I am trying to load the data into a dropdownlist in a nested master page but the Model in View is always null. How can I do this?
In model
public class AllInOneModel
{
public string City { get; set; }
public IEnumerable<City> cities { get; set; }
}
In controller
public ActionResult Add()
{
return View(new AllInOneModel());
}
In View
#model IBilik.Models.AllInOneModel
#Html.DropDownListFor(model => model.City,(SelectList)Model.cities)
Personally I would skip the "AllInOneModel" and stick to sending the single city to the view.
The controller action could look somewhat like this.
public ActionResult Index()
{
//TODO: get current cities from database
List<City> cities = new List<City>
{
new City { CityID = 1, CityName = "City1" },
new City { CityID = 2, CityName = "City2" },
new City { CityID = 3, CityName = "City3" }
};
// Create the list of selectlistitems to populate the dropdown
List<SelectListItem> listItems = new List<SelectListItem>();
foreach(var c in cities)
{
listItems.Add(new SelectListItem { Value = c.CityID.ToString(), Text = c.CityName });
}
//Throw them into viewbag
ViewBag.ListItems = listItems;
//TODO get some city (perhaps from db) to send to view
var city = new City { CityID = 1, CityName = "City1" };
return View(city);
}
And then you would render the view in this way.
#model IBilik.Models.City
#Html.DropDownListFor(model => model.CityID, ViewBag.ListItems as List<SelectListItem>)
Related
I have a model,
public class Customer
{
public string Name { get; set;}
public string CountryCode { get; set;}
}
In the controller
var model = new List<Customer>
{
new Customer { Name = "foo", CountryCode = "US"},
new Customer { Name = "bar", CountryCode = "UK",
};
return PartialView("_Edit", model);
An extension method for displaying all countries:-
public class CountryList
{
public static IEnumerable<SelectListItem> CountrySelectList
{
get
{
var list = new List<SelectListItem>()
{
new SelectListItem { Value = "US", Text="US" },
new SelectListItem { Value = "UK", Text="UK" },
};
return list;
}
}
}
In the PartialView
#model List<Customer>
#Html.DropDownListFor(model => model[i].CountryCode, CountryList.CountrySelectList, "Select Country Type")
But the drop down doesn't select each customer's country code? Any thoughts?
PS: It is using model[i] => which is of type Customer, for simplicity i had removed the forloop before rendering the html tags.
#using(Html.BeginForm())
{
for(int i = 0; i < Model.Count(); i++)
{
#Html.TextBoxFor(model => model[i].Name)
#Html.DropDownListFor..........
}
}
Because your CoutryList helper does returns a list of SelectListItems that all have Selected property set to False (which is default).
I would rewrite your helper method as follows:
public static IEnumerable<SelectListItem> CountrySelectList(string selectedCountryCode)
{
get
{
var list = new List<SelectListItem>()
{
new SelectListItem { Value = "US", Text="US" },
new SelectListItem { Value = "UK", Text="UK" },
};
var selectedListItem = list.FirstOrDefault(t=>t.Value== selectedCountryCode);
if(selectedListItem!=null)
selectedListItem.Selected=true;
return list;
}
}
In view:
#Html.DropDownListFor(model => model[i].Customer, CountryList.CountrySelectList(model[i].Customer.CountryCode), "Select Country Type")
I created a view that was working wonderfully until I added some JQuery to support cascading drop downs. I believe in doing that, I broke the binding between the view and the model. I'm getting the error "No parameterless constructor defined for this object." when the form is submitted. The obvious solution would be to add a parameterless constructor, but I'm assuming that the postmodel will be null? Code Snippets below.
Thanks in Advance for your help.
View:
<script type="text/javascript">
$(document).ready(function () {
$("#ddlCategories").change(function () {
var iCategoryId = $(this).val();
$.getJSON(
"#Url.Content("~/Remote/SubCategoriesByCateogry")",
{ id: iCategoryId },
function (data) {
var select = ResetAndReturnSubCategoryDDL();
$.each(data, function (index, itemData) {
select.append($('<option/>', { value: itemData.Value, text: itemData.Text }));
});
});
});
function ResetAndReturnSubCategoryDDL() {
var select = $('#ddlSubCategory');
select.empty();
select.append($('<option/>', { value: '', text: "--Select SubCategory--" }));
return select;
}
});
...
