c# - 如何从下拉列表中获取选定的值

Question

我正在绑定(bind)模型中的下拉列表，但无法从下拉列表中获取选定的值，它显示错误:

The value '1' is invalid , while submitting the form

模型代码

[Display(Name="User Type")]
[Required(ErrorMessage = "Select user type")]
public List<SelectListItem> usertype { get; set; }

查看代码

@Html.DropDownListFor(m => m.usertype, Model.usertype, new {  @class="form-control input-lg"})

Controller 代码

//controller
[HttpPost]
public ActionResult Register(Register register,FormCollection form)
{
}

填充下拉列表

[HttpGet]
public ActionResult Register()
{
    var model=new Register();
    List<string> stState = new List<string>();
    List<SelectListItem> selectListItemStates = new List<SelectListItem>();
    selectListItemStates.Add(new SelectListItem() { Value = string.Empty, Text = "Select State" });
    selectListItemStates.Add(new SelectListItem() { Value = "1", Text = "Mentor" });
    selectListItemStates.Add(new SelectListItem() { Value = "1", Text = "Employee" });
    selectListItemStates.Add(new SelectListItem() { Value ="1", Text = "Finance" });


    model.usertype = selectListItemStates.ToList();
    return View(model);
}

Answer 1

您需要在模型中为 SelectedValue 添加一个属性，它很可能是 int。

当前您正在将 DropDownListFor 与 SelectList 绑定(bind)，这是不正确的，DropDownListFor 将发布选定的单个值，通常是整数:

    public List<SelectListItem> usertype { get; set; }

    [Display(Name="User Type")]
    [Required(ErrorMessage = "Select user type")]
    public int UserType { get; set; }

在 View 中:

@Html.DropDownListFor(m=>m.UserType,Model.usertype, new {  @class="form-control input-lg"}