Added support for property change with same object instance (via WrappedValue).

apps/tests/observable-tests.ts

@@ -491,3 +491,51 @@ export function test_ObservablesCreatedWithJSON_shouldNotEmitTwoTimesPropertyCha
 
     TKUnit.assertEqual(propertyChangeCounter, 1, "PropertyChange event should be fired only once for a single change.");
 }
+
+export function test_ObservableShouldEmitPropertyChangeWithSameObjectUsingWrappedValue() {
+    var testArray = [1];
+    var testObservable = new observable.Observable({ "property1": testArray});
+    var propertyChangeCounter = 0;
+    var propertyChangeHandler = function (args) {
+        propertyChangeCounter++;
+    }
+    testObservable.on(observable.Observable.propertyChangeEvent, propertyChangeHandler);
+    testArray.push(2);
+    
+    testObservable.set("property1", testArray);
+
+    TKUnit.assertEqual(propertyChangeCounter, 0, "PropertyChange event should not be fired when the same object instance is passed.");
+    
+    testObservable.set("property1", observable.WrappedValue.wrap(testArray));
+
+    TKUnit.assertEqual(propertyChangeCounter, 1, "PropertyChange event should be fired only once for a single change.");
+}
+
+export function test_CorrectEventArgsWhenWrappedValueIsUsed() {
+    let testArray = [1];
+    let testObservable = new observable.Observable({ "property1": testArray});
+    let actualArgsValue = 0;
+    let propertyChangeHandler = function (args) {
+        actualArgsValue = args.value;
+        
+    }
+    testObservable.on(observable.Observable.propertyChangeEvent, propertyChangeHandler);
+    testArray.push(2);
+    
+    let wrappedArray = observable.WrappedValue.wrap(testArray);
+    
+    testObservable.set("property1", wrappedArray);
+
+    TKUnit.assertEqual(actualArgsValue, wrappedArray, "PropertyChange event should be fired with correct value in arguments.");
+}
+
+export function test_CorrectPropertyValueAfterUsingWrappedValue() {
+    let testArray = [1];
+    let testObservable = new observable.Observable({ "property1": testArray});
+    
+    let wrappedArray = observable.WrappedValue.wrap(testArray);
+    
+    testObservable.set("property1", wrappedArray);
+
+    TKUnit.assertEqual(testObservable.get("property1"), testArray, "WrappedValue is used only to execute property change logic and unwrapped value should be used as proeprty value.");
+}

data/observable/observable.d.ts

@@ -30,6 +30,37 @@ declare module "data/observable" {
         value: any;
     }
     
+    /**
+     * Helper class that is used to fire property change even when real object is the same.
+     * By default property change will not be fired for a same object.
+     * By wrapping object into a WrappedValue instance `same object restriction` will be passed.
+     */
+    class WrappedValue {
+        /**
+         * Property which holds the real value.
+         */
+        wrapped: any;
+        
+        /**
+         * Creates an instance of WrappedValue object.
+         * @param value - the real value which should be wrapped.
+         */
+        constructor(value: any);
+        
+        /**
+         * Gets the real value of previously wrappedValue.
+         * @param value - Value that should be unwraped. If there is no wrappedValue property of the value object then value will be returned.
+         */
+        static unwrap(value: any): any;
+        
+        /**
+         * Returns an instance of WrappedValue. The actual instance is get from a WrappedValues pool.
+         * @param value - Value that should be wrapped. 
+         */
+        static wrap(value: any): WrappedValue
+
+    } 
+
     /**
      * Observable is used when you want to be notified when a change occurs. Use on/off methods to add/remove listener.
      */

data/observable/observable.ts

@@ -6,6 +6,45 @@ interface ListenerEntry {
     thisArg: any;
 }
 
+var _wrappedIndex = 0;
+
+export class WrappedValue implements definition.WrappedValue {
+    private _wrapped: any;
+    
+    public get wrapped(): any {
+        return this._wrapped;
+    }
+    
+    public set wrapped(value) {
+        this._wrapped = value;
+    }
+    
+    constructor(value: any) {
+        this._wrapped = value;
+    }
+    
+    public static unwrap(value: any) {
+        if (value && value.wrapped) {
+            return value.wrapped;
+        }
+        return value;
+    }
+    
+    public static wrap(value: any) {
+        var w = _wrappedValues[_wrappedIndex++ % 5];
+        w.wrapped = value;
+        return w;
+    }
+}
+
+var _wrappedValues = [
+    new WrappedValue(null),
+    new WrappedValue(null),
+    new WrappedValue(null),
+    new WrappedValue(null),
+    new WrappedValue(null)
+]
+
 export class Observable implements definition.Observable {
     public static propertyChangeEvent = "propertyChange";
     private _map: Map<string, Object>;
@@ -126,7 +165,8 @@ export class Observable implements definition.Observable {
 
