Reference

OpcVariableNode Members

Type

OpcVariableNode

Namespace

Opc.UaFx

Assembly

Opc.UaFx.Advanced.dll

Package

Opc.UaFx.Advanced v2.59.0

Inherits members from OpcInstanceNode, OpcNode.

Constructors

OpcVariableNode

protected · 16 overloads

Overload	Description
OpcVariableNode(OpcName)protected	Initializes a new instance of the OpcVariableNode class accessible by the name specified.
OpcVariableNode(OpcNodeModel, OpcName)protected · since v2.50	Initializes a new instance of the OpcVariableNode class accessible by the name specified.
OpcVariableNode(OpcName, object)protected	Initializes a new instance of the OpcVariableNode class accessible by the name specified with the initial value given by value.
OpcVariableNode(OpcNodeModel, OpcName, object)protected · since v2.50	Initializes a new instance of the OpcVariableNode class accessible by the name specified with the initial value given by value.
OpcVariableNode(OpcName, OpcNodeId)protected	Initializes a new instance of the OpcVariableNode class accessible by the name and id specified.
OpcVariableNode(OpcNodeModel, OpcName, OpcNodeId)protected · since v2.50	Initializes a new instance of the OpcVariableNode class accessible by the name and id specified.
OpcVariableNode(OpcName, OpcNodeId, object)protected	Initializes a new instance of the OpcVariableNode class accessible by the name and id specified with the initial value given by value.
OpcVariableNode(OpcNodeModel, OpcName, OpcNodeId, object)protected · since v2.50	Initializes a new instance of the OpcVariableNode class accessible by the name and id specified with the initial value given by value.
OpcVariableNode(IOpcNode, OpcName)protected	Initializes a new instance of the OpcVariableNode class accessible by the name specified as a child node of the parent node given.
OpcVariableNode(OpcNodeModel, IOpcNode, OpcName)protected · since v2.50	Initializes a new instance of the OpcVariableNode class accessible by the name specified as a child node of the parent node given.
OpcVariableNode(IOpcNode, OpcName, object)protected	Initializes a new instance of the OpcVariableNode class accessible by the name specified with the initial value defined by value as a child node of the parent node given.
OpcVariableNode(OpcNodeModel, IOpcNode, OpcName, object)protected · since v2.50	Initializes a new instance of the OpcVariableNode class accessible by the name specified with the initial value defined by value as a child node of the parent node given.
OpcVariableNode(IOpcNode, OpcName, OpcNodeId)protected	Initializes a new instance of the OpcVariableNode class accessible by the name and id specified as a child node of the parent node given.
OpcVariableNode(OpcNodeModel, IOpcNode, OpcName, OpcNodeId)protected · since v2.50	Initializes a new instance of the OpcVariableNode class accessible by the name and id specified as a child node of the parent node given.
OpcVariableNode(IOpcNode, OpcName, OpcNodeId, object)protected	Initializes a new instance of the OpcVariableNode class accessible by the name and id specified with the initial value defined by value as a child node of the parent node given.
OpcVariableNode(OpcNodeModel, IOpcNode, OpcName, OpcNodeId, object)protected · since v2.50	Initializes a new instance of the OpcVariableNode class accessible by the name and id specified with the initial value defined by value as a child node of the parent node given.

OpcVariableNode(OpcName)

protected

Initializes a new instance of the OpcVariableNode class accessible by the name specified.

protected OpcVariableNode(OpcName name)

Protected Sub New(name As OpcName)

Parameters

Name	Type	Description
name	OpcName	The OpcName through that the new variable node can be accessed.

OpcVariableNode(OpcNodeModel, OpcName)

protected · since v2.50

Initializes a new instance of the OpcVariableNode class accessible by the name specified.

protected OpcVariableNode(OpcNodeModel model, OpcName name)

Protected Sub New(model As OpcNodeModel, name As OpcName)

Parameters

Name	Type	Description
model	OpcNodeModel	The OpcNodeModel which defines the modelling directives for the new node or a null reference (Nothing in Visual Basic) if there are no directives are to be applied to the node.
name	OpcName	The OpcName through that the new variable node can be accessed.

