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NullReferenceException was unhandled asp.net entity framework

I'm new to asp.net mvc and I'm doing this exercise for myself.
I created an edmx from Northwind Database.
I created a controller:
public ActionResult Index(int id)
{
var model = new IndexViewModel();
using (var db = new ProductDB())
{
model.Products = from p in db.Products
orderby p.ProductName
select new IndexViewModel.InfoProduct
{
ProductName = p.ProductName,
QuantityPerUnit = p.QuantityPerUnit,
UnitPrice = p.UnitPrice
};
}
return View();
}
...the view:
#model aspTest.Models.IndexViewModel
#{
Layout = null;
}
...
<div> <ul>
#foreach (var p in Model.Products){
<li>#p.ProductName</li>
}
</ul>
</div>
...and the ViewModel:
public class IndexViewModel
{
public IEnumerable<InfoProduct> Products { get; set; }
public class InfoProduct
{
public string ProductName { get; set; }
}
}
But this error keeps on appearing in this part:
#foreach (var p in Model.Products){#p.ProductName
Sorry, I know this might be noobish to most of you.

You are declaring in your model that it will work with the IndexViewModel class as:
#model aspTest.Models.IndexViewModel
but you are sending nothing to the View from Controller as :
return View();
Try using:
return View(model);
The error is quite true, you are trying to iterate on properties (Products) of an object (IndexViewModel) which you don't provide.

Besides the fact that you return no ViewModel to your view and shout use return View(model); there is something else fishy with your code:
public class InfoProduct
{
public string ProductName { get; set; }
}
Your class InfoProduct only contains a Productname, yet you also assign a Quantity and Price property in your select clause, this won't compile.
model.Products = from p in db.Products
orderby p.ProductName
select new IndexViewModel.InfoProduct
{
ProductName = p.ProductName,
};
Lastly, materialize your data using .ToList()
public ActionResult Index(int id)
{
var model = new IndexViewModel();
using (var db = new ProductDB())
{
model.Products = (from p in db.Products
orderby p.ProductName
select new IndexViewModel.InfoProduct
{
ProductName = p.ProductName,
}).ToList();
return View(model);
}
}

Populate Data in DropDownList in Create Mode MVC 4

I'm trying to populate data from table in DropDownList using MVC4. Trying to figure it out how to get all the languages' titles into the DropDown in the Edit mode.
Models:
public class CategoryLanguage
{
public int ID { get; set; }
public int LanguageID { get; set; }
public string Title { get; set; }
public string Description { get; set; }
}
public class Language
{
public int ID { get; set; }
public string Title { get; set; }
}
Controller:
public ActionResult Create()
{
using (MyDBContext db = new MyDBContext())
{
ViewBag.ID = new SelectList(db.Languages, "ID", "Title");
return View();
}
}
//
// POST: /Emp/Create
[HttpPost]
public ActionResult Create(CategoryLanguage newCatLang)
{
using (MyDBContext db = new MyDBContext())
{
if (ModelState.IsValid)
{
db.CategoryLanguages.Add(newCatLang);
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.ID = new SelectList(db.Languages, "ID", "Title", newCatLang.LanguageID);
return View(newCatLang);
}
}
View:
#model MultilanguageCategories.CORE.Models.CategoryLanguage
#{
ViewBag.Title = "Create";
}
<h2>Add New Item</h2>
#using (Html.BeginForm())
{
#Html.ValidationSummary(true)
#Html.DropDownList("ID", "--Select--")
}
Trying to figure it out how to get all the languages' titles into the DropDown when creating new CategoryLanguage entity. The error says: "The operation cannot be completed because the DbContext has been disposed." and this line marked: #Html.DropDownList("ID", "--Select--")

