I would like to create a list with a string and an int value at the same time like follows:
#Html.ActionLink("Back to List", "IndexEvent", new { location = "location" })
and
#Html.ActionLink("Back to List", "IndexEvent", new { locationID = 1 })
It didn't work. I guess MVC controller didn't get the type difference of parameter. So, I had to make a new Action as "IndexEvenyByID" but it requires to have a new view. Since I wanted to keep it simple, is there any way to use same view with respect to different parameters?
Try adding two optional parameters to the IndexEvent action like this:
public ActionResult IndexEvent(string location = "", int? locationID = null)
This should not require a new view or view model. You should have two actions as you have described, but the code could be as follows:
Controller
public ActionResult GetEvents(string location){
var model = service.GetEventsByLocation(location);
return View("Events", model);
}
public ActionResult GetEventsById(int id){
var model = service.GetEventsById(id);
return View("Events", model);
}
Service
public MyViewModel GetEventsByLocation(string location){
//do stuff to populate a view model of type MyViewModel using a string
}
public MyViewModel GetEventsById(int id){
//do stuff to populate a view model of type MyViewModel using an id
}
Basically, if your View is going to use the same view model and the only thing that is changing is how you get that data, you can completely reuse the View.
If you really want to stick to a single action and multiple type, you could use a object parameter.
public ActionResult GetEvents(object location)
{
int locationID;
if(int.TryParse(location, out locationID))
var model = service.GetEventsByID(locationID);
else
var model = service.GetEventsByLocation(location as string);
return View("Events", model);
}
Something like that (Not completly right but it gives you an idea). This, however, wouldn't really be a "clean" way to do it IMO.
(Edit)
But the 2 actions method is still by far preferable (eg. What happens if we're able to parse a location name into a int?)
Related
I had a look at this:
ASP.NET MVC - How to pass an Array to the view?
and am struggeling with deploying my DateTime[] as a dropdownlist in the view, herewith my line but it is not correct:
<p style="color:Red"><%: Html.DropDownList("Choose a Sunday: ", (IEnumerable<SelectListItem>)ViewData["Sundays"], "--Select--")%>
</p>
In the controller i have:
[HttpGet]
public ActionResult MyAction()
{
DateTime[] allSundaysInMonth = GetDatesOfSundays(System.DateTime.Now);
ViewData["Sundays"] = allSundaysInMonth;
return View();
}
can someone help please?
thanks
Perhaps what you want to do is this:
[HttpGet]
public ActionResult MyAction()
{
IEnumerable<SelectListItem> allSundaysInMonth = GetDatesOfSundays(System.DateTime.Now).Select(day => new SelectListItem() { Text = day.ToString(), Value = day.ToString() });
ViewData["Sundays"] = allSundaysInMonth;
return View();
}
That is depending on your display format. What I'm trying to point out is that DateTime and SelectListItem may not have an implicit cast, so you get a type mismatch at runtime.
If you ever think (realize) dynamic magic variables like ViewData/ ViewBag is an evil and thinking about using strongly typed ViewModel for your view, you can do like this
create a ViewModel specific for your View (UI).
public class EventViewModel
{
public IEnumerable<SelectListItem> AllSundays { set;get;}
public string SelectedSunday { set;get;}
}
In your action method, set the value and send it to the view
public ActionResult MyAction()
{
var vm=new EventViewModel();
vm.AllSundays = GetDatesOfSundays(System.DateTime.Now).
Select(d => new SelectListItem() {
Text = d.ToString(), Value = d.ToString() }).ToList();
return View(vm);
}
Change your view like this
#model EventViewModel
#Html.DropDownListFor(x => x.SelectedSunday, Model.AllSundays, "--Select One--")
ViewBag/ViewData is bad. It makes your code ugly. Stick to strongly typed.
You cast the list to IEnumerable<SelectListItem>, but its a list of DateTimes. Casting the list to IEnumerable<DateTime> should fix it.
Or you might want to put list of SelectListItem on the ViewData instead!
Actually I'm very new to ASP.NET MVC and I need your help.