OpcVariableNode(OpcName, object)

protected

Initializes a new instance of the OpcVariableNode class accessible by the name specified with the initial value given by value.

protected OpcVariableNode(OpcName name, object value)

Protected Sub New(name As OpcName, value As Object)

Parameters

Name	Type	Description
name	OpcName	The OpcName through that the new variable node can be accessed.
value	Object	The initial value of the new variable node.

OpcVariableNode(OpcNodeModel, OpcName, object)

protected · since v2.50

Initializes a new instance of the OpcVariableNode class accessible by the name specified with the initial value given by value.

protected OpcVariableNode(OpcNodeModel model, OpcName name, object value)

Protected Sub New(model As OpcNodeModel, name As OpcName, value As Object)

Parameters

Name	Type	Description
model	OpcNodeModel	The OpcNodeModel which defines the modelling directives for the new node or a null reference (Nothing in Visual Basic) if there are no directives are to be applied to the node.
name	OpcName	The OpcName through that the new variable node can be accessed.
value	Object	The initial value of the new variable node.

OpcVariableNode(OpcName, OpcNodeId)

protected

Initializes a new instance of the OpcVariableNode class accessible by the name and id specified.

protected OpcVariableNode(OpcName name, OpcNodeId id)

Protected Sub New(name As OpcName, id As OpcNodeId)

Parameters

Name	Type	Description
name	OpcName	The OpcName through that the new variable node can be accessed.
id	OpcNodeId	The OpcNodeId through that the new variable node can be identified and accessed.

OpcVariableNode(OpcNodeModel, OpcName, OpcNodeId)

protected · since v2.50

Initializes a new instance of the OpcVariableNode class accessible by the name and id specified.

protected OpcVariableNode(OpcNodeModel model, OpcName name, OpcNodeId id)

Protected Sub New(model As OpcNodeModel, name As OpcName, id As OpcNodeId)

Parameters

Name	Type	Description
model	OpcNodeModel	The OpcNodeModel which defines the modelling directives for the new node or a null reference (Nothing in Visual Basic) if there are no directives are to be applied to the node.
name	OpcName	The OpcName through that the new variable node can be accessed.
id	OpcNodeId	The OpcNodeId through that the new variable node can be identified and accessed.

OpcVariableNode(OpcName, OpcNodeId, object)

protected

Initializes a new instance of the OpcVariableNode class accessible by the name and id specified with the initial value given by value.

protected OpcVariableNode(OpcName name, OpcNodeId id, object value)

Protected Sub New(name As OpcName, id As OpcNodeId, value As Object)

Parameters

Name	Type	Description
name	OpcName	The OpcName through that the new variable node can be accessed.
id	OpcNodeId	The OpcNodeId through that the new variable node can be identified and accessed.
value	Object	The initial value of the new variable node.

OpcVariableNode(OpcNodeModel, OpcName, OpcNodeId, object)

protected · since v2.50

Initializes a new instance of the OpcVariableNode class accessible by the name and id specified with the initial value given by value.

protected OpcVariableNode(
    OpcNodeModel model,
    OpcName name,
    OpcNodeId id,
    object value)

Protected Sub New(
    model As OpcNodeModel,
    name As OpcName,
    id As OpcNodeId,
    value As Object)

Parameters

Name	Type	Description
model	OpcNodeModel	The OpcNodeModel which defines the modelling directives for the new node or a null reference (Nothing in Visual Basic) if there are no directives are to be applied to the node.
name	OpcName	The OpcName through that the new variable node can be accessed.
id	OpcNodeId	The OpcNodeId through that the new variable node can be identified and accessed.
value	Object	The initial value of the new variable node.

OpcVariableNode(IOpcNode, OpcName)

protected

Initializes a new instance of the OpcVariableNode class accessible by the name specified as a child node of the parent node given.

protected OpcVariableNode(IOpcNode parent, OpcName name)

Protected Sub New(parent As IOpcNode, name As OpcName)

Parameters

Name	Type	Description
parent	IOpcNode	The IOpcNode used as the parent node or a null reference (Nothing in Visual Basic) in the case there is no parent node available.
name	OpcName	The OpcName through that the new variable node can be accessed.

