Asp.net mvc 4 DefaultModelBinder返回子类MVC4

几天来，我一直在努力阅读关于这个DefaultModelBinder的文章，但我仍然很困惑。我使用的是MVC4和EF5表格结构

我的问题是我有一个资源基类：

  public class Resource : PocoBaseModel
  {
    private int _resourceID;
    private string _title;
    private string _description;

    //public accessors
  }

有子类（DVD、电子书、书籍等）

我的控制器代码使用自定义ModelBinder

[HttpPost]
public ActionResult Create([ModelBinder(typeof(ResourceModelBinder))] Resource resource)
{
     //controller code
}

public class ResourceModelBinder : DefaultModelBinder
{

  public override object BindModel(ControllerContext controllerContext,
  ModelBindingContext bindingContext)
  {
      var type = controllerContext.HttpContext.Request.Form["DiscriminatorValue"];
      bindingContext.ModelName = type;
      bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, resourceTypeMap[type]);

      return base.BindModel(controllerContext, bindingContext);

    }
static Dictionary<string, Type> resourceTypeMap = new Dictionary<string, Type>
    {
      {"Resource", typeof(Resource)},
      {"Book", typeof(Book)},
      {"DVD", typeof(DVD)},
      {"EBook", typeof(EBook)},
      {"Hardware", typeof(Hardware)},
      {"Software", typeof(Software)}

    };
}

[HttpPost]
公共操作结果创建（[ModelBinder（typeof（ResourceModelBinder））]资源）
{
//控制器代码
}
公共类ResourceModelBinder:DefaultModelBinder
{
公共覆盖对象绑定模型（ControllerContext ControllerContext，
ModelBindingContext（绑定上下文）
{
var type=controllerContext.HttpContext.Request.Form[“DiscriminatorValue”]；
bindingContext.ModelName=类型；
bindingContext.ModelMetadata=ModelMetadataProviders.Current.GetMetadataForType（null，resourceTypeMap[type]）；
返回base.BindModel（controllerContext、bindingContext）；
}
静态字典resourceTypeMap=新字典
{
{“资源”，类型（资源）}，
{“书”，字体（书）}，
{“DVD”，类型（DVD）}，
{“电子书”，类型（电子书）}，
{“硬件”，类型（硬件）}，
{“软件”，类型（软件）}
};
}

这样我就可以将我的视图传递给一个资源（以DVD、书籍或任何其他类型的形式播放）

@model Models.Resource
@{
ViewBag.Title=“创建”；
}
创造
@使用（Html.BeginForm（“Create”、“Admin”、null、FormMethod.Post、null））
{
@Html.ValidationSummary（true）
资源
@Html.HiddenFor（model=>model.ResourceID）
@Html.HiddenFor（model=>model.ResourceTypeID）
@Html.HiddenFor（model=>model.Committed）
@Html.Partial（“_CreateOrEdit”，Model）


}

并根据其派生属性绑定它，该属性发生在partialview内部的开关中

@using Models.ViewModels;
@using Models.ResourceTypes;
@using Helper;
@model Models.Resource
@Html.HiddenFor(model => Model.DiscriminatorValue);
<table cellspacing="2" cellpadding="2" border="0">
    @{
        string type = Model.DiscriminatorValue;
        switch (type)
        {
            case "Book":
                Book book = (Book)Model;
        <tr>
        <td colspan="2">
            <div class="editor-label" style="padding-top: 15px;">
                @Html.LabelFor(model => model.Title)
            </div>

