OPC Studio User's Guide and Reference
Examples - OPC UA Complex Data - Read a value
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The example below shows how to read and display OPC UA complex data.

.NET

// Shows how to read complex data 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 OpcLabs.BaseLib.DataTypeModel;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.ComplexData;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples.ComplexData._EasyUAClient
{
    class ReadValue
    {
        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 which returns complex data. This is done in the same way as regular reads - just the data 
            // returned is different.
            object value;
            try
            {
                value = client.ReadValue(endpointDescriptor, nodeDescriptor);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            // Display basic information about what we have read.
            Console.WriteLine(value);


            // We know that this node returns complex data, so we can type cast to UAGenericObject.
            var genericObject = (UAGenericObject) value;

            // The actual data is in the GenericData property of the UAGenericObject.
            //
            // If we want to see the whole hierarchy of the received complex data, 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}", genericObject.GenericData);

            // For processing the internals of the data, refer to examples for GenericData and DataType classes.

            // .Int32Value
            var int32Value = ((genericObject.GenericData as StructuredData)
                ?.FieldData["Int32Value"] as PrimitiveData)
                ?.Value as int?;
            Console.WriteLine();
            Console.WriteLine($"Int32Value: {int32Value}");


            // Example output (truncated):
            //
            //(ScalarValueDataType) structured
            //
            //(ScalarValueDataType) structured   
            //  [BooleanValue] (Boolean) primitive; True {System.Boolean}
            //  [ByteStringValue] (ByteString) primitive; System.Byte[] {System.Byte[]}
            //  [ByteValue] (Byte) primitive; 153 {System.Byte}
            //  [DateTimeValue] (DateTime) primitive; 5/11/2013 4:32:00 PM {System.DateTime}
            //  [DoubleValue] (Double) primitive; -8.93178007363702E+27 {System.Double}
            //  [EnumerationValue] (Int32) primitive; 0 {System.Int32}
            //  [ExpandedNodeIdValue] (ExpandedNodeId) structured
            //    [NamespaceURI] (CharArray) primitive; "http://samples.org/UA/memorybuffer/Instance" {System.String}
            //    [NamespaceURISpecified] (Bit) primitive; True {System.Boolean}
            //    [NodeIdType] (NodeIdType) enumeration; 3 (String)
            //    [ServerIndexSpecified] (Bit) primitive; False {System.Boolean}
            //    [String] (StringNodeId) structured
            //      [Identifier] (CharArray) primitive; "????" {System.String}
            //      [NamespaceIndex] (UInt16) primitive; 0 {System.UInt16}
            //  [FloatValue] (Float) primitive; 78.37176 {System.Single}
            //  [GuidValue] (Guid) primitive; 8129cdaf-24d9-8140-64f2-3a6d7a957fd7 {System.Guid}
            //  [Int16Value] (Int16) primitive; 2793 {System.Int16}
            //  [Int32Value] (Int32) primitive; 1133391074 {System.Int32}
            //  [Int64Value] (Int64) primitive; -1039109760798965779 {System.Int64}
            //  [Integer] (Variant) structured
            //    [ArrayDimensionsSpecified] sequence[1]
            //      [0] (Bit) primitive; False {System.Boolean}
            //    [ArrayLengthSpecified] sequence[1]
            //      [0] (Bit) primitive; False {System.Boolean}
            //    [Int64] sequence[1]
            //      [0] (Int64) primitive; 0 {System.Int64}
            //    [VariantType] sequence[6]
            //      [0] (Bit) primitive; False {System.Boolean}
            //      [1] (Bit) primitive; False {System.Boolean}
            //      [2] (Bit) primitive; False {System.Boolean}
            //      [3] (Bit) primitive; True {System.Boolean}
            //      [4] (Bit) primitive; False {System.Boolean}
            //      [5] (Bit) primitive; False {System.Boolean}
            //  [LocalizedTextValue] (LocalizedText) structured
            //    [Locale] (CharArray) primitive; "ko" {System.String}
            //    [LocaleSpecified] (Bit) primitive; True {System.Boolean}
            //    [Reserved1] sequence[6]
            //      [0] (Bit) primitive; False {System.Boolean}
            //      [1] (Bit) primitive; False {System.Boolean}
            //      [2] (Bit) primitive; False {System.Boolean}
            //      [3] (Bit) primitive; False {System.Boolean}
            //      [4] (Bit) primitive; False {System.Boolean}
            //      [5] (Bit) primitive; False {System.Boolean}
            //    [Text] (CharArray) primitive; "? ?? ??+ ??? ??) ?: ???? ?! ?!" {System.String}
            //    [TextSpecified] (Bit) primitive; True {System.Boolean}
            //  [NodeIdValue] (NodeId) structured                                                                               
        }
    }
}

COM

// Shows how to read complex data 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 Object Pascal (Delphi) on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-OP .
// 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.

class procedure ReadValue.Main;
var
  Client: _EasyUAClient;
  EndpointDescriptor: string;
  GenericObject: _UAGenericObject;
  NodeDescriptor: string;
  Value: OleVariant;
begin
  // Define which server and node we will work with.
  EndpointDescriptor := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    //'https://opcua.demo-this.com:51212/UA/SampleServer/';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  NodeDescriptor := 'nsu=http://test.org/UA/Data/ ;i=10239';  // [ObjectsFolder]/Data.Static.Scalar.StructureValue

  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  // Read a node which returns complex data. This is done in the same way as regular reads - just the data
  // returned is different.

  try
    Value := Client.ReadValue(EndpointDescriptor, NodeDescriptor);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

  // Display basic information about what we have read.
  WriteLn('value: ', Value);

  // We know that this node returns complex data, so it is a UAGenericObject.
  GenericObject := IUnknown(Value) as _UAGenericObject;

  // The actual data is in the GenericData property of the UAGenericObject.
  //
  // If we want to see the whole hierarchy of the received complex data, we can format it with the "V" (verbose)
  // specifier. In the debugger, you can view the same by displaying the private DebugView property.
  WriteLn;
  WriteLn(GenericObject.GenericData.ToString_2['V', nil]);

  // For processing the internals of the data, refer to examples for GenericData and DataType classes.