OpcVariableNode(OpcNodeModel, IOpcNode, OpcName)

protected · since v2.50

Initializes a new instance of the OpcVariableNode class accessible by the name specified as a child node of the parent node given.

protected OpcVariableNode(OpcNodeModel model, IOpcNode parent, OpcName name)

Protected Sub New(model As OpcNodeModel, parent As IOpcNode, name As OpcName)

Parameters

Name	Type	Description
model	OpcNodeModel	The OpcNodeModel which defines the modelling directives for the new node or a null reference (Nothing in Visual Basic) if there are no directives are to be applied to the node.
parent	IOpcNode	The IOpcNode used as the parent node or a null reference (Nothing in Visual Basic) in the case there is no parent node available.
name	OpcName	The OpcName through that the new variable node can be accessed.

OpcVariableNode(IOpcNode, OpcName, object)

protected

Initializes a new instance of the OpcVariableNode class accessible by the name specified with the initial value defined by value as a child node of the parent node given.

protected OpcVariableNode(IOpcNode parent, OpcName name, object value)

Protected Sub New(parent As IOpcNode, name As OpcName, value As Object)

Parameters

Name	Type	Description
parent	IOpcNode	The IOpcNode used as the parent node or a null reference (Nothing in Visual Basic) in the case there is no parent node available.
name	OpcName	The OpcName through that the new variable node can be accessed.
value	Object	The initial value of the new variable node.

OpcVariableNode(OpcNodeModel, IOpcNode, OpcName, object)

protected · since v2.50

Initializes a new instance of the OpcVariableNode class accessible by the name specified with the initial value defined by value as a child node of the parent node given.

protected OpcVariableNode(
    OpcNodeModel model,
    IOpcNode parent,
    OpcName name,
    object value)

Protected Sub New(
    model As OpcNodeModel,
    parent As IOpcNode,
    name As OpcName,
    value As Object)

Parameters

Name	Type	Description
model	OpcNodeModel	The OpcNodeModel which defines the modelling directives for the new node or a null reference (Nothing in Visual Basic) if there are no directives are to be applied to the node.
parent	IOpcNode	The IOpcNode used as the parent node or a null reference (Nothing in Visual Basic) in the case there is no parent node available.
name	OpcName	The OpcName through that the new variable node can be accessed.
value	Object	The initial value of the new variable node.

OpcVariableNode(IOpcNode, OpcName, OpcNodeId)

protected

Initializes a new instance of the OpcVariableNode class accessible by the name and id specified as a child node of the parent node given.

protected OpcVariableNode(IOpcNode parent, OpcName name, OpcNodeId id)

Protected Sub New(parent As IOpcNode, name As OpcName, id As OpcNodeId)

Parameters

Name	Type	Description
parent	IOpcNode	The IOpcNode used as the parent node or a null reference (Nothing in Visual Basic) in the case there is no parent node available.
name	OpcName	The OpcName through that the new variable node can be accessed.
id	OpcNodeId	The OpcNodeId through that the new variable node can be identified and accessed.

OpcVariableNode(OpcNodeModel, IOpcNode, OpcName, OpcNodeId)

protected · since v2.50

Initializes a new instance of the OpcVariableNode class accessible by the name and id specified as a child node of the parent node given.

protected OpcVariableNode(
    OpcNodeModel model,
    IOpcNode parent,
    OpcName name,
    OpcNodeId id)

Protected Sub New(
    model As OpcNodeModel,
    parent As IOpcNode,
    name As OpcName,
    id As OpcNodeId)

Parameters

Name	Type	Description
model	OpcNodeModel	The OpcNodeModel which defines the modelling directives for the new node or a null reference (Nothing in Visual Basic) if there are no directives are to be applied to the node.
parent	IOpcNode	The IOpcNode used as the parent node or a null reference (Nothing in Visual Basic) in the case there is no parent node available.
name	OpcName	The OpcName through that the new variable node can be accessed.
id	OpcNodeId	The OpcNodeId through that the new variable node can be identified and accessed.

OpcVariableNode(IOpcNode, OpcName, OpcNodeId, object)

protected

Initializes a new instance of the OpcVariableNode class accessible by the name and id specified with the initial value defined by value as a child node of the parent node given.

protected OpcVariableNode(
    IOpcNode parent,
    OpcName name,
    OpcNodeId id,
    object value)

Protected Sub New(
    parent As IOpcNode,
    name As OpcName,
    id As OpcNodeId,
    value As Object)

Parameters

Name	Type	Description
parent	IOpcNode	The IOpcNode used as the parent node or a null reference (Nothing in Visual Basic) in the case there is no parent node available.
name	OpcName	The OpcName through that the new variable node can be accessed.
id	OpcNodeId	The OpcNodeId through that the new variable node can be identified and accessed.
value	Object	The initial value of the new variable node.

