我正在使用React js并构建一个运行良好的应用程序。我已经使用了react-bootstrap作为导航栏，它的工作原理非常适合两级导航栏。但是，作为我未来发展的一部分，菜单项不断增加，我想实现多级（三级）导航栏。我浏览了很多站点并进行了浏览，但是找不到站点，任何人都可以建议/帮助我。预先感谢。
这是我现在使用的代码：
import React from 'react';
import App from './App.jsx';
import { Link } from 'react-router-dom';
import navStyle from './navbar.css';
class Links extends React.Component {
constructor(props) {
super(props);
this.state = {
}
}
// on load od component this method will be called.
componentDidMount() {
this.state.allowedTabs = JSON.parse(sessionStorage.allowedTabs);
console.log(sessionStorage.allowedTabs.indexOf("Employees"));
console.log(this.state.allowedTabs);
console.log(this.state.allowedTabs.indexOf("Employees"));
console.log("roles", sessionStorage.roleRights);
console.log("services", sessionStorage.allowedServices);
}
render() {
return (
<div>
<div className = {navStyle.navbar}>
<img className = "pull-left" src="cerium-logo-bordered.jpg" alt="Smiley face" style =
{{"height":"50px","width":"120px","marginRight":"26px","margin": "0px 12px 0px 0px"}}>
</img>
<Link to="/home">
Home
</Link>
{sessionStorage.allowedServices.indexOf("Employee_List") != -1 &&
<div className = {navStyle.dropdown}>
{sessionStorage.allowedServices.indexOf("Employee_List") != -1 && <button className = {navStyle.dropbtn}>
Ceriumites
<i className="fa fa-caret-down" style={{"marginLeft":"3px"}}></i>
</button>}
<div className = {navStyle.dropdown_content}>
<Link to="/employee">
Ceriumites' List
</Link>
{(sessionStorage.allowedServices.indexOf("Add_Employee") != -1) &&
<Link to="/addNewEmployee">
Add a New Ceriumite
</Link>}
{(sessionStorage.allowedServices.indexOf("Bulk_Upload") != -1) &&
<Link to="/employeeBulkUpload">
Bulk Data Upload
</Link>}
{(sessionStorage.allowedServices.indexOf("Resignation_Formalities") != -1) &&
<Link to="/resignationMainPage">
Leaving Formalities
</Link>}
{(sessionStorage.allowedServices.indexOf("Exit_Formalities") != -1) &&
<Link to="/exitFormalities">
Exit Formalities
</Link>}
</div>
</div>}
{sessionStorage.allowedServices.indexOf("Project_List") != -1 &&
<div className = {navStyle.dropdown}>
<button className = {navStyle.dropbtn}>
Project
<i className="fa fa-caret-down" style={{"marginLeft":"3px"}}></i>
</button>
<div className = {navStyle.dropdown_content}>
{(sessionStorage.allowedServices.indexOf("Project_List") != -1) && <Link to="/project">
Project List
</Link>}
{sessionStorage.allowedServices.indexOf("Add_Project") != -1 &&
<Link to="/addNewProject">
Add a New Project
</Link>}
</div>
</div>}
{sessionStorage.allowedServices.indexOf("Staffing_List") != -1 &&
<div className = {navStyle.dropdown}>
<button className = {navStyle.dropbtn}>
Staffing
<i className="fa fa-caret-down" style={{"marginLeft":"3px"}}></i>
</button>
<div className = {navStyle.dropdown_content}>
{sessionStorage.allowedServices.indexOf("Staffing_List") != -1 && <Link to="/staffing">
Staffing List
</Link>}
{sessionStorage.allowedServices.indexOf("Add_Staffing") != -1 &&
<Link to="/addNewStaffing">
Staffing into Project
</Link>}
</div>
</div>}
{(sessionStorage.allowedServices.indexOf("Invoice_List") != -1 || sessionStorage.allowedServices.indexOf("Timesheets") != -1) &&
<div className = {navStyle.dropdown}>
<button className = {navStyle.dropbtn}>
Finance
<i className="fa fa-caret-down" style={{"marginLeft":"3px"}}></i>
</button>
<div className = {navStyle.dropdown_content}>
{sessionStorage.allowedServices.indexOf("Invoice_List") != -1 &&
<Link to="/invoice">
Invoices
</Link>}
{sessionStorage.allowedServices.indexOf("Raise_Invoice") != -1 &&