Here I have some Create Method that takes an argument from the URL to use it as id:
in 'vote' controller :
public ActionResult Create(int id)
{
Meeting meeting = db.Meetings.Find(id); // get the object
ViewBag.meetingID = meeting.meetingID; // get its id and assign it to a ViewBag
return View();
}
and I would like to do something like :
vote.meetingID = #ViewBag.meetingID
in the model so that is directly assgin this property without excplicitely typing it from the HTML view (I mean #Html.EditorFor(model=>meetingID) )
The question is not that clear, but try this.
You could pass the entire model to the view.
Controller:
public ActionResult Create(int id)
{
Meeting meeting = db.Meetings.Find(id); // get the object
ViewData["myMeeting"] = meeting;
return View();
}
To use in the view you can declare it as a variable at the top of the view:
Declare:
#
{
var meetingData = ViewData["myMeeting"] as Meeting;
}
Usage:
<div>
#meetingData.meetingID
</div>
I have the following action method:-
[HttpPost]
public ActionResult Edit(int id, FormCollection collection)
{
Assessment a = elearningrepository.GetAssessment(id);
try
{
if (TryUpdateModel(a))
{
elearningrepository.Save();
return RedirectToAction("Details", new { id = a.AssessmentID });
}
}
//code does here
but I can not write something like if (TryUpdateModel(a, "Assessment", new string { "Date"})) to specify that I only allow the Date property to be updated.
So how I can add a bind list to the above if (TryUpdateModel(a))?
BR
but I can not write something like
if (TryUpdateModel(a, "Assessment", new string { "Date"}))
That's because you should write it like this, since the allowed properties argument represents a string array:
if (TryUpdateModel(a, "Assessment", new[] { "Date" }))
{
}
I would suggest that you stay away from using TryUpdateModel in general.
The repository usually has an update method that sets the entityState to modified before Save() is called, i cannot see that in the code above.
If your goal is to display a record and only allow date to be saved, then create a view for that model, and render fields with:
This sets the model for the view:
#model YourNamespace.Models.Assessment
#Html.DisplayFor(model=>model.propertyToDisplay)
on the items you only want to display, and a
#Html.EditorFor(model=>model.Date)
In your action controller you take the properties you want to bind to as input parameters:
Edited
class Assessment
{
public int Id { get; set; }
public DateTime Date { get; set; }
//Other properties
}
public ActionResult Edit(int Id, DateTime Date)
{
var assessment = elearningrepository.GetAssessment(id);
assessment.Date = Date;
elearningrepository.UpdateAssessment(assessment);
elearningrepository.Save();
//Redirect to action Detail
}
In this case the model binder should just bind to Id, and Date, so even if someone tries to post other values (editing the html form is easy), parameters in ActionResult should be named exactly as in the Model and use that to fetch and update the entity.
You should validate that the user actually can access and edit that id, or as an alternative use MVC Security Codeplex to check that the Id parameter has not been tampered with. it is really easy and convenient to use, but that is another discussion.
As an alternative you can use an attribute like this, described in this blog, but I don't use that myself:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create( [Bind(Include="Id,Date")] Assessment assessment)
i tried this an it works fine
string[] allowedProperties = new[] { "Date" };
try
{
if (TryUpdateModel(a, allowedProperties))
{
If I were to pass additional data (other than the model) into my view, like say a list of files from a specific folder, whats the best way to do that?
I was thinking something like making a method and return a list into ViewData:
public List<string> GetFiles(int id, string cat)
{
var files = new List<string>();
var folder = "~/App_Data/uploads/" + cat + "/" + id.ToString();
foreach (var file in Directory.GetFiles(folder))
{
files.Add(file);
}
return files;
}
The controller:
ViewData["files"] = db.GetFiles(id, "random");
The view:
#foreach (var item in ViewData["files"]){ //markup }
First, ive heard that viewdata and viewbag shouldnt be used. Second, this code doesnt work. Something with Viewdata object is not enumerable. Should I make a model class for these files. If so, how? 2 models in one view? Im a bit confused how to do this proberly.
If I were to pass additional data (other than the model) into my view,
like say a list of files from a specific folder, whats the best way to
do that?
Write a view model which will contain all the properties your view needs and have your controller action pass this view model to the view. So:
public class MyViewModel
{
public List<string> Files { get; set; }
public string Foo { get; set; }
... some other properties that your view might need
}
then the controller:
public ActionResult Index(int id)
{
var model = new MyViewModel
{
Files = db.GetFiles(id, "random"),
Foo = "bar"
};
return View(model);
}
and finally in your strongly typed view:
#model MyViewModel
#foreach (var file in Model.Files)
{
<div>#file</div>
}
<div>#Html.DisplayFor(x => x.Foo)</div>
Trying to get my ducks in a row with MVC3 + Razor!
