OPC Studio User's Guide and Reference
EasyDAClient Class Members
Properties  Methods  Events


OpcLabs.EasyOpcClassicComponents Assembly > OpcLabs.EasyOpc.DataAccess Namespace : EasyDAClient Class

The following tables list the members exposed by EasyDAClient.

Public Constructors
 NameDescription
Public ConstructorOverloaded.   
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Public Properties
 NameDescription
Public PropertyThe alias provider to be used for resolving aliases by this component. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public Property (Inherited from System.ComponentModel.Component)
Public PropertyCan be used to distinguish otherwise equal widgets. (Inherited from OpcLabs.BaseLib.Widgets.Widget)
Public PropertyContains parameters that influence the behavior of just this instance of the component. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public PropertySpecifies that you wish that the EasyDAClientCore object instance works with an "isolated" connection to the OPC server, i.e. one that is not shared with other instances. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public PropertyContains parameters that influence the behavior of the component when it is isolated. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public PropertyProvides dictionary of license data fields and their values. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public PropertyCapacity of the notification queue. (Inherited from OpcLabs.BaseLib.Widgets.NotifyingWidget)
Public PropertyThe idle time before the internal thread executing the queued notifications is stopped (in milliseconds). (Inherited from OpcLabs.BaseLib.Widgets.NotifyingWidget)
Public PropertyCapacity of the event pull queue for item changes. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public PropertyDetermines whether the component will deliver all notifications in a queued manner. (Inherited from OpcLabs.BaseLib.Widgets.NotifyingWidget)
Public Propertystatic (Shared in Visual Basic)A default, shared instance of the client object.  
Public Property (Inherited from System.ComponentModel.Component)
Public PropertyGets the OPC technologies supported. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public PropertyContains synchronization context used by the object when performing asynchronous operations (including event notifications). (Inherited from OpcLabs.BaseLib.Widgets.NotifyingWidget)
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Protected Properties
 NameDescription
Protected Property (Inherited from System.ComponentModel.Component)
Protected Property (Inherited from System.ComponentModel.Component)
Protected Property (Inherited from System.ComponentModel.Component)
Protected PropertyThe service container provided by this widget to inheritors. (Inherited from OpcLabs.BaseLib.Widgets.Widget)
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Public Methods
 NameDescription
Public MethodBrowses the possible access paths of a specified OPC item. Specify server descriptor, and node descriptor. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodBrowses the specified branch (or root) in OPC server's address space, and returns information about child nodes (both branches and leaves) found. Specify server descriptor, parent item ID, and node filter. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodBrowse for available item properties of a specified OPC item. Specify server descriptor, and node descriptor. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodBrowses the specified computer and returns information about OPC (Data Access) servers found. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodChanges parameters of subscriptions to multiple OPC items. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodOverridden.   
Public Methodstatic (Shared in Visual Basic)Creates a new instance of the class.  
Public MethodCreates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from System.MarshalByRefObject)
Public MethodOverloaded. Clean up any resources being used. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public Method (Inherited from object)
Public MethodServes as the default hash function. (Inherited from object)
Public MethodObtains parameters of specified item subscription. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodRetrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from System.MarshalByRefObject)
Public MethodGets values of multiple OPC properties, specifying an array of property arguments objects. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public Method (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public Method (Inherited from OpcLabs.BaseLib.Widgets.Widget)
Public Method (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodGets the System.Type of the current instance. (Inherited from object)
Public MethodObtains a lifetime service object to control the lifetime policy for this instance. (Inherited from System.MarshalByRefObject)
Public MethodAttempts to pull multiple OPC item changes subscribed to by the IEasyDAClient.SubscribeMultipleItems or SubscribeItem method. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodReads multiple named items from an OPC server or OPC servers, using array of argument objects as an input. Values, qualities and timestamps are returned. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public Method (Inherited from OpcLabs.BaseLib.Widgets.Widget)
Public MethodSets the object properties back to their defaults. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodSubscribe to changes of multiple OPC items. The IEasyDAClient.ItemChanged event will be generated for each significant item change. Callback methods will be invoked if they are specified in the argument objects. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public Method (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodUnsubscribe from changes of all OPC items. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodUnsubscribe from changes of multiple OPC items, specifying an "enumerable" of integer handles. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodOverloaded. Determines whether the specified EasyDAClientCore is value equal to the current object. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodWrites named items into an OPC server or OPC servers. Values, qualities and timestamps are written. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public MethodWrites values into named items in an OPC server or OPC servers. Only the item values are written (qualities and timestamp are not written). (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public Method (Inherited from OpcLabs.BaseLib.Widgets.Widget)
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Protected Methods
 NameDescription
Protected MethodProcesses an error that has occurred during a callback. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Protected Method (Inherited from System.ComponentModel.Component)
Protected MethodOverloaded. Creates a shallow copy of the current System.MarshalByRefObject object. (Inherited from System.MarshalByRefObject)
Protected MethodInfrastructure. (Inherited from OpcLabs.BaseLib.Widgets.Widget)
Protected MethodInfrastructure. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Protected MethodInfrastructure. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Protected MethodInfrastructure. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Protected MethodProcesses an error that has occurred during a callback. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Protected MethodOverloaded. Invokes the specified action in a synchronized manner. (Inherited from OpcLabs.BaseLib.Widgets.NotifyingWidget)
Protected MethodInfrastructure. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
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Extension Methods
 NameDescription
Public Extension Method

