el-tree 懒加载复选框默认展开和默认选中

.markdown-body { line-height: 1.75; font-weight: 400; font-size: 16px; overflow-x: hidden; color: rgba(37, 41, 51, 1) }
.markdown-body h1, .markdown-body h2, .markdown-body h3, .markdown-body h4, .markdown-body h5, .markdown-body h6 { line-height: 1.5; margin-top: 35px; margin-bottom: 10px; padding-bottom: 5px }
.markdown-body h1 { font-size: 24px; line-height: 38px; margin-bottom: 5px }
.markdown-body h2 { font-size: 22px; line-height: 34px; padding-bottom: 12px; border-bottom: 1px solid rgba(236, 236, 236, 1) }
.markdown-body h3 { font-size: 20px; line-height: 28px }
.markdown-body h4 { font-size: 18px; line-height: 26px }
.markdown-body h5 { font-size: 17px; line-height: 24px }
.markdown-body h6 { font-size: 16px; line-height: 24px }
.markdown-body p { line-height: inherit; margin-top: 22px; margin-bottom: 22px }
.markdown-body img { max-width: 100% }
.markdown-body hr { border-top: 1px solid rgba(221, 221, 221, 1); border-right: none; border-bottom: none; border-left: none; margin-top: 32px; margin-bottom: 32px }
.markdown-body code { border-radius: 2px; overflow-x: auto; background-color: rgba(255, 245, 245, 1); color: rgba(255, 80, 44, 1); font-size: 0.87em; padding: 0.065em 0.4em }
.markdown-body code, .markdown-body pre { font-family: Menlo, Monaco, Consolas, Courier New, monospace }
.markdown-body pre { overflow: auto; position: relative; line-height: 1.75 }
.markdown-body pre>code { font-size: 12px; padding: 15px 12px; margin: 0; word-break: normal; display: block; overflow-x: auto; color: rgba(51, 51, 51, 1); background: rgba(248, 248, 248, 1) }
.markdown-body a { text-decoration: none; color: rgba(2, 105, 200, 1); border-bottom: 1px solid rgba(209, 233, 255, 1) }
.markdown-body a:active, .markdown-body a:hover { color: rgba(39, 91, 140, 1) }
.markdown-body table { display: inline-block !important; font-size: 12px; width: auto; max-width: 100%; overflow: auto; border: 1px solid rgba(246, 246, 246, 1) }
.markdown-body thead { background: rgba(246, 246, 246, 1); color: rgba(0, 0, 0, 1); text-align: left }
.markdown-body tr:nth-child(2n) { background-color: rgba(252, 252, 252, 1) }
.markdown-body td, .markdown-body th { padding: 12px 7px; line-height: 24px }
.markdown-body td { min-width: 120px }
.markdown-body blockquote { color: rgba(102, 102, 102, 1); padding: 1px 23px; margin: 22px 0; border-left: 4px solid rgba(203, 203, 203, 1); background-color: rgba(248, 248, 248, 1) }
.markdown-body blockquote:after { display: block; content: "" }
.markdown-body blockquote>p { margin: 10px 0 }
.markdown-body ol, .markdown-body ul { padding-left: 28px }
.markdown-body ol li, .markdown-body ul li { margin-bottom: 0; list-style: inherit }
.markdown-body ol li .task-list-item, .markdown-body ul li .task-list-item { list-style: none }
.markdown-body ol li .task-list-item ol, .markdown-body ol li .task-list-item ul, .markdown-body ul li .task-list-item ol, .markdown-body ul li .task-list-item ul { margin-top: 0 }
.markdown-body ol ol, .markdown-body ol ul, .markdown-body ul ol, .markdown-body ul ul { margin-top: 3px }
.markdown-body ol li { padding-left: 6px }
.markdown-body .contains-task-list { padding-left: 0 }
.markdown-body .task-list-item { list-style: none }
@media (max-width: 720px) { .markdown-body h1 { font-size: 24px } .markdown-body h2 { font-size: 20px } .markdown-body h3 { font-size: 18px } }.markdown-body pre, .markdown-body pre>code.hljs { color: rgba(51, 51, 51, 1); background: rgba(248, 248, 248, 1) }
.hljs-comment, .hljs-quote { color: rgba(153, 153, 136, 1); font-style: italic }
.hljs-keyword, .hljs-selector-tag, .hljs-subst { color: rgba(51, 51, 51, 1); font-weight: 700 }
.hljs-literal, .hljs-number, .hljs-tag .hljs-attr, .hljs-template-variable, .hljs-variable { color: rgba(0, 128, 128, 1) }
.hljs-doctag, .hljs-string { color: rgba(221, 17, 68, 1) }
.hljs-section, .hljs-selector-id, .hljs-title { color: rgba(153, 0, 0, 1); font-weight: 700 }
.hljs-subst { font-weight: 400 }
.hljs-class .hljs-title, .hljs-type { color: rgba(68, 85, 136, 1); font-weight: 700 }
.hljs-attribute, .hljs-name, .hljs-tag { color: rgba(0, 0, 128, 1); font-weight: 400 }
.hljs-link, .hljs-regexp { color: rgba(0, 153, 38, 1) }
.hljs-bullet, .hljs-symbol { color: rgba(153, 0, 115, 1) }
.hljs-built_in, .hljs-builtin-name { color: rgba(0, 134, 179, 1) }
.hljs-meta { color: rgba(153, 153, 153, 1); font-weight: 700 }
.hljs-deletion { background: rgba(255, 221, 221, 1) }
.hljs-addition { background: rgba(221, 255, 221, 1) }
.hljs-emphasis { font-style: italic }
.hljs-strong { font-weight: 700 }

组织树懒加载 多选组织树必须要加的属性

            <el-tree
              ref="showTree"
              :data="data3"      //所有的组织树的树形结构数据 必须要加
              :load="loadData"    // load是懒加载必须加的在点击的时候获取数据
              show-checkbox  // 看业务需求是否有复选框的需求
              lazy  //懒加载属性
              check-on-click-node  //只有在点击的时候才会选中复选框
              @check="onCheckChange"   //通过点击事件拿到默认展开的数据和默认选中的数据  拿到这两个数据给后端让后端保存  当前端需要回显的时候在一开始调用接口展示
              node-key="id"  //这个必须要有固定的id值 一方面完整渲染 一方面选中回显使用
              :props="defaultProps"
              :default-checked-keys="defaultCheckedNodes"
              :default-expanded-keys="defaultExpandedKeys"
            ></el-tree>

         <script>
         export default {
            data() {
               return {
                 //这个字段是根据后端返回来的数据对应是哪个才可以 是树的渲染和使用
                  defaultProps: {
                   children: 'subAreas',
                    label: 'name',
                   isLeaf: 'leaf',
                 },

                  defaultExpandedKeys: [], //默认展开
                  defaultCheckedNodes: [], //默认选中

             },
             methods:{
             //loadData 方法是对于懒加的使用当触发的时候会调用接口获取后端数据
             loadData(node, resolve) {
               if (node.level === 0) {
               return
               resolve([{ name: 'region' }]); }
               if (node.level > 1) return resolve([]);
               setTimeout(() => {
                 const data =
                [{ name: 'leaf', leaf: true },
                 { name: 'zone' }]; resolve(data); },
               500);
              },
              onCheckChange(data, node) {
               console.log('onCheckChange', data, node)
               this.halfCheckedKeys = node.halfCheckedKeys
               this.checkedKeys = node.checkedKeys
               }
           }
         }
         </script>

对于组织树的默认展开和默认选中，其实归根结底就是一个，查看选中事件，返回来的值将返回的值赋值过去看看是否生效