I am trying to retrieve custom property value for an event using Microsoft Graph. The custom property was created by an Outlook Office.js Add-ing
Here is request
/v1.0/me/events/{id}?$expand=singleValueExtendedProperties($filter=id eq 'String {00020329-0000-0000-C000-000000000046} Name myCusProp')
This returns a successful response from Graph but it does not return the singleValueExtendedProperty. The Outlook add-in, however, is still able to retrieve the property value from the same Event.
{
"@odata.context": "https://graph.microsoft.com/v1.0/$metadata#users('{id}')/events/$entity",
"@odata.etag": "W/\"SdXmMkSN8kCNtzTsQ4x1lwAD7sMWVg==\"",
"id": "{id}",
"createdDateTime": "2019-09-30T10:12:34.110571Z",
"lastModifiedDateTime": "2019-09-30T10:23:57.8338159Z",
"changeKey": "SdXmMkSN8kCNtzTsQ4x1lwAD7sMWVg==",
"categories": [],
"originalStartTimeZone": "blah blah",
"originalEndTimeZone": "blah blah Standard Time",
"iCalUId": "040000008...EBBE4999DC5A61D31AC544",
"reminderMinutesBeforeStart": 15,
"isReminderOn": true,
"hasAttachments": false,
"subject": "WWW-002",
"bodyPreview": "rt",
"importance": "normal",
"sensitivity": "normal",
"isAllDay": false,
"isCancelled": false,
"isOrganizer": true,
"responseRequested": true,
"seriesMasterId": null,
"showAs": "busy",
"type": "singleInstance",
"webLink": "https://outlook.office365.com/owa/?itemid=AQMkADU2OWFjYTFjLWNkMGYtNDdlNS1hNDIxLWIxYjlmY...DqyJu%2FWyzJk6m5v0MbSs7lwcASdXmMkSN8kCNtzTsQ4x1lwAAAgENA...AD7q52owAAAA%3D%3D&exvsurl=1&path=/calendar/item",
"onlineMeetingUrl": null,
"recurrence": null,
"responseStatus": {
"response": "organizer",
"time": "0001-01-01T00:00:00Z"
},
"body": {
"contentType": "html",
"content": "<html>\r\n<head>\r\n<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">\r\n<meta content=\"text/html; charset=us-ascii\">\r\n</head>\r\n<body>\r\n<div>rt</div>\r\n</body>\r\n</html>\r\n"
},
"start": {
"dateTime": "2019-09-19T02:30:00.0000000",
"timeZone": "UTC"
},
"end": {
"dateTime": "2019-09-19T03:00:00.0000000",
"timeZone": "UTC"
},
"location": {
"displayName": "",
"locationType": "default",
"uniqueIdType": "unknown",
"address": {},
"coordinates": {}
},
"locations": [],
"attendees": [],
"organizer": {
"emailAddress": {
"name": "Info a",
"address": "name@domain.com"
}
}
}
----Update 1 - office.js code-----
This is office-js/outlook-add-in code reference above. The custom property value can be read here without an issue.
const item = Office.context.mailbox.item;
item.loadCustomPropertiesAsync(asyncResult => {
if (asyncResult.status == Office.AsyncResultStatus.Succeeded) {
let customProps = asyncResult.value;
customProps.set("myCusProp", "google.com");
customProps.saveAsync(asyncResult => {
if (asyncResult.status == Office.AsyncResultStatus.Succeeded) {
item.loadCustomPropertiesAsync(asyncResult => {
const customProps = asyncResult.value;
const myCusProp = customProps.get("myCusProp");
})
}
});
}
});
From documentation:
id eq 'String {00020329-0000-0000-C000-000000000046} Name cecp-<add-in id from manifest>'
Instead of myCusProp use cecp-/* add-in id from manifest */
Add-in id is the guid from manifest, this response has a custom properties as JSON.
来源：https://stackoverflow.com/questions/58166439/expanding-singlevalueextendedproperty-not-working-when-retrieving-event-details