Browses the possible access paths of a specified OPC item.

Browse for access paths. Specify machine name, server class, and item ID.

Public Extension MethodOverloaded. Browses the specified branch (or root) in OPC server's address space, and returns information about child branches found.

The BrowseBranches methods return the branches available under the specified parent branch in the OPC-DA address space.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Browses the specified branch (or root) in OPC server's address space, and returns information about child leaves found.

The BrowseLeaves methods return the leaves available under the specified parent branch in the OPC-DA address space.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension Method

Browses the specified branch (or root) in OPC server's address space, and returns information about child nodes (both branches and leaves) found.

Browse for child nodes. Specify machine name, server class, parent item ID, and node filter.

Public Extension Method

Browses the nodes in OPC DA server's address space. Starts from the specified node, and returns information about child nodes found.

Browses the nodes in server's address space, given a browse arguments object.

Public Extension Method

Browses the available properties of a specified OPC item.

Browse for available item properties. Specify machine name, server class, and item ID.

Public Extension MethodOverloaded. Browses for available OPC (Data Access) servers.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Allows to traverse through OPC DA address space nodes under the specified node, using given browse arguments.
Public Extension MethodOverloaded. Changes parameters of a subscription to a particular OPC item.

It is more efficient to change multiple subscriptions using IEasyDAClient.ChangeMultipleItemSubscriptions method.

Public Extension MethodOverloaded. Obtains value of Item Access Rights OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Alarm Area List OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Alarm Quick Help OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Rate of Change Limit OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Contact Close Label OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Condition Logic OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Condition Status OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Item Canonical DataType OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Deadband OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Item Description OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Deviation Limit OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Item EUInfo OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Item EU Type OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of EU Units OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of High EU OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of HiHi Limit OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of High Instrument Range OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Hi Limit OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains a DAItemPropertyRecord structure filled with OPC property values for a given OPC item.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Obtains value of Limit Exceeded OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Low EU OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Low Instrument Range OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Lo Limit OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of LoLo Limit OPC property for a given OPC item.
Public Extension MethodOverloaded. Gets values of multiple OPC properties of a specified OPC item.

