INotifyingChangeApplierTarget.SaveChangeWithChangeUnits 方法
在派生类中重写时，将包含单位变更的变更的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 SaveChangeWithChangeUnits ( _
change As ItemChange, _
context As SaveChangeWithChangeUnitsContext _
)
用法
Dim instance As INotifyingChangeApplierTarget
Dim change As ItemChange
Dim context As SaveChangeWithChangeUnitsContext
instance.SaveChangeWithChangeUnits(change, context)
void SaveChangeWithChangeUnits (
ItemChange change,
SaveChangeWithChangeUnitsContext context
)
void SaveChangeWithChangeUnits (
ItemChange^ change,
SaveChangeWithChangeUnitsContext^ context
)
void SaveChangeWithChangeUnits (
ItemChange change,
SaveChangeWithChangeUnitsContext context
)
function SaveChangeWithChangeUnits (
change : ItemChange,
context : SaveChangeWithChangeUnitsContext
)
参数
- change
要应用的项变更。
- context
有关要应用的变更的信息。
备注
实施者注意事项： 如果 context 中包含的操作为 Create，则必须以原子方式保存项变更。这意味着要么必须成功保存所有变更单位，要么必须放弃整个项变更。如果保存了某些变更单位但无法保存其他变更单位，则会导致数据损坏。 当调用 RecordRecoverableErrorForChangeUnit 并且 context 为 Create 时，RecordRecoverableErrorForChangeUnit 将引发 CreateFailuresMustBeForEntireItemException。 如果调用此方法的过程中取消了同步，并且提供程序已应用部分变更单位，则提供程序必须对所有未应用的变更单位调用 RecordRecoverableErrorForChangeUnit。
示例
以下示例说明如何处理 SaveChangeWithChangeUnits 方法中一些最常用的 SaveChangeAction 值。
Public Sub SaveChangeWithChangeUnits(ByVal change As ItemChange, ByVal context As SaveChangeWithChangeUnitsContext) Implements INotifyingChangeApplierTarget.SaveChangeWithChangeUnits
' Enumerate the change units received and apply them by using the specified action.
For Each cuChange As ChangeUnitChange In change.ChangeUnitChanges
Select Case context.GetActionForChangeUnit(cuChange)
Case SaveChangeAction.Create, SaveChangeAction.UpdateVersionAndData
If True Then
' Update the item store and metadata store for the specified change unit.
Try
Dim cuData As String = DirectCast(context.ChangeData, String())(cuChange.ChangeUnitId.GetByteId())
_ContactStore.UpdateContactFromSync(change, cuChange, cuData)
Catch ex As Exception
Dim errData As New RecoverableErrorData(ex)
context.RecordRecoverableErrorForChangeUnit(cuChange, errData)
End Try
Exit Select
End If
Case SaveChangeAction.UpdateVersionAndMergeData
If True Then
' Merge actions are not supported by this implementation.
Throw New NotImplementedException("UpdateVersionAndMergeData is not supported.")
End If
Case SaveChangeAction.UpdateVersionOnly
If True Then
' Update only the version of this change unit in the metadata store.
Try
_ContactStore.UpdateContactVersion(change.ItemId, cuChange.ChangeUnitId, cuChange.ChangeUnitVersion)
Catch ex As Exception
Dim errData As New RecoverableErrorData(ex)
context.RecordRecoverableErrorForChangeUnit(cuChange, errData)
End Try
Exit Select
End If
Case SaveChangeAction.DeleteAndRemoveTombstone, SaveChangeAction.DeleteAndStoreTombstone
If True Then
' Delete actions are handled in SaveItemChange, so throw an exception.
Throw New InvalidOperationException("SaveChangeWithChangeUnits received a delete action.")
End If
Case Else
If True Then
Throw New ArgumentOutOfRangeException("SaveChangeWithChangeUnits received an out-of-range action.")
End If
End Select
Next
' 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 SaveChangeWithChangeUnits(ItemChange change, SaveChangeWithChangeUnitsContext context)
{
// Enumerate the change units received and apply them by using the specified action.
foreach (ChangeUnitChange cuChange in change.ChangeUnitChanges)
{
switch (context.GetActionForChangeUnit(cuChange))
{
case SaveChangeAction.Create:
case SaveChangeAction.UpdateVersionAndData:
{
// Update the item store and metadata store for the specified change unit.
try
{
string cuData = ((string[])context.ChangeData)[cuChange.ChangeUnitId.GetByteId()];
_ContactStore.UpdateContactFromSync(change, cuChange, cuData);
}
catch (Exception ex)
{
RecoverableErrorData errData = new RecoverableErrorData(ex);
context.RecordRecoverableErrorForChangeUnit(cuChange, errData);
}
break;
}
case SaveChangeAction.UpdateVersionAndMergeData:
{
// Merge actions are not supported by this implementation.
throw new NotImplementedException("UpdateVersionAndMergeData is not supported.");
}
case SaveChangeAction.UpdateVersionOnly:
{
// Update only the version of this change unit in the metadata store.
try
{
_ContactStore.UpdateContactVersion(change.ItemId, cuChange.ChangeUnitId, cuChange.ChangeUnitVersion);
}
catch (Exception ex)
{
RecoverableErrorData errData = new RecoverableErrorData(ex);
context.RecordRecoverableErrorForChangeUnit(cuChange, errData);
}
break;
}
case SaveChangeAction.DeleteAndRemoveTombstone:
case SaveChangeAction.DeleteAndStoreTombstone:
{
// Delete actions are handled in SaveItemChange, so throw an exception.
throw new InvalidOperationException("SaveChangeWithChangeUnits received a delete action.");
}
default:
{
throw new ArgumentOutOfRangeException("SaveChangeWithChangeUnits received an out-of-range action.");
}
}
}
// 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