Develop Reference

HttpPost returns null Model in ASP.NET MVC

Advance warning, I am extremely new to ASP.NET.
I'm working on a project which will display rows of data from a db table. When a user clicks the "Ignore" button next to a row, it should update the corresponding "Ignore" column on that row with true in the database.
The view itself works fine, it displays all the data as expected. But when "Ignore" is clicked, and it calls the Ignore() method on the controller, the model is which is passed to the controller is null.
My model, generated by entity framework (with extraneous properties removed):
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace IgnoreDailyItems.Models
{
[Table("DataChecks.tbl.DailyItems")]
public partial class DataChecksTblDailyItems
{
[Column("entryId")]
public int EntryId { get; set; }
[Column("ignore")]
public bool? Ignore { get; set; }
}
}
The view:
#model IEnumerable<IgnoreDailyItems.Models.DataChecksTblDailyItems>
#{
ViewBag.Title = "Placeholder";
Layout = "~/Views/Shared/_Layout.cshtml";
}
<table class="table">
<tr>
<th>
#Html.DisplayNameFor(model => model.EntryId)
</th>
</tr>
#{ var item = Model.ToList(); }
#for(int i = 0; i < Model.Count(); i++)
{
<tr>
<td>
#Html.DisplayFor(modelItem => item[i].EntryId)
</td>
<td>
#using (Html.BeginForm("Ignore", "Home", FormMethod.Post))
{
#Html.HiddenFor(modelItem => item[i].EntryId)
<button type="submit" class="btn btn-danger">Ignore</button>
}
</td>
</tr>
}
</table>
And the Ignore() method on the controller:
[HttpPost]
public ActionResult Ignore(DataChecksTblDailyItems modelData)
{
using (var context = new IgnoreDailyItemsContext())
{
var query = context.DataChecksTblDailyItems
.Where(b => b.EntryId.Equals(modelData.EntryId));
foreach (var q in query)
{
q.Ignore = true;
}
context.SaveChanges();
return RedirectToAction("Index", "Home");
}
}

You're generating the form in wrong way.
#Html.HiddenFor(modelItem => item[i].EntryId)
It will generate an input hidden with item[0].EntryId, item[1].EntryId... as name/id for each row in the table, for that reason the post model definition does not match.
To solve it, set the input hidden name manually:
#Html.Hidden("EntryId", item[i].EntryId)

You need to pass IEnumerable<IEnumerable> as a parameter.
public ActionResult Ignore(IEnumerable<DataChecksTblDailyItems> modelData)
{

