'Declaration
 
<NotNullAttribute()>
Public Overloads Shared Function Create(Of TValue)( _
   ByVal serverDescriptor As ServerDescriptor, _
   ByVal itemDescriptor As DAItemDescriptor, _
   ByVal groupParameters As DAGroupParameters, _
   Optional ByVal state As Object _
) As DAItemChangedObservable(Of TValue)

'Usage
 
Dim serverDescriptor As ServerDescriptor
Dim itemDescriptor As DAItemDescriptor
Dim groupParameters As DAGroupParameters
Dim state As Object
Dim value As DAItemChangedObservable(Of TValue)
 
value = DAItemChangedObservable.Create(Of TValue)(serverDescriptor, itemDescriptor, groupParameters, state)

[NotNull()]
public static DAItemChangedObservable<TValue> Create<TValue>( 
   ServerDescriptor serverDescriptor,
   DAItemDescriptor itemDescriptor,
   DAGroupParameters groupParameters,
   object state
)

[NotNull()]
public:
static DAItemChangedObservable<TValue^>^ Creategeneric<typename TValue>
( 
   ServerDescriptor^ serverDescriptor,
   DAItemDescriptor^ itemDescriptor,
   DAGroupParameters^ groupParameters,
   Object^ state
) 

Parameters

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 OpcLabs.EasyOpc.ServerDescriptor.FromGuid, OpcLabs.EasyOpc.ServerDescriptor.FromString or OpcLabs.EasyOpc.ServerDescriptor.FromServerElement static method instead.

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

itemDescriptor

The OPC item to be subscribed to.

Because the OpcLabs.EasyOpc.DataAccess.DAItemDescriptor 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 item descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the OpcLabs.EasyOpc.DataAccess.DAItemDescriptor.FromString or OpcLabs.EasyOpc.DataAccess.DAItemDescriptor.FromDANodeElement static method instead.

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

groupParameters

An object containing subscription parameters, such as the requested update rate.

Because the OpcLabs.EasyOpc.DataAccess.DAGroupParameters has an implicit conversion from System.Int32, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use an integer (representing the requested update rate in milliseconds) in place of this parameter, and the corresponding OPC DA group parameters object will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the OpcLabs.EasyOpc.DataAccess.DAGroupParameters.DAGroupParameters Constructor(Int32) constructor instead.

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

state

The state object (can be any object supplied by your code); available in notifications.

The value of this parameter can be null (Nothing in Visual Basic).

Type Parameters

TValue

Return Value

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