How can I write code in View so as to access the groupby fields in linq. Here the data is rendered through a web service.
public class HomeController : Controller
{
public ActionResult Index()
{
ViewBag.Message = "Find Member";
var obj = new SearchMemberServiceClient();
List<MemberProxy> members = obj.FindMember("Mason", "Birkes", "", "", "", "").Members;
var sorted = from a in members
orderby a.FirstName ascending
group a by new { a.FormattedFullName, a.PersonId, a.Associations, a.MembershipsProxy[0].MembershipId } into k
select new { formattedname = k.Key.FormattedFullName, id = k.Key.PersonId, assoc = k.Key.Associations, memprox = k.Key.MembershipId };
return View(sorted.ToList());
}
}
You are passing an anonymous object to your view. Anonymous objects are emitted as internal by the compiler. Internal classes can only be used within the same assembly. ASP.NET MVC views are dynamically compiled by the ASP.NET runtime in separate assemblies. This basically means that you cannot access the anonymous types created in your controller actions inside your views. As a consequence this means that you should absolutely never pass anonymous objects to your views. So if you cannot pass anonymous objects, well, pass a named object by creating one. In this case they will be called a view model. A view model is class that you specifically define to meet the requirements of your view.
So what are the requirements of your view is the first question you should ask yourself when designing an ASP.NET MVC application? Well, in this case you seem to need a couple of properties (formattedname, id, assoc and memprox). Great, let's write a view model:
// you probably want to find a more suitable name
public class MyViewModel
{
public int Id { get; set; }
public int MemProx { get; set; }
public string FormattedName { get; set; }
public IEnumerable<Association> Associations { get; set; }
}
and then have your action pass this view model to the view:
public ActionResult Index()
{
var obj = new SearchMemberServiceClient();
var members = obj.FindMember("Mason", "Birkes", "", "", "", "").Members;
IEnumerable<MyViewModel> sorted =
from a in members
orderby a.FirstName ascending
group a by new
{
a.FormattedFullName,
a.PersonId,
a.Associations,
a.MembershipsProxy[0].MembershipId
} into k
select new MyViewModel
{
FormattedName = k.Key.FormattedFullName,
Id = k.Key.PersonId,
Associations = k.Key.Associations,
MemProx = k.Key.MembershipId
};
return View(sorted.ToList());
}
OK, now you can strongly type your view to this view model and present the information that it contains however you want:
#model IEnumerable<MyViewModel>
#foreach (var item in Model)
{
<div>#item.FormattedName</div>
...
}
Related
I am fairly new to MVC, and I've been reading a bit about ViewModels, but how do I go about sending two models to my View, where the queries are like so
public ActionResult Index(int Id)
{
var People = from a in db.Person
select a;
var Data = from a in db.Member
where a.Person.PersonId.Equals(Id)
select new
{
a.Project.ProjectId,
a.Project.Name,
a.Project.Customer,
a.Project.TechProfile.Select(x => new
{
x.TechId,
x.Name,
x.Elements
}),
a.MemberId,
a.Role,
a.Start,
a.End
};
return View(People);
}
I was using #model IQueryable<GeoCV.Models.Person> before so I could use a #foreach in my View but I don't know how to get my other query to the View so I can get data from it too.
Update
And I'm making a custom class for my Data query, but I don't know how to set the property of TechProfile
Right now I have
public IEnumerable<TechProfile> ProjectTechProfile { get; set; }
In my custom class, but it doesn't work, so I guess I have to specify TechId, Name and Elements?
But how?
A ViewModel wraps around the 2 models you are getting with your 2 queries, so you can return it as a single object to your view. In your case we need to adress another issue first. You are returning an anonymous object in your data query.
This means, your data query needs to return a strongly typed object instead of an anonymous object.
Create a class for your data query:
public class MyCustomDataObject
{
public int ProjectId { get; set; }
//... map all properties as needed
}
then edit your data query to return this object:
var Data = from a in db.Member
where a.Person.PersonId.Equals(Id)
select new MyCustomDataObject
{
ProjectId = a.Project.ProjectId,
//assign all properties
};
Now you need to create the actual ViewModel class:
public class MyViewModel
{
public IEnumerable<Person> Persons { get; set; }
public IEnumerable<MyCustomDataObject> Data { get; set; }
}
And after this you just need to assign the values to it in your Actionmethod:
public ActionResult Index(int Id)
{
var People = from a in db.Person
select a;
var Data = from a in db.Member
where a.Person.PersonId.Equals(Id)
select new MyCustomDataObject
{
ProjectId = a.Project.ProjectId,
//...
