feat(combo,simple-combo): add selectionChanged event (#16968)

georgianastasov · web-flow · commit 7f715de84df2 · 2026-03-13T18:34:19.000+02:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,13 @@
 
 All notable changes for each version of this project will be documented in this file.
 
+## 21.2.0
+
+### New Features
+
+- `IgxCombo`, `IgxSimpleCombo`
+    - Introduced the `selectionChanged` event for both components. The event is not cancelable and is emitted after the selection is committed and the component state is updated.
+
 ## 21.1.0
 
 ### New Features
diff --git a/projects/igniteui-angular/combo/README.md b/projects/igniteui-angular/combo/README.md
@@ -86,6 +86,15 @@ export class MyCombo {
 }
 ```
 
+### Selection Events
+
+The `igx-combo` exposes both `selectionChanging` and `selectionChanged`.
+
+- `selectionChanging` is emitted **before** a new selection state is committed and can be canceled.
+- If `selectionChanging` is not canceled, the component commits the final selection state and then emits `selectionChanged`.
+- `selectionChanged` is emitted **after** the selection completes and the component state is updated.
+- `selectionChanged` is not cancelable and reports the final committed selection state.
+
 ### Value Binding
 
 If we want to use a two-way data-binding, we could just use `ngModel` like this:
@@ -330,7 +339,8 @@ When igxCombo is opened, allow custom values are enabled and add item button is
 
 | Name                | Description                                                             | Cancelable   | Emitted with                      |
 |---------------------|-------------------------------------------------------------------------|--------------|-----------------------------------|
-| `selectionChanging`   | Emitted when item selection is changing, before the selection completes | true         | `IComboSelectionChangingEventArgs`  |
+| `selectionChanging` | Emitted when item selection is changing, before the selection completes | true         | `IComboSelectionChangingEventArgs` |
+| `selectionChanged`  | Emitted after the selection completes and the component state has been updated | false | `IComboSelectionChangedEventArgs` |
 | `searchInputUpdate` | Emitted when an the search input's input event is triggered             | true         | `IComboSearchInputEventArgs`      |
 | `addition`          | Emitted when an item is being added to the data collection              | true         | `IComboItemAdditionEvent`         |
 | `dataPreLoad`       | Emitted when new chunk of data is loaded from the virtualization        | false        | `IForOfState`                     |
diff --git a/projects/igniteui-angular/combo/src/combo/combo.common.ts b/projects/igniteui-angular/combo/src/combo/combo.common.ts
@@ -982,6 +982,7 @@ export abstract class IgxComboBaseDirective implements IgxComboBase, AfterViewCh
 
     public abstract dropdown: IgxComboDropDownComponent;
     public abstract selectionChanging: EventEmitter<any>;
+    public abstract selectionChanged: EventEmitter<any>;
 
     constructor() {
         onResourceChangeHandle(this.destroy$, () => {
diff --git a/projects/igniteui-angular/combo/src/combo/combo.component.spec.ts b/projects/igniteui-angular/combo/src/combo/combo.component.spec.ts
@@ -7,7 +7,6 @@ import {
 import { By } from '@angular/platform-browser';
 import { NoopAnimationsModule } from '@angular/platform-browser/animations';
 import { BehaviorSubject, Observable, firstValueFrom } from 'rxjs';
-import { take } from 'rxjs/operators';
 import { IgxSelectionAPIService } from 'igniteui-angular/core';
 import { IBaseCancelableBrowserEventArgs } from 'igniteui-angular/core';
 import { SortingDirection } from '../../../core/src/data-operations/sorting-strategy';
@@ -20,7 +19,7 @@ import { IgxComboDropDownComponent } from './combo-dropdown.component';
 import { IgxComboItemComponent } from './combo-item.component';
 import { IComboFilteringOptions, IGX_COMBO_COMPONENT } from './combo.common';
 import {
-    IComboItemAdditionEvent, IComboSearchInputEventArgs, IComboSelectionChangingEventArgs, IgxComboComponent
+    IComboItemAdditionEvent, IComboSearchInputEventArgs, IComboSelectionChangedEventArgs, IComboSelectionChangingEventArgs, IgxComboComponent
 } from './combo.component';
 import { IgxComboFooterDirective, IgxComboHeaderDirective, IgxComboItemDirective } from './combo.directives';
 import { IgxComboFilteringPipe, comboIgnoreDiacriticsFilter } from './combo.pipes';
@@ -658,6 +657,83 @@ describe('igxCombo', () => {
                 });
                 expect(selectionSpy).toHaveBeenCalledWith(expectedResults);
             });
+            it('should emit selectionChanged after selectionChanging with the committed state', () => {
+                const dropdown = jasmine.createSpyObj('IgxComboDropDownComponent', ['selectItem']);
+                combo.ngOnInit();
+                combo.data = data;
+                combo.dropdown = dropdown;
+                spyOnProperty(combo, 'totalItemCount').and.returnValue(combo.data.length);
+
+                const callOrder: string[] = [];
+                spyOn(combo.selectionChanging, 'emit').and.callFake(() => callOrder.push('changing'));
+                spyOn(combo.selectionChanged, 'emit').and.callFake(() => callOrder.push('changed'));
+
+                const selectedItems = [combo.data[1], combo.data[5]];
+                combo.select(selectedItems);
+
+                expect(callOrder).toEqual(['changing', 'changed']);
+                expect(combo.selectionChanged.emit).toHaveBeenCalledTimes(1);
+                expect(combo.selectionChanged.emit).toHaveBeenCalledWith({
+                    oldValue: [],
+                    newValue: selectedItems,
+                    oldSelection: [],
+                    newSelection: selectedItems,
+                    added: selectedItems,
+                    removed: [],
+                    event: undefined,
+                    owner: combo,
+                    displayText: selectedItems.join(', ')
+                } satisfies IComboSelectionChangedEventArgs);
+            });
+            it('should not emit selectionChanged when selectionChanging is canceled', () => {
+                const dropdown = jasmine.createSpyObj('IgxComboDropDownComponent', ['selectItem']);
+                combo.ngOnInit();
+                combo.data = data;
+                combo.dropdown = dropdown;
+                spyOnProperty(combo, 'totalItemCount').and.returnValue(combo.data.length);
+
+                spyOn(combo.selectionChanging, 'emit').and.callFake((args: IComboSelectionChangingEventArgs) => {
+                    args.cancel = true;
+                });
+                spyOn(combo.selectionChanged, 'emit');
+
+                combo.select([combo.data[1], combo.data[5]]);
+
