Am using strongly typed view to show a complex object in a data entry/edit form. for eg: Model.UserInformation.Name, Model.LivingPlace.FacilitiesSelectList, Model.Education.DegreesList... etc. These information are shown in multiselect listbox, grids.. etc. User can change the information in the edit screen. Is there any way to post the Model object with user changes to controller on sumbit button click. Please suggest.
Regards,
SHAN
The same object instance that has been passed to the view: No. ASP.NET MVC uses a default Model binder to instantiate new action parameters from request values. So for example if you had the following action method:
public ActionMethod DoWork(User model)
{
return View();
}
public class Address
{
public string Street { get; set; }
}
public class User
{
public string FirstName { get; set; }
public string LastName { get; set; }
public Address[] Addresses { get; set; }
}
the binder will look in the request and try to bind model values. You could to the following in your View:
<%= Html.TextBox("FirstName") %>
<%= Html.TextBox("LastName") %>
<%= Html.TextBox("Addresses[0].Street") %>
<%= Html.TextBox("Addresses[1].Street") %>
This will automatically populate the values of your model in the controller action.
To avoid mass assignment of properties that shouldn't be bound from request values it is always a good idea to use the BindAttribute and set Exclude or Include properties.
Use <input type="text" name="UserInformation.Name"><input> to bind to subobjects.
Related
I have a ViewModel that has a complex object as one of its members. The complex object has 4 properties (all strings). I'm trying to create a re-usable partial view where I can pass in the complex object and have it generate the html with html helpers for its properties. That's all working great. However, when I submit the form, the model binder isn't mapping the values back to the ViewModel's member so I don't get anything back on the server side. How can I read the values a user types into the html helpers for the complex object.
ViewModel
public class MyViewModel
{
public string SomeProperty { get; set; }
public MyComplexModel ComplexModel { get; set; }
}
MyComplexModel
public class MyComplexModel
{
public int id { get; set; }
public string Name { get; set; }
public string Address { get; set; }
....
}
Controller
public class MyController : Controller
{
public ActionResult Index()
{
MyViewModel model = new MyViewModel();
model.ComplexModel = new MyComplexModel();
model.ComplexModel.id = 15;
return View(model);
}
[HttpPost]
public ActionResult Index(MyViewModel model)
{
// model here never has my nested model populated in the partial view
return View(model);
}
}
View
#using(Html.BeginForm("Index", "MyController", FormMethod.Post))
{
....
#Html.Partial("MyPartialView", Model.ComplexModel)
}
Partial View
#model my.path.to.namespace.MyComplexModel
#Html.TextBoxFor(m => m.Name)
...
how can I bind this data on form submission so that the parent model contains the data entered on the web form from the partial view?
thanks
EDIT: I've figured out that I need to prepend "ComplexModel." to all of my control's names in the partial view (textboxes) so that it maps to the nested object, but I can't pass the ViewModel type to the partial view to get that extra layer because it needs to be generic to accept several ViewModel types. I could just rewrite the name attribute with javascript, but that seems overly ghetto to me. How else can I do this?
EDIT 2: I can statically set the name attribute with new { Name="ComplexModel.Name" } so I think I'm in business unless someone has a better method?
You can pass the prefix to the partial using
#Html.Partial("MyPartialView", Model.ComplexModel,
new ViewDataDictionary { TemplateInfo = new TemplateInfo { HtmlFieldPrefix = "ComplexModel" }})
which will perpend the prefix to you controls name attribute so that <input name="Name" ../> will become <input name="ComplexModel.Name" ../> and correctly bind to typeof MyViewModel on post back
Edit
To make it a little easier, you can encapsulate this in a html helper
public static MvcHtmlString PartialFor<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression, string partialViewName)
{
string name = ExpressionHelper.GetExpressionText(expression);
object model = ModelMetadata.FromLambdaExpression(expression, helper.ViewData).Model;
var viewData = new ViewDataDictionary(helper.ViewData)
{
TemplateInfo = new System.Web.Mvc.TemplateInfo
{
HtmlFieldPrefix = string.IsNullOrEmpty(helper.ViewData.TemplateInfo.HtmlFieldPrefix) ?
name : $"{helper.ViewData.TemplateInfo.HtmlFieldPrefix}.{name}"
}
};
return helper.Partial(partialViewName, model, viewData);
}
and use it as
#Html.PartialFor(m => m.ComplexModel, "MyPartialView")
If you use tag helpers, the partial tag helper accepts a for attribute, which does what you expect.
