它简单得多，不需要任何额外的东西。在我的例子中，我声明变量“open”，然后使用它。

   <mat-accordion class="accord-align" #open>
      <mat-expansion-panel hideToggle="true" (opened)="open.value=true" (closed)="open.value=false">
        <mat-expansion-panel-header>
          <span class="accord-title">Review Policy Summary</span>
          <span class="spacer"></span>
          <a *ngIf="!open.value" class="f-accent">SHOW</a>
          <a *ngIf="open.value" class="f-accent">HIDE</a>
        </mat-expansion-panel-header>
        <mat-divider></mat-divider>
        <!-- Quote Details Component -->
        <quote-details [quote]="quote"></quote-details>
      </mat-expansion-panel>
    </mat-accordion>

丑,但是:

<div *ngFor="let a of [aVariable]">
  <span>{{a}}</span>
</div>

当与async管道一起使用时:

<div *ngFor="let a of [aVariable | async]">
  <span>{{a.prop1}}</span>
  <span>{{a.prop2}}</span>
</div>

下面是我编写的一个指令，它扩展了exportAs装饰器参数的使用，并允许您使用字典作为局部变量。

import { Directive, Input } from "@angular/core";
@Directive({
    selector:"[localVariables]",
    exportAs:"localVariables"
})
export class LocalVariables {
    @Input("localVariables") set localVariables( struct: any ) {
        if ( typeof struct === "object" ) {
            for( var variableName in struct ) {
                this[variableName] = struct[variableName];
            }
        }
    }
    constructor( ) {
    }
}

你可以在模板中使用它:

<div #local="localVariables" [localVariables]="{a: 1, b: 2, c: 3+2}">
   <span>a = {{local.a}}</span>
   <span>b = {{local.b}}</span>
   <span>c = {{local.c}}</span>
</div>

当然，#local可以是任何有效的局部变量名。

在Angular 12中:

  <div *ngIf="error$ | async as error">
     <span class="text-warn">{{error.message}}</span>
   </div>

如果你需要Angular语言服务中模板内部的自动补全支持:

同步:

myVar = { hello: '' };

<ng-container *ngIf="myVar; let var;">
  {{var.hello}}
</ng-container>

使用async管道:

myVar$ = of({ hello: '' });

<ng-container *ngIf="myVar$ | async; let var;">
  {{var.hello}}
</ng-container>

像这样试试

<ng-container
     [ngTemplateOutlet]="foo"
     [ngTemplateOutletContext]="{ test: 'Test' }"
></ng-container>

<ng-template #foo let-test="test">
    <div>{{ test }}</div>
</ng-template>