<div class="editor-field">
#Html.DropDownList("iCategoryID", Model.Categories,"--Select Category--", new Dictionary<string,object>{ {"class","dropdowns"},{"id","ddlCategories"}})
#Html.ValidationMessage("iCategoryID")
</div>
<div class="editor-label">
#Html.LabelFor(model => model.SubCategories, "SubCategory")
</div>
<div class="editor-field">
#Html.DropDownListFor(model => model.SubCategories, new SelectList(Enumerable.Empty<SelectListItem>(), "iSubCategoryID", "SubCategory",Model.SubCategories), "--Select SubCategory--", new { id = "ddlSubCategory" })
#Html.ValidationMessage("iSubCategoryID")
</div>
Controller:
[HttpPost]
public ActionResult Create(VendorCreateModel postModel)
{
VendorCreateEditPostValidator createValidator = new VendorCreateEditPostValidator(
postModel.iCategoryID,
postModel.iSubCategoryID,
postModel.AppliedPrograms,
m_unitOfWork.ProgramRepository,
new ModelStateValidationWrapper(ModelState));
if (ModelState.IsValid)
{
int categoryId = int.Parse(postModel.iCategoryID);
int subcategoryId = int.Parse(postModel.iSubCategoryID);
var programIds = postModel.AppliedPrograms.Select(ap => int.Parse(ap));
var programs = m_unitOfWork.ProgramRepository.GetPrograms(programIds);
Vendor vendor = postModel.Vendor;
vendor.Category = m_unitOfWork.CategoryRepository.GetCategory(categoryId);
vendor.SubCategory = m_unitOfWork.SubCategoryRepository.GetSubCategory(subcategoryId);
foreach (Program p in programs)
vendor.Programs.Add(p);
m_unitOfWork.VendorRepository.Add(vendor);
m_unitOfWork.SaveChanges();
return RedirectToAction("Index");
}
VendorCreateModel model = new VendorCreateModel(
postModel.Vendor,
postModel.iCategoryID,
postModel.iSubCategoryID,
postModel.AppliedPrograms,
User.Identity.Name,
m_unitOfWork.CategoryRepository,
m_unitOfWork.SubCategoryRepository,
m_unitOfWork.PermissionRepository);
return View(model);
}
RemoteController:
[AcceptVerbs(HttpVerbs.Get)]
public JsonResult SubCategoriesByCateogry(int id)
{
System.Diagnostics.Debug.WriteLine(id);
var SubCategories = db.SubCategories
.Where(v => v.iCategoryID == id)
.OrderBy(v => v.sDesc)
.ToList();
var modelData = SubCategories.Select(v => new SelectListItem()
{
Text = v.sDesc,
Value = v.iSubCategoryID.ToString()
});
return Json(modelData, JsonRequestBehavior.AllowGet);
}
VendorCreateModel:
public class VendorCreateModel
{
public VendorCreateModel()
{
}
public VendorCreateModel(
Vendor vendor,
string categoryId,
string subcategoryId,
IEnumerable<string> appliedPrograms,
string username,
ICategoryRepository categoryRepository,
ISubCategoryRepository subcategoryRepository,
IPermissionRepository permissionRepository)
{
UserHasProgramsValidator programValidator = new UserHasProgramsValidator(username, permissionRepository);
var availablePrograms = programValidator.AvailablePrograms;
HashSet<Category> applicableCategories = new HashSet<Category>();
foreach (var p in availablePrograms)
foreach (var c in categoryRepository.GetCategoriesByProgram(p.iProgramID))
applicableCategories.Add(c);
this.Vendor = vendor;
this.AppliedPrograms = appliedPrograms;
this.Categories = new SelectList(applicableCategories.OrderBy(x => x.sDesc).ToList(), "iCategoryID", "sDesc");
this.SubCategories = new SelectList(subcategoryRepository.GetAllSubCategories().OrderBy(x => x.sDesc).ToList(), "iSubCategoryID", "sDesc");
if (!string.IsNullOrEmpty(categoryId))
{
int temp;
if (!int.TryParse(categoryId, out temp))
throw new ApplicationException("Invalid Category Identifier.");
}
this.iCategoryID = categoryId;
this.iSubCategoryID = subcategoryId;
this.ProgramItems = availablePrograms
.Select(p => new SelectListItem()
{
Text = p.sDesc,
Value = p.iProgramID.ToString(),
Selected = (AppliedPrograms != null ? AppliedPrograms.Contains(p.iProgramID.ToString()) : false)
});
}
public Vendor Vendor { get; set; }
public SelectList Categories { get; set; }
public SelectList SubCategories { get; set; }
public string iCategoryID { get; set; }
public string iSubCategoryID { get; set; }
public IEnumerable<SelectListItem> ProgramItems { get; set; }
[AtLeastOneElementExists(ErrorMessage = "Please select at least one program.")]
