I have created a partial view which returns a list of items where the ItemsId matches the one passed to it.
//
// GET: /ItemOptions/Item/5
public ActionResult Item(int id = 0)
{
var itemoptions = db.ItemOptions.Where(o => o.ItemsId == id);
return PartialView(itemoptions.ToList());
}
I am trying to display this on the details page of the parent item using the following code:
#Html.Partial("../ItemOptions/Item", Model.ItemsId)
If I visit {URL}/ItemOptions/Item/1 it returns the table I am expecting to see. But if I navigate to the parent item where I am trying to include the partial view I get the following error:
The model item passed into the dictionary is of type 'System.Int32', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable`1[shopServer.Models.ItemOptions]'.
I have read other posts but can't work out where I am going wrong. I also read that I may need to use #Html.Action instead of Partial views, but I am unsure which is appropriate in which situation.
The method Html.Partial is directly rendering the partial view (without executing the controller logic), using the object passed in the second parameter as the model instance. So as the error says, the code line #Html.Partial("../ItemOptions/Item", Model.ItemsId) is trying to render your partial view using an integer (Model.ItemsId) as the model, but your partial view expects IEnumerable[shopServer.Models.ItemOptions].
You have 2 options for resolving your issue, depending if the data for the partial view is already loaded in the model for the parent view or not.
If in the parent view the model already contains the collection of item options, then you can just pass them to the partial view using the Html.Partial method. So assuming you could have a property like ItemOptions in the model of your parent view, then you could render the partial as:
#Html.Partial("../ItemOptions/Item", Model.ItemOptions)
If that is not possible, and the data you need for the partial view is unknown to the parent model, then you need to execute the controller logic (so you can populate the model for the partial view retrieving the extra data from the databaes.) In that case what you need is a child action, achived using the method Html.Action. You will need to pass the controller name, action name and parameters for the action method as in:
#Html.Action("Item", "ItemOptions", new {id = Model.ItemsId})
With the second option, the logic in the controller action method is executed, retrieving the ItemOptions from the database, rendering the partial view and including the resulting html into your main view.
You can find a quick rule of thumb for Html.Partial and Html.Action usage `here.
Hope that helps!
Related
I think i know some of the basics of MVC but there's one thing which I don't understand yet.
In the view Create which is generated automatically when you set up your project, how is data sent to the controller? I'm used to seeing ActionLinks with parameters but here there's no actionLink so I can't understand how data travel from the view to the controller.
Could you explain it to me please?
as you know, in your view, the very first line (usually) tells the view, about the Model being used within this view. like:
#model Models.CarViewModel
lets suppose, you have a form on this view, and it is posted to some action called Edit. Then you must have your Edit action, expecting the parameter of type you used as model in your view. like:
[HttpPost]
public ActionResult(CarViewModel model)
{
//logic
}
This convention is known as Strongly Typed View. Suppose Then you have some textbox for a property Name of your model as:
#Html.TextBoxFor(x => x.Name)
when the form is posted to Edit Action, the variable model in parameter of Edit action will be holding the respective values. i.e, model.Name
I have a partial view which I am using in 2 parent pages. I want to detect from which parent page I am calling that partial view.
Does there is any event to find this?
The PartialExtensions.Partial helper has an extension that takes a ViewDataDictionary as well the partial name, see http://msdn.microsoft.com/en-us/library/ee407439(v=vs.100).aspx. You can use this to pass in whatever you want as key:value pairs, e.g. ParentViewName as a string. So from the parent views you can do
#Html.Partial("PartialName", new ViewDataDictionary { {"ParentViewName", "ParentView1"} })
Then in your partial you can access that view data via:
#ViewData["ParentViewName"]
I've seen how to use Partial Views from within a View and I understand how a model is passed from the View to a Partial View. What I don't grasp is how to include a Partial View inside of _Layout.cshtml so that I can pass it to the Partial View - or, how the Partial View itself can call a Controller Action to create a Model for use.
Specifically, I want to include a Partial View within _Layout.cshtml to display in the header of every page. The Partial View will display a custom setting in the User Profile. I can't think of any way to obtain the Model without making a Controller Action call - but how is this done in/for a Partial View from within _Layout.cshtml?
Is my only option of accessing a Controller Action to build my Partial View's required Model to use a jQuery call? Or is there another way?
