Question

我有一刻。我似乎无法将ListBox中的选定项目绑定到处理post事件的操作方法的参数中。

Model的类型为SystemRoleList：

public class SystemRoleList {
    public IEnumerable<SystemRole> List { get; set; }
}

SystemRole定义为：

public class SystemRole {
    public Int32 Id { get; set; }

    public String Name { get; set; }
}

此代码生成ListBox：

<%: this.Html.ListBox("Roles", new SelectList(Model.List, "Id", "Name")) %>

接收所选项目的操作方法设置如下：

[AcceptVerbs(HttpVerbs.Post)]
public ActionResult UpdateSystemRoles(Int32[] roles) {
    // do something with the results....
}

问题是roles总是null。我尝试过使用其他数据类型 - string[]，ICollection<int>等。如果我Request.Form，我可以在Request.Form["Roles[]"]集合中看到这些值。如果我从1,3,4选择了这些项目，则典型值可能为ListBox。

如何命名ListBox或我的参数，以便MVC自动绑定值？

Answer 1

很奇怪，以下对我来说非常好。

型号：

public class SystemRoleList
{
    public IEnumerable<SystemRole> List { get; set; }
}

public class SystemRole
{
    public int Id { get; set; }
    public string Name { get; set; }
}

控制器：

[HandleError]
public class HomeController : Controller
{
    public ActionResult Index()
    {
        var model = new SystemRoleList
        {
            List = new[]
            {
                new SystemRole { Id = 1, Name = "role 1" },
                new SystemRole { Id = 2, Name = "role 2" },
                new SystemRole { Id = 3, Name = "role 3" },
            }
        };
        return View(model);
    }

    [HttpPost]
    public ActionResult Index(int[] roles)
    {
        return Content("thanks for submitting");
    }
}

查看：

<%@ Page 
    Language="C#" 
    MasterPageFile="~/Views/Shared/Site.Master" 
    Inherits="System.Web.Mvc.ViewPage<MvcApplication1.Controllers.SystemRoleList>" 
%>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

    <% using (Html.BeginForm()) { %>
        <%= Html.ListBox("Roles", new SelectList(Model.List, "Id", "Name")) %>
        <button type="submit">OK</button>
    <% } %>

</asp:Content>

据说我会使用ListBox助手的强类型版本，如下所示：

型号：

public class SystemRoleList
{
    public int[] Roles { get; set; }
    public IEnumerable<SystemRole> List { get; set; }
}

控制器：

[HandleError]
public class HomeController : Controller
{
    public ActionResult Index()
    {
        var model = new SystemRoleList
        {
            List = new[]
            {
                new SystemRole { Id = 1, Name = "role 1" },
                new SystemRole { Id = 2, Name = "role 2" },
                new SystemRole { Id = 3, Name = "role 3" },
            }
        };
        return View(model);
    }

    [HttpPost]
    public ActionResult Index(SystemRoleList model)
    {
        return Content("thanks for submitting");
    }
}

查看：

<%@ Page 
    Language="C#" 
    MasterPageFile="~/Views/Shared/Site.Master" 
    Inherits="System.Web.Mvc.ViewPage<MvcApplication1.Controllers.SystemRoleList>" 
%>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

    <% using (Html.BeginForm()) { %>
        <%= Html.ListBoxFor(x => x., new SelectList(Model.List, "Id", "Name")) %>
        <button type="submit">OK</button>
    <% } %>

</asp:Content>

麻烦绑定ListBox中的选定项目

1 个答案: