Question

当页面上的默认选项提交时，

DropDownListFor不会抛出验证错误消息。它不允许提交页面但不会抛出错误。除了下拉列表外，还会显示其他验证消息。

public class CallLogViewModel
{
    [Required(ErrorMessage = "please select")]
    [Display(Name = "Details of Issue/Incident")]
    public IEnumerable<IssueCategory> IssueDetails { get; set; }
    public int SelectedIssue { get; set; }

    public CallLogViewModel()
    {
        HomeRepository hr = new HomeRepository();
        IssueDetails = hr.GetIssueCategories();//gets the list
    }       
}

public class IssueCategory
{
    public int UniqueId { get; set; }
    public string Issue { get; set; }
}

Controller.cs

public ActionResult Index()
{
    var viewModel = new CallLogViewModel();
    return View(viewModel);
}

查看

<div class="form-group">
    @Html.LabelFor(model => model.IssueDetails, htmlAttributes: new { @class = "control-label col-md-3" })
    <div class="col-md-9">
        @Html.DropDownListFor(model => model.SelectedIssue,  new SelectList(Model.IssueDetails, "UniqueId", "Issue", Model.SelectedIssue), "Please Select",new { @class = "form-control" } )
        @Html.ValidationMessageFor(model => model.IssueDetails,"", new { @class = "text-danger" })
    </div>
</div>

的Web.config

<add key="ClientValidationEnabled" value="true" />
<add key="UnobtrusiveJavaScriptEnabled" value="true" />

Answer 1

您将ValidationMessageFor()应用于SelectList，而非绑定到的属性。

将模型更改为

public class CallLogViewModel
{
    public IEnumerable<IssueCategory> IssueDetails { get; set; }
    // Apply the attributes to the property your binding to
    [Required(ErrorMessage = "please select")]
    [Display(Name = "Details of Issue/Incident")]
    public int SelectedIssue { get; set; }
    ....

并更改视图以将标签和验证消息绑定到SelectedIssue属性

<div class="form-group">
    @Html.LabelFor(m => m.SelectedIssue, new { @class = "control-label col-md-3" })
    <div class="col-md-9">
        @Html.DropDownListFor(m => m.SelectedIssue, new SelectList(Model.IssueDetails, "UniqueId", "Issue"), "Please Select",new { @class = "form-control" } )
        @Html.ValidationMessageFor(m => m.SelectedIssue, "", new { @class = "text-danger" })
    </div>
</div>

另请注意，SelectList构造函数的第4个参数不是必需的（Selected SelectListItem DropDownListFor()属性被public IEnumerable<SelectListItem> IssueDetails { get; set; }方法忽略。但是因为您使用了视图模型，你的属性应该是@Html.DropDownListFor(m => m.SelectedIssue, Model.IssueDetails, "Please Select", new { @class = "form-control" } )（你在GET方法中填充，视图就是

execute()

dropdownlistfor未显示错误消息

1 个答案: