排除列表框中的所選項目的故障

Question

我有一個時刻。我似乎無法將ListBox中的選定項目綁定到處理post事件的操作方法的參數中。

Model是SystemRoleList類型的：該代碼生成ListBox

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

    public String Name { get; set; } 
} 

：

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

動作方法接收所選擇的項目是

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

SystemRole被定義爲像t一樣成立他：

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

麻煩的是，roles總是null。我試過使用其他數據類型 - string[],ICollection<int>，等等。如果我做Request.Form["Roles[]"]，我可以看到Request.Form集合中的值。如果我從ListBox中選擇了那些項目，典型值可能是1,3,4。

如何命名ListBox或我的參數，以便MVC自動綁定這些值？

Answer 1

奇怪的是，下面的作品完全適合我。

型號：

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> 

這是說我會用ListBox助手的強類型版本，像這樣：

型號：

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>