Virtual mode browse handling.
Called only from the Professional edition generic server.
OPC DA V3 Browse method to browse the specified branch. This method is called when the server is configured for virtual mode browsing and a client calls the OPC DA V3 browse function. This method handles only the item browsing part of the OPC DA browse function. The GetItemProperties method is called to get the item's properties information.
Visual Basic (Declaration) | |
---|---|
Public Function Browse( _ ByVal branch As String, _ ByVal maxElements As Integer, _ ByVal browseType As Integer, _ ByVal nameFilter As String, _ ByVal vendorFilter As String, _ ByRef continuationPoint As String, _ ByRef numNodes As Integer, _ ByRef nodes As BrowseNodeInfo() _ ) As Integer |
C# | |
---|---|
public int Browse( string branch, int maxElements, int browseType, string nameFilter, string vendorFilter, ref string continuationPoint, out int numNodes, out BrowseNodeInfo[] nodes ) |
Parameters
- branch
- The fully qualified name of the branch to be browsed
- maxElements
- The method must not return any more elements than this value. If the server supports Continuation Points, then the Server may return a Continuation Point at a value less than dwMaxElementsReturned. If the server does not support Continuation Points, and more than dwMaxElementsReturned are available, then the Server shall return the first dwMaxElementsReturned elements and set the pbMoreElements parameter to TRUE. If dwMaxElementsReturned is 0 then there is no client side restriction on the number of returned elements.
- browseType
- An OPCV3BrowseType enumeration value {All, Branch, Item} specifying which subset of browse elements to return.
- nameFilter
- A wildcard string that conforms to the Visual Basic LIKE operator, which will be used to filter Element names. A NUL String implies no filter.
- vendorFilter
- A server specific filter string. This is entirely free format and may be entered by the user via an EDIT field. A pointer to a NUL string indicates no filtering.
- continuationPoint
- If this is a secondary call to Browse, the previous call might have returned a Continuation Point where the Browse can restart from. Clients must pass a NUL string in the initial call to Browse. This is an opaque value, which the server creates. A Continuation Point will be returned if a Server does support Continuation Point, and the reply is larger than dwMaxElementsReturned. The Continuation Point will allow the Client to resume the Browse from the previous completion point.
The continuationPoint is also used to indicate if there are more elements than the maxElements parameter allows to be returned in this call. If there are more elements then continuationPoint must be set to NULL. Otherwise it is set to "" (an empty string) if exactly all elements could be returned or to an implementation specific string for an actual continuation point. - numNodes
- OUT: Number of nodes returned
- nodes
- OUT: Array of BrowseNodeInfo objects with the information of the browsed nodes.
Return Value
HRESULT error/success codeTarget Platforms: Windows XP Professional, Windows Server 2003 family, Windows Vista, Windows 7, Windows Server 2008 family