如何在vb.net中向电子邮件添加一个或多个附件

Question

I've searched on this issue for a few days and referenced many questions on this site and others, all to no avail. I have every other feature working, except for this. I've also referenced the tooltips that appear in Visual Studio, but nothing seems to work. My code doesn't generate an error, but the email doesn't have the attachment(s), either. Here is a piece of my code to use as a reference.

'Add Attachments from alist array'
If alist.Count > 1 Then
    For x As Integer = 1 To alist.Count - 1
        Quick_Mail.email.Attachments.Add(New System.Net.Mail.Attachment(alist(x).ToString))
    Next
End If

I have it this way because I have a separate form that adds the attachments. The path to the attachment is stored as a string in the alist array. Every time a new attachment is added alist is preserved. This causes the first position to be empty which is why I initialize x to 1.

Here is my code for the rest of the email setup

Public Shared email As New MailMessage()
Dim smtp As SmtpClient = New SmtpClient
smtp.Credentials = New Net.NetworkCredential(user, pass)
smtp.Host = host
smtp.Port = port
smtp.EnableSsl = False
email = New MailMessage()
email.From = New MailAddress(user)
email.To = txt_to.text
email.CC = txt_cc.text
email.BCC = txt_bcc.text
email.Subject = txt_subject.Text
email.Body = txt_message.Text

I have email as public and shared so the attachment form can reference it.

Any assistance is greatly appreciated. Thanks in advance.

Answer 1

I suppose that you call the loop to add the attachments before the code to send the email. If this is the case then you reinitialize the variable email again and you lose the previous attachments

Public Shared email As New MailMessage()
Dim smtp As SmtpClient = New SmtpClient
smtp.Credentials = New Net.NetworkCredential(user, pass)
smtp.Host = host
smtp.Port = port
smtp.EnableSsl = False
' THIS LINE REINITIALIZE THE EMAIL AND KILLS THE ATTACHMENTS 
' email = New MailMessage()
email.From = New MailAddress(user)
email.To = txt_to.text
email.CC = txt_cc.text
email.BCC = txt_bcc.text
email.Subject = txt_subject.Text
email.Body = txt_message.Text

However keeping a Shared variable for this kind of problem will be always a problem. Why don't you isolate this code in a sub and pass the list of attachments to this sub avoiding to keep the Shared variable exposed?

Public Sub SendMail(alist as List(Of String))
    Dim email = New MailMessage()
    Dim smtp = New SmtpClient()

    For x As Integer = 1 To alist.Count - 1
        email.Attachments.Add(New Attachment(alist(x).ToString))
    Next

    smtp.Credentials = New Net.NetworkCredential(user, pass)
    smtp.Host = host
    smtp.Port = port
    smtp.EnableSsl = False
    email.From = New MailAddress(user)
    email.To = txt_to.text
    email.CC = txt_cc.text
    email.BCC = txt_bcc.text
    email.Subject = txt_subject.Text
    email.Body = txt_message.Text
    smtp.Send(email)
End Sub