OPC Studio User's Guide and Reference
DataType Class
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OpcLabs.BaseLib Assembly > OpcLabs.BaseLib.DataTypeModel Namespace : DataType Class
An abstract data type.
Syntax
'Declaration
 
<CLSCompliantAttribute(True)>
<ComDefaultInterfaceAttribute(OpcLabs.BaseLib.DataTypeModel.ComTypes._DataType)>
<ComVisibleAttribute(True)>
<GuidAttribute("D196D5B2-AC5D-41DB-9886-D41CD12A4A32")>
<DebuggerDisplayAttribute("{DebuggerDisplay,nq}")>
<TypeConverterAttribute(System.ComponentModel.ExpandableObjectConverter)>
<ValueControlAttribute("OpcLabs.BaseLib.Forms.Common.ObjectSerializationControl, OpcLabs.BaseLibForms, Version=5.81.455.1, Culture=neutral, PublicKeyToken=6faddca41dacb409", 
   DefaultReadWrite=False, 
   Export=True, 
   PageId=10001)>
<SerializableAttribute()>
Public MustInherit Class DataType 
   Inherits TypeMemberInfo
   Implements OpcLabs.BaseLib.ComTypes._Info, OpcLabs.BaseLib.ComTypes._Object2, OpcLabs.BaseLib.DataTypeModel.ComTypes._DataType, OpcLabs.BaseLib.DataTypeModel.ComTypes._TypeMemberInfo, System.ICloneable, System.IFormattable, System.Runtime.Serialization.ISerializable, System.Xml.Serialization.IXmlSerializable 
 
'Usage
 
Dim instance As DataType
Remarks

Classes derived from DataType form following class hierarchy:

.

Example
// Shows how to process a data type, displaying some of its properties, recursively.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

using System;
using System.Linq;
using OpcLabs.BaseLib.DataTypeModel;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.ComplexData;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples.ComplexData._DataType
{
    class Kind
    {
        public static void Main1()
        {
            // Define which server and node we will work with.
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"
            UANodeDescriptor nodeDescriptor = 
                "nsu=http://test.org/UA/Data/ ;i=10239"; // [ObjectsFolder]/Data.Static.Scalar.StructureValue

            // Instantiate the client object.
            var client = new EasyUAClient();

            // Read a node. We know that this node returns complex data, so we can type cast to UAGenericObject.
            UAGenericObject genericObject;
            try
            {
                genericObject = (UAGenericObject)client.ReadValue(endpointDescriptor, nodeDescriptor);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }
            // The data type is in the GenericData.DataType property of the UAGenericObject.
            DataType dataType = genericObject.GenericData.DataType;

            // Process the data type. We will inspect some of its properties, and dump them.
            ProcessDataType(dataType, maximumDepth: 3);
        }
        

        // Process the data type. It can be recursive in itself, so if you do not know the data type you are dealing with, 
        // it is recommended to make safeguards against infinite looping or recursion - here, the maximumDepth.
        public static void ProcessDataType(DataType dataType, int maximumDepth)
        {
            if (maximumDepth == 0)
                return;

            Console.WriteLine();
            Console.WriteLine("dataType.Name: {0}", dataType.Name);

            switch (dataType.Kind)
            {
                case DataTypeKind.Enumeration:
                    Console.WriteLine("The data type is an enumeration.");
                    var enumerationDataType = (EnumerationDataType) dataType;
                    Console.WriteLine("It has {0} enumeration members.", enumerationDataType.EnumerationMembers.Count);
                    Console.WriteLine("The names of the enumeration members are: {0}.",
                        String.Join(", ", enumerationDataType.EnumerationMembers.Select(member => member.Name)));
                    // Here you can process the members, or inspect SizeInBits etc.
                    break;

                case DataTypeKind.Opaque:
                    Console.WriteLine("The data type is opaque.");
                    var opaqueDataType = (OpaqueDataType) dataType;
                    Console.WriteLine("Its size is {0} bits.", opaqueDataType.SizeInBits);
                    // There isn't much more you can learn about an opaque data type (well, it may have Description and 
                    // other common members). It is, after all, opaque...
                    break;

                case DataTypeKind.Primitive:
                    Console.WriteLine("The data type is primitive.");
                    var primitiveDataType = (PrimitiveDataType) dataType;
                    Console.WriteLine("Its .NET value type is \"{0}\".", primitiveDataType.ValueType);
                    // There isn't much more you can learn about the primitive data type.
                    break;

                case DataTypeKind.Sequence:
                    Console.WriteLine("The data type is a sequence.");
                    var sequenceDataType = (SequenceDataType) dataType;
                    Console.WriteLine("Its length is {0} (-1 means that the length can vary).", sequenceDataType.Length);