OpcVariableNode(OpcNodeModel, IOpcNode, OpcName, OpcNodeId, object)

protected · since v2.50

Initializes a new instance of the OpcVariableNode class accessible by the name and id specified with the initial value defined by value as a child node of the parent node given.

protected OpcVariableNode(
    OpcNodeModel model,
    IOpcNode parent,
    OpcName name,
    OpcNodeId id,
    object value)

Protected Sub New(
    model As OpcNodeModel,
    parent As IOpcNode,
    name As OpcName,
    id As OpcNodeId,
    value As Object)

Parameters

Name	Type	Description
model	OpcNodeModel	The OpcNodeModel which defines the modelling directives for the new node or a null reference (Nothing in Visual Basic) if there are no directives are to be applied to the node.
parent	IOpcNode	The IOpcNode used as the parent node or a null reference (Nothing in Visual Basic) in the case there is no parent node available.
name	OpcName	The OpcName through that the new variable node can be accessed.
id	OpcNodeId	The OpcNodeId through that the new variable node can be identified and accessed.
value	Object	The initial value of the new variable node.

Properties

AccessLevel

Gets or sets a value which indicates in which ways the Value attribute of the variable node can be accessed (read/write) and if it provides current and/or historic data.

public OpcAccessLevel AccessLevel { get; set; }

Public Property AccessLevel As OpcAccessLevel

Property value

OpcAccessLevel

One of the members defined by the OpcAccessLevel enumeration. Which is used to indicate the ways the Value attribute of the current OpcVariableNode can be accessed (read/write) and if it provides current and/or historic data. The AccessLevel does not take any user access rights into account, although the variable is writable this may be restricted to a certain user / user group.

Implements

AccessLevel

ArrayDimensions

since v2.9

Gets the number/lengths of dimensions for an array Value with one or more fixed dimensions.

public OpcArrayDimensions ArrayDimensions { get; set; }

Public Property ArrayDimensions As OpcArrayDimensions

Property value

OpcArrayDimensions

An instance of the OpcArrayDimensions class which offers the number/lengths of dimensions for an array Value.

Implements

ArrayDimensions

Remarks

If the ValueRank does not identify an array of a specific dimension (i.e. ValueRank <= 0) ArrayDimensions can be a null reference (Nothing in Visual Basic).

A node created with an array as its initial value takes the lengths of that array as its array dimensions, which states them to clients as the maximum lengths (OPC 10000-3). The server does not enforce them, and they are not adjusted when the value changes. If the length of the array varies, state a length of 0 for each dimension, which means that the length is not known, for example new OpcArrayDimensions(0).

DataType

virtual

Gets or sets a value which defines a pre-defined used DataTypeId as one of the members defined by the OpcDataType enumeration to simplify querying standard data types.

public virtual OpcDataType DataType { get; set; }

Public Overridable Property DataType As OpcDataType

Property value

OpcDataType

One of the members defined by the OpcDataType enumeration.

DataTypeId

Gets or stets the identifier which identifies the node that defines the type of data represented by the variable node.

public OpcNodeId DataTypeId { get; set; }

Public Property DataTypeId As OpcNodeId

Property value

OpcNodeId

The OpcNodeId of the data type node which defines the type of data represented by the variable node. These data type node defines either a simple or a complex type of data accessible by the Value property.

Implements

DataTypeId

DefaultReferenceTypeId

protected · override

Gets the default identifier which identifies the type that defines the underlying node reference within this OpcInstanceNode is referenced by its parent node.

protected override OpcNodeId DefaultReferenceTypeId { get; }

Protected Overrides ReadOnly Property DefaultReferenceTypeId As OpcNodeId

Property value

OpcNodeId

The OpcNodeId of the reference wihin this OpcInstanceNode is referenced. These reference defines the typical behaviour of an instance node and its role in the address space regarding its parent. If there exists no specific reference type a null reference (Nothing in Visual Basic).