This method does not throw an exception in case of OPC operation failures. Instead, the eventual exception related to each property is returned in Exception property of each returned OpcLabs.BaseLib.OperationModel.ValueResult element.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Obtains value of Contact Open Label OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Primary Alarm Area OPC property for a given OPC item.
Public Extension MethodOverloaded. Gets a value of OPC property of a specified OPC item.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Gets a value of typed OPC property, using descriptor objects for the OPC server, node, and the property.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.Boolean.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.Byte.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.Char.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.DateTime.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.Decimal.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.Double.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.Int16.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.Int32.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.Int64.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.IntPtr.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.Single.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to an array of System.String.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.Boolean.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.Byte.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.Char.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.DateTime.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.Decimal.
Public Extension MethodOverloaded. Obtains a DAPropertyValueDictionary filled with OPC property values for a given OPC item.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.Double.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.Int16.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.Int32.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.Int64.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.IntPtr.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.Single.
Public Extension MethodOverloaded. Gets a value of OPC property, using descriptor object for the OPC server, and an OPC Item ID, and converts it to System.String.
Public Extension MethodOverloaded. Obtains value of Item Quality OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Server Scan Rate OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Sound File OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Item Timestamp OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Item Timezone OPC property for a given OPC item.
Public Extension MethodOverloaded. Obtains value of Item Value OPC property for a given OPC item.
Public Extension MethodAttempts to pull an OPC item change subscribed to by the IEasyDAClient.SubscribeMultipleItems or SubscribeItem method.
Public Extension MethodOverloaded. Reads an OPC-DA item. Value, quality and timestamp are returned.

The ReadItem method reads the data of an OPC-DA item. It uses the first available data from the server; it does not wait until the quality becomes "uncertain" or "good".

The server(s) can be local or can be remotely accessed via DCOM.

Optionally, a specific data type can be requested, or an access path can be specified (OPC DA 1.0 only).

Public Extension MethodOverloaded. Reads a typed named item from an OPC server. A typed value, quality and timestamp are returned.

The ReadItem method uses the first available data from the server; it does not wait until the quality becomes "uncertain" or "good".

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Reads an OPC-DA item value. Reads a single named item from an OPC-DA server. Only the item value is returned (quality and timestamp are not returned).

Use this method if you are only interested in the actual value of the OPC item. Use ReadItem method if you also need the quality or timestamp. The ReadItemValue method makes it very easy to obtain the actual data value with just one function call.

The ReadItemValue method requires that the value quality is "good".

The server(s) can be local or can be remotely accessed via DCOM.

Optionally, a specific data type can be requested, or an access path can be specified (OPC DA 1.0 only).

Public Extension MethodOverloaded. Reads a typed named item from an OPC server. Only the item's typed value is returned (quality and timestamp are not returned).

Use this method if you are only interested in the actual typed value of the OPC item. Use ReadItem method if you also need the quality or timestamp. The ReadItemValue method makes it very easy to obtain the actual typed data value with just one function call.

The ReadItemValue method requires that the value quality is "good".

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.Boolean. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.Byte. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.Char. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.DateTime. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.Decimal. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.Double. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.Int16. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.Int32. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.Int64. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.IntPtr. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.Single. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to an array of System.String. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.Boolean. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.Byte. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.Char. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.DateTime. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.Decimal. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.Double. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.Int16. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.Int32. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.Int64. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.IntPtr. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.Single. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads a value of named OPC item, and converts it to System.String. The value is requested from the OPC server using a corresponding data type.
Public Extension MethodOverloaded. Reads data of multiple OPC-DA items.

The ReadMultipleItems method reads the data (values, timestamps and qualities) of multiple items from one or more OPC-DA servers. It uses the first available data from the server for each item; it does not wait until the quality becomes "uncertain" or "good". The function performs all individual operations in parallel, but only returns after all individual operations are completed (or their timeouts elapse).

This method does not throw an exception in case of OPC operation failures. Instead, the eventual exception related to each item is returned in Exception property of each returned OpcLabs.EasyOpc.DataAccess.OperationModel.DAVtqResult element.

The server(s) can be local or can be remotely accessed via DCOM.

Optionally, a specific data type can be requested, or an access path can be specified (OPC DA 1.0 only).

This method operates on multiple items at once. If you only have one item, you can use the ReadItem(IEasyDAClient,DAReadItemArguments) method instead.

Public Extension MethodOverloaded. Reads values of multiple OPC-DA items. Reads named items from an OPC-DA server or servers. Only the item values are returned (qualities and timestamps are not returned).