                    Console.WriteLine("A dump of the element data type follows.");
                    ProcessDataType(sequenceDataType.ElementDataType, maximumDepth - 1);
                    break;

                case DataTypeKind.Structured:
                    Console.WriteLine("The data type is structured.");
                    var structuredDataType = (StructuredDataType) dataType;
                    Console.WriteLine("It has {0} data fields.", structuredDataType.DataFields.Count);
                    Console.WriteLine("The names of the data fields are: {0}.",
                        String.Join(", ", structuredDataType.DataFields.Select(field => field.Name)));

                    Console.WriteLine("A dump of each of the data fields follows.");
                    foreach (DataField dataField in structuredDataType.DataFields)
                    {
                        Console.WriteLine();
                        Console.WriteLine("dataField.Name: {0}", dataField.Name);
                        // Note that every data field also has properties like IsLength, IsOptional, IsSwitch which might 
                        // be of interest, but we are not dumping them here.
                        ProcessDataType(dataField.DataType, maximumDepth - 1);
                    }
                    break;

                case DataTypeKind.Union:
                    Console.WriteLine("The data type is union.");
                    var unionDataType = (UnionDataType)dataType;
                    Console.WriteLine("It has {0} data fields.", unionDataType.DataFields.Count);
                    Console.WriteLine("The names of the data fields are: {0}.",
                        String.Join(", ", unionDataType.DataFields.Select(field => field.Name)));
                    break;
            }
        }
    }
}
// Shows how to obtain object describing the data type of complex data node with OPC UA Complex Data plug-in.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

using System;
using Microsoft.Extensions.DependencyInjection;
using OpcLabs.BaseLib.DataTypeModel;
using OpcLabs.BaseLib.OperationModel.Generic;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.AddressSpace;
using OpcLabs.EasyOpc.UA.AddressSpace.Standard;
using OpcLabs.EasyOpc.UA.InformationModel;
using OpcLabs.EasyOpc.UA.Plugins.ComplexData;

namespace UADocExamples.ComplexData._IEasyUAClientComplexData
{
    class ResolveDataType
    {
        public static void Main1()
        {
            // Define which server we will work with.
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"

            // Instantiate the client object.
            var client = new EasyUAClient();

            // Obtain the data type ID.
            //
            // In many cases, you would be able to obtain the data type ID of a particular node by reading its DataType
            // attribute, or easier, by calling the extension method ReadDataType on the IEasyUAClient interface.
            // The sample server, however, shows a more advanced approach in which the data type ID refers to an abstract
            // data type, and the actual values are then sub-types of this base data type. This abstract data type does not
            // have any encodings associated with it and it is therefore not possible to extract its description from the
            // server. We therefore use a hard-coded data type ID for one of the sub-types in this example.
            //
            // The code to obtain the data type ID for given node would normally look like this:
            //    UANodeId dataTypeId = client.ReadDataType(
            //        endpointDescriptor,
            //        "nsu=http://test.org/UA/Data/ ;i=10239");    // [ObjectsFolder]/Data.Static.Scalar.StructureValue
            //
            UANodeId dataTypeId = "nsu=http://test.org/UA/Data/ ;i=9440";    // ScalarValueDataType

            // Get the IEasyUAClientComplexData service from the client. This is needed for advanced complex data 
            // operations.
            IEasyUAClientComplexData complexData = client.GetService<IEasyUAClientComplexData>();
            
            // Resolve the data type ID to the data type object, containing description of the data type.
            ValueResult<DataType> dataTypeResult = complexData.ResolveDataType(
                new UAModelNodeDescriptor(endpointDescriptor, dataTypeId), 
                UABrowseNames.DefaultBinary);
            // Check if the operation succeeded. Use the ThrowIfFailed method instead if you want exception be thrown.
            if (!dataTypeResult.Succeeded)
            {
                Console.WriteLine("*** Failure: {0}", dataTypeResult.ErrorMessageBrief);
                return;
            }

            // The actual data type is in the Value property.
            // Display basic information about what we have obtained.
            Console.WriteLine(dataTypeResult.Value);

            // If we want to see the whole hierarchy of the received data type, we can format it with the "V" (verbose)
            // specifier. In the debugger, you can view the same by displaying the private DebugView property.
            Console.WriteLine();
            Console.WriteLine("{0:V}", dataTypeResult.Value);

            // For processing the internals of the data type, refer to examples for GenericData class.


