10T04:30:26.95+00:00
Hi @vamsi Sai Venkat, Matta

Thank you for confirming that you are using the newer Smart Alerts events and for providing the additional details.

I did some additional research and testing on Smart Alerts to better understand this behavior. Based on my testing and the available Microsoft documentation, OnMessageSend and OnAppointmentSend are triggered when a user selects Send on a message or appointment. I couldn't find any documented API or supported approach for deleting a draft meeting item while suppressing the native warning dialog.

References:

Handle OnMessageSend and OnAppointmentSend events in your Outlook add-in with Smart Alerts - Microsoft Learn

Automatically check for an attachment before a message is sent - Office Add-ins | Microsoft Learn

You mentioned:

“When a mail item is in the draft state and we cancels or deletes it using C# code, we are able to do so without any warning dialog appearing. We can successfully suppress the warning popup and delete the item.”

Could you please clarify how you are using C# to cancel or delete the draft mail item as you described above? If possible, please provide the relevant C# code, the API/method you are using, or the Microsoft documentation you followed to implement this. This would help me reproduce the same scenario and investigate the behavior further on my side.

I look forward to your response.
Dora-T 715 Reputation points Independent Advisor

2026-09-11T02:00:37.6333333+00:00

Hi @vamsi Sai Venkat, Matta

Is there any update from you?

If yes, please feel free to let me know.
vamsi Sai Venkat, Matta 0 Reputation points

2026-09-11T11:39:48.61+00:00

Hi Actually my bad it's actually js code . I wrote c# by-mistake , below is the sample code

snippet.event?.completed({ allowEvent: true });

mailboxItem.closeAsync({ discardItem: true });

and below peace of code is being used I the following launch events

<LaunchEvent Type="OnMessageSend" FunctionName="testSendFunction" SendMode="Block"/>

<LaunchEvent Type="OnAppointmentSend" FunctionName="testSendFunction" SendMode="Block"/>