Binding IPagedList with checkbox as List

So.. i have a class that has has a List.
I pass it to the view like the code below:
[HttpGet]
[Authorize(Roles="user")]
[CustomChecker]
public ActionResult Index(int? page, int id=0)
{
EmployeeContext emp = new EmployeeContext();
student st = emp.students.Single(x=>x.id ==id);
#ViewBag.id = st.id;
return View(st.subjSel.ToPagedList(page ?? 1, 4));
}
And then the View will receive it like this:
#using PagedList;
#using PagedList.Mvc;
#model PagedList<MvcApplication6.Models.subject>
<div style="font-family:Arial">
<fieldset>
<legend><h3>Open Classes</h3></legend>
#using (Html.BeginForm("Test", "Enrollment"))
{
<input type="hidden" name="id" value="#ViewBag.id" />
<table border="1">
<tr>
<th>#Html.LabelFor(model => model[0].subj)</th>
<th>#Html.LabelFor(model => model[0].days)</th>
<th>#Html.LabelFor(model => model[0].cstart)</th>
<th>#Html.LabelFor(model => model[0].cend)</th>
<th>#Html.LabelFor(model => model[0].professor)</th>
<th>#Html.LabelFor(model => model[0].units)</th>
<th>#Html.CheckBox("test") Select all</th>
</tr>
#for (int i = 0; i < Model.Count; i++)
{
<tr>
#Html.HiddenFor(model => model[i].id)
<td>
#Html.DisplayFor(m => m[i].subj)
#Html.HiddenFor(m => m[i].subj)
</td>
<td>
#Html.DisplayFor(m => m[i].days)
#Html.HiddenFor(m => m[i].days)
</td>
<td>
#Html.DisplayFor(m => m[i].cstart)
#Html.HiddenFor(m => m[i].cstart)
</td>
<td>
#Html.DisplayFor(m => m[i].cend)
#Html.HiddenFor(m => m[i].cend)
</td>
<td>
#Html.DisplayFor(m => m[i].professor)
#Html.HiddenFor(m => m[i].professor)
</td>
<td>
#Html.DisplayFor(m => m[i].units)
#Html.HiddenFor(m => m[i].units)
</td>
<td>
#Html.CheckBoxFor(m => m[i].isSelected)
</td>
</tr>
}
</table>
<br />
<br />
<table>
<tr><td align="center" width="500px"></td></tr>
<tr>
<td align="center" width="500px">
<input type="submit" value="submit" /> | <input type="button" value="clear" />
</td>
</tr>
</table>
<br />
<br />
}
</fieldset>
</div>
#Html.PagedListPager(Model, page => Url.Action("Index", "Enrollment", new { page, id = Request.QueryString["id"] }))
My problem is that it will be rendered like this [0].subj and that won't allow me to bind because it should be something like name[0].subj.
I've been experimenting and trying new methods, are there any ways for me to bind them properly? i want to use Html Helpers and as much as possible, i don't want to re-implement a custom one just for this part.
This is the function where they are supposed to be bound. This class has a List of students (the one that i converted to IPagedList)
[HttpPost]
[Authorize(Roles="user")]
public ActionResult Test(student st)
And this is how my View looks like. I am using CheckBoxFor for selections.
Extra question:
How come my navigation looks so ugly?

The model is the view is #model PagedList<subject> which means the parameter in the must be
[HttpPost]
public ActionResult Test(IEnumerable<subject> model)
If you also need the student ID property, then include an additional parameter
[HttpPost]
public ActionResult Test(IEnumerable<subject> model, int ID)
Since you GET method has a parameter int ID and assuming your using the default routing then the ID will be added to the forms action attribute i.e. it will render action="/Enrollment/Test/2" assuming the value of the ID is 2. If not, you can add this as a route parameter
#using (Html.BeginForm("Test", "Enrollment", new { ID = ViewBag.id }))
Alternatively you can use a view model
public class StudentVM
{
public int ID { get; set; }
public PagedList<student> Students { get; set; }
}
and in the GET method
public ActionResult Index(int? page, int id=0)
{
EmployeeContext emp = new EmployeeContext();
student st = emp.students.Single(x=>x.id ==id);
StudentVM model = new StudentVM()
{
ID = id,
Students = st.subjSel.ToPagedList(page ?? 1, 4)
};
return View(model);
}
and base you view on the view model and post it back to public ActionResult Test(StudentVM model)

To get your list of subject back, you should apply a suitable prefix to it. Since the name of property of Student that contains List<subject> is subjSel and you want to get values in your action in a Student object, so you should set prefix like this, before for statement:
#{ViewData.TemplateInfo.HtmlFieldPrefix = "subjSel";}
So fileds of model will be rendered with names like subjSel[0].fieldname.
Then in your post action you will receive subjects in subjSel property of st.
Additional Resource:
Model Binding to a List
For your extra question:
Check if your rendered code has suitable style and your style tags related to paging has been rendered in page.

