ASP.NET MVC DropDownListFor模型绑定 [英] ASP.NET MVC DropDownListFor Model binding

问题描述

我正在尝试将下拉列表绑定到我的模型，但是出现问题.传递给HttpPost函数的模型是NULL，但仅当我尝试绑定到产品"对象的CategoryID字段时，该模型才为NULL.如果我不尝试绑定到product.CatgeoryID，则IncidentNumber字符串不为null.感谢您的输入.

I am trying to bind a dropdown to my model, but I am having issues. My model that is passed into my HttpPost function is NULL, but only if I try to bind to the "product" object's CategoryID field. If I exclude trying to bind to product.CatgeoryID, then the IncidentNumber string is not null. Thanks for any input.

这是我的模特.

public class BIFireTypeModel
{
    public int ID { get; set; }
    public string Name { get; set; }
}


public class Product
{
    public int CategoryID { get; set; }
    public Product()
    {
        CategoryID = 0;
    }
}

这是我的控制器:

//
// GET: /BasicIdentification/
[HttpGet]
public ViewResult BasicIdentificationIndex()
{
    Product newproduct = new Product();
    ViewModelData vmd = new ViewModelData();
    vmd.product = newproduct;
    vmd.product.CategoryID = 2; 
    ViewBag.Categories = GetItems(); 
    return View(vmd); 
}        

[HttpPost]
public ActionResult BasicIdentificationIndex(ViewModelData product)
{      
    ViewBag.Categories = GetItems();         
    return View(product);           
}

public List<BIFireTypeModel> GetItems()
{
    List<BIFireTypeModel> categories = new List<BIFireTypeModel>();
    categories.Add(new BIFireTypeModel() { ID = 1, Name = "IA" });
    categories.Add(new BIFireTypeModel() { ID = 2, Name = "Extended Attack" });
    categories.Add(new BIFireTypeModel() { ID = 3, Name = "Large Fire Support" });
    return categories; 
}        

public class ViewModelData
{
    public String IncidentNumber { get; set; }       
    public Product product { get; set; } 
}

最后是我的cshtml:

And finally my cshtml:

@{

    using (Html.BeginForm())
    {     

        <h4>Incident Number</h4><input id="txtIncidentNumber" name="IncidentNumber" type="text" />           
        @Html.DropDownListFor(x => x.product.CategoryID, new SelectList(ViewBag.Categories, "ID", "Name"))      


        @* WILL CAUSE IncidentNumber in BasicIdentificationIndex(ViewModelData product) TO BE NULL
        <h4>Incident Number</h4><input id="afasf" name="product.CategoryID" type="text" />
            *@

            <input type="submit" value="Submit" />   
    }
}

编辑

在我的Post函数中，我可以像这样通过Request []访问product.CategoryID:

In my Post function, I can access product.CategoryID with Request[] like so:

  [HttpPost]
    public ActionResult BasicIdentificationIndex(ViewModelData product)
    {
        String tmp = Request["product.CategoryID"];
        ViewBag.Categories = GetItems();    

        return View(product);           
    }

它返回正确的值.但是此值不会绑定到我的模型中，如果我尝试对产品完全使用DropDownListFor，则ViewModelData产品中的ALL VALUES将为null.

And it returns the right value. But this value will not bind in my model, and if I try to use DropDownListFor at all with product, ALL VALUES in ViewModelData product will be null.

推荐答案

已修复:

这是问题所在.

public ActionResult BasicIdentificationIndex(ViewModelData product)

public class ViewModelData
{       
   public Employee product { get; set; } 
}

ViewModelData中对象的名称与BasicIdentificationIndex()中的PARAMETER相同.这引起了重大问题.我要做的就是更改名称.

The NAME of my object in my ViewModelData was the same as the PARAMETER in BasicIdentificationIndex(). This caused major issues. All I had to do was change the name.

其他非常重要的事情是，当我使用EditorForModel()时，我的下拉列表没有绑定，但是当我使用@ Html.EnumDropDownListFor手动创建它们时，绑定才起作​​用.很高兴知道.

Something else that is very IMPORTANT is that when I was using EditorForModel(), my dropdowns weren't binding, but when I would manually create them with @Html.EnumDropDownListFor the binding worked. Good to know.

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