如何使用asp.net mvc编辑多选列表？

Question

我想编辑一个如下所示的对象.我想用UsersSelectedList填充UsersGrossList中的一个或多个用户.

使用mvc中的标准编辑视图,我只得到映射的字符串和布尔值(下面未显示).我在谷歌上找到的许多例子都使用了mvc框架的早期版本,而我使用的是官方的1.0版本.

任何观点的例子都表示赞赏.

public class NewResultsState
{
    public IList<User> UsersGrossList { get; set; }
    public IList<User> UsersSelectedList { get; set; }
}

Answer 1

假设User模型具有Id和Name属性:

<%= Html.ListBox("users", Model.UsersGrossList.Select(
    x => new SelectListItem {
        Text = x.Name,
        Value = x.Id,
        Selected = Model.UsersSelectedList.Any(y => y.Id == x.Id)
    }
) %>

或者使用View Model

public class ViewModel {
    public Model YourModel;
    public IEnumerable<SelectListItem> Users;
}

控制器:

var usersGrossList = ...
var model = ...

var viewModel = new ViewModel {
    YourModel = model;
    Users = usersGrossList.Select(
        x => new SelectListItem {
            Text = x.Name,
            Value = x.Id,
            Selected = model.UsersSelectedList.Any(y => y.Id == x.Id)
        }
    }

视图:

<%= Html.ListBox("users", Model.Users ) %>

Answer 2

将Html.ListBox与IEnumerable SelectListItem结合使用

视图

         <% using (Html.BeginForm("Category", "Home",
      null,
      FormMethod.Post))
       { %>  
        <%= Html.ListBox("CategoriesSelected",Model.CategoryList )%>

        <input type="submit" value="submit" name="subform" />
        <% }%>

控制器/型号:

        public List<CategoryInfo> GetCategoryList()
    {
        List<CategoryInfo> categories = new List<CategoryInfo>();
        categories.Add( new CategoryInfo{ Name="Beverages", Key="Beverages"});
        categories.Add( new CategoryInfo{ Name="Food", Key="Food"});
        categories.Add(new CategoryInfo { Name = "Food1", Key = "Food1" });
        categories.Add(new CategoryInfo { Name = "Food2", Key = "Food2" });
        return categories;
    }

    public class ProductViewModel
    {
        public IEnumerable<SelectListItem> CategoryList { get; set; }
        public IEnumerable<string> CategoriesSelected { get; set; }

    }
    public ActionResult Category(ProductViewModel model )
    {
      IEnumerable<SelectListItem> categoryList =
                                from category in GetCategoryList()
                                select new SelectListItem
                                {
                                    Text = category.Name,
                                    Value = category.Key,
                                    Selected = (category.Key.StartsWith("Food"))
                                };
      model.CategoryList = categoryList;

      return View(model);
    }