验证用于在MVC中导航性能（4）和EF（4） [英] Validation for Navigation Properties in MVC (4) and EF (4)

问题描述

我创建了一个EF模型，然后创建了一个MVC控制器和视图。
该机型 A 有一个导航属性​​键入 B 。所以，当我创建 A 我要选择一个 B 。

I created a model with EF and then created a controller and view in MVC. The model type A has a Navigation Property to type B. So when I create A I want to select a B.

MVC的向导来创建控制器和视图，标量属性只创建的字段。于是我去了，改变了我创建行动 A 来：

The MVC wizard to create the controller and view only created fields for Scalar Properties. So I went and changed my create action on A to:

public ActionResult Create() //Create action for A
{
    List<B> b = db.B.ToList(); //db is my DataContext

    ViewData["B"] = companies.Select(option => new SelectListItem
                    {
                        Text = (option.Name.ToString()),
                        Value = (option.Id.ToString())
                    });
    return View();
}

和加入到我的观点：

<div class="editor-label">
    @Html.LabelFor(model => model.B)
</div>
<div class="editor-field">
    @Html.DropDownListFor(model => model.B,  (IEnumerable<SelectListItem>)ViewData["B"], "---- Select B ----")
    @Html.ValidationMessageFor(model => model.B)
</div>

全部是迄今为止很好，我得到的HTML

All is good so far and I get the HTML

<select class="valid" id="B" name="B">
    <option value="">---- Select B ----</option>
    <option selected="selected" value="1">TestB</option>
</select>

然而，当我提出我的错误：

However when I submit I get the error:

The value '1' is invalid.

已经不写它必须是自动生成的某处任何验证。如何纠正它来检查值对计算机[B]集合ID的？

Having not written any validation it must have been auto-generated somewhere. How do I correct it to check the values against the ViewData["B"] collection ID's?

推荐答案

问题是你的下拉列表中的值为编号 - 但属性是 B 。

The problem is the value of your dropdown list is Id - but the property is a B.

您应该绑定到你的导航属性的FK来代替。我不知道你的模型（如果这没有帮助，你应该将它张贴）

You should bind to the FK of your navigation property instead. I'm not sure of your model (if this doesn't help you should post it)

<div class="editor-field">
    @Html.DropDownListFor(model => model.BId,  (IEnumerable<SelectListItem>)ViewData["B"], "---- Select B ----")
    @Html.ValidationMessageFor(model => model.BId)
</div>

请注意我已经改变了 model.B 到 model.BId

Note I've changed model.B to model.BId

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