使用样式化组件，我想构建一个 React 组件，它将模仿 W3 Schools 中的以下代码:
ul {
list-style-type: none;
margin: 0;
padding: 0;
overflow: hidden;
background-color: #333;
}
li {
float: left;
}
li a, .dropbtn {
display: inline-block;
color: white;
text-align: center;
padding: 14px 16px;
text-decoration: none;
}
li a:hover, .dropdown:hover .dropbtn {
background-color: red;
}
li.dropdown {
display: inline-block;
}
.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 {
color: black;
padding: 12px 16px;
text-decoration: none;
display: block;
text-align: left;
}
.dropdown-content a:hover {background-color: #f1f1f1;}
.dropdown:hover .dropdown-content {
display: block;
}<body>
<ul>
<li><a href="#home">Home</a></li>
<li><a href="#news">News</a></li>
<li class="dropdown">
<a href="javascript:void(0)" class="dropbtn">Dropdown</a>
<div class="dropdown-content">
<a href="#">Link 1</a>
<a href="#">Link 2</a>
<a href="#">Link 3</a>
</div>
</li>
</ul>
<h3>Dropdown Menu inside a Navigation Bar</h3>
<p>Hover over the "Dropdown" link to see the dropdown menu.</p>
</body>
</html>这是我的 React 组件:
import React, { Component } from "react";
import PropTypes from "prop-types";
import styled, { ThemeProvider } from "styled-components";
const StyledUl = styled.ul`
list-style-type: none;
margin: 0;
overflow: hidden;
background-color: #333;
padding: 0px;
background-color: lightblue;
color: black;
font-weight: bold;
`;
const StyledLi = styled.li`
float: left;
height: 100%;
padding: 10px;
&:hover {
background-color: red;
}
`;
const DropDownContent = styled.div`
display: none;
position: absolute;
min-width: 160px;
z-index: 1;
`;
const DropDownLi = styled(StyledLi)`
display: inline-block;
&:hover ${DropDownContent} {
display: block;
}
`;
const StyledA = styled.a`
display: inline-block;
text-align: center;
text-decoration: none;
`;
const SubA = styled(StyledA)`
text-decoration: none;
display: block;
text-align: left;
background-color: lightblue;
padding: 10px;
`;
class Menu extends Component {
handleClick = action => {
if (!action) return;
if (this.props.onClick) this.props.onClick(action);
};
render = () => {
return (
<StyledUl>
<StyledLi>
<StyledA onClick={() => this.handleClick("Home")}>
Home
</StyledA>
</StyledLi>
<StyledLi>
<StyledA onClick={() => this.handleClick("News")}>
Home
</StyledA>
</StyledLi>
<DropDownLi>
<StyledA onClick={() => this.handleClick("DropDown")}>
DropDown
</StyledA>
<DropDownContent>
{" "}
<SubA onClick={() => this.handleClick("Link1")}>
Link 1
</SubA>
<SubA onClick={() => this.handleClick("Link2")}>
Link 2
</SubA>
<SubA onClick={() => this.handleClick("Link3")}>
Link 3
</SubA>
</DropDownContent>
</DropDownLi>
</StyledUl>
);
};
}
export default Menu;
结果不一样，主要是因为我不确定如何在 styled-component 中使用选择器。
如何修复我的 ReactJs 组件 Menu 代码，使其表现得与 W3 示例完全一样？
最佳答案
您在翻译代码时犯了一些小错误，但语法和概念都是正确的。您对选择器的使用是正确的:
/* Hovering over current component */
&:hover {
background-color: red;
}
/* Selecting another styled component */
/* calls DropDownContent.toString(), which returns */
/* the class name of the styled component: .sc-bxivhb */
&:hover ${DropDownContent} {
display: block;
}
这是更正后的版本:
import React, { Component } from "react";
import styled from "styled-components";
const StyledUl = styled.ul`
list-style-type: none;
margin: 0;
padding: 0;
overflow: hidden;
background-color: #333;
`;
const StyledLi = styled.li`
float: left;
`;
const Dropbtn = styled.div`
display: inline-block;
color: white;
text-align: center;
padding: 14px 16px;
text-decoration: none;
`;
const DropDownContent = styled.div`
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;
`;
const DropDownLi = styled(StyledLi)`
display: inline-block;
&:hover {
background-color: red;
}
&:hover ${DropDownContent} {
display: block;
}
`;
const StyledA = styled.a`
display: inline-block;
color: white;
text-align: center;
padding: 14px 16px;
text-decoration: none;
&:hover {
background-color: red;
}
`;
const SubA = styled.a`
color: black;
padding: 12px 16px;
text-decoration: none;
display: block;
text-align: left;
&:hover {
background-color: #f1f1f1;
}
`;
class Menu extends Component {
handleClick = action => {
if (!action) return;
if (this.props.onClick) this.props.onClick(action);
};
render = () => {
return (
<StyledUl>
<StyledLi>
<StyledA onClick={() => this.handleClick("Home")}>Home</StyledA>
</StyledLi>
<StyledLi>
<StyledA onClick={() => this.handleClick("News")}>Home</StyledA>
</StyledLi>
<DropDownLi>
<Dropbtn onClick={() => this.handleClick("DropDown")}>
DropDown
</Dropbtn>
<DropDownContent>
{" "}
<SubA onClick={() => this.handleClick("Link1")}>Link 1</SubA>
<SubA onClick={() => this.handleClick("Link2")}>Link 2</SubA>
<SubA onClick={() => this.handleClick("Link3")}>Link 3</SubA>
</DropDownContent>
</DropDownLi>
</StyledUl>
);
};
}
export default Menu;
关于javascript - 使用 styled-components : How to properly use class selectors? 的下拉菜单，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/58963030/