angular - 我对长度有疑问。错误类型错误 : Cannot read property 'length' of undefined

Question

长度应该从angular right继承吗？以及为什么 if (fileList.length> 0) MyPostsComponent.html: 7 ERROR TypeError: Cannot read the 'length' of undefined property.

onFileSelection(event){
  const fileList: FileList = event.target.filse;

  if (fileList.length > 0){
    const file: File = fileList[0];
    this.myFire.uploadFile(file).then(data => {
      //TO DO
      this.notifier.display('success','Picture Uploaded!');
      console.log(data['fileUrl']);
    })
    .catch(err => {
      this.notifier.display('error', err.message);
    });
  }
}

在我的 html 代码上

<input type="file" (change)="onFileSelection($event)" placeholder="Upload a file" accept=".png, .jpeg, .jpg">

Answer 1

const fileList: FileList = event.target.filse;

你似乎有一个错字，这将导致 fileList 被 undefined 因为事件的目标 definitely 不包含名为 filse。