我是一个Angular新手试图使用Material 2实现一个表驱动的级联菜单，但是当我尝试使用变量将mat-menu元素名称的值赋给[matMenuTriggerFor]时会出现运行时错误。我能够找到的所有示例都使用文本字符串来指定mat-menu元素名称;我无法在网络上的任何地方找到帖子，表明其他人都遇到了类似的问题，虽然我确实在github报告上发现了一个月份的帖子，因为绑定到[matMenuTriggerFor]的bug没有用但是已经关闭了作为Material版本4.xx相关的问题。似乎[matMenuTriggerFor]期望表达式的值，但我的尝试不起作用。我做错了什么？
我在Win 10上，我的浏览器是Firefox 57.0.2
My Angular版本：
Angular CLI: 1.5.0
Node: 6.11.3
OS: win32 x64
Angular: 5.1.2
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router
@angular/cdk: 5.0.2
@angular/cli: 1.5.0
@angular/material: 5.0.2
@angular-devkit/build-optimizer: 0.0.36
@angular-devkit/core: 0.0.22
@angular-devkit/schematics: 0.0.42
@ngtools/json-schema: 1.1.0
@ngtools/webpack: 1.8.0
@schematics/angular: 0.1.11
@schematics/schematics: 0.0.11
typescript: 2.4.2
webpack: 3.8.1
我的app.module.ts：
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { MatMenuModule } from '@angular/material/menu';
import { MatToolbarModule } from '@angular/material/toolbar';
import { MatIconModule } from '@angular/material/icon';
import { MatListModule } from '@angular/material/list';
import { AppComponent } from './app.component';
import { NestedMenusComponent } from './nested-menus/nested-menus.component';
@NgModule({
declarations: [
AppComponent,
NestedMenusComponent
],
imports: [
BrowserModule,
BrowserAnimationsModule,
MatMenuModule,
MatToolbarModule,
MatIconModule,
MatListModule,
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
我的component.ts：
import { Component, OnInit } from '@angular/core';
@Component({
selector: 'app-nested-menus',
templateUrl: './nested-menus.component.html',
styleUrls: ['./nested-menus.component.scss']
})
export class NestedMenusComponent implements OnInit {
constructor() { }
ngOnInit() { }
selected :string;
menuItems = [
{text: "Tabledriven.Item1" },
{text: "Tabledriven.Item2", templateName: "submenu"},
];
select(pText :string)
{
this.selected = pText;
}
}
我的component.html：
<div>
<p>You selected: {{ selected }}</p>
<div class="demo-menu">
<div class="menu-section">
<p>Basic Menu</p>
<mat-toolbar>
<button mat-icon-button [matMenuTriggerFor]="basic">
<mat-icon>more_vert</mat-icon>
</button>
</mat-toolbar>
<mat-menu #basic="matMenu">
<button mat-menu-item (click)="select('Basic.Item1')">Basic.Item1</button>
<button mat-menu-item [matMenuTriggerFor]="submenu">Basic.Item2</button>
</mat-menu>
</div>
<div class="menu-section">
<p>Table-driven Menu</p>
<mat-toolbar>
<button mat-icon-button [matMenuTriggerFor]="tabledriven">
<mat-icon>more_vert</mat-icon>
</button>
</mat-toolbar>
<mat-menu #tabledriven="matMenu">
<ng-container *ngFor="let item of menuItems">
<button *ngIf=!item.templateName mat-menu-item (click)="select(item.text)">{{ item.text }}</button>
<button *ngIf=item.templateName mat-menu-item [matMenuTriggerFor]=item.templateName>{{ item.text }}</button>
</ng-container>
</mat-menu>
</div>
<mat-menu #submenu="matMenu">
<button mat-menu-item (click)="select('Submenu.Item1')">Submenu.Item1</button>
<button mat-menu-item (click)="select('Submenu.Item2')">Submenu.Item2</button>
</mat-menu>
</div>
</div>
Table-driven菜单在任何用户输入之前抛出运行时错误：
ERROR
TypeError: this.menu.close is undefined
Stack trace:
