从角度6材质树中的子节点获取父层次结构

Question

我正在按照教程在角度6中实现cdk树.我创建了一个树结构,现在我希望通过使它可点击来从子进程中获取父层次结构,而有些方法如getDescendants来获取节点的子节点,副反之亦然.如何从子节点或叶节点获取父层次结构.

Answer 1

我已将这些方法添加到我的树组件中.请注意,我使用平面树,这不适用于嵌套树.

@Component({
  selector: 'es-outline-tree',
  // ...
})
export class OutlineTreeComponent implements OnInit {
  treeControl: FlatTreeControl<FlatTreeNode>;

  // other code...

  /**
   * Recursively expand all parents of the passed node.
   */
  expandParents(node: FlatTreeNode) {
    const parent = this.getParent(node);
    this.treeControl.expand(parent);

    if (parent && parent.level > 0) {
      this.expandParents(parent);
    }
  }

  /**
   * Iterate over each node in reverse order and return the first node that has a lower level than the passed node.
   */
  getParent(node: FlatTreeNode) {
    const { treeControl } = this;
    const currentLevel = treeControl.getLevel(node);

    if (currentLevel < 1) {
      return null;
    }

    const startIndex = treeControl.dataNodes.indexOf(node) - 1;

    for (let i = startIndex; i >= 0; i--) {
      const currentNode = treeControl.dataNodes[i];

      if (treeControl.getLevel(currentNode) < currentLevel) {
        return currentNode;
      }
    }
  }
}

我打算创建自己的FlatTreeControl(通过扩展Angular CDK FlatTreeControl)并在那里移动这个逻辑.

UPDATE

我已将上述逻辑移至我自己的FlatTreeControl实现中:

import { FlatTreeControl } from '@angular/cdk/tree';

export class CustomTreeControl<T> extends FlatTreeControl<T> {
  /**
   * Recursively expand all parents of the passed node.
   */
  expandParents(node: T) {
    const parent = this.getParent(node);
    this.expand(parent);

    if (parent && this.getLevel(parent) > 0) {
      this.expandParents(parent);
    }
  }

  /**
   * Iterate over each node in reverse order and return the first node that has a lower level than the passed node.
   */
  getParent(node: T) {
    const currentLevel = this.getLevel(node);

    if (currentLevel < 1) {
      return null;
    }

    const startIndex = this.dataNodes.indexOf(node) - 1;

    for (let i = startIndex; i >= 0; i--) {
      const currentNode = this.dataNodes[i];

      if (this.getLevel(currentNode) < currentLevel) {
        return currentNode;
      }
    }
  }
}