TcAdsClient.AdsNotification Event
Occurs when the ADS device sends a ADS Notification to the client.
Namespace: TwinCAT.Ads
Assembly: TwinCAT.Ads (in TwinCAT.Ads.dll)
Version: 4.3.0.0
Syntax
C#
public event AdsNotificationEventHandler AdsNotification
VB
Public Event AdsNotification As AdsNotificationEventHandler
Remarks
In most implementations, these notifications indicate changed values on the client target. These 'ADS notifications' will be received asynchronously from the target system and distributed via this AdsNotification event. IMPORTANT: The Default setting of the Synchronize property has changed to 'false' from Version 4.2.XX on. This has the effect that - by default - the notifications events AdsNotification and are not synchronized into the UI thread anymore. To re-enable the obsolete behavior for legacy applications set to 'true'.AdsNotificationExSynchronize
Examples
The following sample shows how to register/unregister for AdsNotifications (asynchronous change messages) via AddDeviceNotification(UInt32, UInt32, AdsStream, AdsTransMode, Int32, Int32, Object) and DeleteDeviceNotification(Int32)
Receive AdsNotifications
AdsStream readStream = new AdsStream(sizeof(UInt32));
private void ReceiveNotifications()
{
using (TcAdsClient client = new TcAdsClient())
{
// Add the Notification event handler
client.AdsNotification += Client_AdsNotification;
// Connect to target
client.Connect("1.2.3.4.5.6", 851);
int notificationHandle = 0;
try
{
// Notification to a DINT Type (UINT32)
// Check for change every 200 ms
notificationHandle = client.AddDeviceNotification("MAIN.nCounter", readStream, AdsTransMode.OnChange, 200, 0, null);
Thread.Sleep(5000); // Sleep the main thread to get some (asynchronous Notifications)
}
finally
{
// Unregister the Event / Handle
client.DeleteDeviceNotification(notificationHandle);
client.AdsNotification -= Client_AdsNotification;
}
}
}
private void Client_AdsNotification(object sender, AdsNotificationEventArgs e)
{
int offset = (int)e.DataStream.Position;
int length = (int)e.DataStream.Length;
e.DataStream.Position = offset;
AdsBinaryReader reader = new AdsBinaryReader(e.DataStream);
// Read the Unmarshalled data
//byte[] data = reader.ReadBytes(length);
// Or here we know about UDINT type --> can be marshalled as UINT32
uint nCounter = reader.ReadUInt32();
}