INotifyingChangeApplierTarget.SaveItemChange 方法

在派生类中重写时，将项变更保存到项存储区中。

命名空间: Microsoft.Synchronization
程序集: Microsoft.Synchronization（在 microsoft.synchronization.dll 中）

语法

声明
Sub SaveItemChange ( _
    saveChangeAction As SaveChangeAction, _
    change As ItemChange, _
    context As SaveChangeContext _
)
用法
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
)

参数

• saveChangeAction
  要为变更执行的操作。

• change
  要保存的项变更。

• context
  有关要应用的变更的信息。

示例

以下示例说明如何处理 SaveItemChange 方法中一些最常用的 SaveChangeAction 值。

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);
}

提供程序使用变更单位时，仅在处理删除操作时调用 SaveItemChange 方法，如下例所示。

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);
}

请参阅

参考

INotifyingChangeApplierTarget 接口
INotifyingChangeApplierTarget 成员
Microsoft.Synchronization 命名空间