OPC Studio User's Guide and Reference
SubscribeItem Method (IEasyDAClientExtension)



OpcLabs.EasyOpcClassicCore Assembly > OpcLabs.EasyOpc.DataAccess Namespace > IEasyDAClientExtension Class : SubscribeItem Method
Subscribe to changes of a particular OPC item.

The ItemChanged event is generated for each significant item change.

It is more efficient to subscribe to multiple items using the SubscribeMultipleItems method.

The server(s) can be local or can be remotely accessed via DCOM.

Overload List
OverloadDescription
SubscribeItem(IEasyDAClient,EasyDAItemSubscriptionArguments)Subscribe to OPC item using an object that holds all necessary arguments, including an optional callback.  
SubscribeItem(IEasyDAClient,DAItemGroupArguments)Subscribe to OPC item using an object that holds all necessary arguments.  
SubscribeItem(IEasyDAClient,DAItemGroupArguments,EasyDAItemChangedEventHandler)Subscribe to OPC item using an object that holds all necessary arguments, and an optional callback.  
SubscribeItem(IEasyDAClient,ServerDescriptor,DAItemDescriptor,DAGroupParameters,EasyDAItemChangedEventHandler,Object)Subscribe to OPC item. Specify server and item descriptors, group parameters object, callback method, and a user-defined state object.  
SubscribeItem(IEasyDAClient,ServerDescriptor,DAItemDescriptor,DAGroupParameters,Object)Subscribe to OPC item. Specify server and item descriptors, and group parameters object.  
SubscribeItem(IEasyDAClient,String,String,String,VarType,Int32,Single,EasyDAItemChangedEventHandler,Object)Subscribe to OPC item. Specify machine name, server class, item ID, data type, requested update rate, percent deadband, callback method, and a user-defined state object.  
SubscribeItem(IEasyDAClient,String,String,String,VarType,Int32,Single,Object)Subscribe to OPC item. Specify machine name, server class, item ID, data type, requested update rate, and percent deadband.  
SubscribeItem(IEasyDAClient,String,String,String,VarType,Int32,EasyDAItemChangedEventHandler,Object)Subscribe to OPC item. Specify machine name, server class, item ID, data type, requested update rate, callback method, and a user-supplied state object.  
SubscribeItem(IEasyDAClient,String,String,String,VarType,Int32,Object)Subscribe to OPC item. Specify machine name, server class, item ID, data type, and requested update rate.  
SubscribeItem(IEasyDAClient,String,String,String,Int32,EasyDAItemChangedEventHandler,Object)Subscribe to OPC item. Specify machine name, server class, item ID, requested update rate, callback method, and a state object.  
SubscribeItem(IEasyDAClient,String,String,String,Int32,EasyDAItemChangedEventHandler)Subscribe to OPC item. Specify machine name, server class, item ID, requested update rate, and a callback method.  
SubscribeItem(IEasyDAClient,String,String,String,Int32,Object)Subscribe to OPC item. Specify machine name, server class, item ID, requested update rate, and a state object.  
SubscribeItem(IEasyDAClient,String,String,String,Int32)Subscribe to OPC item. Specify machine name, server class, item ID, and requested update rate. No state object is specified (this overload is suitable for simple scenarios only).  
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

Reference

IEasyDAClientExtension Class
IEasyDAClientExtension Members

 

 

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