MVC ASP.NET Interview Questions and Answers:-
1. Define what is MVC?
MVC is a framework methodology that divides an application’s implementation into three component roles: models, views, and controllers. These are Main components of an MVC application
M – Model
V – View
C – Controller
1. “Models” in an MVC based application are the components of an application that is responsible for maintaining state. Often this the state is persisted inside a database (for example we might have a Product class that is used to represent order data from the Products table inside SQL).
2. “Views” in an MVC based application are the components responsible for displaying the application’s user interface. Typically this UI is created off of the model data (for example we might create a Product “Edit” view that surfaces textboxes, dropdowns and check boxes based on the current state of a Product object).
3. “Controllers” in an MVC based application are the components responsible for handling end user interaction, manipulating the model, and ultimately choosing a view to render to display UI. In an MVC application, the view is only about displaying information – it is the controller that handles and responds to user input and interaction.
2. Define what does Model, View and Controller represent in an MVC application?
Model: Model represents the application data domain. In short, the applications business logic is contained in the model.
View: Views represent the user interface, with which the end users interact. In short the all the user interface logic is contained within the UI.
Controller: Controller is the component that responds to user actions. Based on the user actions, the respective controller, work with the model and selects a view to render that displays the user-interface. The user input logic is contained within the controller.
3. In which assembly is the MVC framework defined?
System.Web.Mvc
4. Define what is the greatest advantage of using asp.net MVC over asp.net web forms?
It is difficult to unit test UI with web forms, where views in MVC can be
very easily unit tested.
5. Which approach provides better support for test-driven development –ASP.NET MVC or ASP.NET Web forms?
ASP.NET MVC
6. Define what is the Razor View Engine?
Razor view engine is a new view engine created with ASP.Net MVC model using specially designed Razor parser to render the HTML out of dynamic server-side code. It allows us to write Compact, Expressive, Clean and Fluid code with new syntax to include server-side code into HTML.
7. Define what are the advantages of ASP.NET MVC?
Advantages of ASP.NET MVC:
1. Extensive support for TDD. With asp.net MVC, views can also be very easily unit tested.
2. Complex applications can be easily managed
3. Separation of concerns. Different aspects of the application can be divided into Model, View, and Controller.
4. ASP.NET MVC views are lightweight, as they don’t use ViewState.
8. Is it possible to unit test an MVC application without running the controllers in an ASP.NET process?
Yes, all the features in an asp.net MVC application are interface based and hence mocking is much easier. So, we don’t have to run the controllers in an ASP.NET process for unit testing.
9. Define what is namespace of ASP.NET MVC?
ASP.NET MVC namespaces and classes are located in the System.Web.Mvc assembly. System.Web.Mvc namespace
Contains classes and interfaces that support the MVC pattern for ASP.NET Web applications. This namespace includes classes that represent controllers, controller factories, action results, views, partial views, and model binders. System.Web.Mvc.Ajax namespace Contains classes that support Ajax scripts in an ASP.NET MVC application. The namespace includes support for Ajax scripts and Ajax option settings. System.Web.Mvc.Async namespace Contains classes and interfaces that support asynchronous actions in an ASP.NET MVC application.
System.Web.Mvc.Html namespace Contains classes that help render HTML controls in an MVC application. The namespace includes classes that support forms, input controls, links, partial views, and validation.
10. Is it possible to share a view across multiple controllers?
Yes, but the view into the shared folder. This will automatically make
the view available across multiple controllers.
11. Define what is the role of a controller in an MVC application?
The controller responds to user interactions, with the application, by selecting the action method to execute and selecting the view to render.
12. Where are the routing rules defined in an asp.net MVC application?
In Application_Start event in Global.asax
13. Name a few different return types of a controller action method?
The following are just a few return types of a controller action method. In general, an action method can return an instance of any class that derives from ActionResult class.
1. ViewResult
2. JavaScriptResult
3. RedirectResult
4. ContentResult
5. JsonResult
14. Define what is the ‘page lifecycle’ of an ASP.NET MVC?
The following process is performed by ASP.Net MVC page:
1. App initialization
2. Routing
3. Instantiate and execute controller
4. Locate and invoke controller action
5. Instantiate and render view
15. Define what is the significance of NonActionAttribute?
In general, all public methods of a controller class are treated as action methods. If you want to prevent this default behavior, just decorate the public method with NonActionAttribute.
