DEPRECIATED! This overload is is only called if the overload with the instanceHandle argument is not defined. In new applications implement the method overload with the instanceHandle parameter.
This method is called when the client accesses items that do not yet exist in the server's cache. OPC DA V2 clients typically first call AddItems() or ValidateItems(). OPC DA V3 client may access items directly using the ItemIO read/write functions. In XML DA the calls directly specify the item ID.
If ValidateMode 'ALWAYS' is configured then the method is called for each client call, even if the item exists in the server cache. The access can be denied for a specific client by returning an error code in err[] for such items. This module can: - add the item to the servers real address space and return success. For each item to be added the callback method 'AddItem' has to be called. - return error for all or some items
Overload List
| Overload | Description |
|---|---|
| ValidateItems(String[],Int32,Int32[]) | Only the Professional Edition generic server calls this method. DEPRECIATED! This overload is is only called if the overload with the instanceHandle argument is not defined. In new applications implement the method overload with the instanceHandle parameter. This method is called when the client accesses items that do not yet exist in the server's cache. OPC DA V2 clients typically first call AddItems() or ValidateItems(). OPC DA V3 client may access items directly using the ItemIO read/write functions. In XML DA the calls directly specify the item ID. If ValidateMode 'ALWAYS' is configured then the method is called for each client call, even if the item exists in the server cache. The access can be denied for a specific client by returning an error code in err[] for such items. This module can: - add the item to the servers real address space and return success. For each item to be added the callback method 'AddItem' has to be called. - return error for all or some items |
| ValidateItems(Int32,String[],Int32,Int32[]) | Only the Professional Edition generic server V5.1 or newer calls this method. This method is called when the client accesses items that do not yet exist in the server's cache. OPC DA V2 clients typically first call AddItems() or ValidateItems(). OPC DA V3 client may access items directly using the ItemIO read/write functions. In XML DA the calls directly specify the item ID. If ValidateMode 'ALWAYS' is configured then the method is called for each client call, even if the item exists in the server cache. The access can be denied for a specific client by returning an error code in err[] for such items. This module can: - add the item to the servers real address space and return success. For each item to be added the callback method 'AddItem' has to be called. - return error for all or some items |
Requirements
Target Platforms: Windows XP Professional, Windows Server 2003 family, Windows Vista, Windows 7, Windows Server 2008 family