el-selectchange事件拿到之前的值

        <el-table-column label="产品名称" prop="name" width="240">
          <template slot-scope="scope">
            <el-select
              :ref="scope.row.enterpriseProduceId"
              filterable
              v-model="scope.row.name"
              placeholder="请选择"
              style="width: 225px"
              @change="(e) => nameChange(e, scope.row)"
            >
              <el-option
                v-for="item in scope.row.options.optionProSize"
                :key="item.enterpriseProduceId"
                :label="item.name"
                :value="item.name"
                :disabled="item.disabled"
              >
              </el-option>
            </el-select>
            <div v-if="tableEditType == 'delivery'">{{ scope.row.name }}</div>
          </template>
        </el-table-column>

    nameChange(e,row) {
          const preValue = this.$refs[row.enterpriseProduceId].value
   			//preValue  ===  拿到下拉框选择变更之前的值
        }