' This example shows how to subscribe to changes of a single monitored item and display the value of the item with each change.

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Friend Class SubscribeDataChange
        Public Shared Sub Overload1()

            ' Define which server we will work with.
            Dim endpointDescriptor As UAEndpointDescriptor =
                    "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 and hook events
            Dim client = New EasyUAClient()
            AddHandler client.DataChangeNotification, AddressOf client_DataChangeNotification

            Console.WriteLine("Subscribing...")
            client.SubscribeDataChange(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853", 1000)

            Console.WriteLine("Processing monitored item changed events for 10 seconds...")
            Threading.Thread.Sleep(10 * 1000)

            Console.WriteLine("Unsubscribing...")
            client.UnsubscribeAllMonitoredItems()

            Console.WriteLine("Waiting for 5 seconds...")
            Threading.Thread.Sleep(5 * 1000)
        End Sub

        Private Shared Sub client_DataChangeNotification(ByVal sender As Object, ByVal e As EasyUADataChangeNotificationEventArgs)
            ' Display value
            If e.Succeeded Then
                Console.WriteLine("Value: {0}", e.AttributeData.Value)
            Else
                Console.WriteLine("*** Failure: {0}", e.ErrorMessageBrief)
            End If
        End Sub
    End Class
End Namespace

' This example shows how to subscribe to changes of multiple monitored items and display the value of the monitored item with 
' each change.

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Partial Friend Class SubscribeMultipleMonitoredItems
        Public Shared Sub Main1()

            ' Define which server we will work with.
            Dim endpointDescriptor As UAEndpointDescriptor =
                    "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 and hook events
            Dim client = New EasyUAClient()
            AddHandler client.DataChangeNotification, AddressOf client_DataChangeNotification

            Console.WriteLine("Subscribing...")
            client.SubscribeMultipleMonitoredItems(New EasyUAMonitoredItemArguments() _
                { _
                    New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10845", 1000), _
                    New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853", 1000), _
                    New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10855", 1000) _
                } _
             )

            Console.WriteLine("Processing monitored item changed events for 10 seconds...")
            Threading.Thread.Sleep(10 * 1000)

            Console.WriteLine("Unsubscribing...")
            client.UnsubscribeAllMonitoredItems()

            Console.WriteLine("Waiting for 5 seconds...")
            Threading.Thread.Sleep(5 * 1000)
        End Sub

        Private Shared Sub client_DataChangeNotification(ByVal sender As Object, ByVal e As EasyUADataChangeNotificationEventArgs)
            ' Display value
            If e.Succeeded Then
                Console.WriteLine("{0}: {1}", e.Arguments.NodeDescriptor, e.AttributeData.Value)
            Else
                Console.WriteLine("{0} *** Failure: {1}", e.Arguments.NodeDescriptor, e.ErrorMessageBrief)
            End If
        End Sub
    End Class
End Namespace

' This example shows how to subscribe to changes of multiple monitored items
' and display each change, identifying the different subscriptions by an
' integer.

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Partial Friend Class SubscribeMultipleMonitoredItems
        Public Shared Sub StateAsInteger()

            ' Define which server we will work with.
            Dim endpointDescriptor As UAEndpointDescriptor =
                    "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 and hook events
            Dim client = New EasyUAClient()
            AddHandler client.DataChangeNotification, AddressOf ClientOnDataChangeNotification_StateAsInteger

            Console.WriteLine("Subscribing...")
            Dim handleArray() As Integer = client.SubscribeMultipleMonitoredItems(New EasyUAMonitoredItemArguments() _
                { _
                    New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, _
                        "nsu=http://test.org/UA/Data/ ;i=10845", 1000) _
                         With {.State = 1}, _
                    New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, _
                        "nsu=http://test.org/UA/Data/ ;i=10853", 1000) _
                         With {.State = 2}, _
                    New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, _
                        "nsu=http://test.org/UA/Data/ ;i=10855", 1000) _
                        With {.State = 3} _
                } _
             ) ' An integer we have chosen to identify the subscription

            For i As Integer = 0 To handleArray.Length - 1
                Console.WriteLine("handleArray[{0}]: {1}", i, handleArray(i))
            Next i

            Console.WriteLine("Processing monitored item changed events for 10 seconds...")
            Threading.Thread.Sleep(10 * 1000)

