'Cannot create file' error while trying to send email with image from asp .net windows application using outllook

Question

I am trying to send email from .net windows application using Microsoft.Office.Interop.Outlook. The mail is in html format and has an image embedded to it. Getting the following error when trying to attach the image,

"Cannot create file: XXX.jpg. Right-click the folder you want to create the file in, and then click Properties on the shortcut menu to check your permissions for the folder."

I dont have any issues with folder access. I am running the app on 64 bit computer with 32 bit outlook on it. When i dont embed image, i dont get any errors and it works fine.

string body = string.Empty;
using(StreamReader reader = new StreamReader(Environment.CurrentDirectory + @"/Mail Templates/XXX.txt"))
        {
            body = reader.ReadToEnd();
        }

        Outlook.Application oApp = new Outlook.Application();
        Outlook._MailItem mailItem = (Outlook._MailItem)oApp.CreateItem(Outlook.OlItemType.olMailItem);

        mailItem.To = "XXX";
        string filename = Environment.CurrentDirectory + @"/Mail Templates/XXX.jpg";
        mailItem.Attachments.Add(filename, (int)Outlook.OlAttachmentType.olEmbeddeditem, 1);
        mailItem.HTMLbody = "true"
        mailItem.Display(true);

Answer 1

Microsoft does not currently recommend, and does not support, Automation of Microsoft Office applications from any unattended, non-interactive client application or component (including ASP, ASP.NET, DCOM, and NT Services), because Office may exhibit unstable behavior and/or deadlock when Office is run in this environment.

If you are building a solution that runs in a server-side context, you should try to use components that have been made safe for unattended execution. Or, you should try to find alternatives that allow at least part of the code to run client-side. If you use an Office application from a server-side solution, the application will lack many of the necessary capabilities to run successfully. Additionally, you will be taking risks with the stability of your overall solution.

You can read more about that in the Considerations for server-side Automation of Office article.

You may consider using the EWS (Exchange Web Services) or BCL (Base Class Libraries from the .Net framework). See EWS Managed API, EWS, and web services in Exchange for more information.