Getting an attachment using EWS and C# failing with ServiceMethodException

Question

So i am currently building an application that allows a group of users to view all emails from a certain email address. This all works correctly. The problem I am encountering comes when i am trying to get the attachments.

I am relatively new to this area and used the example from Microsoft found here. Compare this to my code below:

    protected internal override Stream GetAttachmentStreamFinal(MailAttachmentDetails attachment)
    {
        var response = m_service.GetAttachments(new[] { attachment.Id }, BodyType.Text, Enumerable.Empty<PropertyDefinitionBase>());
        if (response.OverallResult != ServiceResult.Success)
        {
            if (response.Count > 0)
            {
                var ex = new MailException(response[0].ErrorMessage);
                ex.Data.Add(response[0].ErrorCode, response[0].ErrorMessage);
                foreach (var ed in response[0].ErrorDetails)
                {
                    ex.Data.Add(ed.Key, ed.Value);
                }
                throw ex;
            }
            throw new MailException("Error occurred while fetching the attachment from the mail service.");
        }

        foreach (var attachmentResponse in response)
        {
            if (attachmentResponse.Attachment is FileAttachment)
            {
                var fa = attachmentResponse.Attachment as FileAttachment;
                var cs = new MemoryStream(fa.Content);
                fa.Load(cs);
                cs.Seek(0, SeekOrigin.Begin);
                return cs;
            }
        }
        return null;
    }

As you can see both sets of code are very similar. However when I step through and get to the attachmentResponse.Attachment is FileAttachment line I get this error thrown

Attempt by method 'Mail.ExchangeEmailService.GetAttachmentStreamFinal(Mail.MailAttachmentDetails)' to access method 'Microsoft.Exchange.WebServices.Data.GetAttachmentResponse.get_Attachment()' failed.

Everything is being passed in correctly and the response returns as success.

I have noticed when stepping through my code that Attachment shows as a non-public member. But as this is encapsulated in Microsofts class im unsure as to why that is the case or what i can do?

Are you doing this from a mail app (that runs inside of Outlook)? The sample you linked is for mail apps and is more complicated than a normal EWS application needs to be. — Jason Johnston, Mar 25 '15 at 13:18
No this runs in a Web application. and this is used when the client requests the file — Major, Mar 25 '15 at 13:21
I am also running into same issue while I have used latest version of assembly form nuget, but when i reference assembly after installing from [MSI](http://www.microsoft.com/en-us/download/details.aspx?id=42951) it works. Do you came across some stable solution to the problem? — Hitendra, Aug 25 '15 at 07:00

score 5 · Answer 1 · answered Mar 22 '16 at 16:44

I just want to expand on @Jason Johnstons answer.

For some reason the version of EWS in NuGet is not correct. It throws the error that you are experiencing.

A workaround is to remove the reference to the NuGet package via

Uninstall-Package Microsoft.Exchange.WebServices

Then download and run the MSI file here

https://www.microsoft.com/en-us/download/details.aspx?id=42951

This will install the DLLs you require to the default location of

[ C:\Program Files\Microsoft\Exchange\Web Services\2.2 ]

Then simply copied they into your lib directory (or such) and created references to the DLLs directly instead.

Credit: http://www.resolvinghere.com/sm/microsoftexchangewebservicesdatagetattachmentresponsegetattachment-failed.shtml

MS should have fixed this in the NuGet feeds by now! Still needed to do this as of Apr-2017. — Monty0018, Apr 07 '17 at 19:34

score 3 · Answer 2 · answered May 18 '18 at 21:00

3

As the other answers already mentioned, the nuget package from Microsoft is not up to date. I also had the same problem as the OP.

First I solved it by following the answer of Daniel - SDS Group. But then I found the nuget package Exchange.WebServices.Managed.Api from marklamley. It is the current version 2.2.1.1 of the ews-managed-api GitHub project.

answered May 18 '18 at 21:00

zgue

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This nuget package worked for me. I am able to download the attachments grammatically when I run the code in Visual Studio . However, when I deploy the same code in AWS hosting , it gives me the error which we faced earlier - 'Attempt by method 'Mail.ExchangeEmailService.GetAttachmentStreamFinal(Mail.MailAttachmentDetails)' to access method 'Microsoft.Exchange.WebServices.Data.GetAttachmentResponse.get_Attachment()' failed." – Balaji Birajdar Jun 13 '18 at 16:50
1

@BalajiBirajdar I do host my app in Azure and have no experience with AWS. But there should no difference between running locally or in the cloud. I never had such an issue. – zgue Jun 13 '18 at 17:26

score 2 · Accepted Answer · answered Mar 25 '15 at 13:47

2

Make sure you have the latest version of the Microsoft.Exchange.WebServices.dll. Older versions didn't return the actual attachment data when calling that particular overload of the GetAttachments method.

answered Mar 25 '15 at 13:47

Jason Johnston

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Im using version 2.2 which i downloaded from [link](http://www.microsoft.com/en-us/download/details.aspx?id=42951) Is this correct? The properties says Version 15.0.0.0 and Runtime Version 2.0.50727 – Major Mar 25 '15 at 15:15
1

You were correct in the end. I had referenced it but in my build it was still using the old version 14. – Major Mar 25 '15 at 16:35
Make sure you've got correct version registered in GAC. Could have saved me a few hours today... – MattheW Jul 26 '17 at 13:02

Getting an attachment using EWS and C# failing with ServiceMethodException

3 Answers3