I have following scenario:
My Index page, uses a layout which has a partial View ebbeded in it. the partial view contains a search text box.
For a particular scenario, i need to set the text of the search box with my viewdata[] for index page.
is it somehow poosiblein mvc3, asp.net 2010 to set the value of textbox in partial view from the viewpage?
You could make your partial strongly typed to some view model:
#model SearchViewModel
#using (Html.BeginForm())
{
#Html.LabelFor(x => x.Keywords)
#Html.EditorFor(x => x.Keywords)
<button type="submit">OK</button>
}
and then when inserting the partial you could pass this view model:
#Html.Partial("_Search", new SearchViewModel { Keywords = "some initial value" })
or even better the view model of your main view will already have a property of type SearchViewModel and you will be able to call the partial like this:
#Html.Partial("_Search", Model.Search)
Now obviously in your Index action you no longer need to use any ViewData, but you could directly work with your strongly typed view model:
public ActionResult Index()
{
var model = new MyViewModel
{
Search = new SearchViewModel
{
Keywords = "some initial value"
}
};
return View(model);
}
You can always make the partial view strongly typed (even if the model is just a string) and pass the value you need.
public class MyModel
{
public int ValueForView {get;set;}
public string TextBoxValue {get;set;}
}
-Index.cshtml
#model MyModel
#{ Html.RenderPartial("PartialView", Model.TextBoxValue); }
-PartialView.cshtml
#model string
#Html.TextBoxFor(m => Model)
As I understand your issue, the partial view is in your layout and you need to get data into it.
In this case layouts are processed last but passing data to it your options are somewhat limited. You can use an ActinFilter or ViewData.
ViewData is the easiest, and also the messiest so I don't recommend it.
ActionFilters would work, but you could just process your partial by simply calling in your layout:
#Html.RenderAction("PartialViewAction", "PartialViewController")
Unless I'm missing something I don't believe the other answers addressed that this is in a layout, hence a different issue.
Related
I have a layout page which has a partial view. The partial view needs to loop through a property on the view model to show a list of categories. When a category is displayed I need to show a list of documents in that category. /Home/Index works, but when I try to view /Documents/Category/{id}, I get an error:
Additional information: The model item passed into the dictionary is of type 'System.Collections.Generic.List`1[ViewModels.DocumentViewModel]', but this dictionary requires a model item of type 'ViewModels.HomeViewModel'.
_Layout.cshtml
...
<body>
#Html.Partial("_CategoryViewModel")
<div class="content">
#RenderBody()
</div>
HomeViewModel.cs
public class HomeViewModel {
...
public ICollection<DocumentCategory> Categories { get; set; }
public ICollection<Documents> Documents { get; set; }
...
}
_CategoryViewModel.cshtml (this should show a list of all categories)
#model ViewModels.HomeViewModel
...
#foreach (DocumentCategory item in Model.Categories)
{
<li>
<a href="#Url.Action("Category", "Documents", new { #id = #item.CategoryId })" title="View documents in the #item.Name category">
<span class="fa fa-files-o"></span> #item.Name
</a>
</li>
}
DocumentsController.cs
public ActionResult Category(int id)
{
var thisCategory = _ctx.Categories.Get(c => c.CategoryId == id).FirstOrDefault();
IEnumerable<DocumentViewModel> docs = null;
if(thisCategory == null)
{
TempData.Add("errorMessage", "Invalid category");
} else {
docs = thisCategory.Documents.ToList();
}
return View("Category", docs);
}
What's happening kind of makes sense - the PartialView on the Layout page needs to enumerate over a collection which isn't present in the ViewModel I'm using. I have no idea how to achieve this - the only way would seem to be to add a Categories property to every ViewModel in my site.
By default, using #Html.Partial() will pass the current model to the partial view, and because your Category.cshtml view uses #model List<DocumentViewModel>, then List<DocumentViewModel> is passed to a partial that expects HomeViewModel.