<partial name="MyPartialView" for="ComplexModel" />
Using the for attribute, rather than the typical model attribute, will cause all of the form fields within the partial to be named with the ComplexModel. prefix.
You can try passing the ViewModel to the partial.
#model my.path.to.namespace.MyViewModel
#Html.TextBoxFor(m => m.ComplexModel.Name)
Edit
You can create a base model and push the complex model in there and pass the based model to the partial.
public class MyViewModel :BaseModel
{
public string SomeProperty { get; set; }
}
public class MyViewModel2 :BaseModel
{
public string SomeProperty2 { get; set; }
}
public class BaseModel
{
public MyComplexModel ComplexModel { get; set; }
}
public class MyComplexModel
{
public int id { get; set; }
public string Name { get; set; }
...
}
Then your partial will be like below :
#model my.path.to.namespace.BaseModel
#Html.TextBoxFor(m => m.ComplexModel.Name)
If this is not an acceptable solution, you may have to think in terms of overriding the model binder. You can read about that here.
I came across the same situation and with the help of such informative posts changed my partial code to have prefix on generated in input elements generated by partial view
I have used Html.partial helper giving partialview name and object of ModelType and an instance of ViewDataDictionary object with Html Field Prefix to constructor of Html.partial.
This results in GET request of "xyz url" of "Main view" and rendering partial view inside it with input elements generated with prefix e.g. earlier Name="Title" now becomes Name="MySubType.Title" in respective HTML element and same for rest of the form input elements.
The problem occurred when POST request is made to "xyz url", expecting the Form which is filled in gets saved in to my database. But the MVC Modelbinder didn't bind my POSTed model data with form values filled in and also ModelState is also lost. The model in viewdata was also coming to null.
Finally I tried to update model data in Posted form using TryUppdateModel method which takes model instance and html prefix which was passed earlier to partial view,and can see now model is bound with values and model state is also present.
Please let me know if this approach is fine or bit diversified!
I have an generic enumerable of type BookCover that I wan't to display to the user. They can only choose one book cover from the selection available.
public class BookCover {
public bool IsSelected { get; set; }
public string CoverPathThumb { get; set; }
public string SpinePathThumb { get; set; }
public string BackPathThumb { get; set; }
}
My action method is similar to
public ActionResult
SelectCover(IEnumerable<BookCover>
covers);
In my template I just enumerate and write out the desired HTML but the problem is I don't know how to get the data from the post back.
How do I name my <input> id's? Is there another reason IEnumerabme isn't populating when the post back occurs?
#Vince: You can customize the ModelBinder. And in the ModelBinder, you can get data from HttpContext.Request.Form, after that you will build your new BookCover collection. Finallly you call
public ActionResult SelectCover(IEnumerable<BookCover> covers);
And remember registering it in Global.asax as:
ModelBinders.Binders[typeof(IEnumerable<BookCover>)] = new YourModelBinderName();
You can get references at here and here is discussion about it. Hope this help you!
You should add an ID you BookCover type, and then use this ID to identify the cover that the user selected. If you retrieve your covers from a database, just use this ID in your class.
I think you can do something like this:
<% foreach(var item in covers) { %>
<%: Html.EditorFor(x => item.IsSelected) %>
<% } %>
The name of your inputs should be in the form:
covers[0].IsSelected
covers[0].CoverPathThumb
covers[0].SpinePathThumb
covers[0].BackPathThumb
E.g.
<input type="text" name="covers[0].CoverPathThumb" />
Increase 0 for each cover entry.
I'm building an internal page that allows trusted users to change a parameter setup manually through a form. The inputs to this setup are a list of setupparameters (of unknown size), each with a specific list of values. The user can then select a value for all or a subset of the parameters.
I have attempted to illustrate this with my current model for the view
public class SetupModel
{
public List<SetupParameter> Parameters { get; set; }
}
public class SetupParameter
{
public string ParameterName { get; set; }
// list with text=paramvalue, value=paramvalueid
public SelectList ParameterValueList { get; set; }
// id of the selected parametervalue if any
public int? SelectedParameterValueID { get; set; }
}
My current attempt at rendering a view for this:
<% using (Html.BeginForm("Update", "Parameters") {%>
...
<% foreach( var parameter in Model.Parameters ) { %>
<div><%: parameter.ParameterName %></div>
<div><%: Html.DropDownListFor(x => parameter.SelectedParameterValueID, parameter.ParameterValueList, "Please select") %></div>
<% } %>
...
