Property or method "logout" is not defined on the instance but referenced during render. Make sure that this property is reactive, either in the data option, or for class-based components, by initializing the property. See: https://vuejs.org/v2/guide/reactivity.html#Declaring-Reactive-Properties.
使用官方给的方式，有效。
<el-dropdown @command="handleCommand"> <span class="el-dropdown-link"> 下拉菜单<i class="el-icon-arrow-down el-icon--right"></i> </span> <el-dropdown-menu slot="dropdown"> <el-dropdown-item command="a">黄金糕</el-dropdown-item> <el-dropdown-item command="b">狮子头</el-dropdown-item> <el-dropdown-item command="c">螺蛳粉</el-dropdown-item> <el-dropdown-item command="d" disabled>双皮奶</el-dropdown-item> <el-dropdown-item command="e" divided>蚵仔煎</el-dropdown-item> </el-dropdown-menu> </el-dropdown> <style> .el-dropdown-link { cursor: pointer; color: #409EFF; } .el-icon-arrow-down { font-size: 12px; } </style> <script> export default { methods: { handleCommand(command) { this.$message('click on item ' + command); } } } </script>