Overrides

DefaultReferenceTypeId

DefaultTypeDefinitionId

protected · override

Gets the default identifier which identifies the node that defines the underlying node type from that this OpcInstanceNode has been created.

protected override OpcNodeId DefaultTypeDefinitionId { get; }

Protected Overrides ReadOnly Property DefaultTypeDefinitionId As OpcNodeId

Property value

OpcNodeId

The OpcNodeId of the type node from that this OpcInstanceNode has been created from. These type node defines the typical structure of an instance node of its type definition. If there exists no specific type definition node a null reference (Nothing in Visual Basic).

Overrides

DefaultTypeDefinitionId

HistoryConfiguration

public OpcHistoryConfigurationNode HistoryConfiguration { get; }

Public ReadOnly Property HistoryConfiguration As OpcHistoryConfigurationNode

Property value

OpcHistoryConfigurationNode

IsArray

since v2.18

Gets a value indicating whether the Value of the OpcVariableNode represented is an array.

public bool IsArray { get; }

Public ReadOnly Property IsArray As Boolean

Property value

Boolean

The value true if the Value of the OpcVariableNode represented is an array; otherwise the false.

IsHistorizing

Gets or sets a value indiciating whether there exists an value history for the node.

public bool IsHistorizing { get; set; }

Public Property IsHistorizing As Boolean

Property value

Boolean

The value true if a value history exists; otherwise the value false. The default value is false.

ReadAccessLevelCallback

public OpcReadAttributeValueCallback<OpcAccessLevel> ReadAccessLevelCallback { get; set; }

Public Property ReadAccessLevelCallback As OpcReadAttributeValueCallback(Of OpcAccessLevel)

Property value

OpcReadAttributeValueCallback<OpcAccessLevel>

ReadArrayDimensionsCallback

since v2.9

public OpcReadAttributeValueCallback<OpcArrayDimensions> ReadArrayDimensionsCallback { get; set; }

Public Property ReadArrayDimensionsCallback As OpcReadAttributeValueCallback(Of OpcArrayDimensions)

Property value

OpcReadAttributeValueCallback<OpcArrayDimensions>

ReadDataTypeCallback

public OpcReadAttributeValueCallback<OpcNodeId> ReadDataTypeCallback { get; set; }

Public Property ReadDataTypeCallback As OpcReadAttributeValueCallback(Of OpcNodeId)

Property value

OpcReadAttributeValueCallback<OpcNodeId>

ReadIsHistorizingCallback

public OpcReadAttributeValueCallback<bool> ReadIsHistorizingCallback { get; set; }

Public Property ReadIsHistorizingCallback As OpcReadAttributeValueCallback(Of Boolean)

Property value

OpcReadAttributeValueCallback<Boolean>

ReadUserAccessLevelCallback

public OpcReadAttributeValueCallback<OpcAccessLevel> ReadUserAccessLevelCallback { get; set; }

Public Property ReadUserAccessLevelCallback As OpcReadAttributeValueCallback(Of OpcAccessLevel)

Property value

OpcReadAttributeValueCallback<OpcAccessLevel>

ReadValueRankCallback

public OpcReadAttributeValueCallback<int> ReadValueRankCallback { get; set; }

Public Property ReadValueRankCallback As OpcReadAttributeValueCallback(Of Integer)

Property value

OpcReadAttributeValueCallback<Int32>

ReadVariableValueCallback

Gets or sets a callback used to read the variable value.

public OpcReadVariableValueCallback ReadVariableValueCallback { get; set; }

Public Property ReadVariableValueCallback As OpcReadVariableValueCallback

Property value

OpcReadVariableValueCallback

A OpcReadVariableValueCallback used to read the variable value as an object. The value can also be a null reference (Nothing in Visual Basic).

Status

public OpcStatus Status { get; }

Public ReadOnly Property Status As OpcStatus

Property value

OpcStatus

Timestamp

public DateTime? Timestamp { get; set; }

Public Property Timestamp As Date?

Property value

Nullable<DateTime>

UserAccessLevel

Gets or sets a value which indicates in which ways the Value attribute of the variable node can be accessed (read/write) and if it provides current and/or historic data taking user access rights into account.

public OpcAccessLevel UserAccessLevel { get; set; }

Public Property UserAccessLevel As OpcAccessLevel

Property value

OpcAccessLevel

One of the members defined by the OpcAccessLevel enumeration. Which is used to indicate the ways the Value attribute of the current OpcVariableNode can be accessed (read/write) and if it provides current and/or historic data. The UserAccessLevel takes user access rights into account therefore its access may be restricted to a certain user / user group.

