c# - 数据注释 MVC 4 位数字

Question

我正在尝试实现一个接受 4 位数字或将其留空的字段。

[RegularExpression(@"^(\d{4})$", ErrorMessage = "Enter a valid 4 digit Year")]
[Display(Name = "Year")]
public int Year { get; set; }

当输入超过 4 个数字时，会显示错误消息。问题是当我输入任何不是数字或数字和非数字的混合值时，验证错误消息不会显示。

我肯定错过了什么。帮帮我 :)

Answer 1

沃伦，

尝试使用nullable int，这样如果模型中什么都没有，它会允许共同发送数据，具体实现见下面的代码

public class TestModel
{
    [RegularExpression(@"^(\d{4})$", ErrorMessage = "Enter a valid 4 digit Year")]
    [Display(Name = "Year")]
    public int? Year { get; set; }
}

更新:我对这段代码的看法如下

@{
    ViewBag.Title = "Index";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Index</h2>

@using (Html.BeginForm()) {
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>TestModel</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.Year)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Year)
            @Html.ValidationMessageFor(model => model.Year)
        </div>

        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

我带 Controller 的模型是:

 public class HomeController : Controller
    {
        //
        // GET: /Home/

        public ActionResult Index()
        {
            var model = new TestModel();

            return View(model);
        }
}


    public class TestModel
    {
        [RegularExpression(@"^(\d{4})$", ErrorMessage = "Enter a valid 4 digit Year")]
        [Display(Name = "Year")]
        public int? Year { get; set; }
    }