监听form的改变，刷新列表数据

computed: {
  _searchForm () {
    return JSON.parse(JSON.stringify(this.searchForm))
  }
},
watch: {
  _searchForm: {
    handler: function (newVal, oldVal) {
      if (newVal.pageNum !== 1 && newVal.pageNum === oldVal.pageNum) {
        this.searchForm.pageNum = 1;
      } else {
        this.getTableData()
      }
    },
    deep: true
  }
},