fix(tree-grid): correct foreignKey value in rowAdd event args (#12979)

* fix(tree-grid): foreignKey value in rowAdd args

* chore(*): fix event args type import in test file

---------

Co-authored-by: Teodosia Hristodorova <[email protected]>

Author: ddaribo

projects/igniteui-angular/src/lib/grids/tree-grid/tree-grid-add-row-ui.spec.ts

@@ -7,6 +7,8 @@ import { configureTestSuite } from '../../test-utils/configure-suite';
 import { NoopAnimationsModule } from '@angular/platform-browser/animations';
 import { IgxActionStripComponent } from '../../action-strip/public_api';
 import { IgxTreeGridRowComponent } from './tree-grid-row.component';
+import { first } from 'rxjs/operators';
+import { IGridEditEventArgs } from '../public_api';
 
 describe('IgxTreeGrid - Add Row UI #tGrid', () => {
     configureTestSuite();
@@ -192,5 +194,28 @@ describe('IgxTreeGrid - Add Row UI #tGrid', () => {
             treeGrid.gridAPI.crudService.endEdit(true);
             fix.detectChanges();
         });
+
+        it('should have correct foreignKey value for the data record in rowAdd event arguments', () => {
+            let newRowId = null;
+            treeGrid.rowAdd.pipe(first()).subscribe((args: IGridEditEventArgs) => {
+                expect(args.newValue[treeGrid.foreignKey]).toBe(2);
+                expect(args.rowData[treeGrid.foreignKey]).toBe(2);
+                newRowId = args.newValue[treeGrid.primaryKey];
+            });
+
+            treeGrid.beginAddRowById(2, true);
+            fix.detectChanges();
+            endTransition();
+
+            const addRow = treeGrid.gridAPI.get_row_by_index(2);
+            expect(addRow.addRowUI).toBeTrue();
+
+            treeGrid.gridAPI.crudService.endEdit(true);
+            fix.detectChanges();
+
+            expect(treeGrid.rowList.length).toBe(9);
+            const addedRow = treeGrid.getRowByKey(newRowId);
+            expect(addedRow.data[treeGrid.foreignKey]).toBe(2);
+        });
     });
 });

projects/igniteui-angular/src/lib/grids/tree-grid/tree-grid.component.ts

@@ -711,7 +711,7 @@ export class IgxTreeGridComponent extends IgxGridBaseDirective implements GridTy
         Object.keys(row.data).forEach(key => {
             // persist foreign key if one is set.
             if (this.foreignKey && key === this.foreignKey) {
-                row.data[key] = treeRowRec.data[key];
+                row.data[key] = treeRowRec.data[this.crudService.addRowParent?.asChild ? this.primaryKey : key];
             } else {
                 row.data[key] = undefined;
             }