};
//store data of both queries in your ViewModel class here:
var vm = new MyCustomDataObject();
vm.Persons = People;
vm.Data = Data
//return ViewModel to View.
return View(vm);
}
And then declare it in your view: #model Namespace.Subfolder.MyCustomDataObject
You can use #Html.Action("actionName","controllerName") method in view. You can divide your original view into multiple partial view and then you can render that partial view with dynamic model binding using #Html.Action("actionName","controllerName") method.
For more details with sample code http://devproconnections.com/development/how-use-aspnet-mvc-render-action-helpers
You can have methods like below to get multiple model in single view
private IList<People> GetPeople()
{
return from a in db.Person
select a;
}
private IList<Data> GetData()
{
return from a in db.Member
where a.Person.PersonId.Equals(Id)
select new
{
a.Project.ProjectId,
a.Project.Name,
a.Project.Customer,
a.Project.TechProfile.Select(x => new
{
x.TechId,
x.Name,
x.Elements
}),
a.MemberId,
a.Role,
a.Start,
a.End
};
}
public ActionResult Index(int Id)
{
var MultipleModel = new Tuple<IList<People>,IList<Data>>(GetPeople(),GetData()) { };
return View(MultipleModel);
}
Here's a codeproject tutorial on the subject.
How can I access my viewmodel from my view? my code is as follows:-,
I have two models (using entity framework) which have a view model of:-
public class ViewModelStory
{
public IEnumerable<tbl_GCB_NewsItem> GCB_NewsItem { get; set; }
public IEnumerable<tbl_GCB_ItemComment> comemnts { get; set; }
}
My contoller populates the models by:-
ViewModelStory.GCB_NewsItem = (from i in db.tbl_GCB_NewsItem
where i.intItemIdentifier.ToString() == StoryId
select i).SingleOrDefault();
ViewModelStory.comemnts = (from i in db.tbl_GCB_ItemComment
where i.intItemIdentifier.ToString() == StoryId
select i).ToList<tbl_GCB_ItemComment>();
I return the model by
return PartialView("NewsStory", ViewModelStory);
then in my view I have the following declaration
#model ViewModelStory
#using GCBSMVC.Models
To access my model I have tried various from Linq to and directly querying the model, but nothing seems to work:-
Html.DisplayFor(m =>m.GCB_NewsItem. ....
ViewModelStory.GCB_NewsItem.strItemCategory
Html.Raw(System.Web.HttpUtility.HtmlDecode(ViewModelStory.GCB_NewsItem.strItemHeadline))
You are passing the type of you model class instead of the actual class. Try this:
var model = new ViewModelStory();
model.GCB_NewsItem = (from i in db.tbl_GCB_NewsItem
where i.intItemIdentifier.ToString() == StoryId
select i).SingleOrDefault();
model.comemnts = (from i in db.tbl_GCB_ItemComment
where i.intItemIdentifier.ToString() == StoryId
select i).ToList<tbl_GCB_ItemComment>();
return PartialView("NewsStory", model);
I am using C#, MVC3, EF5, SQL Server 2008 R2.
I have an intersection table ie
Lecturer -< LecturerCourse >- Course
The list of Lecturers are populated.
When I add a course, it would be neat to have a list of Lecturers that I could select from, that teach the course in question. When I save the new Course record, this multiselect also should save its data back to the "LecturerCourse" table via Model Binding.
I am using EF5.
Can you recommended a simple and standard approach to solving CRUD for a join, ie "LecturerCourse", table? I have looked online, but some of the approaches seem very complicated.
Many thanks.
Alright, it's going to be a long one. To allow this to happen in "one page" (through POST, or you could use Ajax, technically), you need a combination of a Get and Post version of the method and to construct your view model correctly. Below are the classes that I will use for demonstration purposes:
public class NewCourse
{
[Required]
public string Name { get; set; }
// And your other properties
public int[] LecturerIds { get; set; }
}
public class ViewLecturer
{
public int Id { get; set; }
public int Name { get; set; }
}
public class NewCourseViewModel
{
public NewCourse Course { get; set; }
public IEnumerable<ViewLecturer> Lecturers { get; set; }
}
NewCourseViewModel will be the model for the View (see below). ViewLecturer will give you a lighter mapping between your available Lecturer and the information required to Add to them.