16. Define what is the significance of ASP.NET routing?
ASP.NET MVC uses ASP.NET routing, to map incoming browser requests to controller action methods. ASP.NET Routing makes use of route table. The route table is created when your web application first starts. The route
table is present in the Global.asax file.
17. Define How route table is created in ASP.NET MVC?
When an MVC application first starts, the Application_Start() method is called. This method, in turn, calls the RegisterRoutes() method. The RegisterRoutes() method creates the routing table.
18. Define what are the 3 segments of the default route, that is present in an ASP.NET MVC application?
1st Segment – Controller Name
2nd Segment – Action Method Name
3rd Segment – Parameter that is passed to the action method Controller Name = search
Action Method Name = label
Parameter Id = MVC
19. ASP.NET MVC application makes use of settings at 2 places for routing to work correctly. Define what are these 2 places?
Web.Config File: ASP.NET routing has to be enabled here. Global.asax File: The Route table is created in the application Start event handler, of the Global.asax file.
20. Define what is the advantage of using ASP.NET routing?
In an ASP.NET web application that does not make use of routing, an incoming browser request should map to a physical file. If the file does not exist, we get a page not found an error. An ASP.NET web application that does make use of routing, makes use of URLs that do not have to map to specific files in a Web site. Because the URL does not have to map to a file, you can use URLs that are descriptive of the user’s action and therefore are more easily
understood by users.
21. Define what are the 3 things that are needed to specify a route?
URL Pattern – You can include placeholders in a URL pattern so that variable data can be passed to the request handler without requiring a query string. Handler – The handler can be a physical file such as a .aspx file
or a controller class. Name for the Route – Name is optional.
22. Is the following route definition a valid route definition?
{controller}{action}/{id}
No, the above definition is not a valid route definition, because there is no literal value or delimiter between the placeholders. Therefore, routing cannot determine where to separate the value for the controller placeholder from the value for the action placeholder.
23. Define what is the use of the following default route?
{resource}.axd/{ pathInfo}
This route definition, prevent requests for the Web resource files such as WebResource.axd or ScriptResource.axd from being passed to a controller.
24. Define what is the difference between adding routes, to a webforms application and to an MVC application?
To add routes to a webforms application, we use MapPageRoute() method of the RouteCollection class, whereas to add routes to an MVC application we use MapRoute() method.
25. Define How do you handle a variable number of segments in a route definition?
Use a route with a catch-all parameter. An example is sDefine Hown below. is referred to as a catch-all parameter.
controller/{action}/{ parametervalues}
26. Define what are the 2 ways of adding constraints to a route?
1. Use regular expressions
2. Use an object that implements IRouteConstraint interface
27. Give 2 examples for scenarios when routing is not applied?
1. A Physical File is Found that Matches the URL Pattern – This default behavior can be overridden by setting the RouteExistingFiles property of the RouteCollection object to true.
2. Routing Is Explicitly Disabled for a URL Pattern – Use the RouteCollection.Ignore() method to prevent routing from handling certain requests.
28. Define what is the use of action filters in an MVC application?
Action Filters allow us to add pre-action and post-action behavior to controller action methods.
29. If I have multiple filters implemented, Define what is the order in which these filters get executed?
1. Authorization filters
2. Action filters
3. Response filters
4. Exception filters
30. Define what are the different types of filters, in an asp.net MVC application?
1. Authorization filters
2. Action filters
3. Result filters
4. Exception filters
31. Give an example for Authorization filters in an asp.net MVC application?
RequireHttpsAttribute
AuthorizeAttribute
32. Which filter executes first in an asp.net MVC application?
Authorization filter
33- Define what are the levels at which filters can be applied in an asp.net MVC application?
Action Method
Controller
Application
34. Is it possible to create a custom filter?
Yes
35. Define what filters are executed in the end?
Exception Filters
36. Is it possible to cancel filter execution?
Yes
37. Define what type of filter does OutputCacheAttribute class represents?
Result Filter
38. Define what are the 2 popular asp.net MVC view engines?
1. Razor
2. .aspx
39. Define what is the difference between Viewbag and Viewdata in ASP.NET MVC?
The basic difference between ViewData and ViewBag is that in ViewData instead creating dynamic properties we use properties of Model to transport the Model data in View and in ViewBag we can create dynamic properties without using Model data.
40. Define what symbol would you use to denote, the start of a code block in razor views?
@
41. Define what symbol would you use to denote, the start of a code block in aspx views?
<%= %>
In razor syntax, Define what is the escape sequence character for @ symbol?
