// BrowseAndReadValues: Console application that recursively browses and displays the nodes in the OPC address space, and // attempts to read and display values of all OPC items it finds. using System.Diagnostics; using JetBrains.Annotations; using OpcLabs.EasyOpc; using OpcLabs.EasyOpc.DataAccess; using System; namespace BrowseAndReadValues { class Program { const string ServerClass = "OPCLabs.KitServer.2"; [NotNull] static readonly EasyDAClient Client = new EasyDAClient(); static void BrowseAndReadFromNode([NotNull] string parentItemId) { // Obtain all node elements under parentItemId var nodeFilter = new DANodeFilter(); // no filtering whatsoever DANodeElementCollection nodeElementCollection = Client.BrowseNodes("", ServerClass, parentItemId, nodeFilter); // Remark: that BrowseNodes(...) may also throw OpcException; a production code should contain handling for it, here // omitted for brevity. foreach (DANodeElement nodeElement in nodeElementCollection) { Debug.Assert(nodeElement != null); // If the node is a leaf, it might be possible to read from it if (nodeElement.IsLeaf) { // Determine what the display - either the value read, or exception message in case of failure. string display; try { object value = Client.ReadItemValue("", ServerClass, nodeElement); display = String.Format("{0}", value); } catch (OpcException exception) { display = String.Format("** {0} **", exception.GetBaseException().Message); } Console.WriteLine("{0} -> {1}", nodeElement.ItemId, display); } // If the node is not a leaf, just display its itemId else Console.WriteLine("{0}", nodeElement.ItemId); // If the node is a branch, browse recursively into it. if (nodeElement.IsBranch && (nodeElement.ItemId != "SimulateEvents") /* this branch is too big for the purpose of this example */) BrowseAndReadFromNode(nodeElement); } } static void Main() { Console.WriteLine("Browsing and reading values..."); // Set timeout to only wait 1 second - default would be 1 minute to wait for good quality that may never come. Client.InstanceParameters.Timeouts.ReadItem = 1000; // Do the actual browsing and reading, starting from root of OPC address space (denoted by empty string for itemId) BrowseAndReadFromNode(""); Console.WriteLine("Press Enter to continue..."); Console.ReadLine(); } } }