Change your get method "Create" as mentioned below :
public ActionResult Create()
{
var languages = new List<Language>();
using (MyDBContext db = new MyDBContext())
{
languages = db.Languages.ToList();
}
ViewBag.ID = new SelectList(languages, "ID", "Title");
return View();
}
Now you can use DropDownListFor as mentioned below :
#Html.DropDownListFor(model => model.[PropertyName], (IEnumerable<SelectListItem>)ViewBag.ID)

you're close...
You need to Add the languages select list to the viewbag (which you've already done, but with a badly named key)
ie: ViewBag.LanguagesList = new SelectList(db.Languages, "ID", "Title");
if you want an empty field that's easy enough too:
var langs = db.Languages.ToList().ConvertAll(x => new SelectListItem() { Value = x.ID, Text = x.Title });
langs.Insert(0, new SelectListItem() { Value = "", Text = "--Select--" });
ViewBag.LanguagesList = langs;
The DropdownList should be for a property in the model.
#Html.DropDownListFor(m => m.LanguageID, (IEnumerable<SelectListItem>)ViewBag.LanguagesList)
As it looks like you are using an Entity Framework class as your model you need to ensure the context is not disposed before the view is rendered.
As Per Microsoft's example link instantiate the context at the top of the controller, and drop the using statement in the Create method.
ie :
public class LanguageCategoryController : Controller
{
MyDBContext db = new MyDBContext();
public ActionResult Create()
{
ViewBag.LanguagesList = new SelectList(db.Languages, "ID", "Title");
// or replace the above line with the other example above
// if you want the empty "--select--" option
return View();
}
}

Populate Result Set in SelectList MVC3

I have following SelectList declaration in CourseRegisterModel:
public class CourseRegisterModel
{
public StudentModel Student { get; set; }
public CourseModel Course { get; set; }
public IEnumerable<SelectListItem> CoursesList { get; set; }
public DateTime RegisterDate { get; set; }
}
In CourseController I am retrieving all available courses by calling wcf web service:
public ViewResult Index()
{
ServiceCourseClient client = new ServiceCourseClient();
Course[] courses;
courses = client.GetAllCourses();
List<CourseModel> modelList = new List<CourseModel>();
foreach (var serviceCourse in courses)
{
CourseModel model = new CourseModel();
model.CId = serviceCourse.CId;
model.Code = serviceCourse.Code;
model.Name = serviceCourse.Name;
model.Fee = serviceCourse.Fee;
model.Seats = serviceCourse.Seats;
modelList.Add(model);
}
return View(modelList);//RegisterCourses.chtml
}
I need to populate these courses in a dropdown on view RegisterCourses.chtml. How to put all records in selectlist in above code? Also how would i use that selectlist on view?

For starters, your RegisterCourses.cshtml needs to use:
#model <namespace>.CourseRegisterModel
Then, your controller code would be:
public ViewResult Index()
{
ServiceCourseClient client = new ServiceCourseClient();
Course[] courses;
courses = client.GetAllCourses();
CourseRegisterModel model = new CourseRegisterModel();
//model = other model population here
model.CourseList = courses.Select(sl => new SelectListItem()
{ Text = sl.Name,
Value = sl.CId })
.ToList();
return View(model);
}
And finally, back to your view (RegisterCourses.cshtml) - it should contain:
#Html.DropDownListFor(m => m.Course.CId, Model.CourseList)

Use the Html.DropDownList method: http://msdn.microsoft.com/en-us/library/dd492738(v=vs.108).aspx
Pass in the desired name of the drop down list as first argument, as second argument pass in your CourseList:
#Html.DropDownList("CoursesList", Model.CoursesList)

Dropdown list - MVC3

I am using C# in ASP MVC3. I have two tables from SQL Server.Table names are SMS_User and SMS_Division in SQL Server 2008. When i create a new user, I want to show division id from sms_division table.
SMS_User contains UserName, DivisionID, EmailAddress
SMS_Division contains DivisionID, DivisionName.
Controller Code :
UserController : Controller
{
private NetPerfMonEntities2 db = new NetPerfMonEntities2();
IEnumerableZamZam= db.SMS_Division.Select(c => new SelectListItem { Value = c.divisionid.ToString(), Text = c.divisionid.ToString() } );
}
When I create a new user in User Create() VIEW I want to show a DivisonName as a dropdown list instead of a text box. How I do that ?
#Html.DropDownListFor(model => model.divisionid, (IEnumerable<SelectListItem>) ViewData["Divisions"], "<--Select a divison-->")
#Html.ValidationMessageFor(model => model.divisionid)
I have this error message :
CS0103: The name 'sms_amountlimit2' does not exist in the current context