The ReadMultipleItemValues method requires that the quality is "good" for each item. The function performs all individual operations in parallel, but only returns after all individual operations are completed (or their timeouts elapse).

This method does not throw an exception in case of OPC operation failures. Instead, the eventual exception related to each item is returned in Exception property of each returned OpcLabs.EasyOpc.DataAccess.OperationModel.DAVtqResult element.

The server(s) can be local or can be remotely accessed via DCOM.

Optionally, a specific data type can be requested, or an access path can be specified (OPC DA 1.0 only).

Public Extension MethodSets the arbitrary object associated with the node.
Public Extension MethodOverloaded. Subscribe to changes of a particular OPC item.

The IEasyDAClient.ItemChanged event is generated for each significant item change.

It is more efficient to subscribe to multiple items using the SubscribeMultipleItems method.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Subscribe to changes of multiple OPC items.

The IEasyDAClient.ItemChanged event will be generated for each significant item change.

Public Extension MethodDetermines whether the client object supports a given OPC technology or technologies (such as OPC COM or OPC XML).
Public Extension MethodAttempts to enable the auto-subscribing optimization.
Public Extension Method

Unsubscribe from changes of a particular OPC item.

Unsubscribe from OPC item, specifying its handle.

Public Extension MethodOverloaded. Waits until the OPC-DA item quality becomes "good".

This method subscribes to the specified OPC-DA item, and monitors its data until it has "good" quality, an error occurs, or the alloted time elapses.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Waits until the OPC-DA items satisfy the given conditions.

Subscribes to the specified OPC-DA items, and monitors their data until the predicates specified for each item become true, or the alloted time elapses.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Waits until the OPC-DA items reach the given minimum quality.

Subscribes to the specified OPC-DA items, and monitors their data until they have at least the quality specified for each item, an error occurs, or the alloted time elapses.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Writes into a named item in an OPC server. Value, quality and timestamp are written.

The server(s) can be local or can be remotely accessed via DCOM.

Optionally, a specific data type can be requested, or an access path can be specified (OPC DA 1.0 only).

Public Extension MethodOverloaded. Writes into a typed named item in an OPC server. A typed value, quality and timestamp are written.

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Writes a value into a named item in an OPC server. Only the item value is written (quality and timestamp are not written).

The WriteItemValue only writes the item value into the OPC-DA server; how the quality and timestamp are affected depends on the server. Some servers support writing the quality and timestamp as well; use the WriteItem method for that.

The server(s) can be local or can be remotely accessed via DCOM.

Optionally, a specific data type can be requested, or an access path can be specified (OPC DA 1.0 only).

Public Extension MethodOverloaded. Writes a typed value into a (typed) named item in an OPC server. Only the item's typed value is written (quality and timestamp are not written).

The server(s) can be local or can be remotely accessed via DCOM.

Public Extension MethodOverloaded. Writes an array of System.Boolean value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.Byte value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.Char value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.Decimal value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.Double value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.Int16 value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.Int32 value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.Int64 value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.IntPtr value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.Single value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes an array of System.String value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.Boolean value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.Byte value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.Char value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.Decimal value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.Double value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.Int16 value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.Int32 value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.Int64 value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.IntPtr value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.Single value into a named OPC item. A corresponding data type is passed to the OPC server.
Public Extension MethodOverloaded. Writes a System.String value into a named OPC item. A corresponding data type is passed to the OPC server.
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Public Events
 NameDescription
Public Event (Inherited from System.ComponentModel.Component)
Public EventRaised when a failure in the eventing infrastructure occurs. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public EventRaised for every significant change in an OPC item subscribed to by the SubscribeItem method. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
Public EventRaised for loggable entries originating in the OPC-DA client engine and the EasyDAClient component. (Inherited from OpcLabs.EasyOpc.DataAccess.EasyDAClientCore)
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See Also

Reference

EasyDAClient Class
OpcLabs.EasyOpc.DataAccess Namespace