Make selectedRows an @Input

CHANGELOG.md

@@ -15,6 +15,8 @@ All notable changes for each version of this project will be documented in this
     - Added `closeOnEscape` - with it, the dialog can be allowed or prevented from closing when `Esc` is pressed.
 - `IgxNavbar`:
     - **Breaking Changes** - The `igx-action-icon` has been renamed to `igx-navbar-action`. It should get renamed in your components via `ng update`;
+- `IgxGrid`, `IgxTreeGrid`, `IgxHierarchicalGrid`
+    - **Breaking Change** - The `selectedRows` method is now an `@Input` property. Setting it to an array of Row IDs will update the grid's selection state, any previous selection will be cleared. Setting it to an empty array will clear the selection entirely.
 - `igxGrid`
     - Added `onScroll` event, which is emitted when the grid is scrolled vertically or horizontally.
     - Each grid now expose a default handling for boolean column types. The column will display `check` or `close` icon, instead of true/false by default. 
@@ -46,6 +48,7 @@ The following example shows how you can use the Indigo theme:
 }
 ```
 
+
 ### New Features
 - `IgxGrid`, `IgxTreeGrid`, `IgxHierarchicalGrid`
     - Introduced `showSummaryOnCollapse` grid property which allows you to control whether the summary row stays visible when the groupBy / parent row is collapsed.

projects/igniteui-angular/src/lib/grids/grid-base.directive.ts

@@ -25,7 +25,9 @@ import {
     InjectionToken,
     Optional,
     DoCheck,
-    Directive
+    Directive,
+    OnChanges,
+    SimpleChanges
 } from '@angular/core';
 import ResizeObserver from 'resize-observer-polyfill';
 import 'igniteui-trial-watermark';
@@ -1093,6 +1095,26 @@ export class IgxGridBaseDirective extends DisplayDensityBase implements
         filteringExpressionsTree: IFilteringExpressionsTree,
         done: (values: any[]) => void) => void;
 
+    /**
+     * Gets/Sets the current selection state.
+     * @remarks
+     * Represents the selected rows' IDs (primary key or rowData)
+     * @example
+     * ```html
+     * <igx-grid [data]="localData" primaryKey="ID" rowSelection="multiple" [selectedRows]="[0, 1, 2]"><igx-grid>
+     * ```
+     */
+    @Input()
+    public set selectedRows(rowIDs: any[]) {
+        rowIDs.length > 0
+            ? this.selectRows(rowIDs, true)
+            : this.deselectAllRows();
+    }
+
+    public get selectedRows(): any[] {
+        return this.selectionService.getSelectedRows();
+    }
+
     /**
      * Emitted when `IgxGridCellComponent` is clicked.
      * @remarks
@@ -5291,18 +5313,6 @@ export class IgxGridBaseDirective extends DisplayDensityBase implements
             [...this.unpinnedDataView, ...this.pinnedDataView];
     }
 
-    /**
-     * Get current selection state.
-     * @example
-     * Returns an array with selected rows' IDs (primaryKey or rowData)
-     * ```typescript
-     * const selectedRows = this.grid.selectedRows();
-     * ```
-     */
-    public selectedRows(): any[] {
-        return this.selectionService.getSelectedRows();
-    }
-
     /**
      * Select specified rows by ID.
      * @example

projects/igniteui-angular/src/lib/grids/grid/grid.groupby.spec.ts

@@ -1022,20 +1022,20 @@ describe('IgxGrid - GroupBy #grid', () => {
             grid.selectAllRows();
             fix.detectChanges();
 
-            expect(grid.selectedRows().length).toEqual(8);
+            expect(grid.selectedRows.length).toEqual(8);
             let rows = fix.debugElement.queryAll(By.css('.igx-grid__tr--selected'));
             for (const r of rows) {
                 expect(r.componentInstance instanceof IgxGridRowComponent).toBe(true);
             }
 
             grid.deselectAllRows();
             fix.detectChanges();
-            expect(grid.selectedRows().length).toEqual(0);
+            expect(grid.selectedRows.length).toEqual(0);
 
             GridSelectionFunctions.clickHeaderRowCheckbox(fix);
             fix.detectChanges();
 
-            expect(grid.selectedRows().length).toEqual(8);
+            expect(grid.selectedRows.length).toEqual(8);
 
             rows = fix.debugElement.queryAll(By.css('.igx-grid__tr--selected'));
             for (const r of rows) {
@@ -1600,7 +1600,7 @@ describe('IgxGrid - GroupBy #grid', () => {
         GridSelectionFunctions.clickRowCheckbox(rows[0].element);
         await wait(100);
         grid.cdr.detectChanges();
-        expect(grid.selectedRows().length).toEqual(1);
+        expect(grid.selectedRows.length).toEqual(1);
         GridSelectionFunctions.verifyRowSelected(rows[0]);
 
     });