QuickOPC User's Guide and Reference
OPC UA Qualified Names
In OPC-UA, the qualified name comprises of a namespace, and a text portion (a name). The qualified name is used, for example, as browse name (i.e. it is one of the information pieces that you obtain for a node when browsing nodes in the OPC-UA address space). In the opposite direction (from your application to the server), qualified names are used in OPC-UA browse paths, to specify the target node of each element in the browse path.
QuickOPC-UA has a UAQualifiedName object for representing the qualified names. You can access individual parts of the qualified name by corresponding properties on this object (namely, the NamespaceUriString and Name properties). The ExpandedText property contains a string that fully specifies the qualified name, borrowing a syntax used for expanded node IDs described in an earlier article (except that in this case, the “identifier” part is always of a string type).
In QuickOPC, when formatting the expanded text of OPC UA Node IDs and qualified names, the namespace URI (the text after "nsu=") is separated with an additional space from the following semicolon, allowing the URI be easily separated by tools that are not aware of the specific syntax of OPC UA Node IDs and qualified names. Similarly, any trailing whitespace in the namespace URI part (the text after "nsu=") is ignored when parsing the OPC UA Node IDs and qualified names.
QuickOPC-UA provides a static class with standard qualified names defined by OPC Foundation: UABrowseNames. You can use properties of this static class to easily specify “well-known” browse names you need to refer to. For example, the “SessionsDiagnosticsSummary” browse name is defined by the UABrowseNames.SessionsDiagnosticsSummary property, and you can pass the value of this property to any method that expects UAQualifiedName on input.