I have a basic SpringBoot 2.0.5.RELEASE app. Using Spring Initializer, JPA, embedded Tomcat, Thymeleaf template engine, and package as an executable JAR file. I have this template, where I want to disable a select object based on a condition
<form id="menuFormId" class="form-style-9" action="#" th:action="@{/menu/save}" th:object="${menu}" method="post">
<ul>
<li th:each="e : ${#fields.detailedErrors()}" th:class="${e.global}? globalerr : fielderr">
<span th:text="${e.global}? '*' : ${e.fieldName}" ><b>The field name</b></span> : <span th:text="${e.message}" class="red">
<font color="red">The error message</font>
</span>
</li>
</ul>
<ul class="tab_form">
<li>
<select id="selectMenuId" th:field="*{resto}" th:classappend="${menu.id == null} ? disabled='disabled'">
<option value="0">PLEASE SELECT A MENU</option>
</select>
...
But I got this error:
Could not parse as expression: "${menu.id == null} ? disabled='disabled'"