My question is how can I render a view that allows me to submit the form and get a reasonably understandable model back to my form action that will allow me to obtain the list of selected parameter values. I'm not aware of the best practices or tricks here, so I will appreciate any feedback I get :)
You could try using a FormCollection:
public ActionResult Submit(FormCollection formCollection)
{
//Iterate form collection to get fields
return View();
}
You might find this post by Phil Haack useful: Model Binding To A List.
Also note that you'll need to post back an identifier (ParameterName, for example) for each parameter too, so you can indentify which value corresponds to a parameter back in the controller.
I’m using the Membership Provider and would like to display a list of all the users and their First Name, Last Name etc using the GetAllUsers function.
I'm having trouble understanding how to implement this function in MVC.
Has anyone implemented this in MVC or is there an easier way to list all the users in my application?
Any help or advise would be really helpful.
Controller
public ActionResult GetUsers()
{
var users = Membership.GetAllUsers();
return View(users);
}
View Model
public class GetUsers
{
[Required]
[DisplayName("User name")]
public string UserName { get; set; }
[Required]
[DisplayName("User name")]
public string FirstName { get; set; }
}
View
<%= Html.Encode(item.UserName) %>
Error
The model item passed into the dictionary is of type 'System.Web.Security.MembershipUserCollection', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable`1[Account.Models.GetUsers]'.
View
Inherits="System.Web.Mvc.ViewPage<MembershipUserCollection>"
<ul>
<%foreach (MembershipUser user in Model){ %>
<li><%=user.UserName %></li>
<% }%>
</ul>
Controller
public ActionResult Admin()
{
var users = Membership.GetAllUsers();
return View(users);
}
What's the difficulty you have with it? the GetAllUsers method simply returns a collection of users that you can then display ... either manually, or using a grid component from a vendor like Telerik.
something like:
<% foreach(var user in Membership.GetAllUsers()) { %>
<p>Name: <%= user.UserName %></p>
<% } %>
Obviously, heed the warning in the documentation:
Be careful when using the GetAllUsers
method with very large user databases,
as the resulting
MembershipUserCollection in your
ASP.NET page may degrade the
performance of your application.
There is an overload which lets you do paging to get around this :-)
#Jemes, the problem you're having is that you're passing a System.Web.Security.MembershipUserCollection as the model to your view and you specified that the model of your view was of type Account.Models.GetUsers. Change the type to System.Web.Security.MembershipUserCollection. However, if you're using the default Membership provider in your solution, you will not have the First Name available as the MembershipUser class doesn't have a FirstName property.
I'm new to ASP.NET MVC so this could have an obvious answer. Right now I have a form in my view with a lot of input controls, so I have an action that looks like this:
public ActionResult MyAction(string formItemOne, int? formItemTwo, etc...)
It has like a dozen parameters, which is pretty ugly. I'm trying to change it to this:
public ActionResult MyAction(FormCollection formItems)
and then parse the items dynamically. But when I change to a FormCollection, the form items no longer "automagically" remember their values through postbacks. Why would changing to a FormCollection change this behavior? Anything simple I can do to get it working automagically again?
Thanks for the help,
~ Justin
Another solution is to use models instead of manipulating the raw values. Like this:
class MyModel
{
public string ItemOne { get; set; }
public int? ItemTwo { get; set; }
}
Then use this code:
public ActionResult MyAction(MyModel model)
{
// Do things with model.
return this.View(model);
}
In your view:
<%# Page Inherits="System.Web.Mvc.ViewPage<MyModel>" %>
<%= Html.TextBox("ItemOne", Model.ItemOne) %>
<%= Html.TextBox("ItemTwo", Model.ItemTwo) %>
To replace your big list of parameters with a single one, use a view model. If after the POST you return this model to your view, then your view will remember the values posted.
A view model is simply an class with your action parameters as public properties. For example, you could do something like this, replacing:
public ActionResult MyAction(string formItemOne, int? formItemTwo, etc...)
with
public ActionResult MyAction(FormItems formItems)
{
//your code...
return View(formItems);
}
where FormItems is
public class FormItems
{
public property string formItemOne {get; set;}
public property int? formItemTwo {get; set;}
}
You may see a complete example in Stephen Walter's post ASP.NET MVC Tip #50 – Create View Models.
Maybe because they aren't magically inserted into the ModelState dictionary anymore. Try inserting them there.
If you use UpdateModel() or TryUpdateModel() I think the values are gonna be persisted.