筛选列表时如何保留选中的值

Question

我有一个过滤函数 'filterUsers' 处理 'filteredUsers' 对象数组。每个对象都呈现为带有一些数据和一个复选框的列表项。每次用户更改文本输入值时都会触发该函数。如果在过滤掉时选中某个项目，则选中的值将丢失。我需要一个解决方案来保留选中的值。

const UsersList = () => {
const { users } = useContext(UsersContext);
const [checkedUsersIds, setCheckedUsersIds] = useState([]);
const [filteredUsers, setFilteredUsers] = useState([]);

useEffect(() => setFilteredUsers(users), [users]);
useEffect(() => console.log(checkedUsersIds), [checkedUsersIds]);

const checkUsers = async e => {
    if (e.target.checked) {
        const checkedUser = users.find(user => user.id === Number(e.target.name));
        setCheckedUsersIds([...checkedUsersIds, checkedUser.id]);
    } else {
        setCheckedUsersIds(checkedUsersIds.filter(user => user !== Number(e.target.name)));
    }
};

const filterUsers = e => {
    setFilteredUsers(
        users.filter(
            user =>
                user.first_name.toLowerCase().includes(e.target.value.toLowerCase().trim()) ||
                user.last_name.toLowerCase().includes(e.target.value.toLowerCase().trim())
        )
    );
};

return (
    <>
        <input
            type="text"
            name="filter_users"
            className={classes.filter_input}
            onChange={e => filterUsers(e)}
            placeholder="search user..."
            autoComplete="off"
        />

        <ul>
            {filteredUsers.length ? (
                filteredUsers.map(user => {
                    return (
                        <label key={user.id} htmlFor={user.name}>
                            <li className={classes.user_container}>
                                <div className={classes.user_subcontainer}>
                                    <div
                                        className={`${classes.avatar_container} ${
                                            user.gender === 'Male' ? classes.male : classes.female
                                        }`}
                                    >
                                        {user.avatar ? (
                                            <img className={classes.avatar} src={user.avatar} alt="#" />
                                        ) : (
                                            <div className={classes.img_alt}>
                                                {user.first_name.slice(0, 1)}
                                                {user.last_name.slice(0, 1)}
                                            </div>
                                        )}
                                    </div>
                                    <h3
                                        className={user.gender === 'Male' ? classes.male_text : classes.female_text}
                                    >
                                        {user.first_name} {user.last_name}
                                    </h3>
                                </div>
                                <div className={classes.checkbox_container}>
                                    <input type="checkbox" name={user.id} onChange={e => checkUsers(e)} />
                                </div>
                            </li>
                        </label>
                    );
                })
            ) : (
                <h1 className={classes.list_loading}>List loading...</h1>
            )}
        </ul>
    </>
);

};

Answer 1

我在这里弄乱了你的代码的一些细节，但希望它演示了如何使用 checked 属性：

const UsersList = ({ users }) => {
  const [checkedUsersIds, setCheckedUsersIds] = React.useState([]);
  const [filteredUsers, setFilteredUsers] = React.useState([]);

  React.useEffect(() => setFilteredUsers(users), [users]);
  // React.useEffect(() => console.log(checkedUsersIds), [checkedUsersIds]);

  const checkUsers = e => {
    if (e.target.checked) {
      const checkedUser = users.find(user => user.id === Number(e.target.name));
      setCheckedUsersIds([...checkedUsersIds, checkedUser.id]);
    } else {
      setCheckedUsersIds(checkedUsersIds.filter(user => user !== Number(e.target.name)));
    }
  };

  const filterUsers = e => {
    const value = e.target.value.toLowerCase().trim();
    setFilteredUsers(
      users.filter(
        user =>
          user.first_name.toLowerCase().includes(value) ||
          user.last_name.toLowerCase().includes(value)
      )
    );
  };

  return (
    <React.Fragment>
      <input
        type="text"
        name="filter_users"
        onChange={e => filterUsers(e)}
        placeholder="search user..."
        autoComplete="off"
      />

      <ul>
        { filteredUsers.map(user => {
          return (
            <li key={user.id}>
              <label htmlFor={user.name}>
                {user.first_name} {user.last_name}
                <input
                  type="checkbox"
                  name={user.id}
                  onChange={e => checkUsers(e)}
                  checked={checkedUsersIds.includes(user.id)}
                />
              </label>
            </li>
          );
        })
        }
      </ul>
    </React.Fragment>
  );
};

const App = () =>
  <UsersList
    users={[
      { id: 1, first_name: 'Harry', last_name: 'Bibbleson' },
      { id: 2, first_name: 'Sally', last_name: 'Refsted' },
      { id: 3, first_name: 'Swonky', last_name: 'Trevor' },
    ]}
  />;

ReactDOM.render(<App />, document.getElementById('root'));

<script crossorigin src="https://unpkg.com/react@17/umd/react.development.js"></script>
<script crossorigin src="https://unpkg.com/react-dom@17/umd/react-dom.development.js"></script>
<div id="root"></div>

筛选列表时如何保留选中的值

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