Changing from System.Web.Mail to System.Net.Mail

I've updated my old style of sending emails from

System.Web.Mail

to a more updated style:

System.Net.Mail

Sub SendEmail()
    Using objMailMessage As New MailMessage()

        objMailMessage.From = New MailAddress(txtFrom.Text)
        objMailMessage.To.Add(txtTo.Text)

        objMailMessage.Subject = txtSubject.Text
        objMailMessage.Body = txtContent.Text & " | email sent from " & strUser & "'s pc"

        objMailMessage.IsB开发者_Go百科odyHtml = True
        objMailMessage.Priority = MailPriority.Normal

        objSmtpClient = New SmtpClient("server_name_goes_here")
        objSmtpClient.Send(objMailMessage)

    End Using
End Sub

The problem is that the new style, does not let me type in a mail group name.

For example, in the old style, I was able to type in

objMailMessage.From = "HR Department"

HR Department was a group of emails set on the exchange server which had everyone in the HR listed and would send the email to all of them.

In the new coding style, It does not let me do that. Each time I try, it gives me a message saying that I have not entered in a proper email address.

i.e, this does not work:

objMailMessage.From = New MailAddress("HR Department")

I have to do this

objMailMessage.From = New MailAddress("hr_user_1@mail.com, hr_user_2@mail.com, hr_user_3@mail.com")

---

Try replacing this:

objMailMessage.From = New MailAddress("HR Department")

To this:

objMailMessage.From = New MailAddress("HR Department@yourdomain.com", "HR Department")