I am using jQuery
and ASP.NET MVC 3
with the razor view engine
.
I have 2 dropdowns on my view. The first dropdown displays a list of parent categories. The second dropdown is supposed to load a list of child categories based on what was selected in the parent category dropdown.
Here is my Category
object:
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public string MetaKeywords { get; set; }
public string MetaDescription { get; set; }
public bool IsActive { get; set; }
public int? ParentCategoryId { get; set; }
public virtual Category ParentCategory { get; set; }
public virtual ICollection<Category> ChildCategories { get; set; }
}
Action method that creates an instance of my view model and populates the dropdowns:
public ActionResult Create()
{
EditProductViewModel viewModel = new EditProductViewModel
{
ParentCategories = categoryService.GetParentCategories()
.Where(x => x.IsActive)
.OrderBy(x => x.Name),
ChildCategories = Enumerable.Empty<Category>(),
IsActive = true
};
return View(viewModel);
}
Part of my view model:
public class EditProductViewModel
{
public int Id { get; set; }
public string Name { get; set; }
public bool IsActive { get; set; }
public int ParentCategoryId { get; set; }
public IEnumerable<Category> ParentCategories { get; set; }
public int ChildCategoryId { get; set; }
public IEnumerable<Category> ChildCategories { get; set; }
}
HTML for the dropdowns:
<tr>
<td><label>Parent Category:</label> <span class="red">*</span></td>
<td>@Html.DropDownListFor(x => x.ParentCategoryId,
new SelectList(Model.ParentCategories, "Id", "Name", Model.ParentCategoryId),
"-- Select --",
new { data_url = Url.Action("AjaxBindingChildCategories"), id = "ParentCategories" }
)
@Html.ValidationMessageFor(x => x.ParentCategoryId)
</td>
</tr>
<tr>
<td><label>Child Category:</label> <span class="red">*</span></td>
<td>@Html.DropDownListFor(x => x.ChildCategoryId,
new SelectList(Model.ChildCategories, "Id", "Name", Model.ChildCategoryId),
"-- Select --",
new { id = "ChildCategories" }
)
@Html.ValidationMessageFor(x => x.ChildCategoryId)
</td>
</tr>
jQuery
to populate my child dropdown on my view:
<script type="text/javascript">
$(document).ready(function () {
$('#ParentCategories').change(function () {
var url = $(this).data('url');
var data = { parentCategoryId: $(this).val() };
$.getJSON(url, data, function (childCategories) {
var childCategoriesDdl = $('#ChildCategories');
childCategoriesDdl.empty();
$.each(childCategories, function (index, childCategory) {
alert('childCategory = ' + childCategory.Value);
childCategoriesDdl.append($('<option/>', {
value: childCategory, text: childCategory
}));
});
});
});
});
</script>
My AJAX method that brings back my child categories in JSON format.
public ActionResult AjaxBindingChildCategories(int parentCategoryId)
{
IEnumerable<Category> childCategoryList = categoryService.GetChildCategoriesByParentCategoryId(parentCategoryId);
IEnumerable<Category> childList =
from c in childCategoryList
select new Category
{
Id = c.Id,
Name = c.Name
};
return Json(childList, JsonRequestBehavior.AllowGet);
}
It's not populating my child dropdown. I had a look in Fire Bug and it seems to be ok as well.
Here is my response from firebug:
[{"Id":3,"Name":"Test category 3","Description":null,"MetaKeywords":null,"MetaDescription":null,"IsActive":false,"ParentCategoryId":null,"ParentCategory":null,"ChildCategories":null}]
It looks fine to me.
Can someone please help me get this sorted out?
Your Category
class doesn't seem to have a Value
property. In your controller action you are populating only the Id
and Name
properties, so use them to bind the dropdown:
$.each(childCategories, function(index, childCategory) {
childCategoriesDdl.append(
$('<option/>', {
value: childCategory.Id,
text: childCategory.Name
})
);
});
By the way because you only need an Id and a Name there is no need to send the other properties over the wire and waste bandwidth. Use a view model or in this case an anonymous object would do just fine:
public ActionResult AjaxBindingChildCategories(int parentCategoryId)
{
IEnumerable<Category> childCategoryList = categoryService.GetChildCategoriesByParentCategoryId(parentCategoryId);
var childList =
from c in childCategoryList
select new
{
Id = c.Id,
Name = c.Name
};
return Json(childList, JsonRequestBehavior.AllowGet);
}
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