如何以编程方式在Material Ui中展开或折叠Tree Item? [英] How to programmatically expand or collapse Tree Item in Material Ui?

问题描述

有什么方法可以以编程方式扩展和折叠材料ui中的树项目?我可以通过单击项目来做到这一点，但是有时我想根据树状视图中的动作折叠和展开树状项目.有可能吗?

Is there any way to programmatically expand and collapse tree items in material ui? I can do that by clicking on the item, but there are other times when I would like to collapse and expand the tree items based on an action in the tree view. is it possible?

推荐答案

您可以使用TreeView expanded 道具来实现.
下面的代码在挂载时扩展了 ID 为1"的 TreeItem.

You can achieve that using TreeView expanded prop.
The code below expands the TreeItem with id "1" on mount.

import React, {useEffect, useState} from 'react';
import TreeView from '@material-ui/lab/TreeView';
import ExpandMoreIcon from '@material-ui/icons/ExpandMore';
import ChevronRightIcon from '@material-ui/icons/ChevronRight';
import TreeItem from '@material-ui/lab/TreeItem';

export default function FileSystemNavigator() {
  const [expanded, setExpanded] = useState([]);

  useEffect(() => {
    setExpanded(["1"])
  },[])

  return (
    <TreeView
      defaultCollapseIcon={<ExpandMoreIcon />}
      defaultExpandIcon={<ChevronRightIcon />}
      expanded={expanded}
    >
      <TreeItem nodeId="1" label="Applications"    
>
        <TreeItem nodeId="2" label="Calendar" />
        <TreeItem nodeId="3" label="Chrome" />
        <TreeItem nodeId="4" label="Webstorm" />
      </TreeItem>
      <TreeItem nodeId="5" label="Documents"
>
        <TreeItem nodeId="6" label="Material-UI">
          <TreeItem nodeId="7" label="src">
            <TreeItem nodeId="8" label="index.js" />
            <TreeItem nodeId="9" label="tree-view.js" />
          </TreeItem>
        </TreeItem>
      </TreeItem>
    </TreeView>
  );
}

代码沙箱

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