Prevent valueChanges event when patchValue method is used with emitEvent=false

src/core/events-strategy.ts

@@ -67,11 +67,15 @@ export class NgEventsStrategy {
 
 export class EmitterHelper {
     strategy: NgEventsStrategy;
+    lockedValueChangeEvent = false;
 
     constructor(ngZone: NgZone, public component: DxComponent) {
         this.strategy = new NgEventsStrategy(component, ngZone);
     }
     fireNgEvent(eventName: string, eventArgs: any) {
+        if (this.lockedValueChangeEvent && eventName === 'valueChange') {
+            return;
+        }
         let emitter = this.component[eventName];
         if (emitter) {
             emitter.next(eventArgs && eventArgs[0]);

templates/component.tst

@@ -147,7 +147,9 @@ export class <#= it.className #>Component extends <#= baseClass #> <#? implement
     }
 <#? it.isEditor #>
     writeValue(value: any): void {
+        this.eventHelper.lockedValueChangeEvent = true;
         this.value = value;
+        this.eventHelper.lockedValueChangeEvent = false;
     }
 <#? it.widgetName !== "dxRangeSelector" #>
     setDisabledState(isDisabled: boolean): void {

tests/src/ui/custom-value-accessor-implementation.spec.ts

@@ -78,6 +78,7 @@ describe('DxTextBox value accessor', () => {
 
         expect(instance.option('disabled')).toBe(false);
     }));
+
     it('should change the value', async(() => {
         let fixture = TestBed.createComponent(TestContainerComponent);
         fixture.detectChanges();
@@ -89,6 +90,7 @@ describe('DxTextBox value accessor', () => {
 
         expect(instance.option('value')).toBe('text');
     }));
+
     it('should change touched option', async(() => {
         let fixture = TestBed.createComponent(TestContainerComponent);
         fixture.detectChanges();
@@ -102,4 +104,23 @@ describe('DxTextBox value accessor', () => {
 
         expect(fixture.componentInstance.formControl.touched).toBe(true);
     }));
+
+    it('should not fire valueChanges event when patchValue method is used with emitEvent=false (T614207)', () => {
+        let fixture = TestBed.createComponent(TestContainerComponent);
+        fixture.detectChanges();
+
+        let component = fixture.componentInstance,
+            form = component.form,
+            testSpy = jasmine.createSpy('testSpy');
+
+        form.valueChanges.subscribe(testSpy);
+
+        form.controls['formControl'].patchValue('text', { emitEvent: false });
+        fixture.detectChanges();
+        expect(testSpy).toHaveBeenCalledTimes(0);
+
+        form.controls['formControl'].patchValue('text2');
+        fixture.detectChanges();
+        expect(testSpy).toHaveBeenCalledTimes(1);
+    });
 });