public IEnumerable<string> AppliedPrograms { get; set; }
}
I correct the issue and wanted to share in case someone else was banging their head against their desk like Ihave been. Basically I changed the dropdownlistfor to reflect:
#Html.DropDownListFor(model => model.iSubCategoryID, new SelectList(Enumerable.Empty<SelectListItem>(), "iSubCategoryID", "SubCategory",Model.SubCategories), "--Select SubCategory--", new Dictionary<string,object>{ {"class","dropdowns"},{"id","ddlSubCategory"},{"name","iSubCategoryID"}})
Assuming here the problem is in your VendorCreateModel, you either need to add a parameterless constructor or remove it, and create an instance in your action method and populate it by TryUpdateModel. Or parse the form using FormsCollection (not a fan).
You don't have the code for your viewmodel posted here but the basic assumption is that it will map.
I'm new towards MVC3 Razor. Currently, I'm facing this error "Object reference not set to an instance of an object.", which I have no idea what is this about.
In Model
public List<SelectListItem> CatList { get; set; }
[Display(Name = "Category")]
public string CatID { get; set; }
In Controller
public ActionResult DisplayCategory()
{
var model = new CatModel();
model.CatList = GetCat();
return View(model);
}
private List<SelectListItem> GetCat()
{
List<SelectListItem> itemList = new List<SelectListItem>();
itemList.Add(new SelectListItem { Text = "1", Value = "1" });
itemList.Add(new SelectListItem { Text = "2", Value = "2" });
return itemList;
}
In CSHTML
#using (Html.BeginForm())
{
<table>
<tr>
<td>#Html.LabelFor(c => c.CatID)</td>
<td>#Html.DropDownListFor(c => c.CatID, Model.CatList)</td>
</tr>
</table>
}
Thanks for any help.
I suspect that you have a POST action in which you forgot to reassign the CatList property of your view model so you are getting the NRE when you submit the form, not when the form is initially rendered:
public ActionResult DisplayCategory()
{
var model = new CatModel();
model.CatList = GetCat();
return View(model);
}
[HttpPost]
public ActionResult Index(CatModel model)
{
// some processing ...
// since we return the same view we need to populate the CatList property
// the same way we did in the GET action
model.CatList = GetCat();
return View(model);
}
private List<SelectListItem> GetCat()
{
List<SelectListItem> itemList = new List<SelectListItem>();
itemList.Add(new SelectListItem { Text = "1", Value = "1" });
itemList.Add(new SelectListItem { Text = "2", Value = "2" });
return itemList;
}
I looked at similar posts but nothing working for my case.
I have a form which loads fine and I see the categories dropdown with all categories in it.
The problem is when I try to post the form.
I get this error:
The ViewData item that has the key 'Category' is of type 'System.String' but must be of type 'IEnumerable'.
