Merge pull request #7969 from IgniteUI/mdragnev/fix-7951

fix(*): Add selection service provider to child grid so that it does not use the parent one

Author: ChronosSF

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

@@ -688,6 +688,28 @@ describe('IgxHierarchicalGrid selection #hGrid', () => {
             expect(hierarchicalGrid.getRowByKey('2').selected).toBeTrue();
             expect(hierarchicalGrid.getRowByKey('0').selected).toBeFalse();
         });
+
+        it('Should not clear root selection state when changing selection mode of child grid', () => {
+            rowIsland1.rowSelection = GridSelectionMode.multiple;
+            fix.componentInstance.selectedRows = ['0', '1'];
+            fix.detectChanges();
+            expect(hierarchicalGrid.getRowByKey('0').selected).toBeTrue();
+
+            const thirdRow = hierarchicalGrid.getRowByIndex(2) as IgxHierarchicalRowComponent;
+            thirdRow.toggle();
+            fix.detectChanges();
+
+            const childGrid = rowIsland1.rowIslandAPI.getChildGrids()[0];
+            childGrid.selectedRows = ['20', '21'];
+            fix.detectChanges();
+            expect(hierarchicalGrid.selectedRows.length).toEqual(2);
+            expect(childGrid.selectedRows.length).toEqual(2);
+
+            rowIsland1.rowSelection = GridSelectionMode.single;
+            fix.detectChanges();
+            expect(hierarchicalGrid.selectedRows.length).toEqual(2);
+            expect(childGrid.selectedRows.length).toEqual(0);
+        });
     });
 
     describe('Row Selection CRUD', () => {

projects/igniteui-angular/src/lib/grids/hierarchical-grid/row-island.component.ts

@@ -51,7 +51,8 @@ export interface IGridCreatedEventArgs extends IBaseEventArgs {
     changeDetection: ChangeDetectionStrategy.OnPush,
     selector: 'igx-row-island',
     template: ``,
-    providers: [IgxRowIslandAPIService]
+    providers: [IgxRowIslandAPIService,
+                IgxGridSelectionService]
 })
 export class IgxRowIslandComponent extends IgxHierarchicalGridBaseDirective
             implements AfterContentInit, AfterViewInit, OnChanges, OnInit, OnDestroy, DoCheck {