I finally understand the concept of a 'View-Model' to wrap my entity classes and tailor them to a View.
Now I'm assembling a page with partial views representing different elements necessary to the page (such as drop down lists, forms, etc.) each of these will be represented by a 'View-Model' that maps to an entity class and back to my database.
First I am trying to create a partial view representing a component that is a drop-down list of elements in the database, that when selected will render another partial view, etc.
I just can't put together why I can't generate this drop-down list, and once I do how the main 'controller' maps all this together?
In short I'm curious - does each partial view need a controller even if it's based on a strongly typed model?
Breaking it down:
My Entity Model-View Wrapper (getting all the elements available from the database
*Updated* - to a working example now, note I don't think I was asking the right question before, but this will give you an idea of what I was trying to accomplish! Next step is to move all these operations 'off' the controller (and populate them in the models default constructor, for ease of use later).
CharactersListViewModel.cs
Going to move avoid the 'View Model' for now until I get a little more comfortable
Creating a partial view that displays a drop down list with the Characters' ID as a value, and name as the text, create strongly-typed view, partial view
controller for main-page in section:
HistoryController.cs
public class HistoryController : Controller
{
public ActionResult Index()
{
var list = new List<SelectListItem>();
using (var _database = new fff_newEntities())
{
foreach(Character c in (from c in _database.Characters select c)){
list.Add(new SelectListItem(){Text = c.CharacterName, Value = c.Id.ToString()});
}
}
ViewBag.Clients = list;
}
}
//
// GET: /History/Details/5
public ActionResult Details(int id)
{
return View();
}
//
// GET: /History/Create
public ActionResult Create()
{
return View();
}
//
// POST: /History/Create
[HttpPost]
public ActionResult Create(FormCollection collection)
{
try
{
// TODO: Add insert logic here
return RedirectToAction("Index");
}
catch
{
return View();
}
}
//
// GET: /History/Edit/5
public ActionResult Edit(int id)
{
return View();
}
//
// POST: /History/Edit/5
[HttpPost]
public ActionResult Edit(int id, FormCollection collection)
{
try
{
// TODO: Add update logic here
return RedirectToAction("Index");
}
catch
{
return View();
}
}
public ActionResult Delete(int id)
{
return View();
}
//
// POST: /History/Delete/5
[HttpPost]
public ActionResult Delete(int id, FormCollection collection)
{
try
{
// TODO: Add delete logic here
return RedirectToAction("Index");
}
catch
{
return View();
}
}
The index to display the whole page including the partial component (my drop down list)
index.cshtml:
#{
ViewBag.Title = "Index";
}
<h2>Index</h2>
#Html.DropDownListFor(x => x.CurrentCharacterId, (IEnumerable<SelectListItem>)ViewBag.Clients);
On the last line here, #Html.Action(...) where do I actually create the drop-down list?
Sorry if this seems trivial but I can't wrap my head around it and I really want to learn MVC3 + Razor correctly!
A partial view is meant to abstract out some HTML/View Logic so that it can be re-used either in multiple places or for repeating (looping).
Though you can have an action that maps to the partial and if the partial in question does some explicit data access this might be the way to go but if you're just passing down all the data it needs from the controller itself then - no, you don't need a Controller/Action for it.
Since you're doing some explicit data access I would probably make an action for it...
[ChildActionOnly]
public ActionResult Characters()
{
using (var _database = new entities())
{
CharactersViewModel viewModel = new CharactersViewModel();
viewModel.Characters = _database.Characters.ToDictionary(c => c.Id, c => c.CharacterName);
return PartialView(viewModel);
}
}
In your view...
#Html.Action("Characters")
Of course there's nothing wrong with the way you're doing it but I find having it map to an action can make things easier down the road if you ever wanted to retrieve the HTML from this rendered partial view via an ajax request or something of the sort.
Notes:
Try to wrap your entity context object in a using so it can dispose of the connection.
You can use ToDictionary to select your dictionary directly from the query scope.