If you want to render a partial view for HomeViewModel on every page, then use #Html.Action() to call a ChildActionOnly method that returns the partial
[ChildActionOnly]
public ActionResult Categories
{
var model = new HomeViewModel()
{
.... // initialize properties
}
return PartialView("_CategoryViewModel", model)
}
and in the layout
#Html.Action("Categories", yourControllerName)
// or
#{ Html.RenderAction("Categories", yourControllerName); }
As I see it you have a few different alternatives.
1. Use Html.Action and create an Action that returns your view.
#Html.Action("Index", "Category") // Or your controller name.
I believe that there are some performance draw-backs with this approach because the whole MVC lifecycle will run again in order to render the result of the action. But then you can render the result of an action without having the correct model in the view that called it.
One may also argue that this breaks the MVC pattern, but it might be worth it.
2. Use a generic model (or an interface) in your _Layout.cshtml, and let your viewmodels inherit from that model.
In your _Layout.cshtml:
#model IBaseViewModel
And let all your viewmodels implement this interface.
public interface IBaseViewModel
{
ICollection<DocumentCategory> Categories { get; set; }
}
public interface IBaseViewModel<T> : IBaseViewModel
{
T ViewModel {get; set;}
}
Since you're placing #Html.Partial("_CategoryViewModel") in _Layout.cshtml I assume that it should be visible in all pages, so I think it's logical that all the controllers that are using _Layout.cshtml make sure that it gets the information it needs, and thus adding Categories to the model.
I use this approach all the time for stuff like breadcrumbs and menu-information (stuff that is used in all pages). Then I have a basecontroller that makes sure that Categories is populated with the correct info.
I am Newer in ASP.NET MVC. I can not Clearly Understand the difference among
Strongly Typed view vs Normal View vs Partial View vs Dynamic-type View
in Asp.NET MVC. Anyone describe me about this terms.
Thanks in advance!!!
Strongly Typed view
A view which is bound to a view model. For example if you have the following view model:
public class MyViewModel
{
public string SomeProperty { get; set; }
}
that is passed to the view by the controller action:
public ActionResult Index()
{
var model = new MyViewModel();
model.SomeProperty = "some property value";
return View(model);
}
the strongly typed view will have the #model directive at the top pointing to this view model:
#model MyViewModel
...
<div>#Model.SomeProperty</div>
Partial View
The difference between a view and a partial view is that a partial view only contains some small HTML fragments that can be reused in multiple parts of a normal view. For example you could define the following partial view:
#model AddressViewModel
<div>Street: #Model.Street</div>
<div>Country: #Model.Country</div>
and then render this partial view at multiple places in your main view to avoid repetition of the same code over and over:
#model MainViewModel
...
<h3>Personal address</h3>
<div>#Html.Partial("_Address.cshtml", Model.PersonalAddress)</div>
...
<h3>Business address</h3>
<div>#Html.Partial("_Address.cshtml", Model.BusinessAddress)</div>
Dynamic-type View
A view which doesn't have a model or one that uses weakly typed structures such as ViewBag. For example you could have a controller action which sets some property in the ViewBag:
public ActionResult Index()
{
ViewBag["SomeProperty"] = "some property value";
return View();
}
and the corresponding view you could access this property by using the same key in the ViewBag:
<div>#ViewBag["SomeProperty"]</div>
I've been reading too many tutorials already and none of it explain what this means in an action result
return View(model);
Why can't we simple return view?
Why do we put a model parameter in our action result's return view()?
Also, anyone can give an example for a situation where I have to use return view(model)?
Because your view uses the model to build its content.
If you had a model like this:
public class Order
{
public decimal Total { get; set; }
}
And your controller:
public ActionResult GetOrderInformation(int orderID)
{
var order = LoadOrder(orderID);
return View(order);
}
With this view:
#model Order
<html>
<head> </head>
<body>
Your order costs #Model.Total
</body>
</html>
You can see how the view is completely independent from the controller, or how the information is retrieved - which is the whole idea behind MVC. The view only knows about the model, and how to display the model - nothing else.
The controller knows who to ask for the data, but not how to display it
You don't need to.
