这个错我遇到了好几次，每一次都花了很长时间解决，还是决定写个笔记记录一下。

在使用elementu官网的布局容器时，他是这样的。

<el-container>
  <el-header>Header</el-header>
  <el-main>Main</el-main>
</el-container>

<el-container>
  <el-header>Header</el-header>
  <el-main>Main</el-main>
  <el-footer>Footer</el-footer>
</el-container>

<el-container>
  <el-aside width="200px">Aside</el-aside>
  <el-main>Main</el-main>
</el-container>

<el-container>
  <el-header>Header</el-header>
  <el-container>
    <el-aside width="200px">Aside</el-aside>
    <el-main>Main</el-main>
  </el-container>
</el-container>

<el-container>
  <el-header>Header</el-header>
  <el-container>
    <el-aside width="200px">Aside</el-aside>
    <el-container>
      <el-main>Main</el-main>
      <el-footer>Footer</el-footer>
    </el-container>
  </el-container>
</el-container>

<el-container>
  <el-aside width="200px">Aside</el-aside>
  <el-container>
    <el-header>Header</el-header>
    <el-main>Main</el-main>
  </el-container>
</el-container>

<el-container>
  <el-aside width="200px">Aside</el-aside>
  <el-container>
    <el-header>Header</el-header>
    <el-main>Main</el-main>
    <el-footer>Footer</el-footer>
  </el-container>
</el-container>

<style>
  .el-header, .el-footer {
    background-color: #B3C0D1;
    color: #333;
    text-align: center;
    line-height: 60px;
  }
  
  .el-aside {
    background-color: #D3DCE6;
    color: #333;
    text-align: center;
    line-height: 200px;
  }
  
  .el-main {
    background-color: #E9EEF3;
    color: #333;
    text-align: center;
    line-height: 160px;
  }
  
  body > .el-container {
    margin-bottom: 40px;
  }
  
  .el-container:nth-child(5) .el-aside,
  .el-container:nth-child(6) .el-aside {
    line-height: 260px;
  }
  
  .el-container:nth-child(7) .el-aside {
    line-height: 320px;
  }
</style>

我在确定elementui引入正确的情况下是这样写的。

<template>
  <el-container>
    <SideNav></SideNav>
    <el-container>
      <el-main><Main></Main></el-main>
      <el-footer><Footer></Footer></el-footer>
    </el-container>
  </el-container>
</template>

<script>
import SideNav from "@/components/SideNav";
import HomeHeader from "@/pages/Home/HomeHeader";
import "element-ui/lib/theme-chalk/index.css";
import Header from "@/components/Header";
export default {
  name: "Home",
  components: { SideNav, HomeHeader, Header },
};
</script>
<style  scoped>
.baseContainer {
  height: 100%;
  width: 100%;
  position: relative;
  left: 0px;
  right: 0px;
  top: 0px;
  bottom: 0px;
}

.el-header,
.el-footer {
  background-color: #b3c0d1;
  color: #333;
  text-align: center;
  line-height: 60px;
}

.el-aside {
  background-color: #d3dce6;
  color: #333;
  text-align: center;
  line-height: 200px;
}

.el-main {
  background-color: #e9eef3;
  color: #333;
  text-align: center;
  line-height: 160px;
}

body > .el-container {
  margin-bottom: 40px;
}

.el-container:nth-child(5) .el-aside,
.el-container:nth-child(6) .el-aside {
  line-height: 260px;
}

.el-container:nth-child(7) .el-aside {
  line-height: 320px;
}
</style>

注意，我在SideNav，Header,Main,Footer组件套了el-aside,el-header...然后暴露出来在Home中引用。

当然错误，布局一片混乱。想了一下午终于懂了。

原来，elementui不支持这种写法，在Home里面应该完全遵循官网的写法，el-aside,el-header,el-mian,el-footer等必须写在container的同一个组件，不能写在子组件里面然后引入，不然elementui不会识别为布局容器。

正确写法

<template>
  <el-container>
    <el-aside>
      <SideNav></SideNav>
    </el-aside>
    <el-container>
      <el-main><Main></Main></el-main>
      <el-footer><Footer></Footer></el-footer>
    </el-container>
  </el-container>
</template>

<script>
import SideNav from "@/components/SideNav";
import HomeHeader from "@/pages/Home/HomeHeader";
import "element-ui/lib/theme-chalk/index.css";
import Header from "@/components/Header";
export default {
  name: "Home",
  components: { SideNav, HomeHeader, Header },
};
</script>
<style  scoped>
.baseContainer {
  height: 100%;
  width: 100%;
  position: relative;
  left: 0px;
  right: 0px;
  top: 0px;
  bottom: 0px;
}

.el-header,
.el-footer {
  background-color: #b3c0d1;
  color: #333;
  text-align: center;
  line-height: 60px;
}

.el-aside {
  background-color: #d3dce6;
  color: #333;
  text-align: center;
  line-height: 200px;
}

.el-main {
  background-color: #e9eef3;
  color: #333;
  text-align: center;
  line-height: 160px;
}

body > .el-container {
  margin-bottom: 40px;
}

.el-container:nth-child(5) .el-aside,
.el-container:nth-child(6) .el-aside {
  line-height: 260px;
}

.el-container:nth-child(7) .el-aside {
  line-height: 320px;
}
</style>

言语稚嫩，希望对你有帮助！