使用mat-menu作为上下文菜单:正确定位

Question

我正在尝试使用mat-menu构建一个上下文菜单,我觉得我非常接近.我希望菜单弹出用户右键单击的位置.问题是它会弹出用户最后右键单击的位置,而不是它们当前右键单击的位置.我该如何解决？

HTML:

<span #contextMenuTrigger [matMenuTriggerFor]="contextMenu" class="context-menu-trigger" [style.left.px]="menuLeft" [style.top.px]="menuTop"></span>
<div (contextmenu)="openContextMenu($event)> stuff that I want right-click available to goes here</div>
<mat-menu #contextMenu="matMenu"> 
    <button mat-menu-item>Item 1</button>
    <button mat-menu-item>Item 2</button>
</mat-menu>

CSS:

.context-menu-trigger { position: absolute }

TS:

...
@Component( ... )
export class AppComponent {
    @ViewChild(MatMenuTrigger) public menuTrigger : MatMenuTrigger;
    public menuLeft = 0;
    public menuTop = 0;
    ...
    openContextMenu(event) {
        event.preventDefault();
        this.menuLeft = event.x;
        this.menuTop = event.y;
        this.menuTrigger.openMenu();
    }
}

我们目前在@angular 4.4和@ angular/material 2.0.0-beta.12.

Answer 1

依赖超时是不安全的。为跨度触发器设置直接样式以获得即时位置更新：

<span style="position:fixed;" #spanTrigger class="context-menu-trigger" #matTrigger="matMenuTrigger" [matMenuTriggerFor]="contextMenu"></span>
<div (contextmenu)="openContextMenu($event, matTrigger, spanTrigger)"> stuff that I want right-click available to goes here</div>
<mat-menu #contextMenu="matMenu"> 
    <button mat-menu-item>Item 1</button>
    <button mat-menu-item>Item 2</button>
</mat-menu>

处理程序：

openContextMenu(
    event: MouseEvent,
    trigger: MatMenuTrigger,
    triggerElement: HTMLElement
) {
    triggerElement.style.left = event.clientX + 5 + "px";
    triggerElement.style.top = event.clientY + 5 + "px";
    if (trigger.menuOpen) {
        trigger.closeMenu();
        trigger.openMenu();
    } else {
        trigger.openMenu();
    }
    event.preventDefault();
}

Answer 2

我遇到了这个问题，并通过延迟在样式位置发生后发生trigger.openMenu() 找到了解决方案

Observable.timer(100).subscribe(t => { this.menuTrigger.openMenu() });