There are two primary ways to retrieve the file content depending on the SDK version and your specific needs:
var attachment = await graphClient.Me.Messages["{message-id}"] .Attachments["{attachment-id}"] .GetAsync(); if (attachment is FileAttachment fileAttachment) { byte[] contentBytes = fileAttachment.ContentBytes; await File.WriteAllBytesAsync(fileAttachment.Name, contentBytes); } Use code with caution. Method B: Downloading the Raw Content Stream microsoft graph api - How to retrieve ItemAttachment bytes graph api download email attachment c#
Method A: Using FileAttachment and ContentBytes (Recommended for Small Files) There are two primary ways to retrieve the
// List attachments for a specific message var attachments = await graphClient.Me.Messages["{message-id}"] .Attachments .GetAsync(); Use code with caution. 2. Download the Attachment Content You must cast the generic Attachment object to
Downloading email attachments using the Microsoft Graph API and C# is a common task for automating document processing and data integration. Whether you are using the Microsoft Graph SDK or making raw HTTP requests, the process involves authenticating, retrieving the message's attachment metadata, and then accessing the actual file content. Prerequisites Before you begin, ensure you have:
For files under 3 MB, the content is often returned as a base64-encoded string in the ContentBytes property. You must cast the generic Attachment object to a FileAttachment to access this property.