            Console.WriteLine("Unsubscribing...")
            client.UnsubscribeAllMonitoredItems()

            Console.WriteLine("Waiting for 5 seconds...")
            Threading.Thread.Sleep(5 * 1000)

            Console.WriteLine("Finished.")
        End Sub

        Private Shared Sub ClientOnDataChangeNotification_StateAsInteger(ByVal sender As Object, ByVal eventArgs As EasyUADataChangeNotificationEventArgs)
            ' Obtain the integer state we have passed in.
            Dim stateAsInteger As Integer = CInt(eventArgs.Arguments.State)

            ' Display the data
            If eventArgs.Succeeded Then
                Console.WriteLine("{0}: {1}", stateAsInteger, eventArgs.AttributeData)
            Else
                Console.WriteLine("{0} *** Failure: {1}", stateAsInteger, eventArgs.ErrorMessageBrief)
            End If
        End Sub
    End Class
End Namespace

' This example shows how to subscribe to changes of multiple monitored items
' and display each change, identifying the different subscriptions by an
' object.

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Partial Friend Class SubscribeMultipleMonitoredItems
        Class CustomObject
            Public Sub New(ByVal name As String)
                _Name = name
            End Sub
            Public ReadOnly Property Name As String
                Get
                    Return _Name
                End Get
            End Property
            Private ReadOnly _Name As String
        End Class

        Public Shared Sub StateAsObject()

            ' Define which server we will work with.
            Dim endpointDescriptor As UAEndpointDescriptor =
                    "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 and hook events
            Dim client = New EasyUAClient()
            AddHandler client.DataChangeNotification, AddressOf ClientOnDataChangeNotification_StateAsObject

            Console.WriteLine("Subscribing...")
            Dim handleArray() As Integer = client.SubscribeMultipleMonitoredItems(New EasyUAMonitoredItemArguments() _
                { _
                    New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, _
                        "nsu=http://test.org/UA/Data/ ;i=10845", 1000) _
                         With {.State = New CustomObject("First")}, _
                    New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, _
                        "nsu=http://test.org/UA/Data/ ;i=10853", 1000) _
                         With {.State = New CustomObject("Second")}, _
                    New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, _
                        "nsu=http://test.org/UA/Data/ ;i=10855", 1000) _
                        With {.State = New CustomObject("Third")} _
                } _
            ) ' A custom object that corresponds to the subscription

            For i As Integer = 0 To handleArray.Length - 1
                Console.WriteLine("handleArray[{0}]: {1}", i, handleArray(i))
            Next i

            Console.WriteLine("Processing monitored item changed events for 10 seconds...")
            Threading.Thread.Sleep(10 * 1000)

            Console.WriteLine("Unsubscribing...")
            client.UnsubscribeAllMonitoredItems()

            Console.WriteLine("Waiting for 5 seconds...")
            Threading.Thread.Sleep(5 * 1000)

            Console.WriteLine("Finished.")
        End Sub

        Private Shared Sub ClientOnDataChangeNotification_StateAsObject(ByVal sender As Object, ByVal eventArgs As EasyUADataChangeNotificationEventArgs)
            ' Obtain the custom object we have passed in.
            Dim stateAsObject As CustomObject = CType(eventArgs.Arguments.State, CustomObject)

            ' Display the data
            If eventArgs.Succeeded Then
                Console.WriteLine("{0}: {1}", stateAsObject.Name, eventArgs.AttributeData)
            Else
                Console.WriteLine("{0} *** Failure: {1}", stateAsObject.Name, eventArgs.ErrorMessageBrief)
            End If
        End Sub
    End Class
End Namespace

' This example shows how to subscribe to changes of all data variables under a specified object in OPC UA address space.

