第一个建议的解决方案是有效的，我们只需要改变

selBox.value = val;

To

selBox.innerText = val;

也就是说,

HTML:

<button (click)="copyMessage('This goes to Clipboard')" value="click to copy" >Copy this</button>

.ts文件:

copyMessage(val: string){
    const selBox = document.createElement('textarea');
    selBox.style.position = 'fixed';
    selBox.style.left = '0';
    selBox.style.top = '0';
    selBox.style.opacity = '0';
    selBox.innerText = val;
    document.body.appendChild(selBox);
    selBox.focus();
    selBox.select();
    document.execCommand('copy');
    document.body.removeChild(selBox);
  }

修改版本的jockeisorby的回答，修复事件处理程序没有被正确删除。

copyToClipboard(item): void {
    let listener = (e: ClipboardEvent) => {
        e.clipboardData.setData('text/plain', (item));
        e.preventDefault();
    };

    document.addEventListener('copy', listener);
    document.execCommand('copy');
    document.removeEventListener('copy', listener);
}

从Angular Material v9开始，它现在有了一个剪贴板CDK

剪贴板|角材料

它可以简单地使用

<button [cdkCopyToClipboard]="This goes to Clipboard">Copy this</button>

// for copy the text
import { Clipboard } from "@angular/cdk/clipboard"; // first import this in .ts
 constructor(
    public clipboard: Clipboard
  ) { }   
 <button class="btn btn-success btn-block"(click) = "onCopy('some text')" > Copy< /button>

 onCopy(value) {
     this.clipboard.copy(value);
    }


 // for paste the copied text on button click :here is code
    
    <button class="btn btn-success btn-block"(click) = "onpaste()" > Paste < /button>
    
    onpaste() {
      navigator['clipboard'].readText().then(clipText => {
        console.log(clipText);
      });
    }

以下方法可用于复制消息:-

export function copyTextAreaToClipBoard(message: string) {
  const cleanText = message.replace(/<\/?[^>]+(>|$)/g, '');
  const x = document.createElement('TEXTAREA') as HTMLTextAreaElement;
  x.value = cleanText;
  document.body.appendChild(x);
  x.select();
  document.execCommand('copy');
  document.body.removeChild(x);
}

很简单，兄弟

在.html文件

<button (click)="copyMessage('This goes to Clipboard')" value="click to copy" >Copy this</button>

在.ts文件

copyMessage(text: string) {
  navigator.clipboard.writeText(text).then().catch(e => console.log(e));
}