c# - MVC 嵌套模型绑定(bind)只能部分工作——我错过了什么？

Question

我有一个名为 AssetSearchModel 的 ViewModel，其属性类型为:List。

当我从 ViewModel 发布时，我的列表的所有属性都成功绑定(bind)回模型，除了这个:public DomainsDto DomainControl { get;放; 定义在底部。

那个域控件有几个属性，然后是它自己的嵌套列表......它的任何属性都没有设置，它们都是空的

public class AssetSearchModel
{
    public List<SearchControlModel> SearchControls { get; set; }

    public AssetSearchModel()
    {
    }

}

public class SearchControlModel
{

    /// <summary>
    /// Asset identifier.
    /// </summary>
    [DisplayName("AssetId ID")]
    public int SearchOptionID { get; set; } // this gets bound ok

    [DisplayName("Asset Customer ID")]
    public int AssetCustomerID { get; set; } // this gets bound ok

    [DisplayName("Portal ID")]
    public int PortalID { get; set; } // this gets bound ok

    [DisplayName("Calling Page")]
    public string CallingPage { get; set; } // this gets bound ok

    [DisplayName("Display Control")]
    public string DisplayControl { get; set; } // this gets bound ok

    [DisplayName("Display Text")]
    public string DisplayText { get; set; } // this gets bound ok

    public string ControlValue { get; set; } // this gets bound ok

    [DisplayName("Search Table")]
    public string SearchTable { get; set; } // this gets bound ok

    [DisplayName("Search Column")]
    public string SearchColumn { get; set; } // this gets bound ok

    [DisplayName("Source Table")]
    public string SourceTable { get; set; } // this gets bound ok

    [DisplayName("Source Display Column")]
    public string SourceDisplayColumn { get; set; } // this gets bound ok

    [DisplayName("Source Value Column")]
    public string SourceValueColumn { get; set; } // this gets bound ok

    [DisplayName("SourceCustomFilter")]
    public string SourceCustomFilter { get; set; } // this gets bound ok

    [DisplayName("SortOrder")]
    public int SortOrder { get; set; } // this gets bound ok

    [DisplayName("DomainControl")]
    public DomainsDto DomainControl { get; set; } // THIS DOES NOT BIND

    public SearchControlModel()
    {



    }

}

---

public class DomainsDto
{
    public int DomainMasterId;      // this does not bind
    public string DisplayName;     // this does not bind
    public List<DomainDto> Domains;  // this does not bind
    public DomainsDto()
    {

    }

}

[DataContract(Name = "Domain", Namespace = "http://www.comcom.com/")]

public class DomainDto
{
    [DataMember]
    public int DomainID { get; set; }   // this does not bind

    [DataMember]
    public string DomainName { get; set; }  // this does not bind

    [DataMember]
    public bool Checked { get; set; }   // this does not bind


    public DomainDto()
    {

    }
}

我的观点:

         @for (int y = 0; y < Model.SearchControls.Count; y++)
     {

        @Html.Label("Search option: " + Model.SearchControls[y].DisplayText)
        <br />
        @Html.HiddenFor(x => x.SearchControls[y].DisplayText)
        @Html.HiddenFor(x => x.SearchControls[y].CallingPage)
        @Html.HiddenFor(x => x.SearchControls[y].DisplayControl)
        @Html.HiddenFor(x => x.SearchControls[y].SourceCustomFilter)
        @Html.HiddenFor(x => x.SearchControls[y].SearchTable)
        @Html.HiddenFor(x => x.SearchControls[y].SearchColumn)
        @Html.HiddenFor(x => x.SearchControls[y].SourceValueColumn)


         if (Model.SearchControls[y].DomainControl != null)
         {

             @Html.HiddenFor(x => x.SearchControls[y].DomainControl.DisplayName) 

             @Html.HiddenFor(x => x.SearchControls[y].DomainControl.DomainMasterId)

             if (Model.SearchControls[y].DomainControl.Domains != null)
             {
                 for (int z = 0; z < Model.SearchControls[y].DomainControl.Domains.Count; z++)
                 {

                    @Html.HiddenFor(x => x.SearchControls[y].DomainControl.Domains[z].DomainID)
                    @Html.HiddenFor(x => x.SearchControls[y].DomainControl.Domains[z].DomainName)
                    @Html.HiddenFor(x => x.SearchControls[y].DomainControl.Domains[z].Checked)


