OPC Studio User's Guide and Reference
ThrowIfFailed Method (_ValueResult)
Example 



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OpcLabs.BaseLib Assembly > OpcLabs.BaseLib.OperationModel.ComTypes Namespace > _ValueResult Interface : ThrowIfFailed Method
Throws Exception if it is not a null reference.
Syntax
'Declaration
 
Sub ThrowIfFailed() 
 
'Usage
 
Dim instance As _ValueResult
 
instance.ThrowIfFailed()
Exceptions
ExceptionDescription
An error has occurred during application execution.
Example

.NET

COM

// 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 .

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)
        }
    }
}
// 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 .

class procedure ResolveDataType.Main;
var
  Client: _EasyUAClient;
  ComplexData: _EasyUAClientComplexData;
  DataType: _DataType;
  DataTypeId: string;
  DataTypeResult: _ValueResult;
  EncodingName: _UAQualifiedName;
  EndpointDescriptor: string;
  ModelNodeDescriptor: _UAModelNodeDescriptor;
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';

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

  // 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.
  // 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.
  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.
  ComplexData := IInterface(Client.GetServiceByName('OpcLabs.EasyOpc.UA.Plugins.ComplexData.IEasyUAClientComplexData, OpcLabs.EasyOpcUA')) as _EasyUAClientComplexData;

  // Resolve the data type ID to the data type object, containing description of the data type.
  ModelNodeDescriptor := CoUAModelNodeDescriptor.Create;
  ModelNodeDescriptor.EndpointDescriptor.UrlString := EndpointDescriptor;
  ModelNodeDescriptor.NodeDescriptor.NodeId.ExpandedText := DataTypeId;
  EncodingName := CoUAQualifiedName.Create;
  EncodingName.StandardName := 'DefaultBinary';
  DataTypeResult := ComplexData.ResolveDataType(ModelNodeDescriptor, EncodingName);
  if not DataTypeResult.Succeeded then
  begin
    WriteLn(Format('*** Failure: %s', [DataTypeResult.ErrorMessageBrief]));
    Exit;
  end;

  // The actual data type is in the Value property.
  DataType := IUnknown(DataTypeResult.Value) as _DataType;

  // Display basic information about what we have obtained.
  WriteLn(DataType.ToString);

  // If we want to see the whole hierarchy of the received data type, we can format it with the "V" (verbose)
  // specifier.
  Writeln;
  Writeln(DataType.ToString_2['V', nil]);

  // 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)

end;
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