OpcFileOpenMethodNode.FileOpenCallback Delegate

Namespace: Opc.UaFx
Assemblies: Opc.UaFx.Advanced.dll

Opens the file represented. When a client opens a file it gets a file handle that is valid while the session is open. Clients shall use the Close Method to release the file handle when they do not need access to the file anymore. Clients can open the same file several times for read.


public delegate uint FileOpenCallback([OpcArgument("Mode", Description = "A OpcFileMode value that determines whether the contents of existing files are retained or overwritten and how a file is accessed.")] byte mode);

Attributes CLSCompliantAttribute


mode Byte

Indicates whether the file should be opened only for read operations or for read and write operations and where the initial position is set.



A handle for the file used in other method calls indicating not the file but the access request and thus the position in the file. The file handle is generated by the server and is unique for the Session. Clients cannot transfer the file handle to another Session but need to get a new file handle by calling the Open Method.