Implements

UserAccessLevel

Value

Gets or sets the value of the variable node which may be simple or complex.

public object Value { get; set; }

Public Property Value As Object

Property value

Object

A object representing the value of the variable node. This can be also a null reference (Nothing in Visual Basic).

Implements

Value

Remarks

Setting the value is not synchronized with a client writing the value at the same time. Clients learn about the new value once the changes are applied, see ApplyChanges.

ValueRank

public int ValueRank { get; set; }

Public Property ValueRank As Integer

Property value

Int32

Implements

ValueRank

WriteAccessLevelCallback

public OpcWriteAttributeValueCallback<OpcAccessLevel> WriteAccessLevelCallback { get; set; }

Public Property WriteAccessLevelCallback As OpcWriteAttributeValueCallback(Of OpcAccessLevel)

Property value

OpcWriteAttributeValueCallback<OpcAccessLevel>

WriteArrayDimensionsCallback

since v2.9

public OpcWriteAttributeValueCallback<OpcArrayDimensions> WriteArrayDimensionsCallback { get; set; }

Public Property WriteArrayDimensionsCallback As OpcWriteAttributeValueCallback(Of OpcArrayDimensions)

Property value

OpcWriteAttributeValueCallback<OpcArrayDimensions>

WriteDataTypeCallback

public OpcWriteAttributeValueCallback<OpcNodeId> WriteDataTypeCallback { get; set; }

Public Property WriteDataTypeCallback As OpcWriteAttributeValueCallback(Of OpcNodeId)

Property value

OpcWriteAttributeValueCallback<OpcNodeId>

WriteIsHistorizingCallback

public OpcWriteAttributeValueCallback<bool> WriteIsHistorizingCallback { get; set; }

Public Property WriteIsHistorizingCallback As OpcWriteAttributeValueCallback(Of Boolean)

Property value

OpcWriteAttributeValueCallback<Boolean>

WriteUserAccessLevelCallback

public OpcWriteAttributeValueCallback<OpcAccessLevel> WriteUserAccessLevelCallback { get; set; }

Public Property WriteUserAccessLevelCallback As OpcWriteAttributeValueCallback(Of OpcAccessLevel)

Property value

OpcWriteAttributeValueCallback<OpcAccessLevel>

WriteValueRankCallback

public OpcWriteAttributeValueCallback<int> WriteValueRankCallback { get; set; }

Public Property WriteValueRankCallback As OpcWriteAttributeValueCallback(Of Integer)

Property value

OpcWriteAttributeValueCallback<Int32>

WriteVariableValueCallback

Gets or sets a callback used to write the variable value.

public OpcWriteVariableValueCallback WriteVariableValueCallback { get; set; }

Public Property WriteVariableValueCallback As OpcWriteVariableValueCallback

Property value

OpcWriteVariableValueCallback

A OpcWriteVariableValueCallback used to write the variable value as an object. The value can also be a null reference (Nothing in Visual Basic).

Methods

InitializeDefaults

protected · override

Initializes the default values used by the OpcVariableNode.

protected override void InitializeDefaults()

Protected Overrides Sub InitializeDefaults()

Overrides

InitializeDefaults

Remarks

This method is used to ensure the availability of appropriate node specific default values. For more information like when this method is to be overwritten see InitializeDefaults.

ReadAttributeValueCore

protected · override

protected override OpcAttributeValue<T> ReadAttributeValueCore<T>(
    OpcReadAttributeValueContext context,
    OpcAttributeValue<T> value)

Protected Overrides Function ReadAttributeValueCore(Of T)(
    context As OpcReadAttributeValueContext,
    value As OpcAttributeValue(Of T)) As OpcAttributeValue(Of T)

Type parameters

Name	Description
T

Parameters

Name	Type	Description
context	OpcReadAttributeValueContext
value	OpcAttributeValue<T>

Returns

OpcAttributeValue<T>

Overrides

ReadAttributeValueCore<T>(OpcReadAttributeValueContext, OpcAttributeValue<T>)

ReadValue

Reads the variable node value using the context specified.

public object ReadValue(OpcReadVariableValueContext context)

Public Function ReadValue(context As OpcReadVariableValueContext) As Object

Parameters

Name	Type	Description
context	OpcReadVariableValueContext	The OpcReadVariableValueContext to use to read the variable node value.