  // Example output (truncated):
  //
  //(ScalarValueDataType) structured
  //
  //(ScalarValueDataType) structured
  //  [BooleanValue] (Boolean) primitive; True {System.Boolean}
  //  [ByteStringValue] (ByteString) primitive; System.Byte[] {System.Byte[]}
  //  [ByteValue] (Byte) primitive; 153 {System.Byte}
  //  [DateTimeValue] (DateTime) primitive; 5/11/2013 4:32:00 PM {System.DateTime}
  //  [DoubleValue] (Double) primitive; -8.93178007363702E+27 {System.Double}
  //  [EnumerationValue] (Int32) primitive; 0 {System.Int32}
  //  [ExpandedNodeIdValue] (ExpandedNodeId) structured
  //    [NamespaceURI] (CharArray) primitive; "http://samples.org/UA/memorybuffer/Instance" {System.String}
  //    [NamespaceURISpecified] (Bit) primitive; True {System.Boolean}
  //    [NodeIdType] (NodeIdType) enumeration; 3 (String)
  //    [ServerIndexSpecified] (Bit) primitive; False {System.Boolean}
  //    [String] (StringNodeId) structured
  //      [Identifier] (CharArray) primitive; "????" {System.String}
  //      [NamespaceIndex] (UInt16) primitive; 0 {System.UInt16}
  //  [FloatValue] (Float) primitive; 78.37176 {System.Single}
  //  [GuidValue] (Guid) primitive; 8129cdaf-24d9-8140-64f2-3a6d7a957fd7 {System.Guid}
  //  [Int16Value] (Int16) primitive; 2793 {System.Int16}
  //  [Int32Value] (Int32) primitive; 1133391074 {System.Int32}
  //  [Int64Value] (Int64) primitive; -1039109760798965779 {System.Int64}
  //  [Integer] (Variant) structured
  //    [ArrayDimensionsSpecified] sequence[1]
  //      [0] (Bit) primitive; False {System.Boolean}
  //    [ArrayLengthSpecified] sequence[1]
  //      [0] (Bit) primitive; False {System.Boolean}
  //    [Int64] sequence[1]
  //      [0] (Int64) primitive; 0 {System.Int64}
  //    [VariantType] sequence[6]
  //      [0] (Bit) primitive; False {System.Boolean}
  //      [1] (Bit) primitive; False {System.Boolean}
  //      [2] (Bit) primitive; False {System.Boolean}
  //      [3] (Bit) primitive; True {System.Boolean}
  //      [4] (Bit) primitive; False {System.Boolean}
  //      [5] (Bit) primitive; False {System.Boolean}
  //  [LocalizedTextValue] (LocalizedText) structured
  //    [Locale] (CharArray) primitive; "ko" {System.String}
  //    [LocaleSpecified] (Bit) primitive; True {System.Boolean}
  //    [Reserved1] sequence[6]
  //      [0] (Bit) primitive; False {System.Boolean}
  //      [1] (Bit) primitive; False {System.Boolean}
  //      [2] (Bit) primitive; False {System.Boolean}
  //      [3] (Bit) primitive; False {System.Boolean}
  //      [4] (Bit) primitive; False {System.Boolean}
  //      [5] (Bit) primitive; False {System.Boolean}
  //    [Text] (CharArray) primitive; "? ?? ??+ ??? ??) ?: ???? ?! ?!" {System.String}
  //    [TextSpecified] (Bit) primitive; True {System.Boolean}
  //  [NodeIdValue] (NodeId) structured

end;

Python

# Shows how to read complex data 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 Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python .
# 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.
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from System import *
from OpcLabs.BaseLib.DataTypeModel import *
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.OperationModel import *


endpointDescriptor = UAEndpointDescriptor('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/'

# [ObjectsFolder]/Data.Static.Scalar.StructureValue
nodeDescriptor = UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10239')

# Instantiate the client object.
client = EasyUAClient()

# Read a node which returns complex data. This is done in the same way as regular reads - just the data
# returned is different.
try:
    value = IEasyUAClientExtension.ReadValue(client, endpointDescriptor, nodeDescriptor)
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

# Display basic information about what we have read.
print(value)


# We know that this node returns complex data, so we can type cast to UAGenericObject.
genericObject = value

# The actual data is in the GenericData property of the UAGenericObject.
#
# If we want to see the whole hierarchy of the received complex data, we can format it with the "V" (verbose)
# specifier. In the debugger, you can view the same by displaying the private DebugView property.
print()
print(String.Format('{0:V}', genericObject.GenericData))

# For processing the internals of the data, refer to examples for GenericData and DataType classes.

# .Int32Value
structuredData = genericObject.GenericData if isinstance(genericObject.GenericData, StructuredData) else None
fieldData = None if structuredData is None else structuredData.FieldData
fieldValue = None if fieldData is None else fieldData.get_Item('Int32Value')
primitiveData = fieldValue if isinstance(fieldValue, PrimitiveData) else None
int32Value = None if primitiveData is None else primitiveData.Value
print()
print('Int32Value: ', int32Value, sep='')

print()
print('Finished.')

 

See Also

Concepts

Examples - Client OPC Unified Architecture