Parameters
- endpointDescriptor
- Endpoint descriptor. Identifies the OPC-UA server.
- directoryNodeDescriptor
- Node descriptor of the OPC UA directory.
- fileName
- The name of the file to find.
Return Value
null
otherwise.null
otherwise.Exception | Description |
---|---|
System.ArgumentNullException |
A This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception. |
OpcLabs.EasyOpc.UA.OperationModel.UAException | The OPC UA operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause. This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately. |
The directoryNodeDescriptor must be an existing node in the server, of object type OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAObjectTypeIds.FileDirectoryType.
If the directoryNodeDescriptor does not denote an existing node of the OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAObjectTypeIds.FileDirectoryType object type, the method throws OpcLabs.EasyOpc.UA.OperationModel.UAException. If, however, the directoryNodeDescriptor denotes an existing directory node, but the file named fileName does not exist, the method returns null
.
This method finds an OPC UA node of object type FileType, which is described here: . The organization of files under directories is described here: . Files are referenced from their parent directory using the OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAReferenceTypeIds.Organizes reference type.