ASP.NET MVC NHibernate的 - 绑定多选择列表的IList＆LT; T＆GT; [英] ASP.NET MVC NHibernate - Bind multi select list to IList<T>

问题描述

我如何能多选下拉列表绑定到一个手动添加中间表的列表属性？

类

 公共类系
{
    公共虚拟INT标识{搞定;组; }
    公共虚拟的IList＆LT;＆林GT;拉姆塞{搞定;组; }
}公共类Person
{
    公共虚拟INT标识{搞定;组; }
    公共虚拟的IList＆LT;＆林GT;拉姆塞{搞定;组; }
}公共类林
{
    公共虚拟INT标识{搞定;组; }
    公共虚拟部门部门{搞定;组; }
    公共虚拟人人{搞定;组; }
}
 

视图模型

 公共类DepartmentCreateEditViewModel
{
    公共部门部门{搞定;组; }
    公众的IList＆LT;＆人GT;人{搞定;组; }
}
 

的ActionResult

 公众的ActionResult的Create（）
    {
        //获取所有的人
        变种人= repositoryPerson.GetAll（）;        //创建视图模型
        VAR视图模型=新DepartmentCreateEditViewModel（）{部=新部门（），人=人};        //显示视图
        返回视图（视图模型）;
    }
 

创建视图

我尝试添加一个ListBox是这样的。

  @ Html.ListBoxFor（型号=＆GT; model.Department.Lams，新的SelectList（Model.Persons，ID，姓名），新{@class =形式-controll}）
 

---

要救我想回去一处对象的对象

  [HttpPost]
公众的ActionResult创建（系科）
 

从下拉列表中（与人）到IList中的结合是行不通的。我应该怎么做呢？这甚至可能？

---

code埃里克的建议后

创建的ActionResult

  [HttpPost]
公众的ActionResult创建（DepartmentCreateEditViewModel viewModelPostBack）
 

查看

  @ Html.ListBoxFor（型号=＆GT; model.Department.Lams，新MultiSelectList（Model.Persons，ID，姓名），新{@class =形式-controll}）
 

我会得到什么：

  viewModelPostBack
{} EmpLaceMgmt.ViewModels.DepartmentCreateEditViewModel
    部门：{} EmpLaceMgmt.Models.Department
    人数：空
viewModelPostBack.Department
{} EmpLaceMgmt.Models.Department
    ID：0
    拉姆塞：计数= 0
 

生成的HTML看起来像这样

 ＆LT;选择类=表单控制研究ID =Department_Lams多个=多​​个名=Department.Lams＆GT;
    ＆LT;期权价值=1物实施例人＆LT; /选项＆GT;
＆LT; /选择＆GT;
 

解决方案

您有三个问题。首先，您要绑定到的IList＆LT; T＆GT; ，但不会工作，因为模型绑定不会知道它应该建立什么样的具体对象满足该... ...有支持的IList＆LT很多对象; T＆GT; ，所以哪一个

其次，您需要使用 MultiSelectList ，而不是放在你的助手的SelectList 。

三，你是不是您正在使用创建的网页回发一个不同的型号。以及该类型具有非常不同的结构。在您使用创建页面结构，你的数据与命名创建的 Department.Lams （因为处是你的ViewModel的一个属性），但您的帖子动作发生当中，粘结剂将寻找简称为对象的处模式拉姆塞，而不是 Department.Lams 。

所以，转换你的模型用一个具体类型，如列表＆LT;林＆GT; ，然后回发到您的视图模型，而不是部门，并提取部出视图模型，并最终改变你的助手这样的：

  @ Html.ListBoxFor（型号=＆GT; model.Department.Lams，
    新MultiSelectList（Model.Persons，ID，姓名），新{@class =表单控制研究}）
 

How can I bind a multi select dropdown list to a list property of a manually added intermediate table?

Classes

public class Department
{
    public virtual int Id { get; set; }
    public virtual IList<Lam> Lams { get; set; }
}

public class Person
{
    public virtual int Id { get; set; }
    public virtual IList<Lam> Lams { get; set; }
}

public class Lam
{
    public virtual int Id { get; set; }
    public virtual Department Department { get; set; }
    public virtual Person Person { get; set; }
}

ViewModel

public class DepartmentCreateEditViewModel
{
    public Department Department { get; set; }
    public IList<Person> Persons { get; set; }
}

ActionResult

    public ActionResult Create()
    {
        // Get all Persons
        var persons = repositoryPerson.GetAll();

        // Create ViewModel
        var viewModel = new DepartmentCreateEditViewModel() { Department = new Department(), Persons = persons };

        // Display View
        return View(viewModel);
    }

Create View

I tried to add a ListBox like this.

@Html.ListBoxFor(model => model.Department.Lams, new SelectList(Model.Persons, "Id", "Name"), new { @class = "form-controll" })

---

To save the object I want to get back a Department object

[HttpPost]
public ActionResult Create(Department department)

The binding from the dropdown (with persons) to the IList is not working. How am I supposed to do this? Is this even possible?

---

[Edit] Code after Erik's suggestion

Create ActionResult

[HttpPost]
public ActionResult Create(DepartmentCreateEditViewModel viewModelPostBack)

View

@Html.ListBoxFor(model => model.Department.Lams, new MultiSelectList(Model.Persons, "Id", "Name"), new { @class = "form-controll" })

What I get back:

viewModelPostBack
{EmpLaceMgmt.ViewModels.DepartmentCreateEditViewModel}
    Department: {EmpLaceMgmt.Models.Department}
    Persons: null
viewModelPostBack.Department
{EmpLaceMgmt.Models.Department}
    Id: 0
    Lams: Count = 0

The generated HTML looks like this

<select class="form-controll" id="Department_Lams" multiple="multiple" name="Department.Lams">
    <option value="1">Example Person</option>
</select>

解决方案

You have three problems. First, you are trying to bind to an IList<T>, but that won't work because the model binder won't know what kind of concrete object it should create to satisfy that... There are many objects that support IList<T>, so which one?

Secondly, You need to use a MultiSelectList and not a SelectList in your helper.

Third, you are posting back a different model type than you are using to create your pages. And that type has a very different structure. In the structure that you create your page with, your data is created with the naming of Department.Lams (because Department is a property of your ViewModel) but in your Post action takes a Department model which, the binder would be looking for an object simply called Lams, not Department.Lams.

So, convert your models to use a concrete type, such as List<Lam>, then post back to your ViewModel rather than Department, and extract the department out of the ViewModel, and finally change your helper to this:

@Html.ListBoxFor(model => model.Department.Lams, 
    new MultiSelectList(Model.Persons, "Id", "Name"), new { @class = "form-controll" })

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