Returns

Object

The object variable node value associated with this node and read using the context specified. This can also be a null reference (Nothing in Visual Basic).

Exceptions

Exception	Condition
ArgumentNullException	The context is a null reference (Nothing in Visual Basic).

ReadVariableValue

public OpcVariableValue<object> ReadVariableValue(
    OpcReadVariableValueContext context)

Public Function ReadVariableValue(
    context As OpcReadVariableValueContext) As OpcVariableValue(Of Object)

Parameters

Name	Type	Description
context	OpcReadVariableValueContext

Returns

OpcVariableValue<Object>

Exceptions

Exception	Condition
ArgumentNullException

ReadVariableValueCore

protected · virtual

Reads the value of the variable node using the context and value information specified.

protected virtual OpcVariableValue<object> ReadVariableValueCore(
    OpcReadVariableValueContext context,
    OpcVariableValue<object> value)

Protected Overridable Function ReadVariableValueCore(
    context As OpcReadVariableValueContext,
    value As OpcVariableValue(Of Object)) As OpcVariableValue(Of Object)

Parameters

Name	Type	Description
context	OpcReadVariableValueContext	The OpcReadVariableValueContext to use to read the variable node value.
value	OpcVariableValue<Object>	The OpcVariableValue<T> containing the currently used value constructed by the value information contained in the variable node cache.

Returns

OpcVariableValue<Object>

The OpcVariableValue<T> read using the ReadVariableValueCallback or the value if there is no custom callback routine defined.

WriteAttributeValueCore

protected · override

protected override OpcAttributeValue<T> WriteAttributeValueCore<T>(
    OpcWriteAttributeValueContext context,
    OpcAttributeValue<T> value)

Protected Overrides Function WriteAttributeValueCore(Of T)(
    context As OpcWriteAttributeValueContext,
    value As OpcAttributeValue(Of T)) As OpcAttributeValue(Of T)

Type parameters

Name	Description
T

Parameters

Name	Type	Description
context	OpcWriteAttributeValueContext
value	OpcAttributeValue<T>

Returns

OpcAttributeValue<T>

Overrides

WriteAttributeValueCore<T>(OpcWriteAttributeValueContext, OpcAttributeValue<T>)

WriteValue

Writes the value to the variable node value using the context specified.

public void WriteValue(OpcWriteVariableValueContext context, object value)

Public Sub WriteValue(context As OpcWriteVariableValueContext, value As Object)

Parameters

Name	Type	Description
context	OpcWriteVariableValueContext	The OpcWriteVariableValueContext to use to write the variable node value specified.
value	Object	The object to write to the variable node value.

Exceptions

Exception	Condition
ArgumentNullException	The context is a null reference (Nothing in Visual Basic).

WriteVariableValue

public void WriteVariableValue(
    OpcWriteVariableValueContext context,
    OpcVariableValue<object> value)

Public Sub WriteVariableValue(
    context As OpcWriteVariableValueContext,
    value As OpcVariableValue(Of Object))

Parameters

Name	Type	Description
context	OpcWriteVariableValueContext
value	OpcVariableValue<Object>

Exceptions

Exception	Condition
ArgumentNullException

WriteVariableValueCore

protected · virtual

Writes the value of the variable node using the context and value information specified.

protected virtual OpcVariableValue<object> WriteVariableValueCore(
    OpcWriteVariableValueContext context,
    OpcVariableValue<object> value)

Protected Overridable Function WriteVariableValueCore(
    context As OpcWriteVariableValueContext,
    value As OpcVariableValue(Of Object)) As OpcVariableValue(Of Object)

Parameters

Name	Type	Description
context	OpcWriteVariableValueContext	The OpcWriteVariableValueContext to use to write the variable node value.
value	OpcVariableValue<Object>	The OpcVariableValue<T> containing the currently used value constructed by the value information contained in the variable node cache.

Returns

OpcVariableValue<Object>

The OpcVariableValue<T> written using the WriteVariableValueCallback or the value if there is no custom callback routine defined.