QuickOPC User's Guide and Reference
EasyDAClientCore Class Methods


OpcLabs.EasyOpcClassic Assembly > OpcLabs.EasyOpc.DataAccess Namespace : EasyDAClientCore Class

For a list of all members of this type, see EasyDAClientCore members.

Public Methods
 NameDescription
Public MethodBrowses the possible access paths of a specified OPC item. Specify server descriptor, and node descriptor.  
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.  
Public MethodBrowse for available item properties of a specified OPC item. Specify server descriptor, and node descriptor.  
Public MethodBrowses the specified computer and returns information about OPC (Data Access) servers found.  
Public MethodChanges parameters of subscriptions to multiple OPC items.  
Public MethodOverridden.   
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. Overridden. Clean up any resources being used.  
Public Method (Inherited from object)
Public MethodServes as the default hash function. (Inherited from object)
Public MethodObtains parameters of specified item subscription.  
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.  
Public MethodOverridden.   
Public Method (Inherited from OpcLabs.BaseLib.Widgets.Widget)
Public MethodOverridden.   
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.  
Public MethodRaises a callback or event using a given handler and passing it specified event arguments, optionally specifying whether to enqueue the call. (Inherited from OpcLabs.BaseLib.Widgets.NotifyingWidget)
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.  
Public Method (Inherited from OpcLabs.BaseLib.Widgets.Widget)
Public MethodSets the object properties back to their defaults.  
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.  
Public MethodOverridden. Returns a string that represents the current object.  
Public MethodUnsubscribe from changes of all OPC items.  
Public MethodUnsubscribe from changes of multiple OPC items, specifying an enumerable of integer handles.  
Public MethodOverloaded. Determines whether the specified EasyDAClientCore is value equal to the current object.  
Public MethodWrites named items into an OPC server or OPC servers. Values, qualities and timestamps are written.  
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).  
Public Method (Inherited from OpcLabs.BaseLib.Widgets.Widget)
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Protected Methods
 NameDescription
Protected MethodOverridden. Processes an error that has occurred during a callback. Processes an error that has occurred during a callback.  
Protected Method (Inherited from System.ComponentModel.Component)
Protected MethodOverloaded. Creates a shallow copy of the current System.MarshalByRefObject object. (Inherited from System.MarshalByRefObject)
Protected MethodOverridden. Infrastructure. Infrastructure.  
Protected MethodOverridden. Infrastructure. Infrastructure.  
Protected MethodInfrastructure. (Inherited from OpcLabs.BaseLib.Widgets.Widget)
Protected MethodOverridden. Infrastructure. Infrastructure.  
Protected MethodOverridden. Processes an error that has occurred during sending of a callback. Processes an error that has occurred during a callback.  
Protected MethodOverloaded. Invokes the specified action in a synchronized manner. (Inherited from OpcLabs.BaseLib.Widgets.NotifyingWidget)
Protected MethodOverridden. Infrastructure. Infrastructure.  
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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.

.NET

COM

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

.NET

COM

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. 

.NET

COM

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.

.NET

.NET

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.

.NET

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.

.NET

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.

.NET

.NET

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.

.NET

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 a named item from an OPC server. Value, quality and timestamp are returned.

The server can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

The ReadItem method only waits for the first update from the server (or until the timeout elapses); it does not wait until the quality becomes "uncertain" or "good".

.NET

.NET

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

The server can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

The ReadItem method only waits for the first update from the server (or until the timeout elapses); it does not wait until the quality becomes "uncertain" or "good".

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

The server can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

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 waits until the quality becomes "good", or the timeout elapses.

.NET

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).

The server can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

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 waits until the quality becomes "good", or the timeout elapses.

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

The servers can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

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.

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.

.NET

Public Extension MethodOverloaded. Subscribe to changes of multiple OPC items.
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. Subscribes to the specified OPC-DA item, and monitors its data until it has "good" quality, an error occurs, or the alloted time elapses.
Public Extension MethodOverloaded. 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.
Public Extension MethodOverloaded. 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.
Public Extension MethodOverloaded. Writes into a named item in an OPC server. Value, quality and timestamp are written.

The server can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

.NET

COM

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

The server can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

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 server can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

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 can be local or can be remotely accessed via DCOM. Optionally, an access path can be specified or a specific data type can be requested.

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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See Also

Reference

EasyDAClientCore Class
OpcLabs.EasyOpc.DataAccess Namespace