Sending email from Outlook with C#

A common need in both the world of system management and within the scope of automation is to be able to send an email automatically, without user intervention, either periodically or when a certain alert or event occurs.

For example, we can define a notification for a system crash, the installation of a certain software, intrusion alerts, water level alarms, or the periodic sending of a report with server usage statistics, the status of warehouse stocks… among endless possibilities.

There are different ways to send an email from a program, but one that is really simple is to take advantage of the interconnectivity provided by the .NET Framework. In this way, we can use Outlook to send an email without any user intervention on any computer that has a correctly configured account.

Preparing the project

To use the function we can create a new C# project in Visual Studio, or simply use an existing project.

Once we have the project ready and properly configured we must add the following references:

• Microsoft.Office.Interop.Outlook

Once added we can move on to code our function.

Function code

Below is the function that performs the sending. It receives the address, the subject field, and the main content as parameters. We can use HTML to format the email content, or use plain text as well.

public static Boolean SendEmailWithOutlook(string mailDirection, string mailSubject, string mainContent)
{
  try
  {
    var oApp = new Outlook.Application();

    Microsoft.Office.Interop.Outlook.NameSpace ns = oApp.GetNamespace("MAPI");
    var f = ns.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderInbox);

    System.Threading.Thread.Sleep(1000);

    var mailItem = (Outlook.MailItem)oApp.CreateItem(Outlook.OlItemType.olMailItem);
    mailItem.Subject = mailSubject;
    mailItem.HTMLBody = mailContent;
    mailItem.To = mailDirection;
    mailItem.Send();

  }
  catch (Exception ex)                            
  {
    return false;
  }
  finally
  {
  }
  return true;
}

As you can see, it is a really simple code. We simply create an Outlook application object and use it to create a new email. Then we assign the address, subject, and content, and finally proceed to send it.

Using the function

Using the function is equally simple. Below is an example directly from the Main function.

[STAThread]
static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);

    string mailDirection = @"direccionTest@test.com";
    string mailSubject = "Subject test";

    string mainContent;
    mainContent = "Test message";
    mainContent += "<br>" + "Another line";
    mainContent += "<br>" + "Another line";

    SendEmailWithOutlook(mailDirection, mailSubject, mailContent);
}

We simply create text strings with the necessary fields, and use our function to send the email.

As you can see, it is really simple and convenient to send an email using C# and Outlook. In future posts, we will explain more potential uses of the .Net Framework to interconnect applications.