how to best conditional template show in angular 4

问题

currently, i am practiced angular 4. when a normal user view this then show public content When A Registered user enter the web page then show edit or some content. how to the best practices show conditionally template Or Some Html Contents Example:

<div *ngIf="isUser">
    some Content  here......
</div>
<div *ngIf="!isUser">
    some Content here .....
</div>

actually, i want to know how to the best.

回答1:

In angular 4 you can use if.. else.. structure for html templates

You can use it in this way:

<div *ngIf="isUser; else otherContent">
    some Content  here......
</div>
<ng-template #otherContent>
    <div>
        some Content here .....
    </div>
</ng-template>

but in your case, the prettiest solutions will be if... then... else... conditional

<ng-container *ngIf="isUser; then someContent else otherContent"></ng-container>

<ng-template #someContent ><div>some content...</div></ng-template>
<ng-template #otherContent ><div>other content...</div></ng-template>

回答2:

NgIf is a structural directive. That means your component would be destroyed when the expression becomes false.

So if your component is often destroyed and created again than this can be an issue. In this case the [hidden] directive should be considered. It only sets display:none. In this case your component would not be destroyed.

<div [hidden]="expression">{{val}}</div>

回答3:

use NgIf with else condition

<div *ngIf="isUser;else Other">
    some Content  here......
</div>

<ng-template #Other> some Content here .....</ng-template>

来源：https://stackoverflow.com/questions/46770046/how-to-best-conditional-template-show-in-angular-4

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angular

angular-template