GetDataTypePropertyValue(IEasyDAClient,ServerDescriptor,DANodeDescriptor) Method

Obtains value of Item Canonical DataType OPC property for a given OPC item.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function GetDataTypePropertyValue( _
   ByVal client As IEasyDAClient, _
   ByVal serverDescriptor As ServerDescriptor, _
   ByVal nodeDescriptor As DANodeDescriptor _
) As VarType

'Usage
 
Dim client As IEasyDAClient
Dim serverDescriptor As ServerDescriptor
Dim nodeDescriptor As DANodeDescriptor
Dim value As VarType
 
value = IEasyDAClientExtension2.GetDataTypePropertyValue(client, serverDescriptor, nodeDescriptor)

[Extension()]
[NotNull()]
public static VarType GetDataTypePropertyValue( 
   IEasyDAClient client,
   ServerDescriptor serverDescriptor,
   DANodeDescriptor nodeDescriptor
)

[Extension()]
[NotNull()]
public:
static VarType^ GetDataTypePropertyValue( 
   IEasyDAClient^ client,
   ServerDescriptor^ serverDescriptor,
   DANodeDescriptor^ nodeDescriptor
)

Parameters

client: The client object that will perform the operation.
serverDescriptor: The OPC server involved in the operation.
nodeDescriptor: The descriptor of the OPC node involved in the operation.

Return Value

Returns a value of this OPC property for a specified OPC item, converted to a proper type.

Exceptions

Exception	Description
OpcLabs.EasyOpc.OperationModel.OpcException	The OPC "Classic" (or OPC XML-DA) operation has failed.
System.ArgumentNullException	A `null` reference (`Nothing` in Visual Basic) is passed to a method that does not accept it as a valid argument.

Remarks

Using implicit conversions, you can pass an item ID in place of node descriptor.

Example

CSharp
VB.NET

// This example shows how to obtain a data type of an OPC item.

using System;
using OpcLabs.BaseLib.ComInterop;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.Extensions;
using OpcLabs.EasyOpc.OperationModel;

namespace DocExamples.DataAccess._EasyDAClientExtension
{
    class GetDataTypePropertyValue
    {
        public static void Main1()
        {
            // Instantiate the client object.
            var client = new EasyDAClient();

            // Get the DataType property value, already converted to VarType
            VarType varType;
            try
            {
                varType = client.GetDataTypePropertyValue("", "OPCLabs.KitServer.2", "Simulation.Random");
            }
            catch (OpcException opcException)
            {
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
                return;
            }

            // Display the obtained data type
            Console.WriteLine("VarType: {0}", varType); // Display data type symbolically
        }
    }
}

' This example shows how to obtain a data type of an OPC item.

Imports OpcLabs.BaseLib.ComInterop
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.Extensions
Imports OpcLabs.EasyOpc.OperationModel

Namespace DocExamples.DataAccess._EasyDAClientExtension
    Friend Class GetDataTypePropertyValue
        Public Shared Sub Main1()
            Dim client = New EasyDAClient()

            ' Get the DataType property value, already converted to VarType
            Dim varType As VarType
            Try
                varType = client.GetDataTypePropertyValue("", "OPCLabs.KitServer.2", "Simulation.Random")
            Catch opcException As OpcException
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
                Exit Sub
            End Try

            ' Display the obtained data type
            Console.WriteLine("VarType: {0}", varType) ' Display data type symbolically
        End Sub
    End Class
End Namespace

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2012, Windows Server 2016; .NET Core, .NET 5, .NET 6: Linux, macOS, Microsoft Windows

Reference

IEasyDAClientExtension2 Class
IEasyDAClientExtension2 Members
Overload List