OPC Studio User's Guide and Reference
GetPropertyValueDictionary(IEasyDAClient,String,String,String,IEnumerable<DAPropertyId>) Method
Example 



OpcLabs.EasyOpcClassicCore Assembly > OpcLabs.EasyOpc.DataAccess.Extensions Namespace > IEasyDAClientExtension2 Class > GetPropertyValueDictionary Method : GetPropertyValueDictionary(IEasyDAClient,String,String,String,IEnumerable<DAPropertyId>) Method
The client object that will perform the operation.

This is typically the OpcLabs.EasyOpc.DataAccess.EasyDAClient object.

The value of this parameter cannot be null (Nothing in Visual Basic).

Name of the machine. Determines the computer on which the OPC server is located. It may be an empty string, in which case the OPC server is assumed to exist on the local computer or at the computer specified for it by DCOM configuration.

The value represents a UNC or DNS computer name. Any string can be passed to this parameter (i.e. will not cause System.ArgumentException), but not all values make sense and will work when an operation using them is attempted. IPv6 addresses are normally enclosed between '[' and ']'.

The value of this parameter cannot be null (Nothing in Visual Basic).

Contains ProgID of the OPC server to read from.

The value of this parameter cannot be null (Nothing in Visual Basic).

Contains OPC item identifier.

The value of this parameter cannot be null (Nothing in Visual Basic).

Specifies which OPC properties should be obtained and returned.

The value of this parameter cannot be null (Nothing in Visual Basic).

Obtains a dictionary filled with known OPC property values for a given OPC item. You can specify the property Ids.
Syntax
'Declaration
 
<ExtensionAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function GetPropertyValueDictionary( _
   ByVal client As IEasyDAClient, _
   ByVal machineName As String, _
   ByVal serverClass As String, _
   ByVal itemId As String, _
   ByVal propertyIds As IEnumerable(Of DAPropertyId) _
) As DAPropertyValueDictionary
'Usage
 
Dim client As IEasyDAClient
Dim machineName As String
Dim serverClass As String
Dim itemId As String
Dim propertyIds As IEnumerable(Of DAPropertyId)
Dim value As DAPropertyValueDictionary
 
value = IEasyDAClientExtension2.GetPropertyValueDictionary(client, machineName, serverClass, itemId, propertyIds)

Parameters

client
The client object that will perform the operation.

This is typically the OpcLabs.EasyOpc.DataAccess.EasyDAClient object.

The value of this parameter cannot be null (Nothing in Visual Basic).

machineName
Name of the machine. Determines the computer on which the OPC server is located. It may be an empty string, in which case the OPC server is assumed to exist on the local computer or at the computer specified for it by DCOM configuration.

The value represents a UNC or DNS computer name. Any string can be passed to this parameter (i.e. will not cause System.ArgumentException), but not all values make sense and will work when an operation using them is attempted. IPv6 addresses are normally enclosed between '[' and ']'.

The value of this parameter cannot be null (Nothing in Visual Basic).

serverClass
Contains ProgID of the OPC server to read from.

The value of this parameter cannot be null (Nothing in Visual Basic).

itemId
Contains OPC item identifier.

The value of this parameter cannot be null (Nothing in Visual Basic).

propertyIds
Specifies which OPC properties should be obtained and returned.

The value of this parameter cannot be null (Nothing in Visual Basic).

Return Value

Returns a dictionary of OpcLabs.BaseLib.OperationModel.ValueResult objects keyed by OpcLabs.EasyOpc.DataAccess.DAPropertyId.

This method never returns null (Nothing in Visual Basic).

The individual elements of the returned value are never null (Nothing in Visual Basic).

Exceptions
ExceptionDescription

A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

Remarks
This method allows you to obtain a dictionary of property values for a given OPC item, where a key to the dictionary is the property Id. You can pass in a set of property Ids that you are interested in, or have the method obtain all well-known OPC properties. You can then easily extract the value of any property by looking it up in a dictionary (as opposed to having to numerically index into an array, as with the base OpcLabs.EasyOpc.DataAccess.IEasyDAClientExtension.GetMultiplePropertyValues method).