As for the Controller:
public class CourseController : Controller, IDisposable
{
private Lazy<YourContext> lazyContext =
new Lazy<YourContext>(() => new YourContext());
private YourContext Context
{
get { return lazyContext.Value; }
}
public ActionResult New()
{
var model = new NewCourseViewModel {
Course = new NewCourse(),
Lecturers = Context.Lecturers
.Select(l => new ViewLecturer { Id = l.Id, Name = l.Name })
};
return View(model);
}
[HttpPost]
public ActionResult New(NewCourse course)
{
if(ModelState.IsValid)
{
var lecturers = course.Lecturers
.Select(l => new Lecturer { Id = l.Id })
.ToList();
foreach(var lecturer in lecturers)
Context.Lecturers.Attach(lecturer);
var newCourse = new Course {
Name = course.Name,
// ... and the rest of the mapping
Lecturer = lecturers
};
context.Courses.Add(newCourse);
context.SaveChanges();
// Could have to handle DbUpdateException if you want
return RedirectToAction(...);
}
return View(new NewCourseViewModel {
Course = course,
Lecturers = Context.Lecturers
.Select(l => new ViewLecturer { Id = l.Id, Name = l.Name })
});
}
public void Dispose()
{
if(lazyContext.IsValueCreated)
lazyContext.Value.Dispose();
}
}
Your first New method will give you the entry point for your Course creation page. The rest of the validation and actual adding will be done through the [HttpPost]overload. As for your View (that should be in the ~/Views/Course/New.cshtml):
#model NewCourseViewModel
// ... Then when you are ready to begin the form
#using(Html.BeginForm("New", "Course", FormMethod.Post))
{
// Your List of Lecturers
#Html.ListBoxFor(m => m.Course.LecturerIds,
new MultiSelectList(
Model.Lecturers,
"Id",
"Name",
m.Course.LecturerIds ?? new int[0]
))
// Your Other Model binding
}
When the submit button will be pressed, the action matched will be the New(NewCourse course). The names are important because of the way the HtmlHelpers generate their Ids. Because we are only included one property of the whole view model, it will match the parameter name course based on the view model's Course property. You will get a list of Ids for the Lecturers which you will be able to use to attach to the DbContext and add directly to the new Course model (Entity Framework will do the rest). In cases where there was a problem, we can get back the list of lecturers and re-use the same NewCourse in the view model.
Now this is example is very basic but it should give you a good starting point as to how you can structure your view model.
I've read many articles which they state that querying should not be placed in the Controller, but I can't seem to see where else I would place it.
My Current Code:
public class AddUserViewModel
{
public UserRoleType UserRoleType { get; set; }
public IEnumerable<SelectListItem> UserRoleTypes { get; set; }
}
public ActionResult AddUser()
{
AddUserViewModel model = new AddUserViewModel()
{
UserRoleTypes = db.UserRoleTypes.Select(userRoleType => new SelectListItem
{
Value = SqlFunctions.StringConvert((double)userRoleType.UserRoleTypeID).Trim(),
Text = userRoleType.UserRoleTypeName
})
};
return View(model);
}
The View:
<li>#Html.Label("User Role")#Html.DropDownListFor(x => Model.UserRoleType.UserRoleTypeID, Model.UserRoleTypes)</li>
How do I retain the View Model and Query and exclude the User Type that should not show up?
I think that you are doing it just fine.
Any way... all you can do to remove the querying logic from controller is having a ServiceLayer where you do the query and return the result.
The MVC pattern here is used correctly... what your are lacking is the other 2 layers (BusinessLayer and DataAccessLayer)... since ASP.NET MVC is the UI Layer.
UPDATE, due to comment:
Using var userroletypes = db.UserRoleTypes.Where(u=> u.UserRoleType != 1);
is OK, it will return a list of UserRoleType that satisfy the query.
Then, just create a new SelectList object using the userroletypes collection... and asign it to the corresponding viewmodel property. Then pass that ViewModel to the View.
BTW, I never used the db.XXXX.Select() method before, not really sure what it does... I always use Where clause.
SECOND UPDATE:
A DropDownList is loaded from a SelectList that is a collection of SelectItems.
