INotifyingChangeApplierTarget.SaveItemChange-Methode
Speichert, wenn in einer abgeleiteten Klasse überschrieben, eine Elementänderung im Elementspeicher.
Namespace: Microsoft.Synchronization
Assembly: Microsoft.Synchronization (in microsoft.synchronization.dll)
Syntax
'Declaration
Sub SaveItemChange ( _
saveChangeAction As SaveChangeAction, _
change As ItemChange, _
context As SaveChangeContext _
)
'Usage
Dim instance As INotifyingChangeApplierTarget
Dim saveChangeAction As SaveChangeAction
Dim change As ItemChange
Dim context As SaveChangeContext
instance.SaveItemChange(saveChangeAction, change, context)
void SaveItemChange (
SaveChangeAction saveChangeAction,
ItemChange change,
SaveChangeContext context
)
void SaveItemChange (
SaveChangeAction saveChangeAction,
ItemChange^ change,
SaveChangeContext^ context
)
void SaveItemChange (
SaveChangeAction saveChangeAction,
ItemChange change,
SaveChangeContext context
)
function SaveItemChange (
saveChangeAction : SaveChangeAction,
change : ItemChange,
context : SaveChangeContext
)
Parameter
- saveChangeAction
Die Aktion, die für die Änderung ausgeführt werden soll.
- change
Die zu speichernde Elementänderung.
- context
Informationen über die anzuwendende Änderung.
Beispiel
Im folgenden Beispiel wird die Behandlung einiger der häufigsten SaveChangeAction-Werte in der SaveItemChange-Methode veranschaulicht.
Public Sub SaveItemChange(ByVal saveChangeAction__1 As SaveChangeAction, ByVal change As ItemChange, ByVal context As SaveChangeContext) Implements INotifyingChangeApplierTarget.SaveItemChange
Select Case saveChangeAction__1
' Update the item store and metadata store when an item is created or updated.
Case SaveChangeAction.Create, SaveChangeAction.UpdateVersionAndData
If True Then
Try
_itemStore.UpdateContactFromSync(change, DirectCast(context.ChangeData, String))
Catch ex As Exception
Dim errData As New RecoverableErrorData(ex)
context.RecordRecoverableErrorForItem(errData)
End Try
Exit Select
End If
' Update only the version of this item in the metadata store.
Case SaveChangeAction.UpdateVersionOnly
If True Then
Try
_itemStore.UpdateContactVersion(change.ItemId, change.ChangeVersion)
Catch ex As Exception
Dim errData As New RecoverableErrorData(ex)
context.RecordRecoverableErrorForItem(errData)
End Try
Exit Select
End If
' Delete the item from the item store and store a tombstone for it in the metadata store.
Case SaveChangeAction.DeleteAndStoreTombstone
If True Then
Try
_itemStore.DeleteContactFromSync(change.ItemId, change.ChangeVersion)
Catch ex As Exception
Dim errData As New RecoverableErrorData(ex)
context.RecordRecoverableErrorForItem(errData)
End Try
Exit Select
End If
' Neither merging of data nor removing tombstones is supported.
Case SaveChangeAction.UpdateVersionAndMergeData, SaveChangeAction.DeleteAndRemoveTombstone
If True Then
Throw New NotImplementedException()
End If
Case Else
If True Then
Throw New ArgumentOutOfRangeException()
End If
End Select
' Save the knowledge in the metadata store as each change is applied. Saving knowledge as each change is applied is
' not required. It is more robust than saving the knowledge only after each change batch, because if synchronization is interrupted
' before the end of a change batch, the knowledge will still reflect all of the changes applied. However, it is less efficient because
' knowledge must be stored more frequently.
Dim knowledge As SyncKnowledge = Nothing
Dim forgottenKnowledge As ForgottenKnowledge = Nothing
context.GetUpdatedDestinationKnowledge(knowledge, forgottenKnowledge)
_itemStore.ContactReplicaMetadata.SetKnowledge(knowledge)
End Sub
public void SaveItemChange(SaveChangeAction saveChangeAction, ItemChange change, SaveChangeContext context)
{
switch (saveChangeAction)
{
// Update the item store and metadata store when an item is created or updated.
case SaveChangeAction.Create:
case SaveChangeAction.UpdateVersionAndData:
{
try
{
_itemStore.UpdateContactFromSync(change, (string)context.ChangeData);
}
catch (Exception ex)
{
RecoverableErrorData errData = new RecoverableErrorData(ex);
context.RecordRecoverableErrorForItem(errData);
}
break;
}
// Update only the version of this item in the metadata store.
case SaveChangeAction.UpdateVersionOnly:
{
try
{
_itemStore.UpdateContactVersion(change.ItemId, change.ChangeVersion);
}
catch (Exception ex)
{
RecoverableErrorData errData = new RecoverableErrorData(ex);
context.RecordRecoverableErrorForItem(errData);
}
break;
}
// Delete the item from the item store and store a tombstone for it in the metadata store.
