public List<OpcMeasure> ReadMeasures(MeasureType mType, string rootTag="") { var res = new List<OpcMeasure>(); try { VarType[] dataTypes = null; switch (mType) { case MeasureType.Analogic: dataTypes = OpcDataTypesGenerator.AnalogDataTypes(); break; case MeasureType.Digital: dataTypes = OpcDataTypesGenerator.DigitalDataTypes(); break; } foreach (var dataType in dataTypes) { var nodeFilter = new DANodeFilter(DABrowseFilter.Leaves, "", "", dataType); var nodeElements = _client.BrowseNodes(Host, ServerName, rootTag, nodeFilter); // Store the leaf information into the dictionary, and // associate the current data type with it. res.AddRange(nodeElements.Select(nodeElement => new OpcMeasure {ItemId = nodeElement.ItemId, MeasureType = mType})); } } catch (NullReferenceException) { res = null; } catch (OpcException) { res = null; } return res; }

public static VarType[] AnalogDataTypes() { return new VarType[] { VarType.Empty, VarType.BStr, VarType.R4, VarType.R8 }; } public static VarType[] DigitalDataTypes() { return new VarType[] { VarType.Empty, VarType.Array, VarType.Bool, VarType.Date, VarType.Decimal, VarType.Int, VarType.UI1, VarType.UI2, VarType.UI4, VarType.UI8, VarType.UInt }; } }

var obj = server.ReadMeasures(MeasureType.Digital, "Greenhouse");

var nodeElements = _client.BrowseNodes(Host, ServerName, rootTag, nodeFilter);

// This example shows how to obtain data types of leaves in the OPC-DA address // space by browsing and filtering, i.e. without the use of OPC properties. // This technique allows determining the data types with servers that only // support OPC-DA 1.0. It can also be more effective than the use of // GetMultiplePropertyValues, if there is large number of leaves, and // relatively small number of data types to be checked. using System; using System.Collections.Generic; using OpcLabs.EasyOpc; using OpcLabs.EasyOpc.DataAccess; namespace DocExamples { namespace _EasyDAClient { /*partial*/ class BrowseNodes { public static void DataTypes() { var easyDAClient = new EasyDAClient(); // Define the list of data types we will be checking for. // Change as needed for your application. // This technique is only usable if there is a known list of // data types you are interested in. If you are interested in // all leaves, even those that are of data types not explicitly // listed, always include VarType.Empty as the first data type. // The leaves of "unlisted" data types will have VarType.Empty // associated with them. var dataTypes = new VarType[] { VarType.Empty, VarType.I2, VarType.R4 }; // For each leaf found, this dictionary wil hold its associated data type. var dataTypeDictionary = new Dictionary<DANodeElement, VarType>(); // For each data type, browse for leaves of this data type. foreach (VarType dataType in dataTypes) { var nodeFilter = new DANodeFilter(DABrowseFilter.Leaves, "", "", dataType); DANodeElementCollection nodeElements = easyDAClient.BrowseNodes("", "OPCLabs.KitServer.2", "Greenhouse", nodeFilter); // Store the leaf information into the dictionary, and // associate the current data type with it. foreach (var nodeElement in nodeElements) dataTypeDictionary[nodeElement] = dataType; } // Display each leaf found, and its associated data type. foreach (KeyValuePair<DANodeElement, VarType> pair in dataTypeDictionary) { DANodeElement nodeElement = pair.Key; VarType dataType = pair.Value; Console.WriteLine("{0}: {1}", nodeElement, dataType); } } } } }