Element UI Dialog对话框改成固定高度超出部分滚动条滚动

<template>
    <div>
        <el-dialog v-el-drag-dialog :close-on-click-modal="false" v-if="orderDetailVisible"
            :title="$t('workOrder.workOrderDetail')"
            :visible.sync="orderDetailVisible" 
            class="showAll_dialog"
            width="70%" :before-close="close">
            <div id="printJS-form">
                <!-- 需要打印的区域 -->
                <div class="table-d tableBox" id="box">
                    <el-table ref="tableG" :header-cell-style="{ color: '#FFF', background: '#333' }"
                        :cell-style="{ color: '#FFF', background: '#333' }" :default-sort="{ prop: 'stockNo', order: '' }"
                        :data="gridData" id="pagetable" :row-key="getRowKeys" border style="width:100%;"
                        @selection-change="handleSelectionChange">
                        <template slot="empty">
                            <span style="color: #969799">{{ $t("NeoLight.empty") }}</span>
                        </template>
                        <el-table-column prop="feederInfo" :sortable="true" :label="$t('workOrder.stationInfo')" />
                        <el-table-column prop="outNum" :sortable="true" :label="$t('workOrder.quantityIssued')" />
                   </el-table>
                </div>
            </div>
        </el-dialog>
    </div>
</template>

// 修改对话框高度
.showAll_dialog {
    overflow: hidden;

    ::v-deep .el-dialog {
        margin: 0 auto !important;
        height: 70%;
        overflow: hidden;
        background-color: black;

        .el-dialog__body {
            position: absolute;
            left: 0;
            top: 54px;
            bottom: 0;
            right: 0;
            padding: 0;
            z-index: 1;
            overflow: hidden;
            overflow-y: auto;
            // 下边设置字体，我的需求是黑底白字
            color: #ffffff;
            line-height: 30px;
            padding: 0 15px;
        }
    }

// 内容
<template>
  <div>
    <el-dialog
      :visible.sync="dialogVisible"
      width="836px"
      @closed="handleClose">
      <!-- 设置对话框内容高度 -->
      <div style="height:70vh">
        <el-scrollbar>
          <div class="content-box">{{ message }}</div>
        </el-scrollbar>
      </div>
    </el-dialog>
  </div>
</template>
// 样式，只设置了个行高
<style lang="scss" scoped>
  .content-box{
    line-height: 30px;
  }
</style>