            <div class="editor-field">
                @Html.TextAreaFor(model => model.Title, new { style = "width: 750px; height: 65px;" })
                @Html.ValidationMessageFor(model => model.Title)
            </div>
        </td>
    </tr>
    <tr>
        <td>
            <div class="editor-label">
                @Html.LabelFor(model => book.Edition)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(model => book.Edition, new { style = "width: 150px;" })
                @Html.ValidationMessageFor(model => book.Edition)
            </div>
        </td>
        <td>
            <div class="editor-label">
                @Html.LabelFor(model => book.Author)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => book.Author)
                @Html.ValidationMessageFor(model => book.Author)
            </div>
        </td>
    </tr>
    <tr>
        <td> 
            <div class="editor-label">
                @Html.LabelFor(model => book.Pages)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(model => book.Pages, new { style = "width: 75px;" })
                @Html.ValidationMessageFor(model => book.Pages)
            </div>
        </td>
    </tr>
      <tr>
        <td colspan="2">
            <div class="editor-label">
                @Html.LabelFor(model => model.Description)
            </div>
            <div class="editor-field">
                @Html.TextAreaFor(model => model.Description, new { style = "width: 750px; height: 105px;" })
                @Html.ValidationMessageFor(model => model.Description)
            </div>
        </td>
    </tr>
     <tr>
        <td colspan="2">
            <div class="editor-label">
                @Html.LabelFor(model => model.AdminNote)
            </div>
            <div class="editor-field">
                @Html.TextAreaFor(model => model.AdminNote, new { style = "width: 750px; height: 105px;" })
                @Html.ValidationMessageFor(model => model.AdminNote)
            </div>
        </td>
    </tr>
    <tr>
        <td>
            <div class="editor-label">
                @{ int copies = Model == null ? 1 : Model.Copies; }
                @Html.LabelFor(model => model.Copies)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(model => model.Copies, new { style = "width: 75px;", @Value = copies.ToString() })
                @Html.ValidationMessageFor(model => model.Copies)
            </div>
        </td>
    </tr>
    <tr>
        <td>
            <div class="editor-label">
                @Html.LabelFor(model => book.ISBN10)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => book.ISBN10)
                @Html.ValidationMessageFor(model => book.ISBN10)
            </div>
        </td>

        <td>
            <div class="editor-label">
                @Html.LabelFor(model => book.ISBN13)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => book.ISBN13)
                @Html.ValidationMessageFor(model => book.ISBN13)
            </div>
        </td>

    </tr>

  break;

@使用Models.ViewModels；
@使用模型。资源类型；
@使用助手；
@模型。资源
@Html.HiddenFor（model=>model.DiscriminatorValue）；
@{
字符串类型=Model.DiscriminatorValue；
开关（类型）
{
案例“书”：
Book=（Book）模型；
@LabelFor（model=>model.Title）
@Html.TextAreaFor（model=>model.Title，新{style=“宽度：750px；高度：65px；”}）
@Html.ValidationMessageFor（model=>model.Title）
@LabelFor（model=>book.Edition）
@Html.TextBoxFor（model=>book.Edition，新{style=“width:150px；”}）
@Html.ValidationMessageFor（model=>book.Edition）
@LabelFor（model=>book.Author）
@EditorFor（model=>book.Author）
@Html.ValidationMessageFor（model=>book.Author）
@LabelFor（model=>book.Pages）
@Html.TextBoxFor（model=>book.Pages，新{style=“width:75px；”}）
@Html.ValidationMessageFor（model=>book.Pages）
@LabelFor（model=>model.Description）
@Html.TextAreaFor（model=>model.Description，新{style=“宽度：750px；高度：105px；”}）
@Html.ValidationMessageFor（model=>model.Description）
@LabelFor（model=>model.AdminNote）
@Html.TextAreaFor（model=>model.AdminNote，新{style=“宽度：750px；高度：105px；”}）
@Html.ValidationMessageFor（model=>model.AdminNote）
@{int copies=Model==null？1:Model.copies；}
@LabelFor（model=>model.Copies）
@Html.TextBoxFor（model=>model.Copies，新的{style=“width:75px；”，@Value=Copies.ToString（）}）
@Html.ValidationMessageFor（model=>model.Copies）
@LabelFor（model=>book.ISBN10）
@EditorFor（model=>book.ISBN10）
@Html.ValidationMessageFor（model=>book.ISBN10）
@LabelFor（model=>book.ISBN13）
@EditorFor（model=>book.ISBN13）
@Html.ValidationMessageFor（model=>book.ISBN13）
打破

我的第一个问题是，当我将表单发回时，它作为一个资源返回，而不是作为强制类型返回（因此我丢失了所有派生类型属性）这就是我创建ResourceModelBinder的原因。现在它正确地绑定了/postsback铸造类型，但没有绑定资源的基类属性，如Title、ResourceID、ResourceTypeID