I'll be assuming a few missing part of your question in my answer, and give you a generic pattern to have a working dropdown list in ASP.NET MVC 3 :
Let's start with the models :
UserModel would be the class representing the data extracted from sms_user
public class UserModel
{
public string Username { get; set; }
public string EmailAddress { get; set; }
public int DivisionId { get; set; }
}
DivisionModel would be the class representing the data extracted from sms_division
public class DivisionModel
{
public int DivisionId { get; set; }
public string DivisionName { get; set; }
}
By Extracted, I mean anything that can transform the data in your Database in instanciated classes. That can be an ORM (EntityFramework or others), or SQL Queries, etc...
Next, is the viewmodel, because it wouldn't make sense to plug an IEnumerable of divisions in UserModel, and I personally don't really like using ViewData when I can avoid it :
public class UserViewModel
{
public UserModel User { get; set; }
public IEnumerable<DivisionModel> Divisions {get; set;}
}
Next, the controller :
public class UserController : Controller
{
public ActionResult Create()
{
List<DivisionModel> divisions = new List<DivisionModel>();
divisions.Add(new DivisionModel() { DivisionId = 1, DivisionName = "Division1" });
divisions.Add(new DivisionModel() { DivisionId = 2, DivisionName = "Division2" });
UserModel user = new UserModel() { Username = "testUser", EmailAddress = "testAddress#test.com" };
return View(new UserViewModel() { User = user, Divisions = divisions });
}
}
I just create the Division list and the user, but you would get then from you database by any means you are using.
And finally the View :
#model ViewModels.UserViewModel
#{
ViewBag.Title = "Create";
}
<h2>Create</h2>
<p>
#Html.DropDownListFor(model => model.User.DivisionId, new SelectList(Model.Divisions, "DivisionId", "DivisionName"), "-- Select Division --")
#Html.ValidationMessageFor(model => model.User.DivisionId)
</p>
Note that the model binded to the view is the ViewModel.

In your model add a collection of the divisions then create the dropdown list like below:
#Html.DropDownListFor(m => m.SelectedDivisionId,
new SelectList(Model.Divisions, "DivisionId", "DivisionName"),
"-- Select Division --")

How to print after join linq query

I have this code:
public ActionResult Index()
{
MembershipUser currentUser = Membership.GetUser();
Guid UserId = (Guid)currentUser.ProviderUserKey;
var users = from m in db.Users
join m2 in db.MyProfiles on m.UserId equals m2.UserId
where m.UserId == UserId
select new{UserName = m.UserName, LastActivityDate = m.LastActivityDate,
Address = m2.Address, City = m2.City, State = m2.State, Zip = m2.Zip};
return View(users);
}
This code is in my Controller, I want to run this query and then print the results into my view, how would I write the view?

//if your question is how to display(Print!) a view for above query then in ActionResult Index()
//1] As as best practise always Create a ViewModel - UserViewModel
public class UserviewModel
{
public string Username {get;set;}
public string Address {get;set;}
}
//2] Assign db.user values to UserviewModel or you can use Automapper
//and 3] then return this viewmodel to view
return View(UserviewModel);

This code cannot work because your LINQ query is returning an anonymous object so you cannot strongly type your view. So the first step would be to define a view model which will represent the information you are willing to display on your view:
public class UserViewModel
{
public string UserName { get; set; }
public DateTime LastActivityDate { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string State { get; set; }
public string Zip { get; set; }
}
then in your controller action you would return a collection of this view model:
public ActionResult Index()
{
var currentUser = Membership.GetUser();
var userId = (Guid)currentUser.ProviderUserKey;
var users =
from m in db.Users
join m2 in db.MyProfiles on m.UserId equals m2.UserId
where m.UserId == userId
select new UserViewModel
{
UserName = m.UserName,
LastActivityDate = m.LastActivityDate,
Address = m2.Address,
City = m2.City,
State = m2.State,
Zip = m2.Zip
};
return View(users);
}
and finally in your strongly typed view:
#model IEnumerable<AppName.Models.UserViewModel>
#Html.DisplayForModel()
and in the corresponding display template (~/Views/Shared/DisplayTemplates/UserViewModel.cshtml) which will be rendered for each item of the collection:
#model AppName.Models.UserViewModel
<div>
Username: #Html.DisplayFor(x => x.UserName)<br/>
Last activity: #Html.DisplayFor(x => x.LastActivityDate)<br/>
...
</div>

You need to get the type of users and make a List-View of that type. Easiest way to make a view is simply right-clicking in your controller method and selecting Create View. That'll make sure the routing gets done properly as well.