OPC Studio User's Guide and Reference
SubscribeEvents Method (IEasyAEClientExtension)



OpcLabs.EasyOpcClassicCore Assembly > OpcLabs.EasyOpc.AlarmsAndEvents Namespace > IEasyAEClientExtension Class : SubscribeEvents Method
Subscribe to particular OPC events. The Notification is generated for each event.
Overload List
OverloadDescription
Subscribe to OPC events, using an object that holds all necessary arguments, and an optional callback.  
Subscribe to OPC events. Specify server descriptor and subscription parameters objects, "refresh when active" flag, and a callback method.  
Subscribe to OPC events. Specify server and source descriptors, and notification rate.  
Subscribe to OPC events. Specify server and source descriptors, notification rate, and state object.  
Subscribe to OPC events. Specify server descriptor and subscription parameters objects, and "refresh when active" flag.  
Subscribe to OPC events. Specify machine name, server class, notification rate, filter object, returned attributes, callback method, and "active" and "refresh when active" flags.  
Subscribe to OPC events. Specify machine name, server class, notification rate, filter object, returned attributes, and "active" and "refresh when active" flags.  
Subscribe to OPC events. Specify machine name, server class, notification rate, filter object, returned attributes, and an "active" flag. The subscription will automatically perform a Refresh after each successful connection to the server.  
Subscribe to OPC events. Specify machine name, server class, notification rate, filter object, and returned attributes. The subscription is created active, and it will automatically perform a Refresh after each successful connection to the server.  
Subscribe to OPC events. Specify machine name, server class, notification rate, and filter object. The subscription is created active, and it will automatically perform a Refresh after each successful connection to the server. No event attributes will be returned with the notifications.  
Subscribe to OPC events. Specify machine name, server class, notification rate, and a callback method. The subscription is created active, and it will automatically perform a Refresh after each successful connection to the server. No event attributes will be returned with the notifications, and events will not be filtered.  
Subscribe to OPC events. Specify machine name, server class, and notification rate. The subscription is created active, and it will automatically perform a Refresh after each successful connection to the server. No event attributes will be returned with the notifications, and events will not be filtered.  
Subscribe to OPC events. Specify machine name, server class, and notification rate. The subscription is created active, and it will automatically perform a Refresh after each successful connection to the server. No event attributes will be returned with the notifications, and events will not be filtered. Does not pass in a "state" object for use in event notifications.  
Remarks

 

This method operates (at least in part) asynchronously, with respect to the caller. The actual execution of the operation may be delayed, and the outcome of the operation (if any) is provided to the calling code using an event notification, callback, or other means explained in the text. In a properly written program, this method does not throw any exceptions. You should therefore not put try/catch statements or similar constructs around calls to this method. The only exceptions thrown by this method are for usage errors, i.e. when your code violates the usage contract of the method, such as passing in invalid arguments or calling the method when the state of the object does not allow it. Any operation-related errors (i.e. errors that depend on external conditions that your code cannot reliably check) are indicated by the means the operation returns its outcome (if any), which is described in the text. For more information, see Do not catch any exceptions with asynchronous or multiple-operation methods.
Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also