If the view you are rendering is static with no info needed from the controller then you can just end your Action with a return View();
public ActionResult SomeAction()
{
...
return View();
}
Then in your .cshtml file don't declare any #model directive and it'll be fine.
You can return simply view, but when you pass the model into view your can use it as you viewbag, and by that bind view elements with the model data.
You can simply use
return View();
but if you need to bind data then you have to pass like
return View(model);
for an example
Model Class
public class BookViewModel
{
public Guid Id { get; set; }
public string Name { get; set; }
}
Controller Method
public ActionResult Index()
{
return View();
}
public ActionResult Create()
{
return View(new BookViewModel());
}
View
#using (Html.BeginForm())
{
#Html.HiddenFor(m => m.Id)
<div class="editor-label">
#Html.LabelFor(m => m.Name)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.Name)
#Html.ValidationMessageFor(m => m.Name)
</div>
}
You don't need to pass objects to an action result, although if you don't you can't access the model.
i.e. It is common to do this on static pages such as About screens:
public ActionResult About() {return View();}
Also, it is possible to pass other objects instead of the full model.
See post: Must ASP.NET MVC Controller Methods Return ActionResult?
In Asp.net MVC, View(chtml) is for redering UI;
if your View is simple or static, you can construct your html content in the View without external data.
If you need data (from Db, web service, etc), your View must be able to query the data source.
There are several ways to pass data to view; via the View(Model) statement, via viewbag, etc.
we can also pass service layer object so view can query the datasource by itself.
Why do we need to pass Model to View again? Once in View (cshtml) you cannot access Controller -> you can pass ready to read data or service layer object inside your Model
You can just return a view:
View()
In that view, you won't have a #model you can take data of. You can still pass ViewBag or ViewData to send some dynamic data to the view.
Is it possible to have a View without a model?
YES
Some cases:
Semi static page: You don't need a model because almost everything that will be displayed in the page is static.
Container page: It can contain a lot of partials views, javascript calls or whatever you can imagine to retrieve data dinamically.
Many other cases in which the existence of a Model doesn't correspond to a business logic (or a good practice logic)
Just remember that patrons are there to guide us, not to force us to do things just one way. Check what's best for your application, change the bits that you don't like. Try to take the best of the framework, but remember it is there to help you.
I'm using VS2012 RC with MVC4, bot for all intents and purposes let's pretend it's MVC3. I would like to know what the standard best practice(s) is on how to handle PartialViews with a form that uses a different model than the parent View.
For example, here is a view that displays a table of all the available Roles and also has a form that allows the user to add more roles.
Main View - Roles.cshtml:
#model IEnumerable<RobotDog.Models.RoleModel>
<table>
#foreach(var role in Model) {
<tr>
<td class="roleRow">#role.Role</td>
</tr>
}
</table>
<div class="modal hide">
#Html.Partial("_AddRolePartial")
</div>
_AddRolePartial.cshtml
#model RobotDog.Models.RoleModel
#using(Html.BeginForm("AddRole","Admin", FormMethod.Post)) {
#Html.TextBoxFor(x => x.Role, new { #class = "input-xlarge", #placeholder = "Role"})
<input type="submit" value="Submit" class="btn btn-primary btn-large"/>
}
Model:
public class RoleModel {
[Required]
[DataType(DataType.Text)]
[Display(Name = "Role")]
public string Role { get; set; }
}
Controller for View:
public ActionResult Roles() {
var model = from r in System.Web.Security.Roles.GetAllRoles()
select new RoleModel {Role = r};
return View(model);
}
Controller for PartialView:
[HttpPost]
public ActionResult AddRole(RoleModel model) {
try {
System.Web.Security.Roles.CreateRole(model.Role);
RedirectToAction("Roles");
} catch(Exception) {
ModelState.AddModelError("", "Role creation unsuccessful.");
}
return ????; // not sure how to pass ModelState back to partialView
}
I thought about creating a ViewModel that held RoleModel and IEnumerable<RoleModel> but it seems like there would be a more stream lined way to accomplish what I wanted without having to create a ViewModel everytime I wanted to use this PartialView.
