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//---------------------------------------------------------------------
// <copyright file="ObjectSet.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
// ObjectSet<TEntity> is a wrapper around ObjectQuery<TEntity> and CUD
// methods on the ObjectContext. It provides a single source that can
// be used to build queries over an EntitySet as well as perform CUD operations.
//
// devnote: This methods on this class are expected to behave exactly
// like the ObjectContext methods to which they delegate. Therefore,
// they should do very little, if any, extra work aside from a
// single call to delegate to the appropriate ObjectContext method.
// The only exceptions to this are cases where we need to do
// additional validation that is specific to ObjectSet, such as
// verifying that an object is in the appropriate EntitySet during
// DeleteObject and Detach operations. We also should not override
// or otherwise change ObjectQuery<T> behavior. Users should be able to
// use an ObjectSet<TEntity> in exactly the same ways they can use an
// ObjectQuery<T>, except for the fact that the CommandText is
// determined by the EntitySet name, and cannot be controlled by the user.
//---------------------------------------------------------------------
using System.Collections;
using System.Collections.Generic;
using System.Data.Metadata.Edm;
using System.Globalization;
using System.Diagnostics;
namespace System.Data.Objects
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix")]
public class ObjectSet<TEntity> : ObjectQuery<TEntity>, IObjectSet<TEntity>
where TEntity : class
{
private readonly EntitySet _entitySet;
#region Internal Constructors
/// <summary>
/// Creates a new ObjectSet that has a base ObjectQuery with the CommandText that represents
/// all of the entities in the specified EntitySet.
/// Sets the query's command text to the fully-qualified, quoted, EntitySet name, i.e. [EntityContainerName].[EntitySetName]
/// Explicitly set MergeOption to AppendOnly in order to mirror CreateQuery behavior
/// </summary>
/// <param name="entitySet">Metadata EntitySet on which to base the ObjectSet.</param>
/// <param name="context">ObjectContext to be used for the query and data modification operations.</param>
internal ObjectSet(EntitySet entitySet, ObjectContext context)
: base(entitySet, context, MergeOption.AppendOnly)
{
Debug.Assert(entitySet != null, "ObjectSet constructor requires a non-null EntitySet");
Debug.Assert(context != null, "ObjectSet constructor requires a non-null ObjectContext");
_entitySet = entitySet;
}
#endregion
#region Public Properties
/// <summary>
/// Provides metadata for the EntitySet that is represented by the ObjectSet
/// </summary>
public EntitySet EntitySet
{
get
{
return _entitySet;
}
}
#endregion
#region Public Methods
/// <summary>
/// Adds an object to the ObjectContext using the EntitySet referenced by this ObjectSet.
/// See ObjectContext.AddObject for more details.
/// </summary>
/// <param name="entity">Entity to be added</param>
public void AddObject(TEntity entity)
{
// this method is expected to behave exactly like ObjectContext.AddObject -- see devnote at the top of this class
this.Context.AddObject(FullyQualifiedEntitySetName, entity);
}
/// <summary>
/// Attaches an object to the ObjectContext using the EntitySet referenced by this ObjectSet.
/// See ObjectContext.AttachTo for more details.
/// </summary>
/// <param name="entity">Entity to be attached</param>
public void Attach(TEntity entity)
{
// this method is expected to behave exactly like ObjectContext.AttachTo -- see devnote at the top of this class
this.Context.AttachTo(FullyQualifiedEntitySetName, entity);
}
/// <summary>
/// Deletes an object from the ObjectContext. Validates that the object is in the referenced EntitySet in the context.
/// See ObjectContext.DeleteObject for more details.
/// </summary>
/// <param name="entity">Entity to be deleted.</param>
/// <exception cref="InvalidOperationException">Throws if the specified object is not in the EntitySet.</exception>
public void DeleteObject(TEntity entity)
{
// this method is expected to behave exactly like ObjectContext.DeleteObject -- see devnote at the top of this class
// Note that in this case we use an internal DeleteObject overload so we can have the context validate
// the EntitySet after it verifies that the specified object is in the context at all.
this.Context.DeleteObject(entity, EntitySet);
}
/// <summary>
/// Detaches an object from the ObjectContext. Validates that the object is in the referenced EntitySet in the context.
/// See ObjectContext.Detach for more details.
/// </summary>
/// <param name="entity">Entity to be detached.</param>
/// <exception cref="InvalidOperationException">Throws if the specified object is not in the EntitySet.</exception>
public void Detach(TEntity entity)
{
// this method is expected to behave exactly like ObjectContext.Detach -- see devnote at the top of this class
// Note that in this case we use an internal Detach overload so we can have the context validate
// the EntitySet after it verifies that the specified object is in the context at all.
this.Context.Detach(entity, EntitySet);
}
/// <summary>
/// Applies changes from one object to another with the same key in the ObjectContext.
/// See ObjectContext.ApplyCurrentValues for more details.
/// </summary>
/// <param name="TEntity">Entity that contains changes to be applied.</param>
public TEntity ApplyCurrentValues(TEntity currentEntity)
{
// this method is expected to behave exactly like ObjectContext.ApplyCurrentValues -- see devnote at the top of this class
return this.Context.ApplyCurrentValues<TEntity>(FullyQualifiedEntitySetName, currentEntity);
}
/// <summary>
/// Apply modified properties to the original object with the same key in the ObjectContext.
/// See ObjectContext.ApplyOriginalValues for more details.
/// </summary>
/// <param name="TEntity">Entity that contains values to be applied.</param>
public TEntity ApplyOriginalValues(TEntity originalEntity)
{
// this method is expected to behave exactly like ObjectContext.ApplyOriginalValues -- see devnote at the top of this class
return this.Context.ApplyOriginalValues<TEntity>(FullyQualifiedEntitySetName, originalEntity);
}
/// <summary>
/// Create an instance of the type <typeparamref name="TEntity"/>.
/// </summary>
/// <returns>
/// An instance of an object of type <typeparamref name="TEntity"/>.
/// The object will either be an instance of the exact type <typeparamref name="TEntity"/>,
/// or possibly an instance of the proxy type that corresponds to <typeparamref name="TEntity"/>.
/// </returns>
public TEntity CreateObject()
{
return this.Context.CreateObject<TEntity>();
}
/// <summary>
/// Create an instance of the type <typeparamref name="TEntity"/>.
/// </summary>
/// <returns>
/// An instance of an object of type <typeparamref name="TEntity"/>.
/// The object will either be an instance of the exact type <typeparamref name="TEntity"/>,
/// or possibly an instance of the proxy type that corresponds to <typeparamref name="TEntity"/>.
/// </returns>
public T CreateObject<T>() where T : class, TEntity
{
return this.Context.CreateObject<T>();
}
#endregion
#region Private Properties
// Used
private string FullyQualifiedEntitySetName
{
get
{
// Fully-qualified name is used to ensure the ObjectContext can always resolve the EntitySet name
// The identifiers used here should not be escaped with brackets ("[]") because the ObjectContext does not allow escaping for the EntitySet name
return string.Format(CultureInfo.InvariantCulture, "{0}.{1}", _entitySet.EntityContainer.Name, _entitySet.Name);
}
}
#endregion
}
}
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