Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Data.Entity/System/Data/Objects/DataClasses/IEntityWithKey.cs

@@ -0,0 +1,29 @@
+//---------------------------------------------------------------------
+// <copyright file="IEntityWithKey.cs" company="Microsoft">
+//      Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//
+// @owner       barryfr
+// @backupOwner sparra
+//---------------------------------------------------------------------
+using System.Data.Objects;
+using System.Reflection;
+
+namespace System.Data.Objects.DataClasses
+{
+    /// <summary>
+    /// Interface that defines an entity containing a key.
+    /// </summary>
+    public interface IEntityWithKey
+    {
+        /// <summary>
+        /// Returns the EntityKey for this entity.
+        /// If an object is being managed by a change tracker, it is expected that
+        /// IEntityChangeTracker methods EntityMemberChanging and EntityMemberChanged will be
+        /// used to report changes on EntityKey. This allows the change tracker to validate the
+        /// EntityKey's new value and to verify if the change tracker is in a state where it can
+        /// allow updates to the EntityKey.
+        /// </summary>
+        EntityKey EntityKey { get; set; }
+    }
+}