BaseEntityWrapper.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Objects / Internal / BaseEntityWrapper.cs / 1305376 / BaseEntityWrapper.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 
using System.Collections;
using System.Data.Objects.DataClasses; 
using System.Diagnostics;
using System.Reflection;
using System.Data.Metadata.Edm;
 
namespace System.Data.Objects.Internal
{ 
    ///  
    /// Base class containing common code for different implementations of the IEntityWrapper
    /// interface.  Generally speaking, operations involving the ObjectContext, RelationshipManager 
    /// and raw Entity are handled through this class.
    /// 
    /// The type of entity wrapped
    internal abstract class BaseEntityWrapper : IEntityWrapper 
    {
        // This enum allows boolean flags to be added to the wrapper without introducing a new field 
        // for each one.  This helps keep the wrapper memory footprint small, which is important 
        // in some high-performance NoTracking cases.
        [Flags] 
        private enum WrapperFlags
        {
            None = 0,
            NoTracking = 1, 
            InitializingRelatedEnds = 2,
        } 
 
        private readonly RelationshipManager _relationshipManager;
        private Type _identityType; 
        private WrapperFlags _flags;

        /// 
        /// Constructs a wrapper for the given entity and its associated RelationshipManager. 
        /// 
        /// The entity to be wrapped 
        /// the RelationshipManager associated with this entity 
        protected BaseEntityWrapper(TEntity entity, RelationshipManager relationshipManager)
        { 
            Debug.Assert(!(entity is IEntityWrapper), "Object is an IEntityWrapper instance instead of the raw entity.");
            Debug.Assert(entity != null, "Factory should ensure wrapped entity here is never null.");
            if (relationshipManager == null)
            { 
                throw EntityUtil.UnexpectedNullRelationshipManager();
            } 
            _relationshipManager = relationshipManager; 
        }
 
        /// 
        /// Constructs a wrapper as part of the materialization process.  This constructor is only used
        /// during materialization where it is known that the entity being wrapped is newly constructed.
        /// This means that some checks are not performed that might be needed when thw wrapper is 
        /// created at other times, and information such as the identity type is passed in because
        /// it is readily available in the materializer. 
        ///  
        /// The entity to wrap
        /// The RelationshipManager associated with this entity 
        /// The entity set, or null if none is known
        /// The context to which the entity should be attached
        /// NoTracking for non-tracked entities, AppendOnly otherwise
        /// The type of the entity ignoring any possible proxy type 
        protected BaseEntityWrapper(TEntity entity, RelationshipManager relationshipManager, EntitySet entitySet, ObjectContext context, MergeOption mergeOption, Type identityType)
        { 
            Debug.Assert(!(entity is IEntityWrapper), "Object is an IEntityWrapper instance instead of the raw entity."); 
            Debug.Assert(entity != null, "Factory should ensure wrapped entity here is never null.");
            if (relationshipManager == null) 
            {
                throw EntityUtil.UnexpectedNullRelationshipManager();
            }
            _identityType = identityType; 
            _relationshipManager = relationshipManager;
            RelationshipManager.SetWrappedOwner(this, entity); 
            if (entitySet != null) 
            {
                Context = context; 
                MergeOption = mergeOption;
                RelationshipManager.AttachContextToRelatedEnds(context, entitySet, mergeOption);
            }
 
        }
 
        // See IEntityWrapper documentation 
        public RelationshipManager RelationshipManager
        { 
            get
            {
                return _relationshipManager;
            } 
        }
 
        // See IEntityWrapper documentation 
        public ObjectContext Context
        { 
            get;
            set;
        }
 
        // See IEntityWrapper documentation
        public MergeOption MergeOption 
        { 
            get
            { 
                return (_flags & WrapperFlags.NoTracking) != 0 ? MergeOption.NoTracking : MergeOption.AppendOnly;
            }
            private set
            { 
                Debug.Assert(value == MergeOption.AppendOnly || value == MergeOption.NoTracking, "Merge option must be one of NoTracking or AppendOnly.");
                if (value == MergeOption.NoTracking) 
                { 
                    _flags |= WrapperFlags.NoTracking;
                } 
                else
                {
                    _flags &= ~WrapperFlags.NoTracking;
                } 
            }
        } 
 