#Html.DropDownList("Category", Model.Categories) <-- red color
Here is my view:
#using (Html.BeginForm("Save", "Album", FormMethod.Post, new { id = "frmNewAlbum" }))
{
#Html.DropDownList("Category", Model.Categories)
}
Here is my model:
public class AlbumModel
{
public string Title { get; set; }
public string Category { get; set; }
public List<SelectListItem> Categories { get; set; } <-- holds categories
}
This is the controller actions to view the page:
[HttpGet]
public ActionResult Save()
{
var model = new AlbumModel();
var categories = new List<SelectListItem>() { new SelectListItem() { Text = "-- pick --" } };
categories.AddRange(svc.GetAll().Select(x => new SelectListItem() { Text = x.Name, Value = x.Name }));
model.Categories = categories;
return View(model);
}
Action that receives the post:
[HttpPost]
public ActionResult Save(AlbumModel model)
{
var album = new AlbumDoc()
{
Category = model.Category,
Title = model.Title,
};
svc.SaveAlbum(album);
return View(model);
}
In your POST action you seem to be redisplaying the same view but you are not populating the Categories property on your view model which will contain the dropdown list values. And by the way I would recommend you using strongly typed helper. So:
public class AlbumController: Controller
{
[HttpGet]
public ActionResult Save()
{
var model = new AlbumModel();
model.Categories = GetCategories();
return View(model);
}
[HttpPost]
public ActionResult Save(AlbumModel model)
{
var album = new AlbumDoc()
{
Category = model.Category,
Title = model.Title,
};
svc.SaveAlbum(album);
model.Categories = GetCategories();
return View(model);
}
private IList<SelectListItem> GetCategories()
{
return svc
.GetAll()
.ToList()
.Select(x => new SelectListItem
{
Text = x.Name,
Value = x.Name
});
}
}
and in your view:
#model AlbumModel
...
#using (Html.BeginForm("Save", "Album", FormMethod.Post, new { id = "frmNewAlbum" }))
{
#Html.DropDownListFor(
x => x.Category,
Model.Categories,
-- pick --
)
}
I have the following error when I click save:
the ViewData item that has the key 'SelectedCategoryId' is of type 'System.Int32' but must be of type 'IEnumerable'?
my controller:
public ActionResult IndexTwee()
{
var listCategories = new List<SelectListItem>();
listCategories.Add(new SelectListItem() {Text="foo",Value="1" });
listCategories.Add(new SelectListItem() { Text = "bar", Value = "2" });
MyViewModelTwee model = new MyViewModelTwee() { };
model.Categories = listCategories;
model.SelectedCategoryId = 2;
return View(model);
}
[HttpPost]
public ActionResult IndexTwee(MyViewModelTwee Model)
{
return View(Model);
}
my model:
public class MyViewModelTwee
{
public int SelectedCategoryId { get; set; }
public IEnumerable<SelectListItem> Categories { get; set; }
}
my view:
#model mvc3DropDown.Models.MyViewModelTwee
#using (Html.BeginForm())
{
#Html.DropDownListFor(
x => x.SelectedCategoryId,
Model.Categories
)
<button>Save</button>
}
Don't forget to rebind the list in your POST action:
[HttpPost]
public ActionResult Index(MyViewModelTwee Model)
{
var listCategories = new List<SelectListItem>();
listCategories.Add(new SelectListItem() { Text = "foo", Value = "1" });
listCategories.Add(new SelectListItem() { Text = "bar", Value = "2" });
Model.Categories = listCategories;
return View(Model);
}
Remember that only the selected value is sent when you submit the html <form>. The other values are lost so you need to refetch them from wherever you fetched them in the GET action. Of course you will externalize this code into a repository layer so that your code now looks like this:
public ActionResult IndexTwee()
{
var model = new MyViewModelTwee
{
SelectedCategoryId = 2,
Categories = _repository.GetCategories()
};
return View(model);
}
[HttpPost]
public ActionResult IndexTwee(MyViewModelTwee Model)
{
Model.Categories = _repository.GetCategories();
return View(Model);
}