这不仅仅是一个Selenium问题，更多的是基于C#。
有一个完整的网站专门详细解释了如何使用C#和System.Net.Mail命名空间发送电子邮件：
http://www.systemnetmail.com/
举个简单的例子：

using System.Net;
using System.Net.Mail;

var fromAddress = new MailAddress("from@gmail.com", "From Name");
var toAddress = new MailAddress("to@example.com", "To Name");
string fromPassword = "fromPassword";
string subject = "Subject";
string body = "Body";

var smtp = new SmtpClient
           {
               Host = "smtp.gmail.com",
               Port = 587,
               EnableSsl = true,
               DeliveryMethod = SmtpDeliveryMethod.Network,
               UseDefaultCredentials = false,
               Credentials = new NetworkCredential(fromAddress.Address, fromPassword)
           };
using (var message = new MailMessage(fromAddress, toAddress)
                     {
                         Subject = subject,
                         Body = body
                     })
{
    smtp.Send(message);
}

您所需要做的就是通过读入您提到的"reports"的内容来构造消息正文。

谢谢你的代码。
我发现一些代码发送电子邮件附件。

using System.Net;
using System.Net.Mail;

public void email_send()
    {
        MailMessage mail = new MailMessage();
        SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");
        mail.From = new MailAddress("your mail@gmail.com");
        mail.To.Add("to_mail@gmail.com");
        mail.Subject = "Test Mail - 1";
        mail.Body = "mail with attachment";

        System.Net.Mail.Attachment attachment;
        attachment = new System.Net.Mail.Attachment("c:/textfile.txt");
        mail.Attachments.Add(attachment);

        SmtpServer.Port = 587;
        SmtpServer.Credentials = new System.Net.NetworkCredential("your mail@gmail.com", "your password");
        SmtpServer.EnableSsl = true;

        SmtpServer.Send(mail);

    }

有关详细信息，请阅读Sending email using SmtpClient。
谢谢你。

System.Net.Mail.SmtpException
  HResult=0x80131500
  Message=Failure sending mail.
  Source=System
  StackTrace:
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
   at Microsoft.Dynamics365.UIAutomation.Sample.UCI.CasePage.SendEmail(Byte[] stream, String pageName, DateTime screenshotTime) in This exception was originally thrown at this call stack:
    [External Code]

Inner Exception 1:
IOException: Unable to read data from the transport connection: net_io_connectionclosed.

Pls help me with this error.