MVC ViewModel 不回发

Question

我正在使用 Viewmodel，但是当我提交表单时，我没有取回值。

我有一个这样的模型...

Public Class ProductSummaryModel

    Property productGUID As Integer
    Property productName As String
    Property productPrice As Double
    Property productSku As String
    Property categories As String()
    Property ShipsWithin As Nullable(Of Integer)
    <AllowHtml>
    Property productWebDescription As String
    Property ImageMainPath As String

End Class

然后我有一个像这样的 ViewModel...

Public Class ProductViewModel
    Public ProductSummary As ProductSummaryModel
End Class

这是我的控制器...

Public Function Add() As ActionResult ' Default View To Add  Item
    Dim prdsummary As ProductViewModel = New ProductViewModel
    Return View("Add", prdsummary)
End Function

在我的“添加”视图中，我关注...

<tr>
    <td>Price: </td>
    <td><%=Html.TextBoxFor(Function(f) f.ProductSummary.productPrice)%></td>
</tr>

问题是，当我提交表单时，我无法获取 POSTED 表单值。

    Public Function AddItem(ByVal Model As ProductViewModel) As ActionResult ' Add Item into DB

        Dim ajaxMessage As New AjaxFormResponse

        Dim prd As ProductSummaryModel = New ProductSummaryModel
        Model.ProductSummary = prd

        Dim skuID As Integer = 0
        msgbox(Model.ProductSummary.categories) ' Empty

End Function

可能有更好的方法来处理这个问题。

* 更新 **

我已经弄清楚问题出在哪里...当将模型传递给 ViewModel 时，我必须这样做...

Dim Product As ProductViewModel = New ProductViewModel
Dim ProductSummary As New ProductSummaryModel
Product.ProductSummary = ProductSummary
Return View("Add", Product)

Answer 1

为什么不使用 ProductSummaryModel 而不是 ProductViewModel 进行绑定。这样你就可以保持简单。如果可以，请避免嵌套绑定。 还要确保您在如下视图中使用，以及 HttpPost attr。在控制器中

产品控制器

Public Class ProductController
Inherits Controller

' Main Action
Public Function Main() As ActionResult 
    Dim prdViewModel As ProductViewModel = New ProductViewModel       
    prdViewModel.ProductSummary = New ProductSummaryModel
    Return View("Main", prdViewModel)
End Function

' Partial Action
Public Function Add() As ActionResult 
    Dim prdViewModel As ProductViewModel = New ProductViewModel
    prdViewModel.ProductSummary = New ProductSummaryModel

    Return View("Add", prdViewModel)
End Function

'POST Action from Partial View
<HttpPost()> _
 Public Function AddItem(ByVal Model As ProductSummaryModel) As ActionResult ' Add Item into DB
   msgbox(Model.productPrice) ' Empty
End Function

End Class

主视图

<%@ Page Title="" Language="VB" MasterPageFile="~/Views/Shared/Site.Master" 
    Inherits="System.Web.Mvc.ViewPage(Of MvcApplication2.ProductViewModel)" %>

<asp:Content ID="manageTitle" ContentPlaceHolderID="TitleContent" runat="server">
    Main Page
</asp:Content>

<asp:Content ID="manageContent" ContentPlaceHolderID="MainContent" runat="server">
    <%
        Html.RenderPartial("_Add", Model.ProductSummary)
     %>
</asp:Content>

局部视图

    <%@ Page Language="VB" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage(Of MvcApplication2.ProductSummaryModel)" %>

<asp:Content ID="registerTitle" ContentPlaceHolderID="TitleContent" runat="server">
    Register
</asp:Content>

<asp:Content ID="registerContent" ContentPlaceHolderID="MainContent" runat="server">

    <% Using Html.BeginForm("AddItem", "Product")%>
        <%: Html.AntiForgeryToken() %>
        <tr>
            <td>Price: </td>
            <td><%: Html.TextBoxFor(Function(f) f.productPrice) %></td>
        </tr>
        <input type="submit" value="Register" />
    <% End Using%>
</asp:Content>

更新视图模型

 Public Class ProductSummaryModel

    Property productGUID As Integer
    Property productName As String
    Property productPrice As Double
    Property productSku As String
    Property categories As String()
    Property ShipsWithin As Nullable(Of Integer)
    <AllowHtml>
    Property productWebDescription As String
    Property ImageMainPath As String

End Class

Public Class ProductViewModel
    Public ProductSummary As ProductSummaryModel
End Class

Answer 2

我发现两个问题：

首先，当你这样做时，你会覆盖发布的值：

Dim prd As ProductSummaryModel = New ProductSummaryModel
Model.ProductSummary = prd

来自您视图的模型中的ProductSummary 属性丢失，您只能在读取其属性时获得默认值。

此外，您没有在视图中显示如何设置 categories 值。您是否允许此属性的用户输入或其他操作？