Angular ChangeDetectorRef : Cannot read property 'detectChanges' of undefined

Question

我收到 ChangeDetectorRef 的以下错误。不确定为什么它突然发生，当其他组件使用 ChangeDetectorRef 时。有谁知道如何解决？它链接到 Kendo Grid 选择。

TypeError: Cannot read property 'detectChanges' of undefined

export class DocumentPropertyGridComponent implements OnInit, OnChanges {

  public documentPropertyGridDataSelected: Array<DocumentPropertyGridData> = new Array<DocumentPropertyGridData>();

  constructor(private cdr: ChangeDetectorRef) { 
  }

  selectTest(e){
    this.documentPropertyGridDataSelected = e.selectedRows;
    this.cdr.detectChanges();
  }

HTML:

<div>
  Selected Count: {{documentPropertyGridDataSelected.length}}
<div>

Answer 1

可能是 this 上下文(顺便说一句，函数是如何调用的？)。可通过将其转换为箭头函数来修复

  selectTest = (e) => {
    this.documentPropertyGridDataSelected = e.selectedRows;
    this.cdr.detectChanges();
  }