The answer is by calling #Html.Action().
It sounds like you're on the right track.
The key is to try to not pass multiple models around, make models complicated, or use the ViewBag needlessly.
Instead, any time you want information on every page, call an action from your _Layout.
For example, you might have a controller called PartialsController or SharedController.
public class PartialsController : Controller
{
[ChildActionOnly]
public ActionResult UserProfilePartial()
{
UserProfileModel model = new UserProfileModel();
return PartialView("_UserProfile", model);
}
}
The ChildActionOnlyAttribute means that users cannot access the action directly. Only your code can call the action. You can also apply the attribute to the controller so that it affects all actions automatically.
Now call the action from your view (_Layout).
#Html.Action("UserProfilePartial", "Partials")
I am trying to figure out how to render a single model from a view that is using an IEnumerable of that model. I can't seem to figure out how to send it using the razor
Right now I am getting the error:
MyApp.Models.DefectsVM' is a 'type' but is being used like a 'variable'
On this line in my main view(Under DefectsVM model I am trying to pass in):
#{Html.RenderPartial("~/Views/Defect/defectsPartial.cshtml", DefectsVM);}
My partial view has this in it to use a model:
#model MyApp.Models.DefectsVM
And my main view is using this:
#model IEnumerable<MyApp.Models.DefectsVM>
I am not sure what all other information is needed, let me know if I need to edit. But thank you for reading and taking your time to help.
You need to refer to your model with Model. But in your case, Model will return an IEnumerable<MyApp.Models.DefectsVM>, so you will need to iterate over that, and then render your partial.
Something like:
foreach(var defectsVM in Model)
{
#{Html.RenderPartial("~/Views/Defect/defectsPartial.cshtml", defectsVM);}
}
Regardless of whether the IEnumerable contains one or more than one, it should work.
I have a view and a partial view. Within the controller action methods, I have a using statement which establishes some back-end threading context, including providing access to a model object for display in the view.
The problem that I'm having is that while the context and the associated model object are available for the main view, they are disposed before the partial view is rendered. This seems to be the case regardless of whether I pass the model object from the view to the partial view, or reference it some other way.
The controller view action method:
public ActionResult Index()
{
using (var context = GetContext()) {
return View(Context.MyModelObject);
}
}
The controller partial view action method:
[ChildActionOnly]
public ActionResult MyPartialView(ModelObject modelObject)
{
return PartialView(modelObject);
}
The view:
#model ModelObject
#Model.Name
#{Html.RenderAction("MyPartialView", "MyController", new {modelObject = #Model});}
The partial view:
#model ModelObject
#foreach(var item in Model.Items) {
<div>#item.Name</div>
}
If I comment out the RenderAction line of the view, the view displays just fine, accessing the property of the model because the context has not yet been disposed at the end of the using.
However, if I leave it in with the intent of the partial view being rendered, the context has been disposed of, leaving my model object no longer accessible. I would think the using in the main view controller method would not be finished until the view and all its partial views are rendered, but that doesn't seem to be the case. Are partial views deferred to be rendered at some other time? Is there a way around this?
Right now I have a solution which will involve writing a lot of extra code: making a "view model" object which has only the bits of the model object that I need for display in this specific view while it hasn't yet been disposed, then having the view and partial views use that. However, this will be very undesirable as it will result in a lot of duplication between the model and the view models, which will be a subset. It would be very convenient to use the model directly in the view.
The other possibility is that we could alter our backend to dispose of things differently such that they are still available for the partial view whenever it gets around to rendering, but this also seems like a hack.
In summary, is there a better way to do this in the view/controller? Am I making some erroneous assumptions?
MVC was designed with Unit testability in mind. As such, it doesn't render the view when you call View(), it just creates a structure which gets rendered after it returns from the controller.
This design makes it easier to unit test controllers because it doesn't actually require an active web server connection to execute the controller logic.
But, this also means that since you have a using statement in your controller, the view is not actually rendered until after you have returned from the function, and thus the using has called delete on the data context. Thus, your queries will not execute.
You get around this by executing the query within the controller, such as calling .ToList() on the object. You still have to be careful not to execute any lazy operations after returning.
However, a better approach is to not pass your data objects directly to the view, but instead use a view model which you populate from the returned data objects.
Try this
#Html.Partial("MyPartialView", Model)