我想在我的角度模板中做一个 if-else 语句。我从那开始:
<ng-container *ngIf="contributeur.deb; else newDeb" >
[... HERE IS A RESULT 1]
</ng-container>
<ng-template #newDeb>
[... HERE IS A RESULT 2]
</ng-template>
我尝试只使用 ng-container :
<ng-container *ngIf="contributeur.deb; else newDeb" >
[... HERE IS A RESULT 1]
</ng-container>
<ng-container #newDeb>
[... HERE IS A RESULT 2]
</ng-container >
不幸的是,这不起作用。我有这个错误:
ERROR TypeError: templateRef.createEmbeddedView is not a function
at ViewContainerRef_.createEmbeddedView (eval at <anonymous> (vendor.bundle.js:11), <anonymous>:10200:52)
at NgIf._updateView (eval at <anonymous> (vendor.bundle.js:96), <anonymous>:2013:45)
at NgIf.set [as ngIfElse] (eval at <anonymous> (vendor.bundle.js:96), <anonymous>:1988:18)
at updateProp (eval at <anonymous> (vendor.bundle.js:11), <anonymous>:11172:37)
at checkAndUpdateDirectiveInline (eval at <anonymous> (vendor.bundle.js:11), <anonymous>:10873:19)
at checkAndUpdateNodeInline (eval at <anonymous> (vendor.bundle.js:11), <anonymous>:12290:17)
at checkAndUpdateNode (eval at <anonymous> (vendor.bundle.js:11), <anonymous>:12258:16)
at debugCheckAndUpdateNode (eval at <anonymous> (vendor.bundle.js:11), <anonymous>:12887:59)
at debugCheckDirectivesFn (eval at <anonymous> (vendor.bundle.js:11), <anonymous>:12828:13)
at Object.eval [as updateDirectives] (ActionsButtons.html:5)
任何人都可以解释一下这段代码出了什么问题吗?
ngIf
指令的代码期望传递对else分支的模板(TemplateRef
)的引用,它将调用createEmbeddedView
来显示嵌套内容。因此,尝试对 else 内容使用任何其他类型的元素是没有意义的 - 它就是行不通。不过,如果需要的话,您可以在 ng-container
内嵌套 ng-template
。这可能看起来不直观,但请记住,
结构指令(即您用 *
调用的指令)在引擎盖下始终表示为
ng-template
,无论它们附加哪种元素to - 这两段代码是相同的:
<ng-container *ngIf="contributeur.deb; else newDeb" >
...
</ng-container>
<ng-template #newDeb>
...
</ng-template>
<ng-template [ngIf]="contributeur.deb; else newDeb">
<ng-container>
...
</ng-container>
</ng-template>
<ng-template #newDeb>
...
</ng-template>
if then else 的标准 Angular 结构。然后我用 ngSwitch 找到了替代解决方案:
<ng-container [ngSwitch]="isFirstChoice(foo) ? 1 : (isSecondChoice(foo) ? 2 : -1)">
<ng-container *ngSwitchCase="1">
...first choice...
</ng-container>
<ng-container *ngSwitchCase="2">
...second choice...
</ng-container>
<ng-container *ngSwitchDefault>
...another choice...
</ng-container>
</ng-container>
为了回答您的请求,我会使用这个:
<ng-container [ngSwitch]="contributeur.deb && 'isDeb'">
<ng-container *ngSwitchCase="'isDeb'">
......
</ng-container>
<ng-container *ngSwitchDefault>
......
</ng-container>
</ng-container>
<ng-container *ngIf="contributeur.deb" >
[... HERE IS A RESULT 1]
</ng-container>
<ng-container *ngIf="!contributeur.deb">
[... HERE IS A RESULT 2]
</ng-container >
@if(contributeur.deb){
[.....any code]
}
@else if(!contributeur.deb){
[.....any code]
}
就这样。谢谢