如何在spring mvc窗体中添加下拉菜单。我收到一个错误“未知的列'domainOptions‘in 'field list'”

public enum DomainOptions {
    OPTION1("Option 1"),
    OPTION2("Option 2"),
    OPTION3("Option 3");

    private final String label;

    DomainOptions(String label) {
        this.label = label;
    }

    public String getLabel() {
        return label;
    }
}

@GetMapping("/form")
public String showForm(Model model) {
    model.addAttribute("domainOptions", DomainOptions.values());
    return "form";
}

<form action="/submit" method="post">
    <select name="selectedDomain">
        <option th:each="option : ${domainOptions}"
                th:value="${option}"
                th:text="${option.label}">
        </option>
    </select>
    <input type="submit" value="Submit">
</form>

@PostMapping("/submit")
public String submitForm(@RequestParam("selectedDomain") DomainOptions selectedDomain) {
    // 处理选中的值
    return "result";
}