ASP.NET MVC · Controllers & Views

Strongly Typed Views

A strongly typed view knows exactly what data it receives. The compiler checks your property names, the editor autocompletes them, and refactoring stops breaking pages silently.

Intermediate 6 min Lesson 13 of 37Covers ASP.NET MVC 5.2 on .NET Framework 4.8.

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Interview questions

Learning objectives#

Declare a view’s model type with @model
Design a view model for one page
Use DisplayFor and DisplayNameFor with [Display] and [DisplayFormat]
Explain why view models are better than entities and ViewBag

Explanation#

@model OrderSummaryViewModel at the top of a view makes the Model property that type. Model.Total is checked when the view compiles; Model.Totl is an error, not a silent blank.

A view model is a class made for one view: it contains exactly what the page shows, already shaped (CustomerName instead of Customer.FirstName + LastName). The controller builds it from entities.

Lambda-based helpers read metadata from the model: Html.DisplayNameFor(m => m.PlacedOn) shows the [Display(Name = "Placed on")] label, and Html.DisplayFor applies [DisplayFormat(DataFormatString = "{0:dd MMM yyyy}")].

View models protect you: the view cannot accidentally show or post fields you did not include (like IsAdmin or PasswordHash), and changes to the database schema do not ripple into every view.

Syntax#

C# Illustrative

1public class OrderSummaryViewModel
2{
3    [Display(Name = "Order number")] public int Id { get; set; }
4    [DisplayFormat(DataFormatString = "{0:N2}")] public decimal Total { get; set; }
5}
6

7@model OrderSummaryViewModel
8@Html.DisplayNameFor(m => m.Total): @Html.DisplayFor(m => m.Total)

Code example: An order summary page with a view model#

C#OrderSummaryViewModel.cs Illustrative

1// Models/OrderSummaryViewModel.cs
2using System;
3using System.Collections.Generic;
4using System.ComponentModel.DataAnnotations;
5

6namespace ShopSite.Models
7{
8    public class OrderSummaryViewModel
9    {
10        [Display(Name = "Order number")]
11        public int Id { get; set; }
12

13        [Display(Name = "Customer")]
14        public string CustomerName { get; set; }
15

16        [Display(Name = "Placed on")]
17        [DisplayFormat(DataFormatString = "{0:dd MMM yyyy}")]
18        public DateTime PlacedOn { get; set; }
19

20        [DisplayFormat(DataFormatString = "{0:N2}")]
21        public decimal Total { get; set; }
22

23        public List<string> Items { get; set; }
24    }
25}
26

27// Controllers/OrdersController.cs
28using System;
29using System.Collections.Generic;
30using System.Web.Mvc;
31using ShopSite.Models;
32

33namespace ShopSite.Controllers
34{
35    public class OrdersController : Controller
36    {
37        public ActionResult Summary(int id)
38        {
39            // In a real app this is mapped from the Order and Customer entities
40            var model = new OrderSummaryViewModel
41            {
42                Id = id,
43                CustomerName = "Asha Patil",
44                PlacedOn = new DateTime(2026, 10, 27),
45                Total = 1234.5m,
46                Items = new List<string> { "Gel Pen x3", "Notebook x2" },
47            };
48            return View(model);
49        }
50    }
51}
52

53@* Views/Orders/Summary.cshtml *@
54@model OrderSummaryViewModel
55<h1>@Html.DisplayNameFor(m => m.Id) @Model.Id</h1>
56<dl>
57    <dt>@Html.DisplayNameFor(m => m.CustomerName)</dt>
58    <dd>@Html.DisplayFor(m => m.CustomerName)</dd>
59    <dt>@Html.DisplayNameFor(m => m.PlacedOn)</dt>
60    <dd>@Html.DisplayFor(m => m.PlacedOn)</dd>
61    <dt>@Html.DisplayNameFor(m => m.Total)</dt>
62    <dd>@Html.DisplayFor(m => m.Total)</dd>
63</dl>
64<p>@Model.Items.Count items: @string.Join(", ", Model.Items)</p>

Expected output

GET /Orders/Summary/5001
200 OK
<h1>Order number 5001</h1>
<dl>
    <dt>Customer</dt>
    <dd>Asha Patil</dd>
    <dt>Placed on</dt>
    <dd>27 Oct 2026</dd>
    <dt>Total</dt>
    <dd>1,234.50</dd>
</dl>
<p>2 items: Gel Pen x3, Notebook x2</p>

This example is illustrative. Copy or download it and run it in your own environment; the expected output is shown above.

