小编joh*_*doe的帖子

在我的控制器的动作中,我有以下代码:

public ActionResult GridAction(string id)
{
    if (String.IsNullOrEmpty(id)) 
    {
        // add errors to the errors collection and then return the view saying that you cannot select the dropdownlist value with the "Please Select" option
    }

    return View(); 
}

更新:

if (String.IsNullOrEmpty(id))
{
    // add error 
    ModelState.AddModelError("GridActionDropDownList", "Please select an option");
    return RedirectToAction("Orders"); 
}

更新2:

这是我更新的代码:

@Html.DropDownListFor(x => x.SelectedGridAction, Model.GridActions,"Please Select") 
@Html.ValidationMessageFor(x => x.SelectedGridAction)  

该模型如下所示:

public class MyInvoicesViewModel
{

    private List<SelectListItem> _gridActions;

    public int CurrentGridAction { get; set; }

    [Required(ErrorMessage = …