---

有人能帮我理解我缺少什么，这样它就可以绑定基本资源类属性和派生类型属性。

所以我所要做的就是在自定义ModelBinder类中重写BindProperty方法

protected override void BindProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, System.ComponentModel.PropertyDescriptor propertyDescriptor)
    {
      if (propertyDescriptor.DisplayName != null)
      {
        var Form = controllerContext.HttpContext.Request.Form;
        string currentPropertyFormValue = string.Empty;
        string formDerivedTypeKey = bindingContext.ModelName.ToLower() + "." + propertyDescriptor.DisplayName;
        string formBaseTypeKey = propertyDescriptor.DisplayName;
        List<string> keywordList = null;
        Type conversionType = propertyDescriptor.PropertyType;

        if (!string.IsNullOrEmpty(Form[formDerivedTypeKey]) || !string.IsNullOrEmpty(Form[formBaseTypeKey]))
        {
          if (!string.IsNullOrEmpty(Form[formDerivedTypeKey]))
          {
            //store current derived type property
            currentPropertyFormValue = Form[formDerivedTypeKey];
          }
          if (!string.IsNullOrEmpty(Form[formBaseTypeKey]))
          {
            //store current base type property
            currentPropertyFormValue = Form[formBaseTypeKey];
          }
        }

        if (conversionType.IsGenericType)
        {
          if (conversionType.GetGenericTypeDefinition() == typeof(List<>))
          {
            if (propertyDescriptor.DisplayName == "KeyWords")
            {
              string[] keywords = currentPropertyFormValue.Split(',');
              if (keywords != null && keywords.Count() > 0)
              {
                //create keyword list
                keywordList = new List<string>();
                foreach (var item in keywords)
                {
                  if (!string.IsNullOrEmpty(item) && !item.Contains(','))
                  {
                    keywordList.Add(item);
                  }
                }
              }
            }
          }
          if (conversionType.GetGenericTypeDefinition() == typeof(Nullable<>))
          {
            // nullable type property.. re-store nullable type to a safe type
            conversionType = Nullable.GetUnderlyingType(conversionType) ?? propertyDescriptor.PropertyType;
          }
        }
        if (!string.IsNullOrEmpty(currentPropertyFormValue))
        {
          //bind property
          if (propertyDescriptor.DisplayName != "KeyWords")
          {
            propertyDescriptor.SetValue(bindingContext.Model, Convert.ChangeType(currentPropertyFormValue, conversionType)); 
          }
          else
            propertyDescriptor.SetValue(bindingContext.Model, Convert.ChangeType(keywordList, conversionType));
        }
      }
      else
        base.BindProperty(controllerContext, bindingContext, propertyDescriptor); //default condition
    }

protected override void BindProperty（ControllerContext ControllerContext，ModelBindingContext bindingContext，System.ComponentModel.PropertyDescriptor PropertyDescriptor）
{
if（propertyDescriptor.DisplayName！=null）
{
var Form=controllerContext.HttpContext.Request.Form；
string currentPropertyFormValue=string.Empty；
string formDerivedTypeKey=bindingContext.ModelName.ToLower（）+“”+propertyDescriptor.DisplayName；
字符串formBaseTypeKey=propert
@using Models.ViewModels;
@using Models.ResourceTypes;
@using Helper;
@model Models.Resource
@Html.HiddenFor(model => Model.DiscriminatorValue);
<table cellspacing="2" cellpadding="2" border="0">
    @{
        string type = Model.DiscriminatorValue;
        switch (type)
        {
            case "Book":
                Book book = (Book)Model;
        <tr>
        <td colspan="2">
            <div class="editor-label" style="padding-top: 15px;">
                @Html.LabelFor(model => model.Title)
            </div>

