C# EWS Api on Exchange 2013 : Get an attachment into a Stream

Question

I want to get attached files from a mail into streams type. But how to create the stream ? I'm correctly getting mail items (content, subject, attached files). Referring to the following link : EWS Managed API : Getting attachment I tried to do the following :

int nbAttachments = message.Attachments.Count;
FileAttachment[] attachedFiles = new FileAttachment[nbAttachments];

for (int i=0; i < nbAttachments; i++)
{
    attachedFiles[i] = message.Attachments[i] as FileAttachment;
}
for (int i = 0; i < attachments.Length; i++)
{
    if (attachments[i].Name != null)
    {
         AttachmentCreationInformation infoAttachment = new AttachmentCreationInformation();
         attachments[i].Load(infoAttachment.ContentStream);
         infoAttachment.FileName = attachments[i].Name;
         newItem.AttachmentFiles.Add(infoAttachment);
    }
}

Ok don't worry I make a lot of test and manage exceptions but it's not relevant to put all the code here.

Some precisions :

• newItem is a List item from a SharePoint website. And I need an AttachmentCreationInformation type to add an attached file to this item.

• I found this post : MSDN Forum and trying the following method :

  FileStream stream = new FileStream(attachments[i].Name, FileMode.Open);

  byte[] byteArray = new byte[stream.Length];

  stream.Read(byteArray, 0, Convert.ToInt32(stream.Length));

  stream.Close();

(Here my text is broken as I cannot convert it as code format so sorry for the italics ... out of luck today)

But it search the attachment on the local drive ...

Please help me

Basically I can't get how my attachment[i] can be added to a FileStream var...

---

Thanks a lot, really.

Answer 1

If I understand correctly you want to save the attachement somewhere? EWS provides you a byte array for every file stored within Content property of FileAttachment object, and from there its extremely easy to do so:

foreach (var a in mail.Attachments)
{
    FileAttachment fa = a as FileAttachment;
    if(fa != null)
    {
        try
        {
            //if you don't call this the Content property may be null,
            //depending on your property loading policy with EWS
            fa.Load();
        }
        catch 
        {
            continue;
        }

        using(FileStream fs = System.IO.File.OpenWrite("path_to_file"))
        {
            fs.Write(fa.Content, 0, fa.Content.Length);
        }
    }
}

If you just want a Stream object to do something else with it just create a MemoryStream:

MemoryStream ms = new MemoryStream(fa.Content);

Answer 2

Thanks to @anusiak :),

Here is my code concerning the stream :

for (int i = 0; i < attachments.Length; i++)
{
    if (attachments[i].Name != null && attachments[i].Content != null)
    {
        MemoryStream mstream = new MemoryStream(attachments[i].Content);
        AttachmentCreationInformation spAttachment = new AttachmentCreationInformation();
        spAttachment.ContentStream = mstream;
        spAttachment.FileName = attachments[i].Name;
        newItem.AttachmentFiles.Add(spAttachment);
    }
}
newItem.Update();

And I had to call Load() method for each attachment extracted from a mail, before I can store them into a FileAttachment var. I then use a MemoryStream to add the data stream into a special type that I needed to use. The rest of the code is about adding it to an item from a SharePoint list, so no need to explain.