+                expect(combo.selectionChanging.emit).toHaveBeenCalledTimes(1);
+                expect(combo.selectionChanged.emit).not.toHaveBeenCalled();
+                expect(combo.selection).toEqual([]);
+                expect(combo.value).toEqual([]);
+            });
+            it('should emit selectionChanged with the actual committed state when selectionChanging modifies newValue', () => {
+                const dropdown = jasmine.createSpyObj('IgxComboDropDownComponent', ['selectItem']);
+                combo.ngOnInit();
+                combo.data = data;
+                combo.dropdown = dropdown;
+                spyOnProperty(combo, 'totalItemCount').and.returnValue(combo.data.length);
+
+                spyOn(combo.selectionChanging, 'emit').and.callFake((args: IComboSelectionChangingEventArgs) => {
+                    args.newValue = [combo.data[2], combo.data[4]];
+                    args.displayText = `${combo.data[2]}, ${combo.data[4]}`;
+                });
+
+                spyOn(combo.selectionChanged, 'emit');
+
+                combo.select([combo.data[0], combo.data[1]]);
+
+                expect(combo.selection).toEqual([combo.data[2], combo.data[4]]);
+                expect(combo.value).toEqual([combo.data[2], combo.data[4]]);
+                expect(combo.selectionChanged.emit).toHaveBeenCalledWith({
+                    oldValue: [],
+                    newValue: [combo.data[2], combo.data[4]],
+                    oldSelection: [],
+                    newSelection: [combo.data[2], combo.data[4]],
+                    added: [combo.data[2], combo.data[4]],
+                    removed: [],
+                    event: undefined,
+                    owner: combo,
+                    displayText: `${combo.data[2]}, ${combo.data[4]}`
+                } satisfies IComboSelectionChangedEventArgs);
+            });
             it('should handle select/deselect ALL items', () => {
                 const dropdown = jasmine.createSpyObj('IgxComboDropDownComponent', ['selectItem']);
                 combo.ngOnInit();
@@ -854,7 +930,7 @@ describe('igxCombo', () => {
                     ComboModelBindingComponent,
                     IgxComboBindingDataAfterInitComponent,
                     IgxComboFormComponent,
-                    IgxComboInTemplatedFormComponent
+                    IgxComboInTemplatedFormComponent,
                 ]
             }).compileComponents();
         }));
diff --git a/projects/igniteui-angular/combo/src/combo/combo.component.ts b/projects/igniteui-angular/combo/src/combo/combo.component.ts
@@ -22,26 +22,29 @@ import { IgxInputGroupComponent, IgxInputDirective, IgxReadOnlyInputDirective, I
 import { IgxIconComponent } from 'igniteui-angular/icon';
 import { IgxDropDownItemNavigationDirective } from 'igniteui-angular/drop-down';
 
-/** Event emitted when an igx-combo's selection is changing */
-export interface IComboSelectionChangingEventArgs extends IBaseCancelableEventArgs {
-    /** An array containing the values that are currently selected */
+/** Event emitted when the Combo's selection has changed */
+export interface IComboSelectionChangedEventArgs extends IBaseEventArgs {
+    /** An array containing the old selection values */
     oldValue: any[];
-    /** An array containing the values that will be selected after this event */
+    /** An array containing the new selection items */
     newValue: any[];
-    /** An array containing the items that are currently selected */
+    /** An array containing the old selection items */
     oldSelection: any[];
-    /** An array containing the items that will be selected after this event */
+    /** An array containing the new selection items */
     newSelection: any[];
-    /** An array containing the items that will be added to the selection (if any) */
+    /** An array containing the items added to the selection (if any) */
     added: any[];
-    /** An array containing the items that will be removed from the selection (if any) */
+    /** An array containing the items removed from the selection (if any) */
     removed: any[];
-    /** The text that will be displayed in the combo text box */
+    /** The display text of the combo text box */
     displayText: string;
     /** The user interaction that triggered the selection change */
     event?: Event;
 }
 
+/** Event emitted when the Combo's selection is changing */
+export interface IComboSelectionChangingEventArgs extends IComboSelectionChangedEventArgs, IBaseCancelableEventArgs {}
+
 /** Event emitted when the igx-combo's search input changes */
 export interface IComboSearchInputEventArgs extends IBaseCancelableEventArgs {
     /** The text that has been typed into the search input */
@@ -125,7 +128,6 @@ export class IgxComboComponent extends IgxComboBaseDirective implements AfterVie
     @Input({ transform: booleanAttribute })
     public autoFocusSearch = true;
 
-
     /**
      * Defines the placeholder value for the combo dropdown search field
      *
@@ -154,6 +156,16 @@ export class IgxComboComponent extends IgxComboBaseDirective implements AfterVie
     @Output()
     public selectionChanging = new EventEmitter<IComboSelectionChangingEventArgs>();
 
+    /**
+     * Emitted when item selection is changed, after the selection completes
+     *
+     * ```html
+     * <igx-combo (selectionChanged)='handleSelection()'></igx-combo>
+     * ```
+     */
+    @Output()
+    public selectionChanged = new EventEmitter<IComboSelectionChangedEventArgs>();
+
     /** @hidden @internal */
     @ViewChild(IgxComboDropDownComponent, { static: true })
     public dropdown: IgxComboDropDownComponent;
@@ -423,7 +435,19 @@ export class IgxComboComponent extends IgxComboBaseDirective implements AfterVie
             } else {
                 this._displayValue = this.createDisplayText(this.selection, args.oldSelection);
             }
-            this._onChangeCallback(args.newValue);
+            this._onChangeCallback(this.value);
+            const changedArgs: IComboSelectionChangedEventArgs = {
+                newValue: this.value,
+                oldValue,
+                newSelection: this.selection,
+                oldSelection,
+                added: this.convertKeysToItems(diffInSets(new Set(this.value), new Set(oldValue))),
+                removed: this.convertKeysToItems(diffInSets(new Set(oldValue), new Set(this.value))),
+                event,
+                owner: this,
+                displayText: this._displayValue
+            };
+            this.selectionChanged.emit(changedArgs);
         } else if (this.isRemote) {
             this.registerRemoteEntries(diffInSets(selection, currentSelection), false);
         }
diff --git a/projects/igniteui-angular/simple-combo/README.md b/projects/igniteui-angular/simple-combo/README.md
@@ -85,6 +85,14 @@ export class MyCombo {
 }
 ```
 