     public _setCore(data: definition.PropertyChangeData) {
         this.disableNotifications[data.propertyName] = true;
-        this[data.propertyName] = data.value;
+        let newValue = WrappedValue.unwrap(data.value);
+        this[data.propertyName] = newValue;
         delete this.disableNotifications[data.propertyName];
     }
 

ui/core/dependency-observable.ts

@@ -1,5 +1,5 @@
 import definition = require("ui/core/dependency-observable");
-import observable = require("data/observable");
+import {Observable, WrappedValue} from "data/observable";
 import types = require("utils/types");
 
 // use private variables in the scope of the module rather than static members of the class since a member is still accessible through JavaScript and may be changed.
@@ -263,7 +263,7 @@ export class PropertyEntry implements definition.PropertyEntry {
 
 var defaultValueForPropertyPerType: Map<string, any> = new Map<string, any>();
 
-export class DependencyObservable extends observable.Observable {
+export class DependencyObservable extends Observable {
     private _propertyEntries = {};
 
     public set(name: string, value: any) {
@@ -285,8 +285,9 @@ export class DependencyObservable extends observable.Observable {
     }
 
     public _setValue(property: Property, value: any, source?: number) {
-        if (!property.isValidValue(value)) {
+        let realValue = WrappedValue.unwrap(value);
-            throw new Error("Invalid value " + value + " for property " + property.name);
+        if (!property.isValidValue(realValue)) {
+            throw new Error("Invalid value " + realValue + " for property " + property.name);
         }
 
         if (types.isUndefined(source)) {
@@ -350,17 +351,18 @@ export class DependencyObservable extends observable.Observable {
     }
 
     public _onPropertyChanged(property: Property, oldValue: any, newValue: any) {
+        let realNewValue = WrappedValue.unwrap(newValue); 
         if (property.metadata.onValueChanged) {
             property.metadata.onValueChanged({
                 object: this,
                 property: property,
-                eventName: observable.Observable.propertyChangeEvent,
+                eventName: Observable.propertyChangeEvent,
-                newValue: newValue,
+                newValue: realNewValue,
                 oldValue: oldValue
             });
         }
 
-        if (this.hasListeners(observable.Observable.propertyChangeEvent)) {
+        if (this.hasListeners(Observable.propertyChangeEvent)) {
             var changeData = super._createPropertyChangeData(property.name, newValue);
             this.notify(changeData);
         }
@@ -371,7 +373,7 @@ export class DependencyObservable extends observable.Observable {
                 eventName: eventName,
                 propertyName: property.name,
                 object: this,
-                value: newValue
+                value: realNewValue
             }
             this.notify(ngChangedData);
         }
@@ -399,10 +401,10 @@ export class DependencyObservable extends observable.Observable {
     }
 
     private _setValueInternal(property: Property, value: any, source: number) {
-
+        let realValue = WrappedValue.unwrap(value);
         // Convert the value to the real property type in case it is coming as a string from CSS or XML.
-        if (types.isString(value) && property.valueConverter) {
+        if (types.isString(realValue) && property.valueConverter) {
-            value = property.valueConverter(value);
+            realValue = property.valueConverter(realValue);
         }
 
         var entry: PropertyEntry = this._propertyEntries[property.id];
@@ -415,21 +417,21 @@ export class DependencyObservable extends observable.Observable {
 
         switch (source) {
             case ValueSource.Css:
-                entry.cssValue = value;
+                entry.cssValue = realValue;
                 break;
             case ValueSource.Inherited:
-                entry.inheritedValue = value;
+                entry.inheritedValue = realValue;
                 break;
             case ValueSource.Local:
-                entry.localValue = value;
+                entry.localValue = realValue;
                 break;
             case ValueSource.VisualState:
-                entry.visualStateValue = value;
+                entry.visualStateValue = realValue;
                 break;
         }
 
         var comparer: (x: any, y: any) => boolean = property.metadata.equalityComparer || this._defaultComparer;
-        if (!comparer(currentValue, entry.effectiveValue)) {
+        if ((value && value.wrapped) || !comparer(currentValue, entry.effectiveValue)) {
             this._onPropertyChanged(property, currentValue, entry.effectiveValue);
         }
     }