Develop Reference

Get Query Parameter from URL into MVC View

I have an a href link to a page which adds a parameter to the link for example:
tsw/register-your-interest?Course=979
What I am trying to do is to extract the value in Course i.e 979 and display it in the view. When attempting with the below code, I only return with 0 rather than the course value expected. ideally I'd like to avoid using routes.
Here is the view:
<div class="contact" data-component="components/checkout">
#using (Html.BeginUmbracoForm<CourseEnquiryPageSurfaceController>("PostCourseEnquiryForm", FormMethod.Post, new { id = "checkout__form" }))
{
//#Html.ValidationSummary(false)
#Model.Course;
}
And my controller:
public ActionResult CourseEnquiry(string Course)
{
var model = Mapper.Map<CourseEnquiryVM>(CurrentContent);
model.Course = Request.QueryString["Course"];
return model
}
This is the View Model:
public class CourseEnquiryVM : PageContentVM
{
public List<OfficeLocation> OfficeLocations { get; set; }
public string Test { get; set; }
public string Course { get; set; }
public List<Source> SourceTypes { get; set; }
}
SOLUTION:
After some research and comments I've adjusted the code to the below which now retrieves the value as expected
#Html.HiddenFor(m => m.Course, new { Value = #HttpContext.Current.Request.QueryString["Course"]});
Thanks all

Based on the form code you provided you need to use #Html.HiddenFor(m => m.Course) instead of just #Model.Course. #Model.Course just displays the value as text instead of building a input element that will be sent back to your controller.
If your problem is with a link prior to the view you referenced above, here's what I'd expect to work:
View with link:
#model CourseEnquiryVM
#Html.ActionLink("MyLink","CourseEnquiry","CourseController", new {course = #Model.Course}, null)
CourseController:
public ActionResult CourseEnquiry(string course)
{
// course should have a value at this point
}

In your view, you are only displaying the value of Course.. which isn't able to be submitted. You need to incorporate the value of course with a form input element (textbox, checkbox, textarea, hidden, etc.).
I would highly suggest using EditorFor or Textboxfor, but because your controller action is expecting just a string parameter you could just use Editor or TextBox.
#using (Html.BeginUmbracoForm<CourseEnquiryPageSurfaceController>("PostCourseEnquiryForm", FormMethod.Post, new { id = "checkout__form" }))
{
//#Html.ValidationSummary(false)
#Html.TextBox(Model.Course, null, new { #class = "form-control"});
<input type="submit" value="Submit" />
}
Then you should just be able to do this in your controller:
public ActionResult CourseEnquiry(string course) // parameter variables are camel-case
{
var model = Mapper.Map<CourseEnquiryVM>(CurrentContent);
if(!string.IsNullOrWhiteSpace(course))
model.Course = course;
return model;
}
Let me know if this helps.

How to pass view data to typed controller object?

I'm moving from WPF development to Asp MVC and have started doing an Asp MVC app. So far I've set up my:
model
controller
and
view(with the relevant fields.)
The next step involves sending the data entered in my form to the controller on the Submit button click.
I know in WPF I can bind the control properties to a property in the viewmodel, also there would be a click event on the button which I don't see in MVC.
This is my pseudo understanding of how to do that in MVC but correct me if I' wrong (Model is of type Case):
1.Set button click event to send form data to controller.
2.Pass data into controller constructor and assign to typed Case object.
Question:
How can you pass view values on button submit to a typed object in a controller?
Code:
View -
<form action="" method="post">
<div class="form-horizontal">
<div class="col-lg-6">
<!-- SELECT STATUS STATIC-->
<div class="form-group">
<label class="col-md-3 control-label" for="Current Status">Status</label>
<div class="col-md-8">
<select id="Status" name="Status" onchange="" class=" form-control">
<option value="Down">Down</option>
<option value="Up">Up</option>
</select>
</div>
</div>
<!-- SELECT APP STATIC-->
<div class="form-group">
<label class="col-md-3 control-label" for="App">App</label>
<div class="col-md-8" >
<select id="App" name="App" onchange="" class=" form-control">
<option value="SAP">SAP</option>
<option value="JAP">JAP</option>
</select>
</div>
</div>
<asp:Button id="b1" Text="Submit" runat="server" />
</div>
</div>
</form> <!--
Controller -
public class CaseController : Controller
{
public ActionResult Index()
{
return View();
}
}
Model -
Public class Case
{
public string Status { get; set; }
public string App { get; set; }
}

