Delete all extended properties from a mailbox using EWS

Question

we are connecting to office 365 mailbox using EWS and creating extended properties on outgoing emails, and we have reached the limit on max number of extended properties can be created. We create the property while sending an email and use it after we send it. But we don't store the property Ids.

Is there an option to delete all or some of the properties without having the property id?

Or, can we get a list of properties or IDs of the properties?

Thanks in advance.

Answer 1

No you can't do that with EWS or MAPI,

we are connecting to office 365 mailbox using EWS and creating extended properties on outgoing emails, and we have reached the limit on max number of extended properties can be created.

You shouldn't get into this situation in the first place if you use Extended properties correctly. Eg your app shouldn't be creating random new extended properties, you should just use one property and then in the Value for that property store a Json string with the key/value combination you need. In that way you will never get to the point of named property exhaustion because you are only using one property that can have an infinite number of Key/Value pairs for whatever application you want.

Answer 2

该文档似乎建议删除扩展属性是可能的，只要您具有构造ExtendedPropertyDefinition的正确信息即可。

Answer 3

I was able to read the extended property of the emails from the Sent Items in Outlook using Outlook Spy. We are using that ID for now. This is not an option to delete the properties from Office 365. But it gave me the ID of an existing property that we can use for the future emails.