Added TryRemove to ConcurrentObservableDictionary and added unit test…

ExamplesAndTests/Swordfish.NET.UnitTestV3/ConcurrentObservableDictionaryTests.cs

@@ -101,6 +101,26 @@ public void AddTest()
             Assert.IsTrue(allItemsPresent, "All items present");
         }
 
+        [TestMethod]
+        public void TestTryRemove()
+        {
+            var testCollection = new ConcurrentObservableDictionary<string, string>();
+            for (int i = 0; i < 10; i++)
+            {
+                testCollection.Add($"Key{i}", $"Value{i}");
+            }
+            Assert.AreEqual(10, testCollection.Count);
+            Assert.IsFalse(testCollection.TryRemove("Key10", out var value));
+            for (int i = 9; i >= 0; i--)
+            {
+                string key = $"Key{i}";
+                string expectedValue = $"Value{i}";
+                Assert.IsTrue(testCollection.TryRemove(key, out var item));
+                Assert.AreEqual(expectedValue, item);
+                Assert.AreEqual(i, testCollection.Count);
+            }
+        }
+
         [TestMethod]
         public void TestManyOperations()
         {

Swordfish.NET.CollectionsV3/ConcurrentObservableDictionary.cs

@@ -182,6 +182,32 @@ public virtual KeyValuePair<TKey, TValue> RemoveAt(int index)
             return localRemovedItem;
         }
 
+        public bool TryRemove(TKey key, out TValue item)
+        {
+            var outputItemAndIndex = DoReadWriteNotify(
+              // Get the list of keys and values from the internal list
+              () => _internalCollection.GetItemAndIndex(key),
+              // remove the keys from the dictionary, remove the range from the list
+              (itemAndIndex) => _internalCollection.Remove(key),
+              // Notify which items were removed
+              (itemAndIndex) => itemAndIndex != null ? new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, itemAndIndex.Item, itemAndIndex.Index) : null
+            );
+
+            // If the return container which holds the item and its index
+            // is not null then asign the item and return true, else
+            // return false.
+            if (outputItemAndIndex != null)
+            {
+                item = outputItemAndIndex.Item.Value;
+                return true;
+            }
+            else
+            {
+                item = default(TValue);
+                return false;
+            }
+        }
+
         public bool Remove(TKey key)
         {
             var retVal = DoReadWriteNotify(