MatMenuTrigger.prototype.ngAfterContentInit@webpack-internal:///../../../material/esm5/menu.es5.js:771:9
callProviderLifecycles@webpack-internal:///../../../core/esm5/core.js:12929:9
callElementProvidersLifecycles@webpack-internal:///../../../core/esm5/core.js:12903:13
callLifecycleHooksChildrenFirst@webpack-internal:///../../../core/esm5/core.js:12886:29
checkAndUpdateView@webpack-internal:///../../../core/esm5/core.js:14036:5
callViewAction@webpack-internal:///../../../core/esm5/core.js:14383:21
execEmbeddedViewsAction@webpack-internal:///../../../core/esm5/core.js:14341:17
checkAndUpdateView@webpack-internal:///../../../core/esm5/core.js:14033:5
callViewAction@webpack-internal:///../../../core/esm5/core.js:14383:21
execEmbeddedViewsAction@webpack-internal:///../../../core/esm5/core.js:14341:17
checkAndUpdateView@webpack-internal:///../../../core/esm5/core.js:14033:5
callViewAction@webpack-internal:///../../../core/esm5/core.js:14383:21
execComponentViewsAction@webpack-internal:///../../../core/esm5/core.js:14315:13
checkAndUpdateView@webpack-internal:///../../../core/esm5/core.js:14038:5
callViewAction@webpack-internal:///../../../core/esm5/core.js:14383:21
execComponentViewsAction@webpack-internal:///../../../core/esm5/core.js:14315:13
checkAndUpdateView@webpack-internal:///../../../core/esm5/core.js:14038:5
callWithDebugContext@webpack-internal:///../../../core/esm5/core.js:15286:39
debugCheckAndUpdateView@webpack-internal:///../../../core/esm5/core.js:14823:12
ViewRef_.prototype.detectChanges@webpack-internal:///../../../core/esm5/core.js:11797:13
ApplicationRef.prototype.tick/<@webpack-internal:///../../../core/esm5/core.js:6104:58
ApplicationRef.prototype.tick@webpack-internal:///../../../core/esm5/core.js:6104:13
ApplicationRef.prototype._loadComponent@webpack-internal:///../../../core/esm5/core.js:6170:9
ApplicationRef.prototype.bootstrap@webpack-internal:///../../../core/esm5/core.js:6058:9
PlatformRef.prototype._moduleDoBootstrap/<@webpack-internal:///../../../core/esm5/core.js:5778:74
PlatformRef.prototype._moduleDoBootstrap@webpack-internal:///../../../core/esm5/core.js:5778:13
PlatformRef.prototype.bootstrapModuleFactory/</</<@webpack-internal:///../../../core/esm5/core.js:5699:21
ZoneDelegate.prototype.invoke@webpack-internal:///../../../../zone.js/dist/zone.js:392:17
onInvoke@webpack-internal:///../../../core/esm5/core.js:4949:24
ZoneDelegate.prototype.invoke@webpack-internal:///../../../../zone.js/dist/zone.js:391:17
Zone.prototype.run@webpack-internal:///../../../../zone.js/dist/zone.js:142:24
scheduleResolveOrReject/<@webpack-internal:///../../../../zone.js/dist/zone.js:873:52
ZoneDelegate.prototype.invokeTask@webpack-internal:///../../../../zone.js/dist/zone.js:425:17
onInvokeTask@webpack-internal:///../../../core/esm5/core.js:4940:24
ZoneDelegate.prototype.invokeTask@webpack-internal:///../../../../zone.js/dist/zone.js:424:17
Zone.prototype.runTask@webpack-internal:///../../../../zone.js/dist/zone.js:192:28
drainMicroTaskQueue@webpack-internal:///../../../../zone.js/dist/zone.js:602:25
NestedMenusComponent.html:29:10
View_NestedMenusComponent_3
NestedMenusComponent.html:29:10
DebugContext_.prototype.logError
core.js:15030
