elementui 输入框下拉面板宽度跟随输入框宽度

elementui 输入框下拉面板宽度跟随输入框宽度

    <el-form-item label="业务系统" prop="businessSystemId" class="select-mul" v-else>
              <el-select
                v-model="projectForm.businessSystemIdList"
                placeholder="请选择业务系统"
                style="width: 100%"
                multiple
                filterable
                collapse-tags
                @focus="setOptionWidth"
              >
                <el-option
                  v-for="item in resList"
                  :key="item.value"
                  :label="item.name"
                  :value="item.id"
                  :style="{width:selectOptionWidth}" 
                  :title="item.name"
                ></el-option>
              </el-select>
            </el-form-item>

    // 下拉框弹出时，设置弹框的宽度
    setOptionWidth(event){
      this.$nextTick(() => {
        this.selectOptionWidth = event.target.parentNode.parentNode.clientWidth + "px";
      });
    },