angular 粘合性指令

粘贴性属性

.sticky {
  position: sticky;
  left: 0;
}

至少应指定top、right、bottom

最近滚动祖先

如果要两个属性都靠左

.company {
  position: sticky;
  left: 0px;
}

.manager {
  position: sticky;
  left: 120px; 
}

需要计算位置

计算示例

• 表格位置 = (100, 200) // <-- x = 100
• Company位置 = (100, 200) // <-- x 相对于表 = 100 - 100 = 0
• Manager的位置 = (300, 200) // <-- x 相对于表 = 300 - 100 = 200

要减去table 距离左侧的距离

Optional

可以理解我是儿子,通过这个属性拿到父母给我的管道或者指令

举个小栗子

app.component

<div one>
    <div two></div>
</div>

在two指令中, 我们可以通过Optional 拿到one的指令和app.component的组件

twoDirective

  constructor( @Optional() private one: oneDirective,@Optional() private app:appComponent) {
  }

上完整的案例

<table appStickyTable style="width: 900px;overflow-x: auto;margin-left:200px;">
  <tr>
    <th appSticky>Company</th>
    <th appSticky>Manager</th>
    <th>Employees</th>
    <th>Contractors</th>
    <th>Jobs</th>
    <th>Contracts</th>
  </tr>
  <ng-container *ngFor="let item of data">
    <tr>
      <td appSticky style="min-width:200px">{{ item.a }}</td>
      <td appSticky>{{ item?.a }}</td>
      <td> {{ item?.b }} </td>
      <td> {{ item?.c }} </td>
      <td> {{ item?.d }} </td>
      <td> {{ item?.f }} </td>
    </tr>
  </ng-container>
</table>

 data:any = [
    {a: 111, b: 222, c: 333, d: 444, f: 555},
    {a: 111, b: 222, c: 333, d: 444, f: 555},
    {a: 111, b: 222, c: 333, d: 444, f: 555},
    {a: 111, b: 222, c: 333, d: 444, f: 555},
  ]

td,th{
  width: 200px;
  text-align: center;
  background-color: #fff;
}

table的指令,主要是拿到距离左侧的距离

@Directive({
  selector: '[appStickyTable]'
})
export class StickyTableDirective {

  constructor(private el: ElementRef) {
  }

  get x() {
    return (this.el.nativeElement as HTMLElement)?.getBoundingClientRect().x;
  }
}

appSticky指令

@Directive({
  selector: '[appSticky]'
})
export class StickyDirective implements AfterViewInit {

  constructor(private el: ElementRef,
              @Optional() private table: StickyTableDirective,@Optional() private One:Text1Component) {
  }

  ngAfterViewInit() {
    console.log(this.One);
    const el = this.el.nativeElement as HTMLElement;
    const { x } = el.getBoundingClientRect();
    el.style.position = 'sticky';
    el.style.left = this.table ? `${x - this.table.x}px` : '0px';
  }
}