Angular 5-在带有管道的选择标签中使用过滤器 [英] Angular 5 - using filter in select tag with pipe
问题描述
我有一个select
html标记,我想按所选值过滤结果列表.我正在使用管道在*ngFor
创建的列表中显示它们.当我添加新项目时,即使有一个具有相同名称的选项,select标记也会添加一个新选项.我该如何解决?我希望我的选择标记仅显示唯一值(过滤器???).我也想设置一个默认值.
I have a select
html tag and I want to filter my list of results by the selected value. I'm using a pipe to show them in a *ngFor
created list. when I add a new item, the select tag add a new option, even if there's an option with the same name yet. How could I fix this? I want my select tag to show unique value only (Filter???). I'd like to set a default value too.
屏幕截图:
App.component.html :
<div class="container">
<div class="row">
<div class="col-xs-12 col-sm-10 col-md-8 col-sm-offset-1 col-md-offset-2">
<select
name="serverStatus"
id="serverStatus"
[(ngModel)]="filteredStatus">
<option
*ngFor="let server of servers"
value="{{server.status}}">{{server.status}}</option>
</select>
<hr>
<ul class="list-group">
<li
class="list-group-item"
*ngFor="let server of servers | filter:filteredStatus:'status'"
[ngClass]="getStatusClasses(server)">
<span
class="badge">
{{ server.status }}
</span>
<strong>{{ server.name }}</strong> |
{{ server.instanceType | uppercase }} |
{{ server.started | date:'fullDate' | uppercase }}
</li>
</ul>
</div>
App.component.ts :
import { Component } from '@angular/core';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
servers = [
{
instanceType: 'medium',
name: 'Production Server',
status: 'stable',
started: new Date(15, 1, 2017)
},
{
instanceType: 'large',
name: 'User Database',
status: 'stable',
started: new Date(15, 1, 2017)
},
{
instanceType: 'small',
name: 'Development Server',
status: 'offline',
started: new Date(15, 1, 2017)
},
{
instanceType: 'small',
name: 'Testing Environment Server',
status: 'critical',
started: new Date(15, 1, 2017)
}
];
filteredStatus = '';
getStatusClasses(server: {instanceType: string, name: string, status: string, started: Date}) {
return {
'list-group-item-success': server.status === 'stable',
'list-group-item-warning': server.status === 'offline',
'list-group-item-danger': server.status === 'critical'
};
}
}
fiter.pipe.ts :
import { Pipe, PipeTransform } from '@angular/core';
@Pipe({
name: 'filter'
})
export class FilterPipe implements PipeTransform {
transform(value: string[], filterString: string, propName:string): any {
if (value.length === 0 || filterString === '') {
return value;
}
const resultArray = [];
for (const item of value) {
if (item[propName] === filterString) {
resultArray.push(item)
}
}
return resultArray;
}
}
这是一个stackblitz工作示例: https://angular-rwmfbj.stackblitz.io 编辑器: https://stackblitz.com/edit/angular-nck1kn
Here is a stackblitz working example: https://angular-rwmfbj.stackblitz.io Editor: https://stackblitz.com/edit/angular-nck1kn
推荐答案
尝试一下
App.component.ts
import { Component } from '@angular/core';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
servers = [
{
instanceType: 'medium',
name: 'Production Server',
status: 'stable',
started: new Date(15, 1, 2017)
},
{
instanceType: 'large',
name: 'User Database',
status: 'stable',
started: new Date(15, 1, 2017)
},
{
instanceType: 'small',
name: 'Development Server',
status: 'offline',
started: new Date(15, 1, 2017)
},
{
instanceType: 'small',
name: 'Testing Environment Server',
status: 'critical',
started: new Date(15, 1, 2017)
}
];
filteredStatus = '';
serverStatus: {
instanceType: string,
name: string,
status: string,
started: Date
}[] = [];
constructor(){
this.initializeStatus();
//For setting the default value of the select try this
if(this.serverStatus.length != 0)
this.filteredStatus = this.serverStatus[0].status;
}
getStatusClasses(server: {instanceType: string, name: string, status: string, started: Date}) {
return {
'list-group-item-success': server.status === 'stable',
'list-group-item-warning': server.status === 'offline',
'list-group-item-danger': server.status === 'critical'
};
}
//Initalize the status
initializeStatus(){
this.serverStatus = [];
//Container for the current status
let currentStatus = "";
for(let x of this.servers){
if(x.status != currentStatus){
this.serverStatus.push(x);
}
//Equate for reference
currentStatus = x.status;
}
}
}
在 App.component.html
将*ngFor="let server of servers"
更改为此*ngFor="let server of serverStatus"
这篇关于Angular 5-在带有管道的选择标签中使用过滤器的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!