GetMultiplePropertyValues(IEasyDAClient,ServerDescriptor,DANodeDescriptor,DAPropertyId[]) Method

Gets values of multiple OPC properties, using descriptor object for the OPC server, and a node descriptor.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function GetMultiplePropertyValues( _
   ByVal client As IEasyDAClient, _
   ByVal serverDescriptor As ServerDescriptor, _
   ByVal nodeDescriptor As DANodeDescriptor, _
   ByVal propertyIdArray() As DAPropertyId _
) As ValueResult()

'Usage
 
Dim client As IEasyDAClient
Dim serverDescriptor As ServerDescriptor
Dim nodeDescriptor As DANodeDescriptor
Dim propertyIdArray() As DAPropertyId
Dim value() As ValueResult
 
value = IEasyDAClientExtension.GetMultiplePropertyValues(client, serverDescriptor, nodeDescriptor, propertyIdArray)

[Extension()]
[NotNull()]
public static ValueResult[] GetMultiplePropertyValues( 
   IEasyDAClient client,
   ServerDescriptor serverDescriptor,
   DANodeDescriptor nodeDescriptor,
   DAPropertyId[] propertyIdArray
)

[Extension()]
[NotNull()]
public:
static array<ValueResult^>^ GetMultiplePropertyValues( 
   IEasyDAClient^ client,
   ServerDescriptor^ serverDescriptor,
   DANodeDescriptor^ nodeDescriptor,
   array<DAPropertyId^>^ propertyIdArray
)

Parameters

client

The client object that will perform the operation.

This is typically the EasyDAClient object.

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

serverDescriptor

The OPC server involved in the operation.

Because the OpcLabs.EasyOpc.ServerDescriptor has an implicit conversion from System.Guid, System.String and OpcLabs.EasyOpc.ServerElement, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a GUID (representing the CLSID of the server), a string (representing the so-called OPC server descriptor string, such as a ProgID or the URL of the server), or a OpcLabs.EasyOpc.ServerElement object (result from OPC browsing), in place of this parameter, and the corresponding OPC server descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the FromGuid, FromString or FromServerElement static method instead.

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

nodeDescriptor

The descriptor of the OPC node involved in the operation.

Because the DANodeDescriptor has an implicit conversion from System.String and OpcLabs.EasyOpc.DataAccess.AddressSpace.DANodeElement, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a string (representing the qualified name of the node), or a OpcLabs.EasyOpc.DataAccess.AddressSpace.DANodeElement object (result from OPC browsing), in place of this parameter, and the corresponding OPC DA node descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the FromString or FromDANodeElement static method instead.

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

propertyIdArray

Array of Property IDs being obtained

Because the DAPropertyId has an implicit conversion from System.Int64 and DAPropertyIds, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a long integer (representing the numerical value of the access rights), or an element of the DAPropertyIds enumeration in place of this parameter, and the corresponding Property Id specification will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the DAPropertyId Constructor(Int64) or DAPropertyId Constructor(DAPropertyIds) constructor instead.

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

The individual elements of the parameter value cannot be null (Nothing in Visual Basic).

Return Value

The function returns an array of OpcLabs.BaseLib.OperationModel.ValueResult objects. The indices of elements in the output array are the same as those in the input array.

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

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

Exceptions

Exception Description

Exception	Description
System.ArgumentNullException	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.

System.ArgumentNullException

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

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

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.

This is a multiple-operation method. In a properly written program, it does not throw any exceptions. You should therefore not put try/catch statements or similar constructs around calls to this method. The only exceptions thrown by this method are for usage errors, i.e. when your code violates the usage contract of the method, such as passing in invalid arguments or calling the method when the state of the object does not allow it. Any operation-related errors (i.e. errors that depend on external conditions that your code cannot reliably check) are indicated in the result objects returned by the method. For more information, see Multiple-operation Methods and Do not catch any exceptions with asynchronous or multiple-operation methods.

Requirements

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

Reference

IEasyDAClientExtension Class
IEasyDAClientExtension Members
Overload List

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