case SaveChangeAction.DeleteAndStoreTombstone:
{
try
{
_itemStore.DeleteContactFromSync(change.ItemId, change.ChangeVersion);
}
catch (Exception ex)
{
RecoverableErrorData errData = new RecoverableErrorData(ex);
context.RecordRecoverableErrorForItem(errData);
}
break;
}
// Neither merging of data nor removing tombstones is supported.
case SaveChangeAction.UpdateVersionAndMergeData:
case SaveChangeAction.DeleteAndRemoveTombstone:
{
throw new NotImplementedException();
}
default:
{
throw new ArgumentOutOfRangeException();
}
}
// Save the knowledge in the metadata store as each change is applied. Saving knowledge as each change is applied is
// not required. It is more robust than saving the knowledge only after each change batch, because if synchronization is interrupted
// before the end of a change batch, the knowledge will still reflect all of the changes applied. However, it is less efficient because
// knowledge must be stored more frequently.
SyncKnowledge knowledge;
ForgottenKnowledge forgottenKnowledge;
context.GetUpdatedDestinationKnowledge(out knowledge, out forgottenKnowledge);
_itemStore.ContactReplicaMetadata.SetKnowledge(knowledge);
}
Wenn ein Anbieter Änderungseinheiten verwendet, wird die SaveItemChange-Methode nur zur Behandlung von Löschaktionen aufgerufen, wie im folgenden Beispiel gezeigt.
Public Sub SaveItemChange(ByVal saveChangeAction__1 As SaveChangeAction, ByVal change As ItemChange, ByVal context As SaveChangeContext) Implements INotifyingChangeApplierTarget.SaveItemChange
' This provider uses change units, so SaveChangeWithChangeUnits is called for all actions except delete actions.
If SaveChangeAction.DeleteAndStoreTombstone = saveChangeAction__1 Then
' Delete the item from the item store and store a tombstone for it in the metadata store.
Try
_ContactStore.DeleteContactFromSync(change.ItemId, change.ChangeVersion)
Catch ex As Exception
Dim errData As New RecoverableErrorData(ex)
context.RecordRecoverableErrorForItem(errData)
End Try
Else
' SaveChangeWithChangeUnits should be called for all actions other than delete actions.
Throw New NotImplementedException("SaveItemChange only handles deletes!")
End If
' Use the metadata storage service to save the knowledge as each change is applied. Saving knowledge as each change is applied is
' not required. It is more robust than saving the knowledge only after each change batch, because if synchronization is interrupted
' before the end of a change batch, the knowledge will still reflect all of the changes applied. However, it is less efficient because
' knowledge must be stored more frequently.
Dim updatedKnowledge As SyncKnowledge = Nothing
Dim updatedForgottenKnowledge As ForgottenKnowledge = Nothing
context.GetUpdatedDestinationKnowledge(updatedKnowledge, updatedForgottenKnowledge)
_ContactStore.ContactReplicaMetadata.SetKnowledge(updatedKnowledge)
End Sub
public void SaveItemChange(SaveChangeAction saveChangeAction, ItemChange change, SaveChangeContext context)
{
// This provider uses change units, so SaveChangeWithChangeUnits is called for all actions except delete actions.
if (SaveChangeAction.DeleteAndStoreTombstone == saveChangeAction)
{
// Delete the item from the item store and store a tombstone for it in the metadata store.
try
{
_ContactStore.DeleteContactFromSync(change.ItemId, change.ChangeVersion);
}
catch (Exception ex)
{
RecoverableErrorData errData = new RecoverableErrorData(ex);
context.RecordRecoverableErrorForItem(errData);
}
}
else
{
// SaveChangeWithChangeUnits should be called for all actions other than delete actions.
throw new NotImplementedException("SaveItemChange only handles deletes!");
}
// Use the metadata storage service to save the knowledge as each change is applied. Saving knowledge as each change is applied is
// not required. It is more robust than saving the knowledge only after each change batch, because if synchronization is interrupted
// before the end of a change batch, the knowledge will still reflect all of the changes applied. However, it is less efficient because
// knowledge must be stored more frequently.
SyncKnowledge updatedKnowledge;
ForgottenKnowledge updatedForgottenKnowledge;
context.GetUpdatedDestinationKnowledge(out updatedKnowledge, out updatedForgottenKnowledge);
_ContactStore.ContactReplicaMetadata.SetKnowledge(updatedKnowledge);
}
Siehe auch
Verweis
INotifyingChangeApplierTarget-Schnittstelle
INotifyingChangeApplierTarget-Member
Microsoft.Synchronization-Namespace