Model binding between view and controller error

I have a list, then i want to pass it to view. I use model binding method.
Here is my code:
Model:
public class Group
{
public string Name { get; set; }
public string GroupID { get; set; }
}
Controller:
public ActionResult Index()
{
return View(ListGroup);
}
[HttpPost]
public ActionResult Index(List<Group> listModel)
{
#ViewBag.Success = "Update Suceess";
return View(listModel);
}
[HttpPost]
public ActionResult Search(Group modelSearch)
{
List<Group> listResult = listGroup.Where(m=>m.GroupID == modelSearch.GroupID).ToList();
if (modelSearch.GroupID == null)
return View("Index", listGroup);
return View("Index", listResult);
}
In view i want to display list by group of GroupID
#using (Html.BeginForm("Index", "DisplayTable", FormMethod.Post))
{
<table>
<tr>
<td>Name</td>
<td>GroupID</td>
</tr>
#foreach(var items in Model.GroupBy(m => m.GroupID).Select(g => g.ToList())){
<tr><td colspan="2">#items.ElementAt(0).GroupID</td></tr>
for (int i = 0; i < items.Count; i++) {
<tr>
<td>#Html.TextBoxFor(m => items[i].Name)</td>
<td>#Html.TextBoxFor(m => items[i].GroupID)</td>
</tr>
}
}
</table>
<input type="submit" value="SAVE" />
}
My problem is: If I use the code above, the view display data in group correctly, but when i click button SAVE, It didn't send any data to controller, ActionResult Index(List<Group> listModel) received a null list.
MORE EXPLANATION:
I have list like this:
NAME | GROUPID
Pen; A
Ink; B
Pecil; A
Book ; C
Ruler; B
NoteBook ; C
I want to display it in view like this:
GroupID: A - Pen: A | Pencil: A
GroupID: B - Ruler: B | Ink: B
GroupID: C - Book: C | NoteBook: C
If i use this code in view:
<td>#Html.TextBoxFor(m => items[i].Name)</td>
<td>#Html.TextBoxFor(m => items[i].GroupID)</td>
The result in view is correct, but this cannot send data back to controller. I found that the name of each field Name GroupID didnt match with the name of textfield in html.
I use group by in view and i dont know what is the best way in this case: Group by in controller or in View. and What is the structure of list if I group by in controller.

From your edit, I see so you have a list of these objects and you must group them by id, so many objects like pen and pencil have the same id 'A', if we group them together, they belong to group with ID 'A'.
Your best practice is to have the correct business logic, and model from controller to view. Like in this answer, actually have the List'group' in your model, if you want to separate business and UI, then create a view model, which holds your 'group' business object. The ui part will hold a list of child groups. Then serialize from viewmodel to business model.
For how to populate the correct model from only having a list of child items. See the controller.
First, you can check the source of the page to see if razor is building the correct html that you expect.
Your problem is due to how list binding works. At the end your page source must appear as below:
Notice the hidden for fields, they bind your original objects and their id's. Each input on the page must have a unique name or ID.
<tr>
<td colspan="2">
0 - name - 0
<input name="[0].GroupID" type="hidden" value="0" />
<input name="[0].Name" type="hidden" value="0 - name" />
</td>
</tr>
<tr>
<td><input class="text-box single-line" name="[0].ListGroup[0].Name" type="text" value="0 - name0 - subname" /></td>
<td><input name="[0].ListGroup[0].GroupID" type="text" value="00" /></td>
</tr>
<tr>
<td><input class="text-box single-line" name="[0].ListGroup[1].Name" type="text" value="0 - name1 - subname" /></td>
<td><input name="[0].ListGroup[1].GroupID" type="text" value="01" /></td>
</tr>
Use the code below to make the solution work. Please don't allow people to edit the groupID as once this is saved it will effect the behavior, IDs must remain unique. This is also true within your DB structure.
Your Controller
public class homeController : Controller
{
//
// GET: /home/
[HttpGet]
public ActionResult Index()
{
List<Group> lst = new List<Group>();
for (var i = 0; i < 5; i++)
{
lst.Add(new Group()
{
GroupID = i.ToString(),
Name = i.ToString() + " - name",
ListGroup = new List<Group>()
});
}
foreach (var g in lst)
{
for (var i = 0; i < 3; i++)
{
g.ListGroup.Add(new Group()
{
GroupID = g.GroupID + i.ToString(),
Name = g.Name + i.ToString() + " - subname",
ListGroup = new List<Group>()
});
}
}
return View(lst);
}
[HttpPost]
public ActionResult Save(List<Group> listModel)
{
#ViewBag.Success = "Update Suceess";
return View(listModel);
}
public class Group
{
public string Name { get; set; }
public string GroupID { get; set; }
public List<Group> ListGroup { get; set; }
}
}
Your View
#model List<TestMVC.Controllers.homeController.Group>
#{
ViewBag.Title = "Index";
}
<h2>Index</h2>
#using (Html.BeginForm("Save", "Home", FormMethod.Post))
{
<table>
<tr>
<td>Name</td>
<td>GroupID</td>
</tr>
#for (var g = 0; g < Model.Count; g++)
{
<tr>
<td colspan="2">
#Model[g].Name - #Model[g].GroupID
#Html.HiddenFor(x => Model[g].GroupID)
#Html.HiddenFor(x => Model[g].Name)
</td>
</tr>
for (var i = 0; i < Model[g].ListGroup.Count; i++)
{
<tr>
<td>#Html.EditorFor(x => Model[g].ListGroup[i].Name)</td>
<td>#Html.TextBoxFor(x => Model[g].ListGroup[i].GroupID)</td>
</tr>
}
}
</table>
<input type="submit" value="SAVE" />
}
Runtime:
Please take a look at this answer here for a different approach using Model Editor For:
MVC Form not able to post List of objects
Further reading, excelent article on List Binding in MVC:
http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx/

