[ObsoleteAttribute("This method is obsolete in .NET 4.5+. Use CloseAsync instead.")]
public IAsyncResult BeginClose(
	bool expungeDeleted,
	AsyncCallback callback,
	Object state
)

<ObsoleteAttribute("This method is obsolete in .NET 4.5+. Use CloseAsync instead.")>
Public Function BeginClose ( 
	expungeDeleted As Boolean,
	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.

Imap imp = null;
bool finished = false;

// A callback function. Since it's called on Imap worker thread,
// it cannot update controls on the form or otherwise access UI.
// The only UI-related action permitted in worker thread is
// displaying a message box (MessageBox.Show).
// Any updates of UI must take place on message loop thread.
// See BeginSearch method example on how to update UI in callbacks.
private void CloseCallback(IAsyncResult result)
{
    imp.EndClose();
    finished = true;
}

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

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

    // Start async close/expunge operation.
    imp.BeginClose(true, new AsyncCallback(CloseCallback), null);

    // Wait until it's finished.
    while (!finished)
    {
        // Process events on message loop thread.
        // Alternatively, we could set imp.RaiseEventsOnMessageLoop
        // to false and use imp.Wait method to perform waiting.
        System.Threading.Thread.Sleep(1);
        Application.DoEvents();
    }

    // Close the connection.
    imp.Disconnect();
}

' 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.
Dim imp As Imap = Nothing
Dim finished As Boolean = False

' A callback function. Since it's called on Imap worker thread,
' it cannot update controls on the form or otherwise access UI.
' The only UI-related action permitted in worker thread is
' displaying a message box (MessageBox.Show).
' Any updates of UI must take place on message loop thread.
' See BeginSearch method example on how to update UI in callbacks.
Private Sub CloseCallback(ByVal result As IAsyncResult)
    imp.EndClose()
    finished = True
End Sub

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

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

    ' Start async close/expunge operation.
    imp.BeginClose(True, New AsyncCallback(AddressOf CloseCallback), Nothing)

    ' Wait until it's finished.
    While Not finished
        ' Process events on message loop thread.
        ' Alternatively, we could set imp.RaiseEventsOnMessageLoop
        ' to false and use imp.Wait method to perform waiting.
        System.Threading.Thread.Sleep(1)
        Application.DoEvents()
    End While

    ' Close the connection.
    imp.Disconnect()
End Sub