Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Objects / DataClasses / EntityObject.cs / 1305376 / EntityObject.cs
//---------------------------------------------------------------------- //// Copyright (c) Microsoft Corporation. All rights reserved. // // // @owner [....] // @backupOwner [....] //--------------------------------------------------------------------- using System.Data; using System.Diagnostics; using System.Reflection; using System.ComponentModel; using System.Runtime.Serialization; namespace System.Data.Objects.DataClasses { ////// This is the class is the basis for all perscribed EntityObject classes. /// [DataContract(IsReference=true)] [Serializable] public abstract class EntityObject : StructuralObject, IEntityWithKey, IEntityWithChangeTracker, IEntityWithRelationships { #region Privates // The following 2 fields are serialized. Adding or removing a serialized field is considered // a breaking change. This includes changing the field type or field name of existing // serialized fields. If you need to make this kind of change, it may be possible, but it // will require some custom serialization/deserialization code. private RelationshipManager _relationships; private EntityKey _entityKey; [NonSerialized] private IEntityChangeTracker _entityChangeTracker = s_detachedEntityChangeTracker; [NonSerialized] private static readonly DetachedEntityChangeTracker s_detachedEntityChangeTracker = new DetachedEntityChangeTracker(); ////// Helper class used when we are not currently attached to a change tracker. /// Simplifies the code so we don't always have to check for null before using the change tracker /// private class DetachedEntityChangeTracker : IEntityChangeTracker { void IEntityChangeTracker.EntityMemberChanging(string entityMemberName) { } void IEntityChangeTracker.EntityMemberChanged(string entityMemberName) { } void IEntityChangeTracker.EntityComplexMemberChanging(string entityMemberName, object complexObject, string complexMemberName) { } void IEntityChangeTracker.EntityComplexMemberChanged(string entityMemberName, object complexObject, string complexMemberName) { } EntityState IEntityChangeTracker.EntityState { get { return EntityState.Detached; } } } private IEntityChangeTracker EntityChangeTracker { get { if (_entityChangeTracker == null) { _entityChangeTracker = s_detachedEntityChangeTracker; } return _entityChangeTracker; } set { _entityChangeTracker = value; } } #endregion #region Publics ////// The storage state of this EntityObject /// ////// This property returns a value from the EntityState enum. /// [System.ComponentModel.Browsable(false)] [System.Xml.Serialization.XmlIgnore] public EntityState EntityState { get { Debug.Assert(EntityChangeTracker != null, "EntityChangeTracker should never return null -- if detached should be set to s_detachedEntityChangeTracker"); Debug.Assert(EntityChangeTracker != s_detachedEntityChangeTracker ? EntityChangeTracker.EntityState != EntityState.Detached : true, "Should never get a detached state from an attached change tracker."); return EntityChangeTracker.EntityState; } } #region IEntityWithKey ////// Returns the EntityKey for this EntityObject. /// [Browsable(false)] [DataMember] public EntityKey EntityKey { get { return _entityKey; } set { // Report the change to the change tracker // If we are not attached to a change tracker, we can do anything we want to the key // If we are attached, the change tracker should make sure the new value is valid for the current state Debug.Assert(EntityChangeTracker != null, "_entityChangeTracker should never be null -- if detached it should return s_detachedEntityChangeTracker"); EntityChangeTracker.EntityMemberChanging(StructuralObject.EntityKeyPropertyName); _entityKey = value; EntityChangeTracker.EntityMemberChanged(StructuralObject.EntityKeyPropertyName); } } #endregion #region IEntityWithChangeTracker ////// Used by the ObjectStateManager to attach or detach this EntityObject to the cache. /// /// /// Reference to the ObjectStateEntry that contains this entity /// void IEntityWithChangeTracker.SetChangeTracker(IEntityChangeTracker changeTracker) { // Fail if the change tracker is already set for this EntityObject and it's being set to something different // If the original change tracker is associated with a disposed ObjectStateManager, then allow // the entity to be attached if (changeTracker != null && EntityChangeTracker != s_detachedEntityChangeTracker && !Object.ReferenceEquals(changeTracker, EntityChangeTracker)) { EntityEntry entry = EntityChangeTracker as EntityEntry; if (entry == null || !entry.ObjectStateManager.IsDisposed) { throw EntityUtil.EntityCantHaveMultipleChangeTrackers(); } } EntityChangeTracker = changeTracker; } #endregion IEntityWithChangeTracker #region IEntityWithRelationships ////// Returns the container for the lazily created relationship /// navigation property objects, collections and refs. /// RelationshipManager IEntityWithRelationships.RelationshipManager { get { if (_relationships == null) { _relationships = RelationshipManager.Create(this); } return _relationships; } } #endregion #endregion #region Protected Change Tracking Methods ////// This method is called whenever a change is going to be made to an EntityObject /// property. /// /// /// The name of the changing property. /// ////// When parameter member is null (Nothing in Visual Basic). /// protected sealed override void ReportPropertyChanging( string property) { EntityUtil.CheckStringArgument(property, "property"); Debug.Assert(EntityChangeTracker != null, "_entityChangeTracker should never be null -- if detached it should return s_detachedEntityChangeTracker"); base.ReportPropertyChanging(property); EntityChangeTracker.EntityMemberChanging(property); } ////// This method is called whenever a change is made to an EntityObject /// property. /// /// /// The name of the changed property. /// ////// When parameter member is null (Nothing in Visual Basic). /// protected sealed override void ReportPropertyChanged( string property) { EntityUtil.CheckStringArgument(property, "property"); Debug.Assert(EntityChangeTracker != null, "EntityChangeTracker should never return null -- if detached it should be return s_detachedEntityChangeTracker"); EntityChangeTracker.EntityMemberChanged(property); base.ReportPropertyChanged(property); } #endregion #region Internal ComplexObject Change Tracking Methods and Properties internal sealed override bool IsChangeTracked { get { return EntityState != EntityState.Detached; } } ////// This method is called by a ComplexObject contained in this Entity /// whenever a change is about to be made to a property of the /// ComplexObject so that the change can be forwarded to the change tracker. /// /// /// The name of the top-level entity property that contains the ComplexObject that is calling this method. /// /// /// The instance of the ComplexObject on which the property is changing. /// /// /// The name of the changing property on complexObject. /// internal sealed override void ReportComplexPropertyChanging( string entityMemberName, ComplexObject complexObject, string complexMemberName) { Debug.Assert(complexObject != null, "invalid complexObject"); Debug.Assert(!String.IsNullOrEmpty(complexMemberName), "invalid complexMemberName"); EntityChangeTracker.EntityComplexMemberChanging(entityMemberName, complexObject, complexMemberName); } ////// This method is called by a ComplexObject contained in this Entity /// whenever a change has been made to a property of the /// ComplexObject so that the change can be forwarded to the change tracker. /// /// /// The name of the top-level entity property that contains the ComplexObject that is calling this method. /// /// /// The instance of the ComplexObject on which the property is changing. /// /// /// The name of the changing property on complexObject. /// internal sealed override void ReportComplexPropertyChanged( string entityMemberName, ComplexObject complexObject, string complexMemberName) { Debug.Assert(complexObject != null, "invalid complexObject"); Debug.Assert(!String.IsNullOrEmpty(complexMemberName), "invalid complexMemberName"); EntityChangeTracker.EntityComplexMemberChanged(entityMemberName, complexObject, complexMemberName); } #endregion } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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