how to add OneDrive Files to Mail Attatchment

Question

Hello,

i have a Question about the Graph API in combination with the C# SDK. I want to add some oneDrives files to an new mailItem. My Soloution is about 3 steps:

1. I create a new mailItem and upload it via GraphAPI:

var Mail = new Message
{
Subject = "Test",
Importance = Importance.Normal,
Body = new ItemBody
{
ContentType = BodyType.Html,
Content = "Test"
},
ToRecipients = Recipients
};

            newMail = await graphClient.Users[$"{data.AzureUserID}"].Messages.Request().AddAsync(Mail);

2. I want to upload new referenceAttatchments via Graph API, but how can I assign an ondriveItem to the reference object?
   On the internet I found the following solution:

{
"@odata.type": "#microsoft.graph.referenceAttachment",
"name": "AttachmentName",
"sourceUrl": "https://1drv.ms/u/s!ASDLKASDLASHDLASKDLJAXCXZ_DASD",
"providerType": "oneDriveConsumer",
"isFolder": false
}

But in C# SDK there isn't a sourceUrl proberty ?! How can i do this?

3. send the mailItem : There isn't a problem ;)

Answer 1

Hi @Denny ,

For adding OneDrive file link as an attachement to a mail, SourceUrl and ProviderType properties must to be set as part the request body. According to this documentation, currently these properties are only available in Microsoft Graph Beta API but not in V1.0 API. In order to call the beta API, you would have to install & use the Microsoft.Graph.Beta package. You can refer this link on Microsoft Graph Beta .NET Client Library (SDK) installation and other details.

Below Microsoft Graph Beta API endpoint is used to attach OneDrive file link to a mail by setting SourceUrl and ProviderType properties in request body :

POST https://graph.microsoft.com/beta/users/{user-id}/messages/{message-id}/attachments  

Important Note :

APIs under the /beta version in Microsoft Graph are subject to change. Use of these APIs or relevant Beta SDK client libaries in production applications is not supported.

Here is the sample code snippet for attaching OneDrive file link to reference object using Beta API or Microsoft.Graph.Beta package & C#.NET SDK :

GraphServiceClient graphClient = new GraphServiceClient( authProvider );  
  
var attachment = new ReferenceAttachment  
{  
	Name = "OneDriveAttachment",  
	SourceUrl = "https://o365-my.sharepoint.com/personal/jxxxx_o365_onmicrosoft_com/Documents/Test.docx",  
	ProviderType = ReferenceAttachmentProvider.OneDriveConsumer,  
	IsFolder = false  
};  
  
await graphClient.Users["abcde-90f8-4088-ad78-38d45cbf3f1a"].Messages["AAMkADMyMDI2MjY5LTc1MzgtNDhiNi1iM2E0LTk0MmUzNzhhMmQyMgBGAAAAAAB8OAEgBrpTSrTOnU1piS01BwBmL_k7qYXPRZQMwo9Nyp1dAAAAAAEPAABmL_k7qYXPRZQMwo9Nyp1dAAGyabceAAA="].Attachments  
	.Request()  
	.AddAsync(attachment);  

I did also verified the above 3 step solution approach using Graph API and it worked with Beta endpoint to attach OneDrive file link attachment with a message / mail. Here are my testing screenshots :

POST  https://graph.microsoft.com/v1.0/users/{user-id}/messages  

  POST https://graph.microsoft.com/beta/users/{user-id}/messages/{message-id}/attachments  

 POST https://graph.microsoft.com/v1.0/users/{user-id}/messages/{message-id}/send  

Final Output of Sent Email (with OneDrive file link attachement) :

You can refer below addtional documentation link for more information and quick comparision :

Reference attachment type (V1.0 API) : https://learn.microsoft.com/en-us/graph/api/resources/referenceattachment?view=graph-rest-1.0
Reference attachment type (Beta API) : https://learn.microsoft.com/en-us/graph/api/resources/referenceattachment?view=graph-rest-beta
Microsoft Graph Beta .NET Client Library (SDK) : https://github.com/microsoftgraph/msgraph-beta-sdk-dotnet

Hope this helps.

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