如何在lightning UI中重置组合框？

resetCombobox: function(component, event, helper) {
    // 重置组合框的值
    component.find("comboboxId").set("v.value", "");
}

<lightning:button label="重置" onclick="{!c.resetCombobox}" />

<lightning:select aura:id="comboboxId" label="选择项" name="comboboxName">
    <!-- 添加选项 -->
    <option value="option1">选项1</option>
    <option value="option2">选项2</option>
    <option value="option3">选项3</option>
</lightning:select>