I think you are asking how to pass a RoleModel to the add RoleModel modal popup. Since you are creating a new Role, I am assuming you are needing an empty model. You can either pass it in like below:
<div class="modal hide">
#Html.Partial("_AddRolePartial", new RoleModel())
</div>
Or just do a #Html.RenderAction("AddRole") with the supporing GET method of the controller to support populating the item.
public ActionResult AddRole() {
var model = new RoleModel();
//populate with any items needed for the Add Role Model View
return View(model);
}
I personally don't like using Partial views with forms, because Partial Views do not render submodels correctly (ie, they don't take into account the hierarchy of the model).
This is why Display and EditorTemplates exist. They work well for rendering specific data types.
However, in your case, since your view doesn't have any forms of its own, and the end result is just a single item of the collection of your parent model, then a Partial View is actually a better approach simply because you CAN pass a different model to it than the views uses.
As others have pointed out, you can easily pass an empty model to the partial as the second parameter. I don't like newing up new objects in the view, but it doesn't look like there's a lot of choice there, as the alternatives would be pretty messy.
How about the form post is changed to an ajax form post with a target update partial id being the div which you will add to the parent view (effectively surrounding Roles.cshtml).
Add a new action public ActionResult _Roles() which will return PartialView("Roles", model)
Next, in the Post Action, Return RedirectToAction(...Roles Partial Action ...) at the end and remove RedirectToAction("Roles") in the try.
I have a view model as such:
public class MyViewModel
{
public MyObject myObject{ get; set; }
public List<MyList> myList{ get; set; }
}
I have a view with a form strongly typed to MyViewModel
This view allows you to enter values for the properties of MyObject, as well as create a list of MyList objects. The List part works fine although I thought that would be the more difficult of the two.
Assuming MyObject has a property Description I create a textbox to enter the value as such:
#Html.EditorFor(x => x.myObject.Description);
The text box renders with an id of MyObject_Description...The problem is when I post this to my controller action, MyObject does not get bound at all(althought the list items do as they recieve the appropriate IDs of "MyViewModel_MyList[guid].myListValue")
What am I doing wrong here??
EDIT: more info
The first line of the view is:
#model MyApp.ViewModels.MyViewModel
And the Action method:
[HttpPost]
public ActionResult Create(MyViewModel myViewModel)
{
}
I am passing a new MyViewModel into the partial view to begin...
public ActionResult Create()
{
MyViewModel model = new MyViewModel();
return PartialView(model);
}
EDIT 2
Ok When I render my partial view that contains the forms I call :
#{Html.RenderAction("Create", "MyController");}
this is called from within a View of type #model IEnumerable<MyApp.Models.MyObject>
(this view displays a list of currently existing MyOjects, and at the bottom the partial is rendered to allow the user to add another MyObject to the DB)
If you are not already doing so, try creating a editor template (e.g., Views->Shared->EditorTemplates) called MyObject.cshtml. Move your partial view content to this view and then call
#Html.Editor("myObject").
from your parent partial view.
Change your ViewModel to have the Description directly
public class MyViewModel
{
public string Description { get; set; }
public List<MyList> myList{ get; set; }
}
then bind accordingly
#Html.EditorFor(x => x.Description);
I would expect the top line of your view to look something like this:
<%# Page Title="" Language="C#" Inherits="System.Web.Mvc.ViewPage<MyViewModel>" %>
This tells the view that the model it is supplied is of type MyViewModel (a la <T> style).
I don't think the out of the box model binding knows how to bind to complex objects. You're probably going to have to write up some sort of custom model binder.
I'm afraid it's not something I've done since MVC1 so I'm a bit hesitant to give you any sample code because the mechanism may well have changed completely since then. A quick google did turn up this article http://www.learnxpress.com/asp-net-mvc-hosting-6-tips-for-asp-net-mvc-model-binding-2.html and this article http://bradwilson.typepad.com/blog/2010/10/service-location-pt9-model-binders.html.
Edit: I've just seen this answer which might help Retrieving data from view, should I use model binder?