建设中的示范一个DropDownList？ [英] Building a DropDownList in the Model?

问题描述

我有一个公开的方法，它返回我一个列表，称为的getStates服务层。

I have a service layer that exposes a method, which returns me a List, called GetStates.

public List<StateObject> GetStates()

我的状态对象就是我创建了一个自定义对象：

My State Object is just a custom object I have created:

public class StateObject
{
    public int stateId { get; set; }
    public string description { get; set; }
    public Boolean isDefault { get; set; }
}

在我的模型，我试图创建将用于任务的我的显示和修改画面的典范。这将用于一件事是处理一个下拉框，这将会给支持我的任务状态列表的显示和选择。所以，我的模型看起来像这样（删除性能我们不车程约 - 这是一个大一点比这个：

In my models, I am trying to create a model that will be used for my display and modification screen of a task. One thing this will be used for is handling the display and selection of a Drop down box, which will give a list of States available for my Task. So, my model looks something like this (Removed properties we don't car about - it's a bit bigger than this:

public class TaskModifyModel
{
    public int stateId { get; set; }
    public string state { get; set; }

    public SelectList states { get; private set; }

    public TaskModifyModel()
    {

        states = new SelectList(
            (new ReferenceService().GetStates()),
            "stateId",
            "description",
            1);

    }
}

所以，STATEID保持选中状态，状态保持选中状态的文本描述。在构造函数中，我试图创建一个国家的SelectList的观点...并填充它。

So, stateId holds the selected state, state holds the text description of the selected state. In the constructor, I am attempting to create a states SelectList for the view... and populate it.

在看，我再尝试以显示下拉列表：

In the view, I then try to display the Drop Down List:

@Html.DropDownListFor(m=>m.stateId, new SelectList(Model.states, "stateId", "description", Model.priorityId))

这是失败的，惨淡经营。

This is failing, dismally.

数据绑定：'System.Web.Mvc.SelectListItem'不包含名为'STATEID属性

我已搜查，我想我这样做的正确方法，但错误说我不是..清楚。 :)可能有人指导我，为什么它不工作，而且，这是做事的正确方法？

I have searched, and I thought I was doing this the right way, but the error says I am not.. clearly. :) Could someone guide me on why it's not working, and also, is this the right way to do things?

编辑：
下面援助之后，它现在的工作。如果我创建一个新的任务（任务id == 0），那么我得下拉的默认值，存储在我的数据库....所以，这是干净的？这是我的对象构造工作：

After assistance below, it's now working. If I am creating a new task (taskId==0), then I have to get the default value of the dropdown, as stored in my database.... So, is this clean? This is my working constructor for the object:

公共TaskModifyModel（）
    {
        VAR referenceService =新ReferenceService（）;
        变种p值= referenceService.GetPriorities（）;
        变种S = referenceService.GetStates（）;

public TaskModifyModel() { var referenceService = new ReferenceService(); var p = referenceService.GetPriorities(); var s = referenceService.GetStates();

    var defaultP = (from a in p where a.isDefault select a).FirstOrDefault();
    var defaultS = (from a in s where a.isDefault select a).FirstOrDefault();

    priorities = new SelectList(
        (p),
        "priorityId",
        "description"
        );
    priorityId = taskId == 0 ? defaultP.priorityId : priorityId;

    states = new SelectList(
        s,
        "stateId",
        "description");
    stateId = taskId == 0 ? defaultS.stateId : stateId;

}

是否确定？

推荐答案

您公开的SelectList状态{搞定;私人集; } 已经是一个的SelectList，所以你并不需要在您的视图中再次施展它。

Your public SelectList states { get; private set; } is already a SelectList so you don't need to cast it again in your View.

试试这个：

@Html.DropDownListFor(m=>m.stateId, Model.states)

而在你的ViewModel，删除参数的SelectedValue。该@ Html.DropDownListFor将下拉初始化为正确的价值。

And in your ViewModel, remove the parameter "SelectedValue". The @Html.DropDownListFor will initialize the dropdown to the right value.

public class TaskModifyModel
{
    public int stateId { get; set; }
    public string state { get; set; }

    public SelectList states { get; private set; }

    public TaskModifyModel()
    {

        states = new SelectList(
            (new ReferenceService().GetStates()),
            "stateId",
            "description");
    }
}

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