Try to use Html.TextBox:
#{ var index = 0; }
#foreach(var items in Model.GroupBy(m=>m.GroupID).Select(g=>g.ToList())){
Html.TextBox("items[" + index + "].Name", items.Name);
Html.TextBox("items[" + index + "].GroupID", items.GroupID);
index++;
}

Redirect to action is not working

Hi I have a table with anchor tag in a column. when user clicks on the link, My action method in controller redirect to another method after doing some update logic. Redirect to another action method then after, is not working in my case?
my View :
<fieldset>
<legend>Emended</legend>
<table border="1">
<tr>
<th>
#Html.DisplayNameFor(model => model.CustomerEmneedOrderedProduct.FirstOrDefault().Prd_Qnty)
</th>
</tr>
#foreach (var item in Model.CustomerEmneedOrderedProduct)
{
<tr>
<td>
#Html.DisplayFor(modelItem => item.Prd_Qnty)
<br />
#Html.ActionLink("Remove", "updateOrderedProdStatuCd", new { orderProductId = item.OrderProductId, OrderedProdStatuCd = 2 })
</td>
</tr>
}
</table>
</fieldset>
My Controller :
public class SellerOrderDetailsController : Controller
{
public ActionResult OrderDetails([Bind(Prefix = "id")] int? orderId)
{
}
public ActionResult updateOrderedProdStatuCd(int orderProductId, int OrderedProdStatuCd)
{
try
{
// Updating few stuffs
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
return RedirectToAction("OrderDetails"); //this is not working
}
}
}

I guess it's because you're not passing orderId to OrderDetails action. The action doesn't match method's signature.
Try something like
return RedirectToAction("OrderDetails ", new { orderId = 123 });

ASP.NET MVC Form Validation. How do you do it on a non-model object?