+### Selection Events
+
+The `igx-simple-combo` exposes both `selectionChanging` and `selectionChanged`.
+
+- `selectionChanging` is emitted **before** the selection is committed and can be canceled.
+- `selectionChanged` is emitted **after** the selection is committed and the component state is updated.
+- `selectionChanged` is not cancelable and always reports the final committed single selection state.
+
 ### Value Binding
 
 If we want to use a two-way data-binding, we could just use `ngModel` like this:
@@ -305,7 +313,8 @@ When the combo is opened, allow custom values are enabled and add item button is
 ### Events
 | Name                | Description                                                             | Cancelable   | Parameters                              |
 |------------------   |-------------------------------------------------------------------------|------------- |-----------------------------------------|
-| `selectionChanging` | Emitted when item selection is changing, before the selection completes | true         | { oldSelection: `any`, newSelection: `any`,  displayText: `string`, owner: `IgxSimpleComboComponent` } |
+| `selectionChanging` | Emitted when item selection is changing, before the selection completes | true         | { oldValue: `any`, newValue: `any`, oldSelection: `any`, newSelection: `any`, displayText: `string`, owner: `IgxSimpleComboComponent` } |
+| `selectionChanged`  | Emitted after the selection completes and the component state has been updated | false | { oldValue: `any`, newValue: `any`, oldSelection: `any`, newSelection: `any`, displayText: `string`, owner: `IgxSimpleComboComponent` } |
 | `searchInputUpdate`     | Emitted when an the search input's input event is triggered             | true         | `IComboSearchInputEventArgs`               |
 | `addition`        | Emitted when an item is being added to the data collection              | false        | { oldCollection: `Array<any>`, addedItem: `<any>`, newCollection: `Array<any>`, owner: `IgxSimpleComboComponent` }|
 | `onDataPreLoad`     | Emitted when new chunk of data is loaded from the virtualization        | false        |            `IForOfState`          |
diff --git a/projects/igniteui-angular/simple-combo/src/simple-combo/simple-combo.component.spec.ts b/projects/igniteui-angular/simple-combo/src/simple-combo/simple-combo.component.spec.ts
diff --git a/projects/igniteui-angular/simple-combo/src/simple-combo/simple-combo.component.ts b/projects/igniteui-angular/simple-combo/src/simple-combo/simple-combo.component.ts
