java - Struts 2 迭代选择中的空顶部选项

Question

有没有办法在以下内容中添加“空顶部选择”选项:

<select id="OrderNameIssueId" name="OrderWork.OrderNameIssueId" style="width: auto">
    <s:iterator value="OrderWork.ClientOrderNameIssues" status="rowIdx" id="ClientIssueOption">
        <option value='<s:property value="#ClientIssueOption.OrderNameIssue.OrderNameIssueId"/>' <s:if test="OrderWork.OrderNameIssueId != null && (OrderWork.OrderNameIssueId == #ClientIssueOption.OrderNameIssue.OrderNameIssueId)">selected</s:if><s:else></s:else>>
            <s:property value="#ClientIssueOption.OrderNameIssue.issueDescription"/>
            <s:if test="#ClientIssueOption.ApprovedOption == true">&nbsp;|&nbsp;Approved</s:if>
            <s:else>
                <s:if test="#ClientIssueOption.RequireFix == true">&nbsp;|&nbsp;Requires Fix</s:if>
                <s:else>&#9;|&nbsp;Unapproved</s:else>
            </s:else>
            &nbsp;|&nbsp;Format:&nbsp;<s:property value="#ClientIssueOption.OrderNameIssue.issueHint"/>
        </option>
    </s:iterator>
</select>

它位于使用 Struts 2 的 JSP 页面上。选择本身可以工作，但是我们需要有一个选项会显示在页面上，如下所示:

<option value="0">--</option>

Answer 1

您应该能够将其添加到“select”下方和“s:iterator”上方。您还需要在选择时指定。

<select id="OrderNameIssueId" name="OrderWork.OrderNameIssueId" style="width: auto">
    <s:if test="OrderWork.OrderNameIssueId == null || OrderWork.OrderNameIssueId == 0">
        <option value="0" selected>--Please select an option--</option>
    </s:if>
    <s:else>
        <option value="0">--Please select an option--</option>
    </s:else>
    <s:iterator value="OrderWork.ClientOrderNameIssues" status="rowIdx" id="ClientIssueOption">
       <option value='<s:property value="#ClientIssueOption.OrderNameIssue.OrderNameIssueId"/>' <s:if test="OrderWork.OrderNameIssueId != null && (OrderWork.OrderNameIssueId == #ClientIssueOption.OrderNameIssue.OrderNameIssueId)">selected</s:if><s:else></s:else>>
       <s:property value="#ClientIssueOption.OrderNameIssue.issueDescription"/>
       <s:if test="#ClientIssueOption.ApprovedOption == true">&nbsp;|&nbsp;Approved</s:if>
       <s:else>
           <s:if test="#ClientIssueOption.RequireFix == true">&nbsp;|&nbsp;Requires Fix</s:if>
           <s:else>&#9;|&nbsp;Unapproved</s:else>
       </s:else>
       &nbsp;|&nbsp;Format:&nbsp;<s:property value="#ClientIssueOption.OrderNameIssue.issueHint"/>
       </option>
   </s:iterator>
</select>