// This example shows how to obtain "data nodes" under the "Objects" node, recursively. using System; using System.Diagnostics; using OpcLabs.EasyOpc.UA; using OpcLabs.EasyOpc.UA.AddressSpace; using OpcLabs.EasyOpc.UA.AddressSpace.Standard; using OpcLabs.EasyOpc.UA.OperationModel; namespace UADocExamples._EasyUAClient { partial class BrowseDataNodes { public static void Recursive() { UAEndpointDescriptor endpointDescriptor = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"; // or "http://opcua.demo-this.com:51211/UA/SampleServer" (not in .NET Standard) // or "https://opcua.demo-this.com:51212/UA/SampleServer/" // Instantiate the client object var client = new EasyUAClient(); try { BrowseFromNode(client, endpointDescriptor, UAObjectIds.ObjectsFolder, level:0); } catch (UAException uaException) { Console.WriteLine($"*** Failure: {uaException.GetBaseException().Message}"); } } private static void BrowseFromNode( EasyUAClient client, UAEndpointDescriptor endpointDescriptor, UANodeDescriptor parentNodeDescriptor, int level) { Debug.Assert(!(client is null)); Debug.Assert(!(endpointDescriptor is null)); Debug.Assert(!(parentNodeDescriptor is null)); // Obtain all node elements under parentNodeDescriptor UANodeElementCollection nodeElementCollection = client.BrowseDataNodes(endpointDescriptor, parentNodeDescriptor); // Remark: BrowseDataNodes(...) may throw UAException; we handle it in the calling method. foreach (UANodeElement nodeElement in nodeElementCollection) { Debug.Assert(!(nodeElement is null)); Console.Write(new string(' ', level*2)); // indent Console.WriteLine(nodeElement); // Browse recursively into the node. // The UANodeElement has an implicit conversion to UANodeDescriptor. BrowseFromNode(client, endpointDescriptor, nodeElement, level + 1); // Note that the number of nodes you obtain through recursive browsing may be very large, or even infinite. // Production code should contain appropriate safeguards for these cases. } } // Example output: // //ServerStatus -> nsu=http://opcfoundation.org/UA/ ;i=2256 (Variable) // StartTime -> nsu=http://opcfoundation.org/UA/ ;i=2257 (Variable) // CurrentTime -> nsu=http://opcfoundation.org/UA/ ;i=2258 (Variable) // State -> nsu=http://opcfoundation.org/UA/ ;i=2259 (Variable) // BuildInfo -> nsu=http://opcfoundation.org/UA/ ;i=2260 (Variable) // ProductUri -> nsu=http://opcfoundation.org/UA/ ;i=2262 (Variable) // ManufacturerName -> nsu=http://opcfoundation.org/UA/ ;i=2263 (Variable) // ProductName -> nsu=http://opcfoundation.org/UA/ ;i=2261 (Variable) // SoftwareVersion -> nsu=http://opcfoundation.org/UA/ ;i=2264 (Variable) // BuildNumber -> nsu=http://opcfoundation.org/UA/ ;i=2265 (Variable) // BuildDate -> nsu=http://opcfoundation.org/UA/ ;i=2266 (Variable) // SecondsTillShutdown -> nsu=http://opcfoundation.org/UA/ ;i=2992 (Variable) // ShutdownReason -> nsu=http://opcfoundation.org/UA/ ;i=2993 (Variable) //ServerCapabilities -> nsu=http://opcfoundation.org/UA/ ;i=2268 (Object) // OperationLimits -> nsu=http://opcfoundation.org/UA/ ;i=11704 (Object) // MaxNodesPerRead -> nsu=http://opcfoundation.org/UA/ ;i=11705 (Variable) // MaxNodesPerHistoryReadData -> nsu=http://opcfoundation.org/UA/ ;i=12165 (Variable) // MaxNodesPerHistoryReadEvents -> nsu=http://opcfoundation.org/UA/ ;i=12166 (Variable) // MaxNodesPerWrite -> nsu=http://opcfoundation.org/UA/ ;i=11707 (Variable) // MaxNodesPerHistoryUpdateData -> nsu=http://opcfoundation.org/UA/ ;i=12167 (Variable) //... } }