            // Example output (truncated):
            //
            //ScalarValueDataType = structured
            //
            //ScalarValueDataType = structured
            //  [BooleanValue] Boolean = primitive(System.Boolean)
            //  [ByteStringValue] ByteString = primitive(System.Byte[])
            //  [ByteValue] Byte = primitive(System.Byte)
            //  [DateTimeValue] DateTime = primitive(System.DateTime)
            //  [DoubleValue] Double = primitive(System.Double)
            //  [EnumerationValue] Int32 = primitive(System.Int32)
            //  [ExpandedNodeIdValue] ExpandedNodeId = structured
            //    [ByteString] optional ByteStringNodeId = structured
            //      [Identifier] ByteString = primitive(System.Byte[])
            //      [NamespaceIndex] UInt16 = primitive(System.UInt16)
            //    [FourByte] optional FourByteNodeId = structured
            //      [Identifier] UInt16 = primitive(System.UInt16)
            //      [NamespaceIndex] Byte = primitive(System.Byte)
            //    [Guid] optional GuidNodeId = structured
            //      [Identifier] Guid = primitive(System.Guid)
            //      [NamespaceIndex] UInt16 = primitive(System.UInt16)
            //    [NamespaceURI] optional CharArray = primitive(System.String)
            //    [NamespaceURISpecified] switch Bit = primitive(System.Boolean)
            //    [NodeIdType] switch NodeIdType = enumeration(6)
            //      TwoByte = 0
            //      FourByte = 1
            //      Numeric = 2
            //      String = 3
            //      Guid = 4
            //      ByteString = 5
            //    [Numeric] optional NumericNodeId = structured
            //      [Identifier] UInt32 = primitive(System.UInt32)
            //      [NamespaceIndex] UInt16 = primitive(System.UInt16)
            //    [ServerIndex] optional UInt32 = primitive(System.UInt32)
            //    [ServerIndexSpecified] switch Bit = primitive(System.Boolean)
            //    [String] optional StringNodeId = structured
            //      [Identifier] CharArray = primitive(System.String)
            //      [NamespaceIndex] UInt16 = primitive(System.UInt16)
            //    [TwoByte] optional TwoByteNodeId = structured
            //      [Identifier] Byte = primitive(System.Byte)
            //  [FloatValue] Float = primitive(System.Single)
            //  [GuidValue] Guid = primitive(System.Guid)
            //  [Int16Value] Int16 = primitive(System.Int16)
            //  [Int32Value] Int32 = primitive(System.Int32)
            //  [Int64Value] Int64 = primitive(System.Int64)
            //  [Integer] Variant = structured
            //    [ArrayDimensions] optional sequence[*] of Int32 = primitive(System.Int32)
            //    [ArrayDimensionsSpecified] switch sequence[1] of Bit = primitive(System.Boolean)
            //    [ArrayLength] length optional Int32 = primitive(System.Int32)
            //    [ArrayLengthSpecified] switch sequence[1] of Bit = primitive(System.Boolean)
            //    [Boolean] optional sequence[*] of Boolean = primitive(System.Boolean)
            //    [Byte] optional sequence[*] of Byte = primitive(System.Byte)
        }
    }
}
Inheritance Hierarchy

System.Object
   OpcLabs.BaseLib.Object2
      OpcLabs.BaseLib.Info
         OpcLabs.BaseLib.DataTypeModel.TypeMemberInfo
            OpcLabs.BaseLib.DataTypeModel.DataType
               OpcLabs.BaseLib.DataTypeModel.CompositeDataType
               OpcLabs.BaseLib.DataTypeModel.EnumerationDataType
               OpcLabs.BaseLib.DataTypeModel.OpaqueDataType
               OpcLabs.BaseLib.DataTypeModel.PrimitiveDataType
               OpcLabs.BaseLib.DataTypeModel.SequenceDataType

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also