            <div class="editor-field">
                @Html.TextAreaFor(model => model.Title, new { style = "width: 750px; height: 65px;" })
                @Html.ValidationMessageFor(model => model.Title)
            </div>
        </td>
    </tr>
    <tr>
        <td>
            <div class="editor-label">
                @Html.LabelFor(model => book.Edition)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(model => book.Edition, new { style = "width: 150px;" })
                @Html.ValidationMessageFor(model => book.Edition)
            </div>
        </td>
        <td>
            <div class="editor-label">
                @Html.LabelFor(model => book.Author)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => book.Author)
                @Html.ValidationMessageFor(model => book.Author)
            </div>
        </td>
    </tr>
    <tr>
        <td> 
            <div class="editor-label">
                @Html.LabelFor(model => book.Pages)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(model => book.Pages, new { style = "width: 75px;" })
                @Html.ValidationMessageFor(model => book.Pages)
            </div>
        </td>
    </tr>
      <tr>
        <td colspan="2">
            <div class="editor-label">
                @Html.LabelFor(model => model.Description)
            </div>
            <div class="editor-field">
                @Html.TextAreaFor(model => model.Description, new { style = "width: 750px; height: 105px;" })
                @Html.ValidationMessageFor(model => model.Description)
            </div>
        </td>
    </tr>
     <tr>
        <td colspan="2">
            <div class="editor-label">
                @Html.LabelFor(model => model.AdminNote)
            </div>
            <div class="editor-field">
                @Html.TextAreaFor(model => model.AdminNote, new { style = "width: 750px; height: 105px;" })
                @Html.ValidationMessageFor(model => model.AdminNote)
            </div>
        </td>
    </tr>
    <tr>
        <td>
            <div class="editor-label">
                @{ int copies = Model == null ? 1 : Model.Copies; }
                @Html.LabelFor(model => model.Copies)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(model => model.Copies, new { style = "width: 75px;", @Value = copies.ToString() })
                @Html.ValidationMessageFor(model => model.Copies)
            </div>
        </td>
    </tr>
    <tr>
        <td>
            <div class="editor-label">
                @Html.LabelFor(model => book.ISBN10)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => book.ISBN10)
                @Html.ValidationMessageFor(model => book.ISBN10)
            </div>
        </td>

        <td>
            <div class="editor-label">
                @Html.LabelFor(model => book.ISBN13)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => book.ISBN13)
                @Html.ValidationMessageFor(model => book.ISBN13)
            </div>
        </td>

    </tr>

  break;

protected override void BindProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, System.ComponentModel.PropertyDescriptor propertyDescriptor)
    {
      if (propertyDescriptor.DisplayName != null)
      {
        var Form = controllerContext.HttpContext.Request.Form;
        string currentPropertyFormValue = string.Empty;
        string formDerivedTypeKey = bindingContext.ModelName.ToLower() + "." + propertyDescriptor.DisplayName;
        string formBaseTypeKey = propertyDescriptor.DisplayName;
        List<string> keywordList = null;
        Type conversionType = propertyDescriptor.PropertyType;

        if (!string.IsNullOrEmpty(Form[formDerivedTypeKey]) || !string.IsNullOrEmpty(Form[formBaseTypeKey]))
        {
          if (!string.IsNullOrEmpty(Form[formDerivedTypeKey]))
          {
            //store current derived type property
            currentPropertyFormValue = Form[formDerivedTypeKey];
          }
          if (!string.IsNullOrEmpty(Form[formBaseTypeKey]))
          {
            //store current base type property
            currentPropertyFormValue = Form[formBaseTypeKey];
          }
        }

        if (conversionType.IsGenericType)
        {
          if (conversionType.GetGenericTypeDefinition() == typeof(List<>))
          {
            if (propertyDescriptor.DisplayName == "KeyWords")
            {
              string[] keywords = currentPropertyFormValue.Split(',');
              if (keywords != null && keywords.Count() > 0)
              {
                //create keyword list
                keywordList = new List<string>();
                foreach (var item in keywords)
                {
                  if (!string.IsNullOrEmpty(item) && !item.Contains(','))
                  {
                    keywordList.Add(item);
                  }
                }
              }
            }
          }
          if (conversionType.GetGenericTypeDefinition() == typeof(Nullable<>))
          {
            // nullable type property.. re-store nullable type to a safe type
            conversionType = Nullable.GetUnderlyingType(conversionType) ?? propertyDescriptor.PropertyType;
          }
        }
        if (!string.IsNullOrEmpty(currentPropertyFormValue))
        {
          //bind property
          if (propertyDescriptor.DisplayName != "KeyWords")
          {
            propertyDescriptor.SetValue(bindingContext.Model, Convert.ChangeType(currentPropertyFormValue, conversionType)); 
          }
          else
            propertyDescriptor.SetValue(bindingContext.Model, Convert.ChangeType(keywordList, conversionType));
        }
      }
      else
        base.BindProperty(controllerContext, bindingContext, propertyDescriptor); //default condition
    }