DataObjectChangeEvents Class

Article
02/23/2011

Provides a set of events which a DDEX provider can raise when changes to data objects are made, and provides the means by which a provider can connect to them.

Inheritance Hierarchy

System.Object
Microsoft.VisualStudio.Data.DataObjectChangeEvents

Namespace: Microsoft.VisualStudio.Data
Assembly: Microsoft.VisualStudio.Data (in Microsoft.VisualStudio.Data.dll)

Syntax

'Declaration
<GuidAttribute("5619B0F3-93CD-4af1-8FFC-458B86B45778")> _
Public MustInherit Class DataObjectChangeEvents

[GuidAttribute("5619B0F3-93CD-4af1-8FFC-458B86B45778")]
public abstract class DataObjectChangeEvents

[GuidAttribute(L"5619B0F3-93CD-4af1-8FFC-458B86B45778")]
public ref class DataObjectChangeEvents abstract

[<AbstractClass>]
[<GuidAttribute("5619B0F3-93CD-4af1-8FFC-458B86B45778")>]
type DataObjectChangeEvents =  class end

public abstract class DataObjectChangeEvents

The DataObjectChangeEvents type exposes the following members.

Constructors

	Name	Description
	DataObjectChangeEvents	Class constructor. Instantiates a new instance of the DataObjectChangeEvents class.

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Methods

	Name	Description
	EndEventGroup	Terminates an event group that was initiated by calling the StartEventGroup method.
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	OnEventGroupEnded	Handler for the EventGroupEnded event.
	OnEventGroupStarted	Handler for the EventGroupStarted event.
	OnObjectAdded	Handler for the ObjectAdded event.
	OnObjectChanged	Handler for the ObjectChanged event.
	OnObjectRemoved	Handler for the ObjectRemoved event.
	RaiseObjectAdded(String, array<Object[])	Raises a standalone ObjectAdded event, specifying the object type and identifier.
	RaiseObjectAdded(Int32, String, array<Object[])	Raises the ObjectAdded event within a specific event group.
	RaiseObjectChanged(String, array<Object[])	Raises a standalone ObjectChanged event, specifying the type name and identifier.
	RaiseObjectChanged(Int32, String, array<Object[])	Raises the ObjectChanged event within a specified event group.
	RaiseObjectChanged(String, array<Object[], array<Object[])	Raises a standalone ObjectChanged event for an object whose identifier was modified during the change.
	RaiseObjectChanged(Int32, String, array<Object[], array<Object[])	Raises an ObjectChanged event within a specific event group for an object whose identifier was modified during the change.
	RaiseObjectRemoved(String, array<Object[])	Raises a standalone ObjectRemoved event, specifying type name and object identifier.
	RaiseObjectRemoved(Int32, String, array<Object[])	Raises the ObjectRemoved event within a specified event group.
	RollbackEventGroup	Ends an event group by removing the queued event set from the group.
	StartEventGroup	Starts a group of events initiated by a call to the StartEventGroup method.
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Events

	Name	Description
	EventGroupEnded	Event raised when an event group has completed.
	EventGroupStarted	Event raised when an event group has started.
	ObjectAdded	Event raised when a data object has been added.
	ObjectChanged	Event raised when a data object has been changed.
	ObjectRemoved	Event raised when a data object has been removed.

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Remarks

In addition to singular events, this class allows you to structure event groups.

Under some circumstances, multiple change events need to be grouped together and be treated as an atomic transaction.

Normally, an event listener reacts to event-group notifications by assembling a queue of events raised inside an event group; then, only after notification that the event group has ended, are the events processed in a transactional manner (that is, all events apply, or none of the events apply).

On the notification side, event grouping is implemented by enabling the specification of a hierarchy of event groups, each of them identified with a group ID. A notifier begins by calling StartEventGroup, which returns an ID for the group. Then the notifier calls the [M:Microsoft.VisualStudio.Data.DataObjectChangeEvents.RaiseObjectAdded(System.String,System.Object[]],RaiseObjectChanged, and RaiseObjectRemoved methods, passing in the group ID. (Optionally, a notifier can start an embedded event group by calling StartEventGroup again, with the current group ID.)

Finally the notifier calls EndEventGroup using the group ID. Once the top-most group (the group created by calling StartEventGroup with a parameter of zero) has ended, all the events raised for that group are dispatched to listeners in a single event group.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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