Angular Material matToolTip 在使用 ngFor 函数时不显示 [英] Angular Material matToolTip does not display when using ngFor function

问题描述

我有一组称为报告的数据，其中包含一组网络 (report.networks).在我返回它之前，我有model.ts 来操作networks 数组.我做了一个 ngFor 来迭代网络数据以显示工作正常的细节.但是，在 ngFor 中添加 matToolTips 不会显示.

component.html

<span matTooltip="Tooltip Works">Tooltip Works</span><div *ngFor="let network of report.networks"><span matTooltip="工具提示不起作用！">工具提示不起作用</span>

component.ts

import { Report } from './../../core/models/report/report.model';@成分({选择器:'app-report-detail',templateUrl: './report-detail.component.html',styleUrls: ['./report-detail.component.scss']})导出类 ReportDetailComponent 实现 OnInit {报告:报告；构造函数(私有路由:ActivatedRoute){}ngOnInit() {this.report = this.route.snapshot.data.report;控制台日志(this.report)；}}

report.model.ts

导出类报告{网络?:任何=空；构造函数(数据?:报告){如果(数据){this.deserialize(data);}}私有反序列化(数据:报告){const 键 = Object.keys(this);for (const key of keys) {如果 (data.hasOwnProperty(key)) {这个[key] = 数据[key];}}}获取网络(){让 n = this.networks;//一些操作返回 n}}

解决方案

正如这里提到的 https://github.com/angular/material2/issues/10039

在 ngFor 中使用函数时，会反复创建数组实例，这会导致多个问题，例如 matToolTip 不显示以及性能问题.

我解决这个问题的另一种方法是更改​​我的 model.ts 文件.所以在下面我为函数的结果分配了一个变量.然后我直接在函数的 ngFor istead 中使用这个变量.

导出类报告{网络?:任何=空；//风俗自定义网络?:任何=空；构造函数(数据?:报告){如果(数据){this.deserialize(data);this.customNetworks = this.generateNetworks()}}私有反序列化(数据:报告){const 键 = Object.keys(this);for (const key of keys) {如果 (data.hasOwnProperty(key)) {这个[key] = 数据[key];}}}生成网络(){让 n = this.networks;//一些操作返回 n}}

I have a set of data called reports which contain an array of networks (report.networks). I have model.ts to manipulate the networks array before i return it back. I do an ngFor to iterate over the network data to display the details which works fine. However, adding a matToolTips within the ngFor does not get displayed.

component.html

<span matTooltip="Tooltip Works">Tooltip Works</span>

<div *ngFor="let network of report.networks">
   <span matTooltip="Tooltip Does NOT work!">Tooltip Does NOT work</span>
</div>

component.ts

import { Report } from './../../core/models/report/report.model';

@Component({
    selector: 'app-report-detail',
    templateUrl: './report-detail.component.html',
    styleUrls: ['./report-detail.component.scss']
})
export class ReportDetailComponent implements OnInit {

    report: Report;

    constructor(private route: ActivatedRoute) { }

    ngOnInit() {

        this.report = this.route.snapshot.data.report;
        console.log(this.report);

    }

}

report.model.ts

export class Report {

    networks?: any = null;

    constructor(data?: Report) {
        if (data) {
            this.deserialize(data);
        }
    }

    private deserialize(data: Report) {

        const keys = Object.keys(this);

        for (const key of keys) {
            if (data.hasOwnProperty(key)) {
                this[key] = data[key];
            }
        }
    }

    get networks() {

        let n = this.networks;
        //some manipulation
        return n
    }
}

解决方案

As mentioned here https://github.com/angular/material2/issues/10039

The array is instance being created over and over again when using a function in a ngFor which causes multiple issues like matToolTip not displaying as-well as performance issues.

Another way i got around this is to change my model.ts file. So below im assigning a variable to the result of the function. Then i use this variable inside the ngFor isntead of the function directly.

export class Report {

    networks?: any = null;

    //custom

    customNetworks? : any = null;

    constructor(data?: Report) {
        if (data) {
            this.deserialize(data);

            this.customNetworks = this.generateNetworks()
        }

    }

    private deserialize(data: Report) {

        const keys = Object.keys(this);

        for (const key of keys) {
            if (data.hasOwnProperty(key)) {
                this[key] = data[key];
            }
        }
    }

    generateNetworks() {

        let n = this.networks;
        //some manipulation
        return n
    }
}

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