Imports System.Linq
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.AddressSpace
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Partial Friend Class SubscribeMultipleMonitoredItems
        Public Shared Sub AllInObject()

            ' Define which server we will work with.
            Dim endpointDescriptor As UAEndpointDescriptor =
                "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 and hook events
            Dim client = New EasyUAClient()
            AddHandler client.DataChangeNotification, AddressOf client_DataChangeNotification_AllInObject

            ' Obtain variables under "Scalar" node
            Console.WriteLine("Subscribing...")
            Dim nodeElementCollection As UANodeElementCollection
            Try
                nodeElementCollection = client.BrowseDataVariables(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;ns=2;i=10787")
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try

            ' Create array with monitored item arguments

            Dim monitoredItemArgumentsArray() As EasyUAMonitoredItemArguments = nodeElementCollection.Select(Function(element) New EasyUAMonitoredItemArguments(Nothing, endpointDescriptor, element)).ToArray()

            Console.WriteLine("Subscribing...")
            client.SubscribeMultipleMonitoredItems(monitoredItemArgumentsArray)

            Console.WriteLine("Processing monitored item changed events for 20 seconds...")
            Threading.Thread.Sleep(20 * 1000)

            Console.WriteLine("Unsubscribing...")
            client.UnsubscribeAllMonitoredItems()

            Console.WriteLine("Waiting for 5 seconds...")
            Threading.Thread.Sleep(5 * 1000)
        End Sub

        Private Shared Sub client_DataChangeNotification_AllInObject(ByVal sender As Object, ByVal e As EasyUADataChangeNotificationEventArgs)
            ' Display value
            If e.Succeeded Then
                Console.WriteLine("{0}: {1}", e.Arguments.NodeDescriptor, e.AttributeData.Value)
            Else
                Console.WriteLine("{0} *** Failure: {1}", e.Arguments.NodeDescriptor, e.ErrorMessageBrief)
            End If
        End Sub
    End Class
End Namespace

' Shows how to subscribe to complex data with OPC UA Complex Data plug-in.

Imports System
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace ComplexData._EasyUAClient

    Friend Class SubscribeDataChange

        Public Shared Sub Main1()

            ' Define which server we will work with.
            Dim endpointDescriptor As UAEndpointDescriptor =
                    "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/"

            ' Define which node we will work with.
            Dim nodeDescriptor As UANodeDescriptor = _
                "nsu=http://test.org/UA/Data/ ;i=10867"  ' [ObjectsFolder]/Data.Dynamic.Scalar.StructureValue

            ' Instantiate the client object and hook the event handler.
            Dim client = New EasyUAClient
            AddHandler client.DataChangeNotification, AddressOf client_DataChangeNotification

            ' Subscribe to a node which returns complex data. This is done in the same way as regular subscribes - just 
            ' the data returned is different.
            Console.WriteLine("Subscribing...")
            client.SubscribeDataChange(endpointDescriptor, nodeDescriptor, samplingInterval:=1000)

            Console.WriteLine("Processing data change events for 20 seconds...")
            Threading.Thread.Sleep((20 * 1000))

            Console.WriteLine("Unsubscribing...")
            client.UnsubscribeAllMonitoredItems()

            Console.WriteLine("Waiting for 5 seconds...")
            Threading.Thread.Sleep((5 * 1000))

            ' Unhook the event handler.
            RemoveHandler client.DataChangeNotification, AddressOf client_DataChangeNotification


            ' Example output:
            '
            'Subscribing...
            'Processing data change events for 20 seconds...
            '(ScalarValueDataType) structured
            '(ArrayValueDataType) structured
            '(ArrayValueDataType) structured
            '(ArrayValueDataType) structured
            '(ArrayValueDataType) structured
            '(ArrayValueDataType) structured
            '(ArrayValueDataType) structured
            '(ArrayValueDataType) structured
            '(ScalarValueDataType) structured
            '(ScalarValueDataType) structured
            '(ArrayValueDataType) structured
            '(ArrayValueDataType) structured
            '(ScalarValueDataType) structured
            '(ArrayValueDataType) structured
            '(ArrayValueDataType) structured
            '(ScalarValueDataType) structured
            '(ScalarValueDataType) structured
            '(ScalarValueDataType) structured
            'Unsubscribing...
            'Waiting for 5 seconds...
        End Sub

        Private Shared Sub client_DataChangeNotification(sender As Object, e As EasyUADataChangeNotificationEventArgs)
            ' Display value
            If e.Succeeded Then
                Console.WriteLine("Value: {0}", e.AttributeData.Value)
            Else
                Console.WriteLine("*** Failure: {0}", e.ErrorMessageBrief)
            End If

            ' For processing the internals of the data, refer to examples for GenericData and DataType classes.
        End Sub
    End Class
End Namespace