I hope that I understand your scenario well? You have a form with two drop down lists and a submit button? When you click the submit button you want to extract the selected values? This is how I understand it and this is how I will try to explain my answer with examples.
I would suggest that you bind your view/page to a view model. A view model is a kind of model that will represent your data in the view, whether it be textboxes, drop down lists, textareas, radio buttons, checkboxes, etc. It can also display static text on your view. I wrote a detailed answer as to what a view model is, if you have the time please go and read it:
What is ViewModel in MVC?
Go and create your view model. It will contain two lists that will represent your two drop down lists. Each list has an id associated with it that will contain the value of the selected drop down list item:
public class CaseViewModel
{
public int StatusId { get; set; }
public List<Status> Statuses { get; set; }
public int AppId { get; set; }
public List<App> Apps { get; set; }
}
Your domain models, namely Status and App, for the above mentioned lists:
public class Status
{
public int Id { get; set; }
public string Name { get; set; }
}
public class App
{
public int Id { get; set; }
public string Name { get; set; }
}
Now that you have this setup your next step is to populate these lists in your controller's action method. Ideally you would populate it with values from a database, but in your case I guess it is ok to hard code these values:
public ActionResult Index()
{
CaseViewModel model = new CaseViewModel();
model.Statuses = new List<Status>();
model.Statuses.Add(new Status { Id = 1, Name = "Down" });
model.Statuses.Add(new Status { Id = 2, Name = "Up" });
model.Apps = new List<App>();
model.Apps.Add(new App { Id = 1, Name = "SAP" });
model.Apps.Add(new App { Id = 2, Name = "JAP" });
return View(model);
}
As soon as you have populated your two lists, you pass the view model directly to the view. The view will receive a strongly type model and will do with it what it needs to do with it. In your case, a form will be created with two drop down lists and a submit button. I have left out all your CSS for clarity (just go and add it):
#model WebApplication_Test.Models.CaseViewModel
#using (Html.BeginForm())
{
<div>
#Html.DropDownListFor(
m => m.StatusId,
new SelectList(Model.Statuses, "Id", "Name", Model.StatusId),
"-- Select --"
)
#Html.ValidationMessageFor(m => m.StatusId)
</div>
<div>
#Html.DropDownListFor(
m => m.AppId,
new SelectList(Model.Apps, "Id", "Name", Model.AppId),
"-- Select --"
)
#Html.ValidationMessageFor(m => m.AppId)
</div>
<div>
<button type="submit">Submit</button>
</div>
}
So now you have two drop down lists populated with data. Select a value in each and press the submit button. Your view is bound to a view model and will retain values on form submission. Values in lists are not kept on form submission and will need to be populated again:
[HttpPost]
public ActionResult Index(CaseViewModel model)
{
// Check form validation
if (!ModelState.IsValid)
{
// If validation fails, rebind the lists and send the current view model back
model.Statuses = new List<Status>();
model.Statuses.Add(new Status { Id = 1, Name = "Down" });
model.Statuses.Add(new Status { Id = 2, Name = "Up" });
model.Apps = new List<App>();
model.Apps.Add(new App { Id = 1, Name = "SAP" });
model.Apps.Add(new App { Id = 2, Name = "JAP" });
return View(model);
}
// Form validation succeeds, do whatever you need to do here
return RedirectToAction("Index");
}
I hope this helps.

In the view just add a button in the form like
<button id="b1" Text="Submit"/>
In the controller add an action method to handle the post.
public class CaseController : Controller
{
[HttpPost]
public ActionResult Index(Case case)
{
//Do Something
return View();
}
public ActionResult Index()
{
return View();
}
}
You may also want to look into using Razor and strongly typed views. Makes things much simpler.

another approach is to use mvc ajax call, by doing these you also can pass parameter to controller from simple parameter to a selected row in gridview.
On the view in the button control add onclick property that point to a javascript function and passing parameter. In these sample will get selected row on the gridview
<input id="GenerateData" type="button" value="GenerateData" onclick="generateData(App.grdNameOfGridview.getRowsValues({selectedOnly:true}) [0]);" />
On the view create a javascript function that use ajax to call the controller, note the paramater that can be passing from click button event to the javascript function that will use ajax to call the controller. In this sample i use extjs framework, if you want you can also use jquery as well
generateData= function (recordData) {
var jsonStringContractUnit = JSON.stringify(recordData);
Ext.Ajax.request({
url: '../ControllerName/GenerateData',
method: 'POST',
params: {
SelectedContractUnit: jsonStringContractUnit
},
On the controller the parameter will be pass from view and will be store on SelectedData
public ActionResult GenerateData(string SelectedData)
{
}

