MVC 3 - Binding to a Complex Type with a List type

问题:

I have a following view model and it will be used by a search control that I'm working on.

public class SearchViewModel
{
    public SearchViewModel()
    {
        SearchLocation = new SearchLocationViewModel();
        SearchCategories = new SearchCategoriesViewModel();
    }

   public SearchLocationViewModel SearchLocation { get; set; }
   public SearchCategoriesViewModel SearchCategories { get; set; }
}

Now, SearchCategoriesViewModel has the following structure:

public class SearchCategoriesViewModel
{
    [Display(Name = "Categories")]
    public IList<SearchCategoryViewModel> Categories { get; set; }

    public SearchCategoriesViewModel()
    {
        Categories = new List<SearchCategoryViewModel>();
    }
}

And, finally, search category view model has the following structure:

    public class SearchCategoryViewModel
    {
        [Required]
        [Display(Name="Id")]
        public int Id { get; set; }

        [Display(Name="Name")]
        public String Name { get; set; }

        public bool IsSelected { get; set; }
    }

When I submit a search request, the SearchLocationViewModel comes through with submitted parameters, however, SearchCategoriesViewModel comes through empty (not null).

Below is an editor template for my SearchCategoryViewModel:

@model MyDLL.WebUI.Models.SearchCategoriesViewModel

@foreach (var c in Model.Categories)
{
    @Html.Label(c.Name);
    @Html.CheckBox(c.Name,c.IsSelected);
}

I use the following view to generate the search controls:

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true) 

    <div id="search">
        @Html.EditorFor(m => m.SearchCategories, "SearchCategory")            
        @Html.EditorFor(m => m.SearchLocation, "SearchLocation")            
    </div>

    <p>
        <input type="submit" value="Create" />
    </p>    
}   

I end up with the following markup:

   <h2>Search</h2>

<form action="/Settings/Search" method="post">        


<label for="SearchCategories_Professional">Professional</label>
<input id="SearchCategories_Professional" name="SearchCategories.Professional" type="checkbox" value="true" />
<input name="SearchCategories.Professional" type="hidden" value="false" />

<label for="SearchCategories_Associate">Associate</label><input id="SearchCategories_Associate" name="SearchCategories.Associate" type="checkbox" value="true" />
<input name="SearchCategories.Associate" type="hidden" value="false" />            

        <p>
            <input type="submit" value="Create" />
        </p> 

</form>

I suspect that the parameters are not coming through because generated markup is wrong. Did any of you try generating partial views from complex objects? I don't want to pass IEnumerable, I would rather have it encapsulated in a seperate class so that I can extend/remove it in the future if needed.

Thank you

回答1:

Because you have a static list, you can quickly hack your way to creating markup which will be bound correctly:

@model MyDLL.WebUI.Models.SearchCategoriesViewModel
@{
    var i = 0;
}
@foreach (var c in Model.Categories) 
{
    @Html.Hidden("Categories[" + i.ToString() + "].Id", c.Id);
    @Html.Hidden("Categories[" + i.ToString() + "].Name", c.Name);
    @Html.Label(c.Name);
    @Html.CheckBox("Categories[" + i.ToString() + "].IsSelected",c.IsSelected);
} 

This is a quick and ugly solution. However, I would suggest that you reconsider how you are generating the markup in your partial view.