This is an extension method (info: C#, VB.NET). In languages that have support for extensions methods (such as C# and VB.NET), you can use the extension method as if it were a regular method on the object that is its first parameter. In other languages (such as with Python.NET), you will call the extension as a static method, and pass it the object on which it acts as its first parameter.

Example
// This example shows how to obtain a dictionary of OPC property values for an OPC item, and extract property values.
//
// 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.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.Extensions;
using OpcLabs.EasyOpc.OperationModel;

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

            // Get dictionary of property values, for all well-known properties
            DAPropertyValueDictionary propertyValueDictionary;
            try
            {
                propertyValueDictionary = client.GetPropertyValueDictionary("", "OPCLabs.KitServer.2", "Simulation.Random");
            }
            catch (OpcException opcException)
            {
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
                return;
            }

            // Display some of the obtained property values
            // The production code should also check for the .Exception first, before getting .Value
            Console.WriteLine("propertyValueDictionary[DAPropertyId.AccessRights].Value: {0}",
                propertyValueDictionary[DAPropertyIds.AccessRights].Value);
            Console.WriteLine("propertyValueDictionary[DAPropertyId.DataType].Value: {0}",
                propertyValueDictionary[DAPropertyIds.DataType].Value);
            Console.WriteLine("propertyValueDictionary[DAPropertyId.Timestamp].Value: {0}",
                propertyValueDictionary[DAPropertyIds.Timestamp].Value);
        }
    }
}
' This example shows how to obtain a dictionary of OPC property values for an OPC item, and extract property values.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET .
' 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.

Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.Extensions
Imports OpcLabs.EasyOpc.OperationModel

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

            ' Get dictionary of property values, for all well-known properties
            Dim propertyValueDictionary As DAPropertyValueDictionary
            Try
                propertyValueDictionary = client.GetPropertyValueDictionary("", "OPCLabs.KitServer.2", "Simulation.Random")
            Catch opcException As OpcException
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
                Exit Sub
            End Try

            ' Display some of the obtained property values
            ' The production code should also check for the .Exception first, before getting .Value
            Console.WriteLine("propertyValueDictionary[DAPropertyId.AccessRights].Value: {0}", propertyValueDictionary(DAPropertyIds.AccessRights).Value)
            Console.WriteLine("propertyValueDictionary[DAPropertyId.DataType].Value: {0}", propertyValueDictionary(DAPropertyIds.DataType).Value)
            Console.WriteLine("propertyValueDictionary[DAPropertyId.Timestamp].Value: {0}", propertyValueDictionary(DAPropertyIds.Timestamp).Value)
        End Sub
    End Class
End Namespace
# This example shows how to obtain a dictionary of OPC property values for an OPC item, and extract property values.
#
# 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 OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.DataAccess.Extensions import *
from OpcLabs.EasyOpc.OperationModel import *


# Instantiate the client object.
client = EasyDAClient()

# Get dictionary of property values, for all well-known properties.
try:
    propertyValueDictionary = IEasyDAClientExtension2.GetPropertyValueDictionary(client,
        '', 'OPCLabs.KitServer.2', 'Simulation.Random')
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message)
    exit()

# Display some of the obtained property values.
# The production code should also check for the .Exception first, before getting .Value
print('propertyValueDictionary[DAPropertyId.AccessRights].Value: ',
    propertyValueDictionary.get_Item(DAPropertyId(DAPropertyIds.AccessRights)).Value, sep='')
print('propertyValueDictionary[DAPropertyId.DataType].Value: ',
    propertyValueDictionary.get_Item(DAPropertyId(DAPropertyIds.DataType)).Value, sep='')
print('propertyValueDictionary[DAPropertyId.Timestamp].Value: ',
    propertyValueDictionary.get_Item(DAPropertyId(DAPropertyIds.Timestamp)).Value, sep='')

print('Finished.')
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