                    <br />
                 }
             }
         }

         <br />
         <br />
         <hr width=100px />


     }

html(抱歉单行，它不会让我以不同的方式粘贴它)

<label for="Search_option:_Product_Lines">Search option: Product Lines</label> <input id="SearchControls_1__DisplayText" name="SearchControls[1].DisplayText" type="hidden" value="Product Lines" /> <input id="SearchControls_1__CallingPage" name="SearchControls[1].CallingPage" type="hidden" value="AssetSearch" /> <input id="SearchControls_1__DisplayControl" name="SearchControls[1].DisplayControl" type="hidden" value="M" /> <input id="SearchControls_1__SourceCustomFilter" name="SearchControls[1].SourceCustomFilter" type="hidden" value="26" /> <input id="SearchControls_1__SearchTable" name="SearchControls[1].SearchTable" type="hidden" value="AssetDomainValue" /> <input id="SearchControls_1__SearchColumn" name="SearchControls[1].SearchColumn" type="hidden" value="Brand" /> <input id="SearchControls_1__SourceValueColumn" name="SearchControls[1].SourceValueColumn" type="hidden" value="DomainCodeValueID" />   <input id="SearchControls_1__DomainControl_DisplayName" name="SearchControls[1].DomainControl.DisplayName" type="hidden" value="Product Line" /> <input id="SearchControls_1__DomainControl_DomainMasterId" name="SearchControls[1].DomainControl.DomainMasterId" type="hidden" value="26" />  <input id="SearchControls_1__DomainControl_Domains_0__DomainID" name="SearchControls[1].DomainControl.Domains[0].DomainID" type="hidden" value="43680" /> <input id="SearchControls_1__DomainControl_Domains_0__DomainName" name="SearchControls[1].DomainControl.Domains[0].DomainName" type="hidden" value="YORK" /> <input id="SearchControls_1__DomainControl_Domains_0__Checked" name="SearchControls[1].DomainControl.Domains[0].Checked" type="hidden" value="False" />                        <input id="SearchControls_1__DomainControl_Domains_1__DomainID" name="SearchControls[1].DomainControl.Domains[1].DomainID" type="hidden" value="43683" /> <input id="SearchControls_1__DomainControl_Domains_1__DomainName" name="SearchControls[1].DomainControl.Domains[1].DomainName" type="hidden" value="Johnson Controls" /> <input id="SearchControls_1__DomainControl_Domains_1__Checked" name="SearchControls[1].DomainControl.Domains[1].Checked" type="hidden" value="False" />                        <br />

Answer 1

啊不，模型 Binder 只适用于 properties只有，不是fields .

所以替换:

public class DomainsDto
{
    public int DomainMasterId;       // this does not bind
    public string DisplayName;       // this does not bind
    public List<DomainDto> Domains;  // this does not bind
    public DomainsDto()
    {

    }
}

与:

public class DomainsDto
{
    public int DomainMasterId { get; set; }       // this does bind
    public string DisplayName  { get; set; }      // this does bind
    public List<DomainDto> Domains { get; set; }  // this does bind
    public DomainsDto()
    {

    }
}

但实际上，在表单中填充大量隐藏字段的意义何在？您的数据库中已经有这些东西了。因此，只需放置一个包含 id 的隐藏字段，即可让您前往数据所在的任何位置获取数据。我一直想知道人们为什么如此拼命地尝试为 MVC 重新发明 ViewState。这不是这种模式的使用方式。您不再使用经典的 WebForms。

在设计 ASP.NET MVC View 时应遵循以下规则:

• 用户应该修改的任何字段都使用相应的输入字段(文本框、 radio 、ddls 和其他东西)
• 用户不应修改的任何字段都不应出现在表单中。每个表单最多应该有一个隐藏字段，其中最多包含一个唯一标识符，以便您检索所需的信息

结论:使用 View 模型。

因此，真正解决您问题的方法是替换:

[DisplayName("DomainControl")]
public DomainsDto DomainControl { get; set; } // THIS DOES NOT BIND

与:

public int DomainControlId { get; set; }

并在 View 中为这个 id 使用一个隐藏字段。就是这样。