Exploring the Potential of Using ngIf-else Expressions in Angular 2

Question

Exploring the Potential of Using ngIf-else Expressions in Angular 2

Here is a code snippet that I wrote:

<tr *ngFor="let sample of data; let i = index" [attr.data-index]="i">
    <ng-container *ngIf="sample.configuration_type == 1; then thenBlock; else elseBlock"></ng-container>
       <ng-template #thenBlock>
           <td>{{sample.item_number}}</td>
           <td>{{sample.make}}</td>
           <td>{{sample.model}}</td>
       </ng-template>
       <ng-template #elseBlock>
           <td>{{sample.serial_number}}</td>
           <td>{{sample.capacity}}</td>
           <td>{{sample.model}}</td>
       </ng-template>
</tr>

I encountered an error while trying to display it:

An issue occurred with binding 'ngIfThen' as it is not recognized as a valid property of 'ng-container'. 1. If 'ng-container' is an Angular component and has 'ngIfThen' input, ensure it belongs to the current module. 2. For Web Components, add "CUSTOM_ELEMENTS_SCHEMA" to '@NgModule.schemas' to prevent this message. ("gFor="let sample of data; let i = index" [attr.data-index]="i")

javascript angular typescript

Answer 1

Answer №1

When encountering this error, remember that using ngFor and ngIf on the same tag is not allowed. Instead, utilize ng-container in the following manner:

<tr *ngFor="let sample of data; let i = index" [attr.data-index]="i">
    <ng-container *ngIf="sample.configuration_type === 1">
        <td>{{sample.item_number}}</td>
        <td>{{sample.make}}</td>
        <td>{{sample.model}}</td>
        <td>{{bucket.class}}</td>
        <td>{{bucket.capacity}}</td>
    </ng-container>
</tr>

Answer 2

When encountering this error, remember that using ngFor and ngIf on the same tag is not allowed. Instead, utilize ng-container in the following manner:

<tr *ngFor="let sample of data; let i = index" [attr.data-index]="i">
    <ng-container *ngIf="sample.configuration_type === 1">
        <td>{{sample.item_number}}</td>
        <td>{{sample.make}}</td>
        <td>{{sample.model}}</td>
        <td>{{bucket.class}}</td>
        <td>{{bucket.capacity}}</td>
    </ng-container>
</tr>

Answer 3

Answer №2

Prior to utilizing any structural directives, make sure to import the CommonModule from @angular/common into your module. As a reminder, ngIfElse functionality is only accessible starting from version 4.0.0.

For the revised question: You have the option to utilize ngIf along with the else syntax to distinguish between different items.

Include this code snippet within your tr element:

<ng-container *ngIf="sample.configuration_type === 1; else elseBlock">
    <td>{{sample.item_number}}</td>
    <td>{{sample.make}}</td>
    <td>{{sample.model}}</td>
</ng-container>
<ng-template #elseBlock>
    <td>{{sample.serial_number}}</td>
    <td>{{sample.capacity}}</td>
    <td>{{sample.model}}</td>
</ng-template>

If you prefer using ng-template exclusively, consider implementing this code:

<ng-template [ngIf]="sample.configuration_type === 1" [ngIfElse]="elseBlock">
    <td>{{sample.item_number}}</td>
    <td>{{sample.make}}</td>
    <td>{{sample.model}}</td>
</ng-template>
<ng-template #elseBlock>
    <td>{{sample.serial_number}}</td>
    <td>{{sample.capacity}}</td>
    <td>{{sample.model}}</td>
</ng-template>

For more detailed information on structural directives, visit the angular official documentation page.

Note: This answer was initially provided for the original question before it was modified by the OP to serve another purpose.

To filter the data within your component, you can use methods like the array filter method.

Here's an example:

export class MyComponent {
    // ...
    public get filteredData() {
       return this.data.filter(sample => sample.configuration_type !== 1);
    }
    // ...
}

Then, in your component, utilize the filteredData property for looping purposes:

<tr *ngFor="let sample of filteredData; let i = index" [attr.data-index]="i">
    <td>{{sample.item_number}}</td>
    <td>{{sample.make}}</td>
    <td>{{sample.model}}</td>
    <td>{{bucket.class}}</td>
    <td>{{bucket.capacity}}</td>
</tr>

Answer 4

Prior to utilizing any structural directives, make sure to import the CommonModule from @angular/common into your module. As a reminder, ngIfElse functionality is only accessible starting from version 4.0.0.

For the revised question: You have the option to utilize ngIf along with the else syntax to distinguish between different items.

Include this code snippet within your tr element:

<ng-container *ngIf="sample.configuration_type === 1; else elseBlock">
    <td>{{sample.item_number}}</td>
    <td>{{sample.make}}</td>
    <td>{{sample.model}}</td>
</ng-container>
<ng-template #elseBlock>
    <td>{{sample.serial_number}}</td>
    <td>{{sample.capacity}}</td>
    <td>{{sample.model}}</td>
</ng-template>

If you prefer using ng-template exclusively, consider implementing this code:

<ng-template [ngIf]="sample.configuration_type === 1" [ngIfElse]="elseBlock">
    <td>{{sample.item_number}}</td>
    <td>{{sample.make}}</td>
    <td>{{sample.model}}</td>
</ng-template>
<ng-template #elseBlock>
    <td>{{sample.serial_number}}</td>
    <td>{{sample.capacity}}</td>
    <td>{{sample.model}}</td>
</ng-template>

For more detailed information on structural directives, visit the angular official documentation page.

Note: This answer was initially provided for the original question before it was modified by the OP to serve another purpose.

To filter the data within your component, you can use methods like the array filter method.

Here's an example:

export class MyComponent {
    // ...
    public get filteredData() {
       return this.data.filter(sample => sample.configuration_type !== 1);
    }
    // ...
}

Then, in your component, utilize the filteredData property for looping purposes:

<tr *ngFor="let sample of filteredData; let i = index" [attr.data-index]="i">
    <td>{{sample.item_number}}</td>
    <td>{{sample.make}}</td>
    <td>{{sample.model}}</td>
    <td>{{bucket.class}}</td>
    <td>{{bucket.capacity}}</td>
</tr>

Answer 5

Answer №3

Ensure that the CommonModule has been correctly imported into your AppModule imports.

import {CommonModule} from '@angular/common';

@NgModule({

  imports: [
    // ... other modules    
    CommonModule
  ],

To see a demonstration of the if-then-else behavior, check out this Plunker link: PLUNKER DEMO

Answer 6

Ensure that the CommonModule has been correctly imported into your AppModule imports.

import {CommonModule} from '@angular/common';

@NgModule({

  imports: [
    // ... other modules    
    CommonModule
  ],

To see a demonstration of the if-then-else behavior, check out this Plunker link: PLUNKER DEMO

Exploring the Potential of Using ngIf-else Expressions in Angular 2

Answer №1

Answer №2

Answer №3

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