C# code
public class customer
{
[Required]
[Display(Name = "Country")]
public int CountryId { get; set; }
}
ViewBag.CountryId = new SelectList(Uow.Countries.GetAll(), "ID", "名前");
modelbuilder
modelBuilder.Entity<Customer>().HasRequired(p => p.Country)
.WithMany(p => p.Customers)
.HasForeignKey(p => p.CountryId)
.WillCascadeOnDelete(false);
<div class="control-group">
@Html.LabelFor(model => model.CountryId, "CountryId", new { @class = "control- label" })
<div class="controls">
@Html.DropDownList("CountryId","select country");
@Html.ValidationMessageFor(model => model.CountryId, null, new { @class = "help-inline" })
</div>
</div>
デフォルト値が「国を選択」の保存ボタンをクリックしても、モデル エラーが発生しません」 代わりにエラーが発生します」 "