如何在ASP.NET MVC Razor中验证DropdowList

Question

请帮我这个问题。 我无法验证我的项目的DropdownList。 我的模型使用了DataAnnontation：

public class Category
{
   public int Id { get; set; }

   public virtual IList<Product> Products { get; set; }
}

public class Product
{
    [Required]
    [StringLength(32)]
    public string Id { get; set; }
    [Required]
    public int CategoryId { get; set; }

    public virtual Category Category { get; set; }
}

最后，一些创建视图的代码：

<script src="~/Scripts/jquery.validate.min.js" type="text/javascript"></script>
<script src="~/Scripts/jquery.validate.unobtrusive.min.js" type="text/javascript"></script>  
@using (Html.BeginForm())
{
    @Html.ValidationSummary(true)   
    @Html.DropDownList("CategoryId", String.Empty) @Html.ValidationMessageFor(x => x.CategoryId)</td>
} 

Answer 1

您需要使用@html.DropDownListFor()

Answer 2

尝试这个。

模型

public class YourViewModel
{
    [Required]
    public string CategoryId { get; set; }

    public IEnumerable<Category> Categories { get; set; }
}

形成

@using (Html.BeginForm())
{
    @Html.DropDownListFor(
        x => x.CategoryId, 
        new SelectList(Model.Categories, "ID", "CategoryName"), 
        "-- Please select a category --"
    )
    @Html.ValidationMessageFor(x => x.CategoryId)
}