<Link to="/raiseInvoice">
Raise Invoice
</Link>}
{sessionStorage.allowedServices.indexOf("Timesheets") != -1 &&
<Link to="/timesheets">
Timesheets
</Link>}
</div>
</div>}
{(sessionStorage.allowedServices.indexOf("Monthly_Employee_Project_Report") != -1 || (sessionStorage.allowedServices.indexOf("Bench_Report") != -1) || (sessionStorage.allowedServices.indexOf("Staffing_Report") != -1)) &&
<div className = {navStyle.dropdown}>
<button className = {navStyle.dropbtn}>
Reports
<i className="fa fa-caret-down" style={{"marginLeft":"3px"}}></i>
</button>
<div className = {navStyle.dropdown_content}>
{(sessionStorage.allowedServices.indexOf("Monthly_Employee_Project_Report") != -1) && <Link to="/monthlyEmployeeReports">
Project Wise Report
</Link>}
{(sessionStorage.allowedServices.indexOf("Staffing_Report") != -1) && <Link to="/staffingReport">
Staffing Report
</Link>}
{(sessionStorage.allowedServices.indexOf("Duplicate_Staffed_Report") != -1) && <Link to="/duplicateStaffingReport">
Duplicate Staffing Report
</Link>}
{(sessionStorage.allowedServices.indexOf("Lead_Wise_Report") != -1) && <Link to="/leadWiseReports">
Lead Wise Report
</Link>}
{(sessionStorage.allowedServices.indexOf("Lead_Wise_Report(Jay)") != -1) && <Link to="/jayLeadWiseReport">
Lead Wise Report(Jay)
</Link>}
{(sessionStorage.allowedServices.indexOf("Customer_Wise_Report") != -1) && <Link to="/customerWiseReports">
Customer Wise Report
</Link>}
{(sessionStorage.allowedServices.indexOf("Location_Wise_Report") != -1) && <Link to="/locationWiseReport">
Location Wise Report
</Link>}
{(sessionStorage.allowedServices.indexOf("Milestone_Report") != -1) && <Link to="/milestoneReport">
Milestone Report
</Link>}
{(sessionStorage.allowedServices.indexOf("Bench_Report") != -1) && <Link to="/benchReport">
Bench Report
</Link>}
{(sessionStorage.allowedServices.indexOf("On_Hold_Report") != -1) && <Link to="/onHoldReport">
On Hold Report
</Link>}
{(sessionStorage.allowedServices.indexOf("Employee_Reports(Joining, Resigned, exit)") != -1) && <Link to="/employeeReports">
Ceriumite Tenure Details
</Link>}
{(sessionStorage.allowedServices.indexOf("Unstaffed_Report") != -1) && <Link to="/unStaffedEmployeeReport">
Unstaffed Ceriumites
</Link>}
{(sessionStorage.allowedServices.indexOf("Offboarding_Report") != -1) && <Link to="/offboardingReport">
Offboarding Report
</Link>}
</div>
</div>}
<Link to="/changePassword">
Change Password
</Link>
<Link to="/">
Logout
</Link>
<label className ="pull-right" style={{"color":"white", "marginTop":"15px", "marginRight":"2%"}}>
Username : {sessionStorage.userName}
</label>
</div>
</div>
)
}
}
export default Links;
Css文件：
.navbar {
overflow: hidden;
background-color: #68bcff;
font-family: Arial, Helvetica, sans-serif;
}
.navbar a {
float: left;
font-size: 16px;
color: white;
text-align: center;
padding: 14px 16px;
text-decoration: none;
}
.dropdown {
float: left;
overflow: hidden;
}
.dropdown .dropbtn {
font-size: 16px;
border: none;
outline: none;
color: white;
padding: 14px 16px;
background-color: inherit;
font-family: inherit;
margin: 0;
}
.navbar a:hover, .dropdown:hover .dropbtn {
background-color: gray;
}
.dropdown_content {
display: none;
position: absolute;
background-color: #f9f9f9;
min-width: 160px;
box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
z-index: 1;
}
.dropdown_content a {
float: none;
color: black;
padding: 6px 16px;
text-decoration: none;
display: block;
text-align: left;
}
.dropdown_content a:hover {
background-color: #ddd;
}
.dropdown:hover .dropdown_content {
display: block;
}