element合并单元格方法及遇到问题的解决办法

效果如图：

代码如下

<!-- 查看选课 -->
<template>
    <div>
        <el-table
                :data="listData"
                :span-method="objectSpanMethod"
                border
                style=" 100%; margin-top: 20px"
        >
            <el-table-column
                    prop="team"
                    label="团队">
            </el-table-column>
            <el-table-column
                    prop="realName"
                    label="姓名">
            </el-table-column>
            <el-table-column
                    prop="courseId"
                    label="课程编号">
            </el-table-column>
            <el-table-column
                    prop="courseName"
                    label="课程名称">
            </el-table-column>
            <el-table-column
                    prop="description"
                    label="课程简介">
            </el-table-column>
            <el-table-column
                    prop="trainingType"
                    label="形式">
            </el-table-column>
            <el-table-column
                    prop="trainingTime"
                    label="开课时间">
            </el-table-column>
            <el-table-column
                    prop="trainingDays"
                    label="时长">
            </el-table-column>
            <el-table-column
                    prop="courseType"
                    label="类型">
                <template slot-scope="scope">
                    <span v-if="scope.row.courseType === 0">待审批</span>
                    <span v-else-if="scope.row.courseType === 1">已审批</span>
                    <span v-else-if="scope.row.courseType === 2">退回重选</span>
                    <span v-else>取消重选</span>
                </template>
            </el-table-column>
            <el-table-column
                    prop="approvalStatus"
                    label="审批状态">
                <template slot-scope="scope">
                    <span v-if="scope.row.approvalStatus === 0">待审批</span>
                    <span v-else-if="scope.row.approvalStatus === 1">已审批</span>
                    <span v-else-if="scope.row.approvalStatus === 2">退回重选</span>
                    <span v-else>取消重选</span>
                </template>
            </el-table-column>
        </el-table>
        <el-pagination
                @size-change="sizeChangeHandle"
                @current-change="currentChangeHandle"
                :current-page="pageIndex"
                :page-sizes="[10, 20, 50, 100]"
                :page-size="pageSize"
                :total="totalPage"
                layout="total, sizes, prev, pager, next, jumper">
        </el-pagination>
    </div>
</template>

<script>
    export default {
        name: "",
        data() {
            return {
                pageIndex: 1,
                pageSize: 10,
                totalPage: 0,
                dataListLoading: false,
                dataForm: {},
                listData: [],
                rowList: [],
                spanArr: [],
                formLabelWidth: '90px',
                roleType: 'bumen'  // 角色，是团队负责人还是部门负责人
            }
        },
        methods: {
            // 每页数
            sizeChangeHandle (val) {
                this.pageSize = val
                this.pageIndex = 1
                this.getDataList()
            },
            // 当前页
            currentChangeHandle (val) {
                this.pageIndex = val
                this.getDataList()
            },
            // 获取数据列表
            getDataList(){//查询操作
                this.dataListLoading = true
                this.$http({
                    url: this.$http.adornUrl('/courseselect/emptraining/getLeaderSelectCourses'),
                    method: 'get',
                    params: this.$http.adornParams({
                        'page': this.pageIndex,
                        'limit': this.pageSize,
                    })
                }).then(({data}) => {
                    if (data && data.code === 0) {
                        this.listData = data.data.list
                        this.totalPage = data.data.totalCount
                        this.roleType = data.leaderType === 1 ? 'bumen' : 'tuandui'
                        this.rowspan()
                    } else {
                        this.listData = []
                        this.totalPage = 0
                    }
                    this.dataListLoading = false
                })
            },

            rowspan() {
                this.listData.forEach((item,index) => {
                    if( index === 0){
                        this.spanArr.push(1);
                        this.position = 0;

                    }else{
                        if(this.listData[index].type === this.listData[index-1].type ){
                            this.spanArr[this.position] += 1;
                            this.spanArr.push(0);
                        }else{
                            this.spanArr.push(1);
                            this.position = index;
                        }
                    }
                })
            },
            objectSpanMethod({ row, column, rowIndex, columnIndex }) {  //表格合并行
                console.log(this.roleType)
                if (this.roleType === 'bumen'){
                    if (columnIndex === 0) {
                        const _row = this.spanArr[rowIndex];
                        const _col = _row>0 ? 1 : 0;
                        return {
                            rowspan: _row,
                            colspan: _col
                        }
                    }
                    if(columnIndex === 1){ //合并第三列 内容相同的
                        const _row = this.spanArr[rowIndex];
                        const _col = _row>0 ? 1 : 0;
                        return {
                            rowspan: _row,
                            colspan: _col
                        }
                    }
                }else {
                    if( columnIndex === 0){ //合并第三列 内容相同的
                        const _row = this.spanArr[rowIndex];
                        const _col = _row>0 ? 1 : 0;
                        return {
                            rowspan: _row,
                            colspan: _col
                        }
                    }
                }

            },
        },
        mounted() {
            this.getDataList();
        }
    }
</script>

<style scoped>

</style>

曾遇到的问题：element表格单元格合并时，合并列数据不显示，数据错位。

原因是，表格的数据还没渲染完，合并的方法就执行了。解决办法：this.rowspan() 一定要放到接口调用成功，表格数据赋值完毕之后在执行。