无法在纸张列表框聚合物3中获取多个选定值

Question

我正在尝试在纸制列表框聚合物中获取多选值

 <paper-dropdown-menu label="{{_getLabel('Activity Type')}}" id="fromMenu" on-paper-dropdown-close="fromAccountChanged" searchable="true"> 
          <paper-listbox selected="{{value}}"  id="ddtype" on-iron-select="SelectedType"  attr-for-selected="value" selected="{{typeList}}" class="dropdown-content" slot="dropdown-content" multi>
            <template is="dom-repeat" items="{{typeList}}">
              <paper-item value="{{item}}">{{item}}</paper-item>
            </template>
          </paper-listbox>
        </paper-dropdown-menu>



SelectedType(e){
var selectedItem = e.target.selectedItem;
console.log(selectedItem.value)
var product_value = selectedItem.value;
this.searchTypeString = selectedItem.value;

}

这是我用来获取值但仅获取单个值的函数

Answer 1