ASP.NET MVC cannot POST view model with binding to checkbox

Here are my view models:
public class UserViewModel
{
public User GroupUser { get; set; }
public bool Checked { get; set; }
}
public class GroupUserViewModel
{
public Guid GroupId { get; set; }
public string GroupName { get; set; }
public IList<UserViewModel> Users;
}
My view:
#model GroupUserViewModel
#{
ViewBag.Title = "Users";
Layout = "~/Views/Shared/_Layout.cshtml";
}
<h2>#Model.GroupName</h2>
#using (Html.BeginForm("AddUserToGroup", "Group", FormMethod.Post))
{
for (var userIter = 0; userIter < Model.Users.Count(); userIter++)
{
<div class="form-group">
#Html.DisplayFor(model => model.Users[userIter].GroupUser.UserName)
#Html.CheckBoxFor(model => model.Users[userIter].Checked)
#Html.HiddenFor(model => model.GroupId)
#Html.HiddenFor(model => model.GroupName)
</div>
}
<input type="submit" class="btn btn-success" value="Save"/>
}
My controller:
[HttpPost]
public ActionResult AddUserToGroup(GroupUserViewModel groupUsers)
{
//do things
}
I had an inspection of the POST data and it is:
Users[0].Checked=true
Users[0].Checked=false
Users[1].Checked=false
For the boxes I've ticked there are 2 entries, one true and one false. Is this normal?
Also in the controller, what I get back is:
groupUsers.GroupId = {00000000-0000-0000-0000-000000000000}
groupUsers.GroupName = null
groupUsers.Users = null
Obviously since the form isn't actually posting the view model I want back to the controller, this happens. Is there any way to pass the required view model back to the controller since I need the GroupId and GroupName?
EDIT:
After some updates and adding in hidden fields for GroupId and GroupName, now the POST data is:
Users[0].Checked=true
Users[0].Checked=false
Id=015f5aef-eb6c-449e-9f08-9d42110c5347
GroupName=MyName
MyObjects[1].Checked=false
Id=015f5aef-eb6c-449e-9f08-9d42110c5347
GroupName=MyName
The GroupId and GroupName are now being passed corrently but the list is still null.

Yes this is normal. The reason is because an unchecked checkbox will not post a value, so ASP.NET renders a hidden field for every checkbox with the same ID as the checkbox just after the checkbox control, and sets its value to false. ASP.NET DefaultModelBinder will, if there are multiple form fields with the same name, take the first value. This results in one value of false being posted from the hidden field if the checkbox is not checked, and two values, one of false for the hidden field and one of true for the checked checkbox. Because the hidden field comes after the checkbox, if the checkbox posts a value, it will override the hidden field.
However, that doesn't answer your question as to why the model isn't binding..

IList<UserViewModel> Users in GroupUserViewModel is a field, not a property so the DefaultModelBinder cannot set its value. Change it to
public class GroupUserViewModel
{
....
public IList<UserViewModel> Users { get; set; } // make it a property
}

How to collect multiple checkbox values using FormCollection?

Based on Darin's answer to my question Ho to display multiple checkbox selection based on user's selection from dropdown?
I am displaying multiple checkboxes based on dropdown selection.
Now, once the user post the form (with multiple inputs) that i have on my page, i collect all the data using FormCollection. And the problem i have is how can i pull those selected checkbox values from formcollection? The number of checkbox will change on different selection from the drop-down, so i think requesting each checkbox value will not work.
Can anyone help me with this problem.
The flow is as shown below:
Properties in Model
public class Subcategory
{
public string Name { get; set; }
public int ID { get; set; }
public bool Flag { get; set; }
}
Displaying PartialView in actual view where other form inputs are there:
<div id="checkboxlist">
#if (Model.SubCategories != null)
{
#Html.Partial("SubCategories", Model.SubCategories)
}
</div>
PartialView SubCategories.cshtml
#model IEnumerable<MyProject.Entities.Subcategory>
#{
// we change the HTML field prefix so that input elements
// such as checkboxes have correct names in order to be able
// to POST the values back
ViewData.TemplateInfo.HtmlFieldPrefix = "checkboxlist";
}
<span>subcategory</span>
<div id="subcategories" style="margin-left: 130px;margin-top: -20px;" data-role="fieldcontain">
<fieldset data-role="controlgroup">
#Html.EditorForModel()
</fieldset>
</div>
EditorTemplates Subcategory.cshtml
#model MyProject.Entities.Subcategory
<div class="editor-label">
#Html.CheckBoxFor(c => c.Flag, new { type = "checkbox" })
<label for="#Model.ID">#Model.Name</label>
#Html.HiddenFor(c => c.Flag)
#Html.HiddenFor(c => c.ID)
#Html.HiddenFor(c => c.Name)
</div>
jquery to display checkboxes based on dropdown selection:
$('#Category').change(function () {
var subcategoriesUrl = $(this).data('subcategoriesurl');
var categoryId = $(this).val();
$('#checkboxlist').load(subcategoriesUrl, { category: categoryId });
});