So you need to convert the collection resulting of your query to a SelectList object.
var userroletypes = new SelectList(db.UserRoleTypes.Where(u=> u.UserRoleType != 1), "idRoleType", "Name");
then you create your ViewModel
var addUserVM = new AddUserViewModel();
addUserVM.UserRoleTypes = userroletypes;
and pass addUserVM to your view:
return View(addUserVM );
Note: I'm assuming your ViewModel has a property of type SelectList... but yours is public IEnumerable<SelectListItem> UserRoleTypes { get; set; } so you could change it or adapt my answer.
I don't see anything wrong with your code other than this db instance that I suppose is some concrete EF context that you have hardcoded in the controller making it impossible to unit test in isolation. Your controller action does exactly what a common GET controller action does:
query the DAL to fetch a domain model
map the domain model to a view model
pass the view model to the view
A further improvement would be to get rid of the UserRoleType domain model type from your view model making it a real view model:
public class AddUserViewModel
{
[DisplayName("User Role")]
public string UserRoleTypeId { get; set; }
public IEnumerable<SelectListItem> UserRoleTypes { get; set; }
}
and then:
public ActionResult AddUser()
{
var model = new AddUserViewModel()
{
UserRoleTypes = db.UserRoleTypes.Select(userRoleType => new SelectListItem
{
Value = SqlFunctions.StringConvert((double)userRoleType.UserRoleTypeID).Trim(),
Text = userRoleType.UserRoleTypeName
})
};
return View(model);
}
and in the view:
#model AddUserViewModel
<li>
#Html.LabelFor(x => x.UserRoleTypeId)
#Html.DropDownListFor(x => x.UserRoleTypeId, Model.UserRoleTypes)
</li>
I have a problem, I have the next controller
namespace RolesMVC3.Areas.Administrador.Controllers
{
[Authorize(Roles = "Adminr")]
public class HomeController : Controller
{
private BASEDATOSCJ_2Entities db = new BASEDATOSCJ_2Entities();
public ActionResult Index()
{
string username = User.Identity.Name;
MembershipUser user = Membership.GetUser(username);
Guid key = (Guid)Membership.GetUser().ProviderUserKey;
var Universities = (from u in db.UNIVERSITy
join s in db.CAMPUS_UNIVERSITy on u.IdUniversity equals s.IdUniversity
join c in db.CIUDAD_CAMPUS on s.IdCiudadSede equals c.IdCiudadSede
join co in db.OFFICE on s.Idoffice equals co.Idoffice
join uxc in db.USERxOFFICE on co.Idoffice equals uxc.Idoffice
where uxc.UserId == key
select new { u.Name, namecity = c.Nombre, s.Idoffice}).ToList();
return View(Universities);
}
With this controller I just want send to View u.Name, and s.Idoffice. How I do? (in fact do not know if this controllet is fine), I want to send fields belong to different tables. I want to send the query as a list and present at the View, ViewBag go with it?, How do I pass these data to the view and display with a foreach?.
I use razor
If you change the following line:
select new { u.Name, namecity = c.Nombre, s.Idoffice}
To
select new { Name = u.Name, Idoffice = s.Idoffice }
This only selects the two fields into a list. In your view you can do the following:
#model List<dynamic>
#foreach(dynamic d in Model) {
<p>#d.Name</p>
<p>#d.Idoffice</p>
}
Edit:
You might want to define a ViewModel to contain your data.
public class MyViewModel {
string Name {get;set;}
string Idoffice {get;set;}
}
Now you can change your select statement as follows:
select new MyViewModel { Name = u.Name, Idoffice = s.Idoffice }
And update your Razor file as such:
#model List<MyViewModel>
#foreach(MyViewModel d in Model) {
<p>#d.Name</p>
<p>#d.Idoffice</p>
}
I would use a view model. I have learnt not to expose my domain objects to the view, I rather map my domain object to the view model and return this view model to the view.
Separate you data access logic from your view logic. You can put that whole statement into a repository class and then you just call this method from the controller.
Here is a partial view model, you might have more properties if you need more data to be displayed:
public class UniversityViewModel
{
IEnumerable<University> Universities { get; set; }
}
University class:
public class University
{
public string Name { get; set; }
public string Idoffice { get; set; }
}
In my action method of my controller it would look something like this:
public ActionResult Index(int id)
{
UniversityViewModel viewModel = new UniversityViewModel
{
Universities = universityRepository.GetAll()
};
return View(viewModel);
}
And in my view I would have the following:
<table>
#foreach(University university in Model.Universities)
{
<tr>
<td>Name:</td>
<td>university.Name</td>
</tr>
}
</table>
This is just a basic display of data in the view, you can use 3rd party components to display your data with some features.