ErrorHandler.prototype.handleError
core.js:1488
ApplicationRef.prototype.tick/<
core.js:5915:54
ZoneDelegate.prototype.invoke
zone.js:392
Zone.prototype.run
zone.js:142
NgZone.prototype.runOutsideAngular
core.js:4701:47
ApplicationRef.prototype.tick
core.js:5915
ApplicationRef.prototype._loadComponent
core.js:5974
ApplicationRef.prototype.bootstrap
core.js:5862
PlatformRef.prototype._moduleDoBootstrap/<
core.js:5582:65
PlatformRef.prototype._moduleDoBootstrap
core.js:5582
PlatformRef.prototype.bootstrapModuleFactory/</</<
core.js:5503
ZoneDelegate.prototype.invoke
zone.js:392
onInvoke
core.js:4753
ZoneDelegate.prototype.invoke
zone.js:391
Zone.prototype.run
zone.js:142
scheduleResolveOrReject/<
zone.js:873
ZoneDelegate.prototype.invokeTask
zone.js:425
onInvokeTask
core.js:4744
ZoneDelegate.prototype.invokeTask
zone.js:424
Zone.prototype.runTask
zone.js:192
drainMicroTaskQueue
zone.js:602
ERROR CONTEXT
Object { view: {…}, nodeIndex: 2, nodeDef: {…}, elDef: {…}, elView: {…} }
NestedMenusComponent.html:29:10
Angular is running in the development mode. Call enableProdMode() to enable the production mode.
core.js:3660
[WDS] Disconnected!
client:164
“基本”菜单可根据需要使用。打开表驱动菜单时，将显示菜单的两个项目，第二个项目包含指示它显示子菜单但会引发以下运行时错误的图标：
ERROR
TypeError: templateRef is undefined
Stack trace:
ViewContainerRef_.prototype.createEmbeddedView@webpack-internal:///../../../core/esm5/core.js:11626:30
DomPortalOutlet.prototype.attachTemplatePortal@webpack-internal:///../../../cdk/esm5/portal.es5.js:448:40
BasePortalOutlet.prototype.attach@webpack-internal:///../../../cdk/esm5/portal.es5.js:303:20
OverlayRef.prototype.attach@webpack-internal:///../../../cdk/esm5/overlay.es5.js:647:45
MatMenuTrigger.prototype.openMenu@webpack-internal:///../../../material/esm5/menu.es5.js:861:13
MatMenuTrigger.prototype._handleClick@webpack-internal:///../../../material/esm5/menu.es5.js:1185:13
View_NestedMenusComponent_3/<@ng:///AppModule/NestedMenusComponent.ngfactory.js:64:23
handleEvent@webpack-internal:///../../../core/esm5/core.js:13777:115
callWithDebugContext@webpack-internal:///../../../core/esm5/core.js:15286:39
debugHandleEvent@webpack-internal:///../../../core/esm5/core.js:14873:12
dispatchEvent@webpack-internal:///../../../core/esm5/core.js:10186:16
renderEventHandlerClosure/<@webpack-internal:///../../../core/esm5/core.js:10807:38
decoratePreventDefault/<@webpack-internal:///../../../platform-browser/esm5/platform-browser.js:2679:53
ZoneDelegate.prototype.invokeTask@webpack-internal:///../../../../zone.js/dist/zone.js:425:17
onInvokeTask@webpack-internal:///../../../core/esm5/core.js:4940:24
ZoneDelegate.prototype.invokeTask@webpack-internal:///../../../../zone.js/dist/zone.js:424:17
Zone.prototype.runTask@webpack-internal:///../../../../zone.js/dist/zone.js:192:28
ZoneTask.invokeTask@webpack-internal:///../../../../zone.js/dist/zone.js:499:24
invokeTask@webpack-internal:///../../../../zone.js/dist/zone.js:1540:9
globalZoneAwareCallback@webpack-internal:///../../../../zone.js/dist/zone.js:1566:17
NestedMenusComponent.html:29:10
ERROR CONTEXT
Object { view: {…}, nodeIndex: 0, nodeDef: {…}, elDef: {…}, elView: {…} }
NestedMenusComponent.html:29:10
答案 0 :(得分：1)