[RESOLVED] Using a 'Namespace' in ASP.net app

[John_SC]

Ultimately I am trying to send email asynchronously, and in by investigation I was routed here http://msdn.microsoft.com/en-us/libr...mtpclient.aspx. Microsoft's sample code mentioned "Namespace Examples.SmptExamples.Async"

I just don't know how to use this code. I tried to put it in a aspx.vb file, but it give me an error saying "Namespace statements can only occur at the file or namespace level." Again not sure what this means.

If all the code goes in a file, what to I call the file? I tried putting it in a module, but I got the same error. I could not find any guidance on how to use the Namespace.

Can anyone tell me how to use this sample code. It appears to be exactly what I was looking for.

[Fishcake]

What is the error you get, if you get an error it's always useful to post it.

As for the namespace it is just an a method of organisation. See this description of namespaces

You can name the namespace whatever you like, in the example you posted they have used Examples.smtpExamples.Async as it describes what the code is doing.

[John_SC]

The error is:

"Namespace statements can only occur at the file or namespace level."

[Fishcake]

In that case check where you are declaring the namespace, it cannot be declared inside a class but it is ok to nest namespaces.

Make sure the namespace is declared directly after your import statements at the top of the file and you should be ok.

[John_SC]

yes, I get this, but what type of file do I put this in (what is the extension)? And how do I reference the public sub SendAnEmail?

Without Namespaces, I would normally put this code in a Module so it is accessible from any class. When I try this (saved as Module.vb)

Module Module1

' All of the NameSpace sample code

End Module

I get the same error that the namespace must be at the file level. If I remove the first and last lines and just leave the sample code, the error goes away, but I can not access the Public sub SendAnEmail.

[John_SC]

I am making progress. I saved the same code in a as modTextMgt.vb code. I left out the Module and end module lines (so just included Microsoft's sample code).

Then I wrote my application, and include an

Imports TextMgmt.Example.Smpt.Async

at the top of the Class. Note, TextMgmt is the name of my app, and Example.smpt.Async was the name of the Namespace.

I can run this but now I have a different problem. I can modify the code so the email is sent immediately (this works), but the Async send does not. This code is only slightly modified from the sample. It sends 2 emails - one immediately and one synchronously.

Imports System
Imports System.Net
Imports System.Net.Mail
Imports System.Net.Mime
Imports System.Threading
Imports System.ComponentModel

Namespace Example.Smpt.Async
    Public Class SimpleAsynchronous
        Private Shared mailSent As Boolean = False
        Private Shared Sub SendCompletedCallback(ByVal sender As Object, ByVal e As AsyncCompletedEventArgs)
            ' Get the unique identifier for this asynchronous operation.
            Dim token As String = CStr(e.UserState)

            If e.Cancelled Then
                Console.WriteLine("[{0}] Send canceled.", token)
            End If
            If e.Error IsNot Nothing Then
                Console.WriteLine("[{0}] {1}", token, e.Error.ToString())
            Else
                Console.WriteLine("Message sent.")
            End If
            mailSent = True
        End Sub
        Public Shared Sub SendAnEmail(ByVal args() As String)
            ' Command line argument must the the SMTP host.
            Dim client As New SmtpClient(args(0))
            ' Specify the e-mail sender.
            ' Create a mailing address that includes a UTF8 character
            ' in the display name.
            client.Credentials = New Net.NetworkCredential("[email protected]", "mypassword")
            client.Port = 587
            client.Host = "smtp.gmail.com"
            client.EnableSsl = True
            Dim mail As New MailMessage
            mail.From = New MailAddress("[email protected]")
            mail.To.Add("[email protected]")

            mail.Subject = "email test"
            mail.Body = "This is the test message"


            AddHandler client.SendCompleted, AddressOf SendCompletedCallback
            ' The userState can be any object that allows your callback 
            ' method to identify this send operation.
            ' For this example, the userToken is a string constant.

            Dim userState As String = "test message1"

            client.Send(mail)                                ' <<< this works
            Try
                client.SendAsync(mail, userState)     '  <<< this does not work
            Catch ex As Exception
                Dim s As String = ex.Message
            End Try

        End Sub
    End Class
End Namespace

The exception is just "Failure Sending Email", and the code never goes into SendCompletedCallBack. Any idea why the Async does not work?

[John_SC]

I am able to send an email using SMTPClient Send, but when I use SendAsync I get an SmtpException error "Failure Sending Email." On further investigation I found from the InnerException the following:

Asynchronous operations are not allowed in this context. Page starting an asynchronous operation has to have the Async attribute set to true and an asynchronous operation can only be started on a page prior to PreRenderComplete event.

So how do you set the Async Attribute of the page to true?

[John_SC]

I did figure it out. I had to set the Async = "True" in the @ Page settings at the top of my aspx page. This allowed the async processing of emails.