StateChanged Event

public event EventHandler<TEventArgs> StateChanged

Public Event StateChanged EventHandler(Of TEventArgs)

public:
 event EventHandler<TEventArgs>^ StateChanged

Show how to handle the StateChanged event.

using System;
using ComponentPro.Net.Mail;

...

public void HandleStateChangedEvent()
{
    // Create a new instance. 
    Pop3 client = new Pop3();

    client.StateChanged += client_StateChanged;

    // Connect to the POP3 server. 
    client.Connect("server");

    // Authenticate. 
    client.Authenticate("test", "test");

    // ... 
 
    // Do something here 
 
    // ... 
 
    // Disconnect. 
    client.Disconnect();
}

void client_StateChanged(object sender, Pop3StateChangedEventArgs e)
{
    Console.WriteLine("State changed, old state: {0}, new state: {1}", e.OldState, e.OldState);
}

Imports ComponentPro.Net.Mail

...

Public Sub HandleStateChangedEvent()
    ' Create a new instance. 
    Dim client As New Pop3()

    AddHandler client.StateChanged, AddressOf client_StateChanged

    ' Connect to the POP3 server. 
    client.Connect("server")

    ' Authenticate. 
    client.Authenticate("test", "test")

    ' ... 
 
    ' Do something here 
 
    ' ... 
 
    ' Disconnect. 
    client.Disconnect()
End Sub 
 
Private Sub client_StateChanged(ByVal sender As Object, ByVal e As Pop3StateChangedEventArgs)
    Console.WriteLine("State changed, old state: {0}, new state: {1}", e.OldState, e.OldState)
End Sub

Reference