ObjectDisposedException was unhandled when closing form using System.Net.Mail namespace - vb.net

Question

This is the error I'm getting when Me.Close() is called:
This is my code:
Imports System.Net.Mail
Imports System.IO
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Try
Dim mail As New MailMessage()
Dim SmtpServer As New SmtpClient("smtp.gmail.com")
mail.From = New MailAddress("your email#domain.com")
mail.[To].Add("to#domain.com")
mail.Subject = "Trial"
mail.Body = "Trial"
Dim path As String = "C:\Users\CrystalUser\Desktop\trial"
Dim dir As New DirectoryInfo(path)
Dim filesInDirectory As FileInfo() = dir.GetFiles()
Dim attach As System.Net.Mail.Attachment
For Each file In filesInDirectory
attach = New System.Net.Mail.Attachment(file.FullName)
mail.Attachments.Add(attach)
Next
SmtpServer.Port = 587
SmtpServer.Credentials = New System.Net.NetworkCredential("username", "password")
SmtpServer.EnableSsl = True
SmtpServer.Send(mail)
MsgBox("Sent Successfuly", MsgBoxStyle.Information, "Send")
Catch alvin As Exception
MessageBox.Show(alvin.Message)
End Try
Me.Close()
End Sub
End Class
I want the program to close automatically after sending the MailMessage.
I have used Me.Hide() and Me.Close() but neither worked.

Answer 1

Although your error is little unclear and this answer may not fix your problem it would be wise to implement Using on the MailMessage, SmtpClient and Attachment classes:
Sometimes your code requires an unmanaged resource, such as a file handle, a COM wrapper, or a SQL connection. A Using block guarantees the disposal of one or more such resources when your code is finished with them. This makes them available for other code to use.
I would also look at reducing some unnecessary code when using .GetFiles().
Code:
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Try
Using mail As New MailMessage("your email#domain.com", "to#domain.com", "Trial", "Trial"),
smtpServer As New SmtpClient("smtp.gmail.com", 587)
Dim filesInDirectory As FileInfo() = New DirectoryInfo("C:\Users\CrystalUser\Desktop\trial").GetFiles()
For Each file In filesInDirectory
Using attach As New Attachment(file.FullName)
mail.Attachments.Add(attach)
End Using
Next
smtpServer.Credentials = New System.Net.NetworkCredential("username", "password")
smtpServer.EnableSsl = True
smtpServer.Send(mail)
MessageBox.Show("Mail sent")
End Using
Catch alvin As Exception
MessageBox.Show(alvin.Message)
End Try
Me.Close()
End Sub
The point of implementing Using is so that the objects are disposed of properly once finished with. The objects will also be disposed of before entering the Catch statement, should any errors occur.
Give this a go and let me know how you get on.