Begins an asynchronous request to start TLS/SSL negotiation with the server.

Parameters

callback

The AsyncCallback delegate. You can leave it a null reference (Nothing in Visual Basic) if you do not use callbacks.

state

An object that contains state information for this request. You can leave it a null reference (Nothing in Visual Basic).

Return Value

An IAsyncResult that references the asynchronous TLS/SSL negotiation.

Remarks

This method is an asynchronous version of StartTls.

Exceptions

Example

Asynchronous TLS/SSL negotiation with the POP3 server in WinForms application. This sample also handles TlsStarted event. Wait method is used to wait for the asynchronous method completion, since .NET's standard WaitOne cannot process events.

[C#]
// To use the code below, import MailBee namespaces at the top of your code
using MailBee;
using MailBee.Pop3Mail;

// Put the code below inside your class

// TlsStarted event handler
private void OnTlsStarted(object sender, TlsStartedEventArgs e)
{
    MessageBox.Show("TLS/SSL negotiation complete. Secure connection is ready.");
}

// The actual code
private void Form1_Load(object sender, System.EventArgs e)
{
    Pop3 pop = new Pop3();

    // Let MailBee process events
    pop.RaiseEventsViaMessageLoop = false;

    pop.TlsStarted += new TlsStartedEventHandler(OnTlsStarted);

    pop.Connect("mail.domain.com");

    // Initiate an asynchronous TLS/SSL negotiation
    pop.BeginStartTls(null, null);

    // Simulate some lengthy work here...
    for (int i = 0; i < 100; i++)
    {
        // Make a portion of the work
        System.Threading.Thread.Sleep(10);

        // Process events which were raised during execution of the work above
        pop.Wait(0);
    }

    // If the connection was not established during execution of the lengthy 
    // work, wait until it's established
    pop.Wait();

    // End the connection request
    pop.EndStartTls();

    // The connection is now under TLS/SSL layer!
    // Disconnect from the server
    pop.Disconnect();
}

[Visual Basic]
' To use the code below, import MailBee namespaces at the top of your code
Imports MailBee
Imports MailBee.Pop3Mail;

' Put the code below inside your class

' TlsStarted event handler
Private Shared Sub OnTlsStarted(ByVal sender As Object, ByVal e As TlsStartedEventArgs)
    MsgBox("TLS/SSL negotiation complete. Secure connection is ready.")
End Sub

' The actual code
Private Shared Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs)
    Dim pop As New Pop3

    ' Let MailBee process events
    pop.RaiseEventsViaMessageLoop = False

    AddHandler pop.TlsStarted, AddressOf OnTlsStarted

    pop.Connect("mail.domain.com")

    ' Initiate an asynchronous TLS/SSL negotiation
    pop.BeginStartTls(Nothing, Nothing)

    ' Simulate some lengthy work here...
    Dim i As Integer
    For i = 1 To 100
        ' Make a portion of the work
        System.Threading.Thread.Sleep(10)

        ' Process events which were raised during execution of the work above
        pop.Wait(0)
    Next

    ' If the connection was not established during execution of the lengthy 
    ' work, wait until it's established.
    pop.Wait()

    ' End the connection request.
    pop.EndStartTls()

    ' The connection is now under TLS/SSL layer!
    ' Disconnect from the server
    pop.Disconnect()
End Sub

See Also

Pop3 Class | MailBee.Pop3Mail Namespace | StartTls

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