Child 组件的本地状态在 parent 组件内部发生变化时发生变化：ReactJS

Question

我有一种情况，我在 React 中为 table 实现自定义下拉过滤器。我为每一列设置了下拉值，并且有一个应用按钮。

我为此维护了一个 child 组件，它接受下拉值并将选定的值发送回 parent。

过滤发生了，但是当我再次打开这个下拉菜单时，复选框值丢失了。

谁能告诉我哪里错了？

我卡在这里了

沙盒：https://codesandbox.io/s/nervous-elgamal-0zztb

我添加了带有适当注释的沙箱 link。请看一看。我有点新反应。

非常感谢帮助

Parent

import * as React from "react";
import { render } from "react-dom";
import ReactTable from "react-table";
import "./styles.css";
import "react-table/react-table.css";
import Child from "./Child";
interface IState {
  data: {}[];
  columns: {}[];
  selectedValues: {};
  optionsForColumns: {};
}

interface IProps {}

export default class App extends React.Component<IProps, IState> {

  // Here I have  hardcoded the values, but data and optionsForColumns comes from the backend and it is set inside componentDidMount
  constructor(props: any) {
    super(props);
    this.state = {
      data: [
        { firstName: "Jack", status: "Submitted", age: "14" },
        { firstName: "Simon", status: "Pending", age: "15" }
      ],
      selectedValues: {},
      columns: [],
      optionsForColumns: {
        firstName: [{ Jack: "4" }, { Simon: "5" }],
        status: [{ Submitted: "5" }, { Pending: "7" }]
      }
    };
  }

  // Get the values for checkboxes that will be sent to child
  getValuesFromKey = (key: any) => {
    let data: any = this.state.optionsForColumns[key];
    let result = data.map((value: any) => {
      let keys = Object.keys(value);
      return {
        field: keys[0],
        checked: false
      };
    });
    return result;
  };

  // Get the consolidated values from child and then pass it for server side filtering
  handleFilter = (fieldName: any, selectedValue: any, modifiedObj: any) => 
  {
    this.setState(
      {
        selectedValues: {
          ...this.state.selectedValues,
          [fieldName]: selectedValue
        }
      },
      () => this.handleColumnFilter(this.state.selectedValues)
    );
  };

  // Function that will make server call based on the checked values from child
  handleColumnFilter = (values: any) => {
    // server side code for filtering
    // After this checkbox content is lost
  };

  // Function where I configure the columns array for the table . (Also data and column fiter values will be set here, in this case I have hardcoded inside constructor)
  componentDidMount() {
    let columns = [
      {
        Header: () => (
          <div>
            <div>
              <Child
                key="firstName"
                name="firstName"
                options={this.getValuesFromKey("firstName")}
                handleFilter={this.handleFilter}
              />
            </div>
            <span>First Name</span>
          </div>
        ),
        accessor: "firstName"
      },
      {
        Header: () => (
          <div>
            <div>
              <Child
                key="status"
                name="status"
                options={this.getValuesFromKey("status")}
                handleFilter={this.handleFilter}
              />
            </div>
            <span>Status</span>
          </div>
        ),
        accessor: "status",
      },
      {
        Header: "Age",
        accessor: "age"
      }
    ];
    this.setState({ columns });
  }

  //Rendering the data table
  render() {
    const { data, columns } = this.state;
    return (
      <div>
        <ReactTable
          data={data}
          columns={columns}
        />
      </div>
    );
  }
}
const rootElement = document.getElementById("root");
render(<App />, rootElement);

Child


import * as React from "react";
import { Button, Checkbox, Icon } from "semantic-ui-react";
interface IProps {
  options: any;
  name: string;
  handleFilter(val1: any, val2: any, val3: void): void;
}
interface IState {
  showList: boolean;
  selected: [];
  checkboxOptions: any;
}
export default class Child extends React.Component<IProps, IState> {
  constructor(props: any) {
    super(props);
    this.state = {
      selected: [],
      showList: false,
      checkboxOptions: this.props.options.map((option: any) => option.checked)
    };
  }

  // Checkbox change handler
  handleValueChange = (event: React.FormEvent<HTMLInputElement>, data: any) => {
    const i = this.props.options.findIndex(
      (item: any) => item.field === data.name
    );
    const optionsArr = this.state.checkboxOptions.map(
      (prevState: any, si: any) => (si === i ? !prevState : prevState)
    );
    this.setState({ checkboxOptions: optionsArr });
  };