        // See IEntityWrapper documentation
        public bool InitializingProxyRelatedEnds 
        {
            get
            {
                return (_flags & WrapperFlags.InitializingRelatedEnds) != 0; 
            }
            set 
            { 
                if (value)
                { 
                    _flags |= WrapperFlags.InitializingRelatedEnds;
                }
                else
                { 
                    _flags &= ~WrapperFlags.InitializingRelatedEnds;
                } 
            } 
        }
 
        // See IEntityWrapper documentation
        public void AttachContext(ObjectContext context, EntitySet entitySet, MergeOption mergeOption)
        {
            Debug.Assert(null != context, "context"); 
            Context = context;
            MergeOption = mergeOption; 
            if (entitySet != null) 
            {
                RelationshipManager.AttachContextToRelatedEnds(context, entitySet, mergeOption); 
            }
        }

        // See IEntityWrapper documentation 
        public void ResetContext(ObjectContext context, EntitySet entitySet, MergeOption mergeOption)
        { 
            Debug.Assert(null != entitySet, "entitySet should not be null"); 
            Debug.Assert(null != context, "context");
            Debug.Assert(MergeOption.NoTracking == mergeOption || 
                         MergeOption.AppendOnly == mergeOption,
                         "mergeOption");

            if (!object.ReferenceEquals(Context, context)) 
            {
                Context = context; 
                MergeOption = mergeOption; 
                RelationshipManager.ResetContextOnRelatedEnds(context, entitySet, mergeOption);
            } 
        }

        // See IEntityWrapper documentation
        public void DetachContext() 
        {
            if (Context != null && 
                Context.ObjectStateManager.TransactionManager.IsAttachTracking && 
                Context.ObjectStateManager.TransactionManager.OriginalMergeOption == MergeOption.NoTracking)
            { 
                // If AttachTo() failed while attaching graph retrieved with NoTracking option,
                // we don't want to clear the Context property of the wrapped entity
                MergeOption = MergeOption.NoTracking;
            } 
            else
            { 
                Context = null; 
            }
 
            RelationshipManager.DetachContextFromRelatedEnds();
        }

        // See IEntityWrapper documentation 
        public EntityEntry ObjectStateEntry
        { 
            get; 
            set;
        } 

        // See IEntityWrapper documentation
        public Type IdentityType
        { 
            get
            { 
                if (_identityType == null) 
                {
                    _identityType = EntityUtil.GetEntityIdentityType(typeof(TEntity)); 
                }
                return _identityType;
            }
        } 

        // All these methods defined by IEntityWrapper 
        public abstract void EnsureCollectionNotNull(RelatedEnd relatedEnd); 
        public abstract EntityKey EntityKey { get; set; }
        public abstract bool OwnsRelationshipManager 
        {
            get;
        }
        public abstract EntityKey GetEntityKeyFromEntity(); 
        public abstract void SetChangeTracker(IEntityChangeTracker changeTracker);
        public abstract void TakeSnapshot(EntityEntry entry); 
        public abstract void TakeSnapshotOfRelationships(EntityEntry entry); 
        public abstract object GetNavigationPropertyValue(RelatedEnd relatedEnd);
        public abstract void SetNavigationPropertyValue(RelatedEnd relatedEnd, object value); 
        public abstract void RemoveNavigationPropertyValue(RelatedEnd relatedEnd, object value);
        public abstract void CollectionAdd(RelatedEnd relatedEnd, object value);
        public abstract bool CollectionRemove(RelatedEnd relatedEnd, object value);
        public abstract object Entity { get; } 
        public abstract TEntity TypedEntity { get; }
        public abstract void SetCurrentValue(EntityEntry entry, StateManagerMemberMetadata member, int ordinal, object target, object value); 
        public abstract void UpdateCurrentValueRecord(object value, EntityEntry entry); 
        public abstract bool RequiresRelationshipChangeTracking { get; }
        public abstract bool RequiresScalarChangeTracking { get; } 
        public abstract bool RequiresComplexChangeTracking { get; }
        public abstract bool RequiresAnyChangeTracking { get; }
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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BaseEntityWrapper.cs source code in C# .NET

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