Fixed Issue ##1235: ObservableArray does not raise its change event when its `length' property is set.

apps/tests/observable-array-tests.ts

@@ -606,6 +606,46 @@ export var test_ObservableArray_lastIndexOfShouldReturnCorrectIndexStartingFrom
     TKUnit.assert(result === 1, "ObservableArray lastIndexOf() should return correct index!");
 };
 
+export var test_ObservableArray_settingLengthToZeroPerformsSplice = function () {
+    var array = new observableArrayModule.ObservableArray([1, 2, 3]);
+
+    var changeRaised = false;
+    array.on("change", (args: observableArrayModule.ChangedData<number>) => {
+        changeRaised = true;
+        TKUnit.assertEqual(args.object, array);
+        TKUnit.assertEqual(args.eventName, "change");
+        TKUnit.assertEqual(args.action, observableArrayModule.ChangeType.Splice);
+        TKUnit.assertEqual(args.index, 0);
+        TKUnit.assertEqual(args.addedCount, 0);
+        TKUnit.arrayAssert(args.removed, [1, 2, 3]);
+    });
+
+    array.length = 0;
+
+    TKUnit.assertEqual(array.length, 0);
+    TKUnit.assertTrue(changeRaised);
+};
+
+export var test_ObservableArray_settingLengthToSomethingPerformsSplice = function () {
+    var array = new observableArrayModule.ObservableArray([1, 2, 3]);
+
+    var changeRaised = false;
+    array.on("change", (args: observableArrayModule.ChangedData<number>) => {
+        changeRaised = true;
+        TKUnit.assertEqual(args.object, array);
+        TKUnit.assertEqual(args.eventName, "change");
+        TKUnit.assertEqual(args.action, observableArrayModule.ChangeType.Splice);
+        TKUnit.assertEqual(args.index, 1);
+        TKUnit.assertEqual(args.addedCount, 0);
+        TKUnit.arrayAssert(args.removed, [2, 3]);
+    });
+
+    array.length = 1;
+
+    TKUnit.assertEqual(array.length, 1);
+    TKUnit.assertTrue(changeRaised);
+};
+
 var array = new observableArrayModule.ObservableArray();
 
 // We do not have indexer!

data/observable-array/observable-array.ts

@@ -70,8 +70,7 @@ export class ObservableArray<T> extends observable.Observable implements observa
     }
     set length(value: number) {
         if (types.isNumber(value) && this._array && this._array.length !== value) {
-            this._array = this._array.slice(0, value);
+            this.splice(value, this._array.length - value);
-            this._notifyLengthChange();
         }
     }