Step-by-step explanation#

@model OrderSummaryViewModel gives the view a typed Model and lambda helpers.
DisplayNameFor reads [Display(Name)]; Total has no Display attribute, so its property name is used.
DisplayFor applies [DisplayFormat]: the date becomes 27 Oct 2026 and the total 1,234.50.
The view model already has CustomerName as one string, so the view does not need to know how names are stored.

Real-world use case#

A bank’s statement page shows formatted dates and amounts using DisplayFor with [DisplayFormat] on the view model. When the format changes to show currency codes, only the attribute changes — every view using DisplayFor updates.

Common mistakes#

Passing EF entities straight to views

Entities often contain fields you must not show or accept, and lazy-loaded navigation properties can trigger database queries while the view renders. Map to a view model.

Model type mismatch

Passing a List<Product> to a view declared @model Product throws “The model item passed into the dictionary is of type…”. Check what the action passes.

Using ViewBag for the main data

ViewBag.Products works until someone renames it in one place. A typed model fails at compile time instead.

Best practices#

One view model per page (or per form)
Keep formatting in [DisplayFormat] and DisplayFor
Map entities to view models in the controller or a mapper
Turn on MvcBuildViews in release builds to catch view errors at compile time

Remember this#

@model = typed Model + IntelliSense.

View model = exactly what the page needs.

DisplayNameFor/DisplayFor read [Display]/[DisplayFormat].

Practice exercise#

Your task: Create a ProfileViewModel with FullName, JoinedOn (format yyyy-MM-dd) and Points (format N0, label “Reward points”) and render it with DisplayNameFor and DisplayFor.

Need a hint?

Use [Display(Name = "Reward points")] and [DisplayFormat(DataFormatString = "{0:N0}")].

Show solution

C# Illustrative

1// Models/ProfileViewModel.cs
2using System;
3using System.ComponentModel.DataAnnotations;
4

5namespace ShopSite.Models
6{
7    public class ProfileViewModel
8    {
9        [Display(Name = "Name")]
10        public string FullName { get; set; }
11

12        [Display(Name = "Member since")]
13        [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}")]
14        public DateTime JoinedOn { get; set; }
15

16        [Display(Name = "Reward points")]
17        [DisplayFormat(DataFormatString = "{0:N0}")]
18        public int Points { get; set; }
19    }
20}
21

22// Controllers/ProfileController.cs
23using System;
24using System.Web.Mvc;
25using ShopSite.Models;
26

27namespace ShopSite.Controllers
28{
29    public class ProfileController : Controller
30    {
31        public ActionResult Index() => View(new ProfileViewModel { FullName = "Ravi Kumar", JoinedOn = new DateTime(2024, 1, 15), Points = 12500 });
32    }
33}
34

35@* Views/Profile/Index.cshtml *@
36@model ProfileViewModel
37<p>@Html.DisplayNameFor(m => m.FullName): @Html.DisplayFor(m => m.FullName)</p>
38<p>@Html.DisplayNameFor(m => m.JoinedOn): @Html.DisplayFor(m => m.JoinedOn)</p>
39<p>@Html.DisplayNameFor(m => m.Points): @Html.DisplayFor(m => m.Points)</p>

Expected output

GET /Profile
200 OK
<p>Name: Ravi Kumar</p>
<p>Member since: 2024-01-15</p>
<p>Reward points: 12,500</p>

Mini quiz#

Strongly Typed Views quizMultiple choice Question 1 of 3

Which directive makes a view strongly typed?

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Related tutorials

Interview questions

Learning objectives#

Explanation#

Syntax#

Code example: An order summary page with a view model#

Step-by-step explanation#

Real-world use case#

Common mistakes#

Best practices#

Remember this#

Practice exercise#

Mini quiz#

Related topics#

My notes#