为什么要传递元素：{ type: string, name: string, content: string };不起作用？

Question

我正在尝试访问元素，但它显示错误

属性“元素”没有初始值设定项

import { Component, OnInit, Input } from '@angular/core';

@Component({
  selector: 'app-server-element',
  templateUrl: './server-element.component.html',
  styleUrls: ['./server-element.component.css']
  })
 export class ServerElementComponent implements OnInit {
  @Input('srvElement') element: {type: string, name: string, content: string};     <--- This doesn't work

constructor() { }

ngOnInit() { }

}

Answer 1

为

element

输入提供一些默认值，或者如果您确定会提供该值，则在此 @Input('srvElement') element!: {type: string, name: string, content: string}; 后面放置

感叹号

。我不建议设置

"strictPropertyInitialization": false

，因为当我们不希望它们被初始化时，看到未初始化的值非常有用。它可以避免您将来出现运行时问题。

Answer 2

您需要初始化输入值并确保提供它

@Input({ required: true, alias: 'srvElement' }) element!: Type; // For required inputs in pre-signal Angular versions

srvElement = input.required<Type>(); // using required input with signals

或者通过提供元素的默认值。

@Input({ required: true, alias: 'srvElement' }) element: Type = {type: 'type', name: 'default name', content: 'default content'};

当您不想使用所需的输入并且希望不定义该值时，您应该处理未定义的值并在输入中使用

?

，例如：

@Input('srvElement') element?: {type: string, name: string, content: string}; // when your component can be used without providing this input at all

或

@Input('srvElement') element: {type: string, name: string, content: string} | undefined; // when your component input is required but it's value can be undefined