Element naming convention in Razor generator withi

问题:

I'm trying to generate element names using Html.NameFor<> method, here's my code:

@foreach (var category in Model.Categories)
{
  <input type="hidden" name="@Html.NameFor(m=> category.CategoryId)" 
    value="@category.CategoryId" />
}

The generated item's name get this value: category.CategoryId, instead of Categories[i].CategoryId (where i refers to the current indexer).

Why isn't it working?

回答1:

in short, use a for loop instead of a foreach loop (see the answer here). You need to manually index it

MVC Razor view nested foreach's model

EDIT: added sample code

@for(int i=0; i < Model.ListTwo.Count; i++) 
{
    @Html.HiddenFor(t => t.ListTwo[i].Id)
}

Okay, for collections that inherit from ICollection, try

@for (int i = 0; i < Model.CollectionThree.Count; i++) 
{
   @Html.Hidden("CollectionThree[" + i + "].Id", Model.CollectionThree.ElementAt(i).Id)
}

Another edit: To avoid using the property name, you could do something like

@for (int i = 0; i < Model.CollectionThree.Count; i++)
{
   @Html.Hidden(Html.NameFor(t => Model.CollectionThree) + "[" + i + "]." +
                Html.NameFor(t =>Model.CollectionThree.ElementAt(i).Id)
               ,Model.CollectionThree.ElementAt(i).Id )
}

Its inelegant, but it doesn't hardcode the property name.

And then lets take those guys out of the loop

 @{
   var collectionname = Html.NameFor(t => Model.CollectionThree);
   var propname = Html.NameFor(t => Model.CollectionThree.First().Id);
  }

@for (int i = 0; i < Model.CollectionThree.Count; i++)
 {
      @Html.Hidden( collectionname+ "[" + i + "]." + propname ,Model.CollectionThree.ElementAt(i).Id )
 }

My apologies for not responding earlier. I logged out as I had other things to do. You also may want to do a null check ie, if count > 0, then assign the propname, otherwise skip the whole thing

回答2:

According to user1778606's answer, I will use the prop. name and indexer separately, like this:

@{
 var modelName = Html.NameFor(m => m.Categories);
 var catIndex = 0;   
}

@foreach (var category in Model.Categories)
{ 
 <input type="hidden" class="checkbox"
   name="@string.Format("{0}[{1}]", modelName, catIndex++)"
   value="@category.CategoryId" />      
}

回答3:

Use @Html.HiddenFor and pass in the array indexed expression for CategoryId

@for(int i=0; i < Model.Categories.Count; i++)
{
    @Html.HiddenFor(m => Model.Categories[i].CategoryId)
}