Don't use FormCollection. That's weakly typed. Use view models. Like this:
[HttpPost]
public ActionResult Foo(MyViewModel model)
{
// model.BusinessSubCategories should contain a list of Subcategory
// where for each element you could use the Flag property to see if
// it was selected or not
...
}
Also notice that you have an inconsistency between the field prefix that you are using in your partial:
ViewData.TemplateInfo.HtmlFieldPrefix = "checkboxlist";
and the view model collection property: Model.BusinessSubCategories. So make sure you fix the prefix to use the correct property name if you want the default model binder to be able to populate this property when you post back.

How can I get multiple selections from ASP.NET CheckBoxs

This seems like it should be prettty easy - but I just can't get it to work!
I have an enum in my model, which I want to display as a list of checkboxes. The user can select multiple checkboxes, and I want to save this in the database.
So the enum is like so (approx 20 elements unabridged):
public enum ReferrerType
{
[Description("No Data")]
NoData = 9999,
[Description("Father or Mother")]
Parents = 1,
[Description("Brother or Sister")]
Sibling = 2,
[Description("Other")]
Other = 10
}
Whereby the Description is what is shown on the UI, and the numeric value is what is to be saved in the database. The numbers have to remain as listed, as they go directly into a stats package.
I then defined a Referrer class:
public class Referrer
{
public virtual Guid Id { get; private set; }
public virtual ReferrerType{ get; set; }
}
I realise this might be an odd (anti)pattern. I developed it in haste, and am repenting at leisure. Any advice on improving this model would also be much appreciated!
My controller sets up the list:
private static IList<string> GenerateReferrerList()
{
var values = from ReferrerType e in Enum.GetValues(typeof(ReferrerType))
select new { Name = e.ToDescription() };
return values.Select(x => x.Name).ToList();
}
And I use it in my View like this:
<div class="radio-boolean form-field" id="Referrers">
<p class="form-field-attribute"> <span class="label">Referred By </span> </p>
<% for (var i = 0; i < ((IList<string>)ViewData["ReferrerList"]).Count; i++)
{ %>
<p class="form-field-value">
<%= Html.CheckBox(string.Format("Referrers[{0}].Type", i) ) %>
<label for="Referrers"> <%= ((IList<string>)ViewData["ReferrerList"])[i]%></label>
</p>
</div>
And it doesn't work! I guess I'm missing something obvious, but I can't work out what. There are no errors - just an empty database table where referrers should be...
As always, any help much appreciated!

Let's take a moment and see what do we need here. We need to show a form which will contain multiple checkboxes (one for each value of the enum) and an associated label (this label should come from the Description attribute use on the enum). When this form is submitted we want to fetch all the values that the use has checked.
So as always once we have clear definition of what we are trying to do we introduce our view model:
public class MyViewModel
{
public bool IsChecked { get; set; }
public ReferrerType ReferrerType { get; set; }
public string Text { get; set; }
}
Then we write a controller:
public class HomeController : Controller
{
public ActionResult Index()
{
var model = Enum.GetValues(typeof(ReferrerType)).Cast<ReferrerType>().Select(x => new MyViewModel
{
ReferrerType = x,
Text = x.ToDescription() // I guess that's an extension method you wrote
});
return View(model);
}
[HttpPost]
public ActionResult Index(IEnumerable<MyViewModel> model)
{
...
}
}
And finally a strongly typed view corresponding to the Index action of our controller (~/Views/Home/Index.aspx):
<% using (Html.BeginForm()) { %>
#Html.EditorForModel()
<input type="submit" value="OK" />
<% } %>
and the last part is the corresponding editor template (~/Views/Home/EditorTemplates/MyViewModel.ascx):
<%# Control
Language="C#"
Inherits="System.Web.Mvc.ViewUserControl<AppName.Models.MyViewModel>" %>
<%= Html.CheckBoxFor(x => x.IsChecked) %>
<%= Html.HiddenFor(x => x.ReferrerType) %>
<label><%: Model.Text %></label>
Now when this form is submitted inside the POST index action you would get a list of all enums with a corresponding boolean value indicating whether the user checked it or not.

OT: Don't perform excess actions:
return (from e in Enum.GetValues(typeof(ReferrerType))
select e.ToDescription()).ToList();
or just
return Enum.GetValues(typeof(ReferrerType)).Select(e => e.ToDescription()).ToList();