  //Passing the checked values back to parent
  passSelectionToParent = (event: any) => {
    event.preventDefault();
    const result = this.props.options.map((item: any, i: any) =>
      Object.assign({}, item, {
        checked: this.state.checkboxOptions[i]
      })
    );
    const selected = result
      .filter((res: any) => res.checked)
      .map((ele: any) => ele.field);
    console.log(selected);
    this.props.handleFilter(this.props.name, selected, result);
  };

  //Show/Hide filter
  toggleList = () => {
    this.setState(prevState => ({ showList: !prevState.showList }));
  };

  //Rendering the checkboxes based on the local state, but still it gets lost after filtering happens
  render() {
    let { showList } = this.state;
    let visibleFlag: string;
    if (showList === true) visibleFlag = "visible";
    else visibleFlag = "";
    return (
      <div>
        <div style={{ position: "absolute" }}>
          <div
            className={"ui scrolling dropdown column-settings " + visibleFlag}
          >
            <Icon className="filter" onClick={this.toggleList} />
            <div className={"menu transition " + visibleFlag}>
              <div className="menu-item-holder">
                {this.props.options.map((item: any, i: number) => (
                  <div className="menu-item" key={i}>
                    <Checkbox
                      name={item.field}
                      onChange={this.handleValueChange}
                      label={item.field}
                      checked={this.state.checkboxOptions[i]}
                    />
                  </div>
                ))}
              </div>
              <div className="menu-btn-holder">
                <Button size="small" onClick={this.passSelectionToParent}>
                  Apply
                </Button>
              </div>
            </div>
          </div>
        </div>
      </div>
    );
  }
}

Answer 1

对不起，我下面的回答是错误的。

在您的主要组件中，您只设置了一次 state.columns，当组件安装时。之后永远不会改变。

但是每次你的 state.data 发生变化时，你的主要组件会得到 re-rendered 并且 ReactTable 组件会得到 re-rendered 以及新数据 AND 与你原来的 state.columns 没有关于所选选项的信息。

我认为你应该在每次更新后重建你的列对象，在你的子组件中传递一个像 selectedOption.

这样的道具

您的子道具取决于您的 state.selectedValues 和 state.data。您可以在 render() 中重建您的列对象。我正在使用一种方法 buildColumns 从渲染中获取细节。

您所在的州不需要 columns属性。

...
constructor(props) {
    super(props);
    this.state = {
      data: [
        { firstName: "Jack", status: "Submitted", age: "14" },
        { firstName: "Simon", status: "Pending", age: "15" },
        { firstName: "Pete", status: "Approved", age: "16" },
        { firstName: "Lucas", status: "Rejected", age: "19" }
      ],
      selectedValues: {},
    };
  }
...
buildColumns = ({ data, selectedValues = {} }) => {
    const { firstName, status } = selectedValues
    return [
      {
        Header: () => (
          <div>
            <div style={{ position: "absolute", marginLeft: "10px" }}>
              <Child
                key="firstName"
                name="firstName"
                options={this.getValuesFromKey(data, "firstName")}
                selectedOption={firstName}
                handleFilter={this.handleFilter}
              />
            </div>
            <span>First Name</span>
          </div>
        ),
        accessor: "firstName",
        sortable: false,
        show: true,
        displayValue: " First Name"
      },
      {
        Header: () => (
          <div>
            <div style={{ position: "absolute", marginLeft: "10px" }}>
              <Child
                key="status"
                name="status"
                options={this.getValuesFromKey(data, "status")}
                selectedOption={status}
                handleFilter={this.handleFilter}
              />
            </div>
            <span>Status</span>
          </div>
        ),
        accessor: "status",
        sortable: false
      },
      {
        Header: "Age",
        accessor: "age"
      }
    ];
  }

  render() {
    const { data, selectedValues } = this.state;
    const columns = this.buildColumns({ data, selectedValues })
    return (
      <div>
        <ReactTable
          data={data}
          columns={columns}
          defaultPageSize={10}
          className="-striped -highlight"
        />
      </div>
    );
  }

您仍然需要在您的子组件中使用 selectedOption 道具来预先选中您的复选框。

旧的（错误的）答案：

当您获取过滤数据并使用它设置状态时，既然您的 state.data 已经更改，它将 re-render 子组件从中获取道具。

这会将您的子组件的状态重新初始化为其 {selected: []}值。

为防止这种情况发生，您应该将您的状态仅保留在主组件中，并通过道具传递所选选项的信息，从而使您的子组件成为 'controlled component'：https://reactjs.org/docs/forms.html#controlled-components

Child 组件的本地状态在 parent 组件内部发生变化时发生变化：ReactJS

Child component's local state changes when change happens inside parent component : ReactJS

javascript

setstate

reactjs

react-table

react-hooks

Parent

Child