From bb7bc43357b9162832d066bc39ec2ba0dde159ce Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Tue, 14 Apr 2020 16:54:26 +0200
Subject: [PATCH] Added the IDictionary<in TKey> interface

---
 .../DictionarySlim{TKey,TValue}.cs               |  4 ++--
 .../IDictionary{TKey}.cs                         | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 Microsoft.Toolkit.Mvvm/Microsoft.Collections.Extensions/IDictionary{TKey}.cs

diff --git a/Microsoft.Toolkit.Mvvm/Microsoft.Collections.Extensions/DictionarySlim{TKey,TValue}.cs b/Microsoft.Toolkit.Mvvm/Microsoft.Collections.Extensions/DictionarySlim{TKey,TValue}.cs
index c9acfd2a..2c1862ac 100644
--- a/Microsoft.Toolkit.Mvvm/Microsoft.Collections.Extensions/DictionarySlim{TKey,TValue}.cs
+++ b/Microsoft.Toolkit.Mvvm/Microsoft.Collections.Extensions/DictionarySlim{TKey,TValue}.cs
@@ -29,7 +29,7 @@ namespace Microsoft.Collections.Extensions
     /// 3) This means it can avoid storing a comparer, and avoid the likely virtual call to a comparer.
     /// </remarks>
     [DebuggerDisplay("Count = {Count}")]
-    internal sealed class DictionarySlim<TKey, TValue>
+    internal sealed class DictionarySlim<TKey, TValue> : IDictionary<TKey>
         where TKey : struct, IEquatable<TKey>
     {
         // See info in CoreFX labs for how this works
@@ -71,7 +71,7 @@ namespace Microsoft.Collections.Extensions
             _entries = InitialEntries;
         }
 
-        /// <inheritdoc cref="Dictionary{TKey,TValue}.Remove"/>
+        /// <inheritdoc/>
         public bool Remove(TKey key)
         {
             Entry[] entries = _entries;
diff --git a/Microsoft.Toolkit.Mvvm/Microsoft.Collections.Extensions/IDictionary{TKey}.cs b/Microsoft.Toolkit.Mvvm/Microsoft.Collections.Extensions/IDictionary{TKey}.cs
new file mode 100644
index 00000000..e4976feb
--- /dev/null
+++ b/Microsoft.Toolkit.Mvvm/Microsoft.Collections.Extensions/IDictionary{TKey}.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+
+namespace Microsoft.Collections.Extensions
+{
+    /// <summary>
+    /// An interface providing value-invariant access to a <see cref="DictionarySlim{TKey,TValue}"/> instance.
+    /// </summary>
+    /// <typeparam name="TKey">The type of keys in the dictionary.</typeparam>
+    internal interface IDictionary<in TKey>
+        where TKey : struct, IEquatable<TKey>
+    {
+        /// <inheritdoc cref="Dictionary{TKey,TValue}.Remove"/>
+        bool Remove(TKey key);
+    }
+}