I have a view with model BlogPostViewModel:
public class BlogPostViewModel
{
public BlogPost BlogPost { get; set; }
public PostComment NewComment { get; set; }
}
This view is rendered when action method BlogPost is hit. The view displays information regarding the blog post as well as a list of comments on the blog post by iterating over Model.BlogPost.PostComments. Below that I have a form allowing users to post a new comment. This form posts to a different action AddComment.
[HttpPost]
public ActionResult AddComment([Bind(Prefix = "NewComment")] PostComment postComment)
{
postComment.Body = Server.HtmlEncode(postComment.Body);
postComment.PostedDate = DateTime.Now;
postCommentRepo.AddPostComment(postComment);
postCommentRepo.SaveChanges();
return RedirectToAction("BlogPost", new { Id = postComment.PostID });
}
My problem is with validation. How do I validate this form? The model of the view was actually BlogPostViewModel. I'm new to validation and am confused. The form uses the strongly-typed helpers to bind to the NewComment property of BlogPostViewModel and I included the validation helpers as well.
#using (Html.BeginForm("AddComment", "Blog")
{
<div class="formTitle">Add Comment</div>
<div>
#Html.HiddenFor(x => x.NewComment.PostID) #* This property is populated in the action method for the page. *#
<table>
<tr>
<td>
Name:
</td>
<td>
#Html.TextBoxFor(x => x.NewComment.Author)
</td>
<td>
#Html.ValidationMessageFor(x => x.NewComment.Author)
</td>
</tr>
<tr>
<td>
Email:
</td>
<td>
#Html.TextBoxFor(x => x.NewComment.Email)
</td>
<td>
#Html.ValidationMessageFor(x => x.NewComment.Email)
</td>
</tr>
<tr>
<td>
Website:
</td>
<td>
#Html.TextBoxFor(x => x.NewComment.Website)
</td>
<td>
#Html.ValidationMessageFor(x => x.NewComment.Website)
</td>
</tr>
<tr>
<td>
Body:
</td>
<td>
#Html.TextAreaFor(x => x.NewComment.Body)
</td>
<td>
#Html.ValidationMessageFor(x => x.NewComment.Body)
</td>
</tr>
<tr>
<td>
</td>
<td>
<input type="submit" value="Add Comment" />
</td>
</tr>
</table>
</div>
}
How in the AddComment action method do I implement validation? When I detect Model.IsValid == false then what? What do I return? This action method is only binding to the PostComment property of the pages initial BlogPostViewModel object because I don't care about any other properties on that model.

You need to repopulate the model and send to view. However, you don't need to do this by hand, you can use action filters.
see:
http://weblogs.asp.net/rashid/archive/2009/04/01/asp-net-mvc-best-practices-part-1.aspx#prg
Specifically:
public abstract class ModelStateTempDataTransfer : ActionFilterAttribute
{
protected static readonly string Key = typeof(ModelStateTempDataTransfer).FullName;
}
public class ExportModelStateToTempData : ModelStateTempDataTransfer
{
public override void OnActionExecuted(ActionExecutedContext filterContext)
{
//Only export when ModelState is not valid
if (!filterContext.Controller.ViewData.ModelState.IsValid)
{
//Export if we are redirecting
if ((filterContext.Result is RedirectResult) || (filterContext.Result is RedirectToRouteResult))
{
filterContext.Controller.TempData[Key] = filterContext.Controller.ViewData.ModelState;
}
}
base.OnActionExecuted(filterContext);
}
}
public class ImportModelStateFromTempData : ModelStateTempDataTransfer
{
public override void OnActionExecuted(ActionExecutedContext filterContext)
{
ModelStateDictionary modelState = filterContext.Controller.TempData[Key] as ModelStateDictionary;
if (modelState != null)
{
//Only Import if we are viewing
if (filterContext.Result is ViewResult)
{
filterContext.Controller.ViewData.ModelState.Merge(modelState);
}
else
{
//Otherwise remove it.
filterContext.Controller.TempData.Remove(Key);
}
}
base.OnActionExecuted(filterContext);
}
}
Usage:
[AcceptVerbs(HttpVerbs.Get), ImportModelStateFromTempData]
public ActionResult Index(YourModel stuff)
{
return View();
}
[AcceptVerbs(HttpVerbs.Post), ExportModelStateToTempData]
public ActionResult Submit(YourModel stuff)
{
if (ModelState.IsValid)
{
try
{
//save
}
catch (Exception e)
{
ModelState.AddModelError(ModelStateException, e);
}
}
return RedirectToAction("Index");
}

In your AddComment ActionResult, do this:
if(ModelState.IsValid)
{
// Insert new comment
..
..
// Redirect to a different view
}
// Something is wrong, return to the same view with the model & errors
var postModel = new BlogPostViewModel { PostComment = postComment };
return View(postModel);

After much time spent I have realized that I have to repopulate the view model and render the correct view, passing in the fully-populated model. Kind of a pain but at least I understand what's going on.