[ObsoleteAttribute("This method is obsolete in .NET 4.5+. Use DownloadEnvelopesAsync instead.")]
public IAsyncResult BeginDownloadEnvelopes(
	string messageIndexSet,
	bool indexIsUid,
	EnvelopeParts parts,
	int bodyPreviewSize,
	string[] extraHeaders,
	string[] extraItems,
	AsyncCallback callback,
	Object state
)

<ObsoleteAttribute("This method is obsolete in .NET 4.5+. Use DownloadEnvelopesAsync instead.")>
Public Function BeginDownloadEnvelopes ( 
	messageIndexSet As String,
	indexIsUid As Boolean,
	parts As EnvelopeParts,
	bodyPreviewSize As Integer,
	extraHeaders As String(),
	extraItems As String(),
	callback As AsyncCallback,
	state As Object
) As IAsyncResult

// To use the code below, import MailBee namespaces at the top of your code.
using MailBee;
using MailBee.ImapMail;

// Put the code below inside your class.

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

    // We do not subscribe to any events in this sample, so we do not
    // need to care about them. However, if you decide to subscribe to
    // an event and your application will block message loop thread
    // using imp.Wait() method, you should uncomment the next line
    // to tell MailBee not to use message loop thread for raising events
    // and use imp.Wait() method instead of ar.AsyncWaitHandle.WaitOne(). 
    // imp.RaiseEventsViaMessageLoop = false;

    // Connect to the server, login and select inbox.
    imp.Connect("imap4.server.com");
    imp.Login("jdoe", "secret");
    imp.SelectFolder("Inbox");

    // Obtain UIDs of new messages (messages which are recent and unseen).
    UidCollection uids = (UidCollection)imp.Search(true, "NEW", null);

    EnvelopeCollection envs = null;

    if (uids.Count > 0)
    {
        // Asynchronously download entire messages and their flags.
        IAsyncResult ar = imp.BeginDownloadEnvelopes(uids.ToString(), true,
            EnvelopeParts.MessagePreview | EnvelopeParts.Flags, -1,
            null, null, null, null);

        // Wait until the asynchronous download completes. Note: this call
        // blocks UI. Thus, if you subscribe to any events, you'll got a
        // deadlock (because events will be raised only after message loop thread
        // gets un-blocked again, while WaitOne() method which blocked the message
        // loop will wait until all events get raised). The solution is to set
        // imp.RaiseEventsViaMessageLoop to false and use imp.Wait() method
        // instead of ar.AsyncWaitHandle.WaitOne() method.
        ar.AsyncWaitHandle.WaitOne();

        // Get downloaded envelopes (messages + flags).
        envs = imp.EndDownloadEnvelopes();
    }

    // Demonstrate that we may disconnect before finished with processing
    // of downloaded envelopes. Although in most samples we disconnect in
    // the very end of the code, it's more efficient to disconnect once the
    // connection is no longer needed. For instance, it may take considerable
    // amount of time to save downloaded messages in the folder (see below).
    // During this time, the connection with the server will just waste system
    // resources since the connection is not actually required any longer.
    // The same optimization can be applied to all other MailBee components.
    imp.Disconnect();

    if (envs != null)
    {
        // Save all downloaded messages into "C:\Temp" folder.
        // Each filename is generated as message's UID + ".eml".
        foreach (Envelope env in envs)
        {
            string filename = env.Uid + ".eml";
            env.MessagePreview.SaveMessage(@"C:\Temp\" + filename);

            // To see this report in VS.NET environment, run the sample
            // in debug mode and monitor the contents of Output window.
            System.Diagnostics.Debug.WriteLine("Message #" + env.MessageNumber +
                " having (" + env.Flags.ToString() + ") flags set was saved as " +
                filename);
        }
    }
}

' To use the code below, import MailBee namespaces at the top of your code.
Imports MailBee
Imports MailBee.ImapMail

' Put the code below inside your class.

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

    ' We do not subscribe to any events in this sample, so we do not
    ' need to care about them. However, if you decide to subscribe to
    ' an event and your application will block message loop thread
    ' using imp.Wait() method, you should uncomment the next line
    ' to tell MailBee not to use message loop thread for raising events
    ' and use imp.Wait() method instead of ar.AsyncWaitHandle.WaitOne(). 
    ' imp.RaiseEventsViaMessageLoop = false

    ' Connect to the server, login and select inbox.
    imp.Connect("imap4.server.com")
    imp.Login("jdoe", "secret")
    imp.SelectFolder("Inbox")

    ' Obtain UIDs of new messages (messages which are recent and unseen).
    Dim uids As UidCollection = CType(imp.Search(True, "NEW", Nothing), UidCollection)

    Dim envs As EnvelopeCollection = Nothing

    If uids.Count > 0 Then
        ' Asynchronously download entire messages and their flags.
        Dim ar As IAsyncResult = imp.BeginDownloadEnvelopes(uids.ToString(), True, _
            EnvelopeParts.MessagePreview Or EnvelopeParts.Flags, -1, _
            Nothing, Nothing, Nothing, Nothing)

        ' Wait until the asynchronous download completes. Note: this call
        ' blocks UI. Thus, if you subscribe to any events, you'll got a
        ' deadlock (because events will be raised only after message loop thread
        ' gets un-blocked again, while WaitOne() method which blocked the message
        ' loop will wait until all events get raised). The solution is to set
        ' imp.RaiseEventsViaMessageLoop to false and use imp.Wait() method
        ' instead of ar.AsyncWaitHandle.WaitOne() method.
        ar.AsyncWaitHandle.WaitOne()

        ' Get downloaded envelopes (messages + flags).
        envs = imp.EndDownloadEnvelopes()
    End If

    ' Demonstrate that we may disconnect before finished with processing
    ' of downloaded envelopes. Although in most samples we disconnect in
    ' the very end of the code, it's more efficient to disconnect once the
    ' connection is no longer needed. For instance, it may take considerable
    ' amount of time to save downloaded messages in the folder (see below).
    ' During this time, the connection with the server will just waste system
    ' resources since the connection is not actually required any longer.
    ' The same optimization can be applied to all other MailBee components.
    imp.Disconnect()

    If Not envs Is Nothing Then
        ' Save all downloaded messages into "C:\Temp" folder.
        ' Each filename is generated as message's UID + ".eml".
        For Each env As Envelope In envs
            Dim filename As String = env.Uid & ".eml"
            env.MessagePreview.SaveMessage("C:\Temp\" & filename)

            ' To see this report in VS.NET environment, run the sample
            ' in debug mode and monitor the contents of Output window.
            System.Diagnostics.Debug.WriteLine("Message #" & env.MessageNumber & _
                " having (" & env.Flags.ToString() & ") flags set was saved as " & filename)
        Next
    End If
End Sub