Attribute is a primitive characteristic of a Node. All Attributes are defined by OPC UA, and may not be defined by clients or servers (i.e. the attribute set is not vendor-extensible). Attributes are the only elements in the address space permitted to have data values.

In most cases, you will probably be working with the Value attribute, which contains the actual value of a variable. If you need to address a different attribute, use the UAAttributeId enumeration, which contains constants for all attribute IDs available in OPC UA address space.

UAAttributeId can be given as AttributeId property of the UAAttributeArguments object (and derived objects, such as UAReadArguments, UAWriteArguments, UAWriteValueArguments, and EasyUAMonitoredItemArguments). You can then pass this object to a corresponding method on the main EasyUAClient object.