Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Objects / Internal / SnapshotChangeTrackingStrategy.cs / 1305376 / SnapshotChangeTrackingStrategy.cs
using System; using System.Collections.Generic; using System.Text; using System.Data.Objects.DataClasses; namespace System.Data.Objects.Internal { ////// Implementation of the change tracking strategy for entities that require snapshot change tracking. /// These are typically entities that do not implement IEntityWithChangeTracker. /// internal sealed class SnapshotChangeTrackingStrategy : IChangeTrackingStrategy { private static SnapshotChangeTrackingStrategy _instance = new SnapshotChangeTrackingStrategy(); ////// Returns the single static instance of this class; a single instance is all that is needed /// because the class is stateless. /// public static SnapshotChangeTrackingStrategy Instance { get { return _instance; } } // Private constructor to help prevent additional instances being created. private SnapshotChangeTrackingStrategy() { } // See IChangeTrackingStrategy documentation public void SetChangeTracker(IEntityChangeTracker changeTracker) { // Nothing to do when using snapshots for change tracking } // See IChangeTrackingStrategy documentation public void TakeSnapshot(EntityEntry entry) { if (entry != null) { entry.TakeSnapshot(false); } } // See IChangeTrackingStrategy documentation public void SetCurrentValue(EntityEntry entry, StateManagerMemberMetadata member, int ordinal, object target, object value) { // If the target is the entity, then this is a change to a member on the entity itself rather than // a change to some complex type hanging off the entity. In this case we can use the change tracking // API in the normal way. if (Object.ReferenceEquals(target, entry.Entity)) { // equivalent of EntityObject.ReportPropertyChanging() ((IEntityChangeTracker)entry).EntityMemberChanging(member.CLayerName); member.SetValue(target, value); // equivalent of EntityObject.ReportPropertyChanged() ((IEntityChangeTracker)entry).EntityMemberChanged(member.CLayerName); if (member.IsComplex) { // This is required because the OSE contains a separate cache of user objects for // complex objects such that original values can be looked up correctly. entry.UpdateComplexObjectSnapshot(member, target, ordinal, value); } } else { // Must be a complex type. We would like to do this: // ((IEntityChangeTracker)entry).EntityComplexMemberChanging(topLevelMember.CLayerName, target, member.CLayerName); // ((IEntityChangeTracker)entry).EntityComplexMemberChanged(topLevelMember.CLayerName, target, member.CLayerName); // // However, we have no way of getting the topLevelMember.CLayerName. This is because the value record does not // contain any reference to its parent. (In non-POCO, ComplexObject takes care of this.) // Therefore, in this case we are going to just call a localized DetectChanges to make sure that changes in the // complex types are found. // // Note that this case only happens when the entity is POCO and complex types are set through the CurrentValues // object. This is probably not a very common pattern. member.SetValue(target, value); if (entry.State != EntityState.Added) { // Entry is not Detached - checked in ValidateState() in EntityEntry.SetCurrentEntityValue entry.DetectChangesInProperties(true); } } } // See IChangeTrackingStrategy documentation public void UpdateCurrentValueRecord(object value, EntityEntry entry) { // No change tracker, but may or may not be a proxy entry.UpdateRecordWithoutSetModified(value, entry.CurrentValues); entry.DetectChangesInProperties(false); } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved. using System; using System.Collections.Generic; using System.Text; using System.Data.Objects.DataClasses; namespace System.Data.Objects.Internal { ////// Implementation of the change tracking strategy for entities that require snapshot change tracking. /// These are typically entities that do not implement IEntityWithChangeTracker. /// internal sealed class SnapshotChangeTrackingStrategy : IChangeTrackingStrategy { private static SnapshotChangeTrackingStrategy _instance = new SnapshotChangeTrackingStrategy(); ////// Returns the single static instance of this class; a single instance is all that is needed /// because the class is stateless. /// public static SnapshotChangeTrackingStrategy Instance { get { return _instance; } } // Private constructor to help prevent additional instances being created. private SnapshotChangeTrackingStrategy() { } // See IChangeTrackingStrategy documentation public void SetChangeTracker(IEntityChangeTracker changeTracker) { // Nothing to do when using snapshots for change tracking } // See IChangeTrackingStrategy documentation public void TakeSnapshot(EntityEntry entry) { if (entry != null) { entry.TakeSnapshot(false); } } // See IChangeTrackingStrategy documentation public void SetCurrentValue(EntityEntry entry, StateManagerMemberMetadata member, int ordinal, object target, object value) { // If the target is the entity, then this is a change to a member on the entity itself rather than // a change to some complex type hanging off the entity. In this case we can use the change tracking // API in the normal way. if (Object.ReferenceEquals(target, entry.Entity)) { // equivalent of EntityObject.ReportPropertyChanging() ((IEntityChangeTracker)entry).EntityMemberChanging(member.CLayerName); member.SetValue(target, value); // equivalent of EntityObject.ReportPropertyChanged() ((IEntityChangeTracker)entry).EntityMemberChanged(member.CLayerName); if (member.IsComplex) { // This is required because the OSE contains a separate cache of user objects for // complex objects such that original values can be looked up correctly. entry.UpdateComplexObjectSnapshot(member, target, ordinal, value); } } else { // Must be a complex type. We would like to do this: // ((IEntityChangeTracker)entry).EntityComplexMemberChanging(topLevelMember.CLayerName, target, member.CLayerName); // ((IEntityChangeTracker)entry).EntityComplexMemberChanged(topLevelMember.CLayerName, target, member.CLayerName); // // However, we have no way of getting the topLevelMember.CLayerName. This is because the value record does not // contain any reference to its parent. (In non-POCO, ComplexObject takes care of this.) // Therefore, in this case we are going to just call a localized DetectChanges to make sure that changes in the // complex types are found. // // Note that this case only happens when the entity is POCO and complex types are set through the CurrentValues // object. This is probably not a very common pattern. member.SetValue(target, value); if (entry.State != EntityState.Added) { // Entry is not Detached - checked in ValidateState() in EntityEntry.SetCurrentEntityValue entry.DetectChangesInProperties(true); } } } // See IChangeTrackingStrategy documentation public void UpdateCurrentValueRecord(object value, EntityEntry entry) { // No change tracker, but may or may not be a proxy entry.UpdateRecordWithoutSetModified(value, entry.CurrentValues); entry.DetectChangesInProperties(false); } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu

This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- TimersDescriptionAttribute.cs
- FillBehavior.cs
- RankException.cs
- BitConverter.cs
- XmlDictionaryReaderQuotas.cs
- WebPartsPersonalizationAuthorization.cs
- WindowsListViewGroupHelper.cs
- InkCanvas.cs
- GeometryHitTestResult.cs
- ChineseLunisolarCalendar.cs
- XmlSchemaSimpleContent.cs
- DataGridViewMethods.cs
- ExtractCollection.cs
- CroppedBitmap.cs
- TabControlEvent.cs
- AccessDataSourceView.cs
- BufferedGraphicsManager.cs
- _SecureChannel.cs
- serverconfig.cs
- SafeViewOfFileHandle.cs
- ColorConvertedBitmap.cs
- CommandDevice.cs
- RewritingPass.cs
- XmlSchemaSimpleContentExtension.cs
- ListItemConverter.cs
- QilLoop.cs
- Matrix3D.cs
- DataGridViewElement.cs
- CapabilitiesAssignment.cs
- ColorAnimationBase.cs
- PathStreamGeometryContext.cs
- BaseCodeDomTreeGenerator.cs
- EncoderReplacementFallback.cs
- ObjectDataSourceDisposingEventArgs.cs
- DefaultExpressionVisitor.cs
- WindowsFormsHost.cs
- RectValueSerializer.cs
- SymbolMethod.cs
- CodeDOMUtility.cs
- CatalogZoneBase.cs
- EntityUtil.cs
- CompilerInfo.cs
- LinqDataSourceDisposeEventArgs.cs
- SelectionUIService.cs
- RegexWriter.cs
- DesignerProperties.cs
- OutputCacheProfile.cs
- ListView.cs
- XPathLexer.cs
- TextStore.cs
- ThreadSafeList.cs
- XmlTextAttribute.cs
- VariableAction.cs
- SqlFunctions.cs
- CreateUserWizardAutoFormat.cs
- VisualStyleRenderer.cs
- ClientSideProviderDescription.cs
- PrimitiveCodeDomSerializer.cs
- HitTestDrawingContextWalker.cs
- SByte.cs
- SqlUDTStorage.cs
- DebugInfoExpression.cs
- DBParameter.cs
- SqlDataSourceView.cs
- PerfCounterSection.cs
- JoinGraph.cs
- SoapCodeExporter.cs
- GetMemberBinder.cs
- Hashtable.cs
- AppearanceEditorPart.cs
- SqlWriter.cs
- EncodingNLS.cs
- XPathArrayIterator.cs
- FunctionImportElement.cs
- BinaryMessageFormatter.cs
- WebProxyScriptElement.cs
- InvalidOperationException.cs
- ReadOnlyTernaryTree.cs
- ContractUtils.cs
- ButtonBase.cs
- ModifiableIteratorCollection.cs
- ValueTypeFixupInfo.cs
- ALinqExpressionVisitor.cs
- TagNameToTypeMapper.cs
- Parameter.cs
- DayRenderEvent.cs
- HashCodeCombiner.cs
- ParseNumbers.cs
- BindingBase.cs
- XmlToDatasetMap.cs
- Command.cs
- ServiceNameElementCollection.cs
- Instrumentation.cs
- ShapeTypeface.cs
- DockPatternIdentifiers.cs
- TextContainerChangeEventArgs.cs
- MenuItemBinding.cs
- HyperLinkField.cs
- ArrayList.cs
- XmlSchemaGroup.cs