asp.net-mvc - 使用数据注释验证ASP.NET MVC 2中的SelectList

Question

我正在尝试在“选择列表”上使用内置的ASP.NET MVC 2客户端验证，如下所示:

 private SelectList _CategoryList;
        [Required(ErrorMessage = "Category Required")]
        [System.ComponentModel.DataAnnotations.Range(1, double.MaxValue, ErrorMessage = "Please Select A Category")]
        [DisplayName("Category")]
        public SelectList CategoryList
        {
            get
            {
                return new SelectList(Categories, "CatID", "CatFullName"); ;
            }
            set
            {
                _CategoryList = value;
            }
        }

但是它不起作用...如果选择默认值0，则不会显示验证消息，并且页面会像已验证一样进行。有什么想法吗？

Answer 1

好的，所以我在一个稍有不同的问题的答案中找到了答案。因此，我将在此处发布完整的代码，该代码在Scott Guthries ASP.NET MVC 2验证帖子上进行了扩展:http://weblogs.asp.net/scottgu/archive/2010/01/15/asp-net-mvc-2-model-validation.aspx

我的ViewModel:

public class Person
{
    [Required(ErrorMessage="First Name Required")]
    [StringLength(50,ErrorMessage="Must be under 50 characters")]
    public string FirstName { get; set; }

    [Required(ErrorMessage="Last Name Required")]
    [StringLength(50, ErrorMessage = "Must be under 50 characters")]
    public string LastName { get; set; }

    [Required(ErrorMessage="Age Required")]
    [Range(1,120,ErrorMessage="Age Must be between 0 and 120")]
    public int Age { get; set; }

    [Required(ErrorMessage="Email Required")]
    public string Email { get; set; }


    public IEnumerable<SelectListItem> FavoriteColor { get; set; }


    [Range(0, 6, ErrorMessage = "Out of range")]
    public int SelectedFavColor { get; set; }
}

我的色彩课:

public class Colors
{
    public int ColorID { get; set; }
    public string ColorName { get; set; }
}

我的列表帮助扩展程序是从Rob Connery那里偷来的，Rob Connery从其他人那里偷了它:

public static class ListExtensions
{
    public static IEnumerable<T> ForEach<T>(this IEnumerable<T> collection, Action<T> action)
    {
        foreach (var item in collection) action(item);
        return collection;
    }

    public static SelectList ToSelectList<T>(this IEnumerable<T> collection)
    {
        return new SelectList(collection, "Key", "Value");
    }

    public static SelectList ToSelectList<T>(this IEnumerable<T> collection, string selectedValue)
    {
        return new SelectList(collection, "Key", "Value", selectedValue);
    }

    public static SelectList ToSelectList<T>(this IEnumerable<T> collection,
                         string dataValueField, string dataTextField)
    {
        return new SelectList(collection, dataValueField, dataTextField);
    }

    public static SelectList ToSelectList<T>(this IEnumerable<T> collection,
                         string dataValueField, string dataTextField, string selectedValue)
    {
        return new SelectList(collection, dataValueField, dataTextField, selectedValue);
    }
}

我的 Controller 代码(是的，可以重构为更干):

public ActionResult Create()
    {
        Person newFriend = new Person();
        IList<Colors> colorslist = new List<Colors>();
        colorslist.Add(new Colors { ColorID = -1, ColorName = "Please Select Color" });
        colorslist.Add(new Colors { ColorID = 1, ColorName = "Red" });
        colorslist.Add(new Colors { ColorID = 2, ColorName = "Green" });
        colorslist.Add(new Colors { ColorID = 3, ColorName = "Blue" });

        newFriend.FavoriteColor = colorslist.ToSelectList("ColorID","ColorName","-1");
        return View(newFriend);
    }

    [HttpPost]
    public ActionResult Create(Person friendToCreate, FormCollection collection)
    {
        friendToCreate.SelectedFavColor = Convert.ToInt32(collection["SelectedFavColor"]);
        if (ModelState.IsValid)
        {
            return Redirect("/");
        }
        IList<Colors> colorslist = new List<Colors>();
        colorslist.Add(new Colors { ColorID = -1, ColorName = "Please Select Color" });
        colorslist.Add(new Colors { ColorID = 1, ColorName = "Red" });
        colorslist.Add(new Colors { ColorID = 2, ColorName = "Green" });
        colorslist.Add(new Colors { ColorID = 3, ColorName = "Blue" });
        friendToCreate.FavoriteColor = colorslist.ToSelectList("ColorID", "ColorName");
        return View(friendToCreate);
    }

我的页面标记:

<% using (Html.BeginForm()) {%>

    <fieldset>
        <legend>Fields</legend>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.FirstName) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.FirstName) %>
            <%= Html.ValidationMessageFor(model => model.FirstName) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.LastName) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.LastName) %>
            <%= Html.ValidationMessageFor(model => model.LastName) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.Age) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.Age) %>
            <%= Html.ValidationMessageFor(model => model.Age) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.Email) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.Email) %>
            <%= Html.ValidationMessageFor(model => model.Email) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.FavoriteColor) %>
        </div>
        <div class="editor-field">
            <%= Html.DropDownList("SelectedFavColor", Model.FavoriteColor, -1)%>
            <%= Html.ValidationMessageFor(model => model.SelectedFavColor) %>
        </div>

        <p>
            <input type="submit" value="Submit" />
        </p>
    </fieldset>

<% } %>