Session.ConnectionStateChanged Event
Occurs when connection status of the IConnectionStateProvider has been changed.
Namespace: TwinCAT
Assembly: TwinCAT.Ads (in TwinCAT.Ads.dll)
Version: 6.0.328+39e3229
Syntax
C#
public event EventHandler<ConnectionStateChangedEventArgs> ConnectionStateChanged
Remarks
The Connection state changes only if the IConnection is established / shut down or active communication is triggered by the User of the IConnection object.
Examples
The following sample shows how to keep the ConnectionState updated by triggering ADS Communication.
Trigger ConnectionState changes in WPF Applications
private DispatcherTimer _timer = null;
private AdsSession _session = null;
//private AdsConnection _connection = null;
private void Window_Loaded(object sender, RoutedEventArgs e)
{
_session = new AdsSession(AmsNetId.Local, 10000);
IConnection connection = _session.Connect();
tbConnectionState.Text = connection.ConnectionState.ToString();
_session.ConnectionStateChanged += _session_ConnectionStateChanged;
_timer = new DispatcherTimer();
_timer.Interval = TimeSpan.FromMilliseconds(200);
_timer.Tick += TimerOnTick;
_timer.Start();
}
private void Window_Unloaded(object sender, RoutedEventArgs e)
{
_timer.Stop();
_session.Dispose();
}
private void _session_ConnectionStateChanged(object sender, TwinCAT.ConnectionStateChangedEventArgs e)
{
// ConnectionStateChanged will be triggered by communication Invokes
tbConnectionState.Text = e.NewState.ToString();
}
private void TimerOnTick(object sender, EventArgs eventArgs)
{
// The Timer Event will occur here in the UI thread because its an DispatcherTimer event!
// An active ADS request will trigger Connection State periodically!
StateInfo stateInfo;
if (_session.Connection.TryReadState(out stateInfo) == AdsErrorCode.NoError)
{
tbAdsState.Text = stateInfo.AdsState.ToString();
}
else
{
tbAdsState.Text = "Invalid";
}
}