asp.net - Entity Framework TryUpdateModel子对象？

我知道你们中的大多数人都建议我应该使用特定于所使用表单的ViewModels，但是我很好奇为什么我的子对象没有绑定到TryUpdateModel上。

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)
    <fieldset>
        <legend>User</legend>

        @Html.HiddenFor(model => model.UserId)
    @Html.HiddenFor(model => model.PrimaryAddress.AddressId)
    <div class="editor-label">
            @Html.LabelFor(model => model.PrimaryAddress.FirstName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.PrimaryAddress.FirstName)
            @Html.ValidationMessageFor(model => model.PrimaryAddress.FirstName)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.PrimaryAddress.LastName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.PrimaryAddress.LastName)
            @Html.ValidationMessageFor(model => model.PrimaryAddress.LastName)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.UserName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.UserName)
            @Html.ValidationMessageFor(model => model.UserName)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Email)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Email)
            @Html.ValidationMessageFor(model => model.Email)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.IsApproved)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.IsApproved)
            @Html.ValidationMessageFor(model => model.IsApproved)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.IsEmployee)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.IsEmployee)
            @Html.ValidationMessageFor(model => model.IsEmployee)
        </div>

        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>
}

和控制器代码：

[HttpPost]
public ActionResult Edit(int id, FormCollection form)
{
    var user = Token.DB.Users.Include("PrimaryAddress").Single(x => x.UserId == id);
    if (TryUpdateModel(user, new string[] { "UserName", "Email", "IsApproved", "IsEmployee", "PrimaryAddress.FirstName", "PrimaryAddress.LastName" }))
    {
        try
        {
            Token.DB.SaveChanges();
            return RedirectToAction("index");
        }
        catch (Exception ex)
        {
            while (ex.InnerException != null)
                ex = ex.InnerException;
            if (ex.Message.ToLowerInvariant().Contains("unique"))
                ModelState.AddModelError("UserName", "UserName already exists");
        }
    }
    return View(User);
}

该代码不会引发任何异常，只是不会从表单中填充user.PrimaryAddress.FirstName或user.PrimaryAddress.LastName。我想知道为什么吗？

我已经知道我可以使用特定的ViewModel并在后台映射信息来解决此问题。我也可以这样做：

<!-- Edit.cshtml -->
<div class="editor-field">
    @Html.EditorFor(model => model.PrimaryAddress.FirstName, null, "FirstName")
    @Html.ValidationMessageFor(model => model.PrimaryAddress.FirstName)
</div>

<div class="editor-label">
    @Html.LabelFor(model => model.PrimaryAddress.LastName)
</div>
<div class="editor-field">
    @Html.EditorFor(model => model.PrimaryAddress.LastName, null, "LastName")
    @Html.ValidationMessageFor(model => model.PrimaryAddress.LastName)
</div>

// UsersController.cs
if (TryUpdateModel(user, new string[] { "UserName", "Email", "IsApproved", "IsEmployee"})
&& TryUpdateModel(user.PrimaryAddress, new string[] {"FirstName", "LastName" }))

因此，真正的问题是，为什么在第一个示例中它不具有约束力？

最佳答案

因此，真正的问题是，为什么在第一个示例中它不具有约束力？


您的问题的答案非常简单：UpdateModel，TryUpdateModel或[Bind]属性在包含/排除属性列表中都不支持“嵌套属性”。因此，请正确处理并使用视图模型。防范大规模财产转让攻击只是应使用视图模型的数百万个原因之一。好吧，您似乎找到了通过执行第二个TryUpdateModel的解决方法，但是如果您在此域对象上具有许多属性，则控制器操作代码可能会迅速变成意大利面条管道代码。