The escape sequence character for @ symbol is another @ symbol
42. When using razor views, do you have to take any special steps to protect your asp.net MVC application from cross-site scripting (XSS) attacks?
No, by default content emitted using a @ block is automatically HTML encoded to protect from cross-site scripting (XSS) attacks.
43. When using the aspx view engine, to have a consistent look and feel, across all pages of the application, we can make use of asp.net master pages. Define what is asp.net master pages equivalent, when using razor views?
To have a consistent look and feel when using razor views, we can make use of layout pages. Layout pages, reside in the shared folder and are named as _Layout.cshtml
44. Define what are sections?
Layout pages can define sections, which can then be overridden by specific views making use of the layout. Defining and overriding sections is optional.
45. Define what are the file extensions for razor views?
.cshtml – If the programming language is C#
.vbhtml – If the programming language is VB
46. Define How do you specify comments using razor syntax?
Razor syntax makes use of @ to indicate the beginning of comment and@ to indicate the end.
47. Define what is Routing?
A route is a URL pattern that is mapped to a handler. The handler can be a physical file, such as a .aspx file in a Web Forms application. Routing module is responsible for mapping incoming browser requests to particular MVC controller actions.
48. Is it possible to combine ASP.NET web forms and ASP?MVC and develop a single web application?
Yes, it is possible to combine ASP.NET web forms and ASP.MVC and develop a single web application.
49. Define How do you avoid XSS Vulnerabilities in ASP.NET MVC?
Use the syntax in ASP.NET MVC instead of using .net framework 4.0.
50. Explain the new features added in version 4 of MVC (MVC4)?
Following are features added newly –
Mobile templates:
Added ASP.NET Web API template for creating REST based services. Asynchronous controller task support.
Bundling the java scripts. Segregating the configs for MVC routing, Web API, Bundle, etc.
51. Can you explain the page life cycle of MVC?
Below are the processed followed in the sequence –
App initialization
Routing
Instantiate and execute controller
Locate and invoke controller action
Instantiate and render view.
52. Define what are the advantages of MVC over ASP.NET?
1. Provides a clean separation of concerns among UI (Presentation layer), model (Transfer objects/Domain Objects/Entities) andBusiness Logic (Controller).
2. Easy to UNIT Test.
3. Improved reusability of model and views. We can have multiple views which can point to the same model and vice versa.
4. Improved structuring of the code.
53. Define what is Separation of Concerns in ASP.NET MVC?
It’s in the process of breaking the program into various distinct features which overlap in functionality as little as possible. MVC pattern concerns on separating the content from presentation and data-processing from the content.
54. Define what is a Razor View Engine?
Razor is the first major update to render HTML in MVC 3. Razor was designed specifically for view engine syntax. The main focus of this would be to simplify and code-focused templating for HTML generation. Below is
the sample of using Razor:
@model MvcMusicStore.Models.Customer
@{ViewBag.Title = “Get Customers”;}
@Model.CustomerName
55. Define what is the meaning of Unobtrusive JavaScript?
This is a general term that conveys a general philosophy, similar to the term REST (Representational State Transfer). Unobtrusive JavaScript doesn’t intermix JavaScript code in your page markup. Eg: Instead of using events like onclick and onsubmit, the unobtrusive JavaScript attaches to elements by their ID or class based on the HTML5 data- attributes.
56. Define what is the use of ViewModel in MVC?
ViewModel is a plain class with properties, which is used to bind it to a strongly typed view. ViewModel can have the validation rules defined for its properties using data annotations.
57. Define what you mean by Routing in MVC?
Routing is a pattern matching mechanism of incoming requests to the URL patterns which are registered in the route table. Class – “UrlRoutingModule” is used for the same process.
58. Define what are Actions in MVC?
Actions are the methods in Controller class which is responsible for returning the view or JSON data. Action will mainly have return type – “ActionResult” and it will be invoked from the method – “InvokeAction()” called by the controller.
59. Define what is Attribute Routing in MVC?
ASP.NET Web API supports this type of routing. This is introduced in MVC5. In this type of routing, attributes are being used to define the routes. This type of routing gives more control over classic URI Routing. Attribute Routing can be defined at controller level or at the Action level
like – [Route(“{action = TestCategoryList}”)] – Controller Level
60. Define How to enable Attribute Routing?
Just add the method – “MapMvcAttributeRoutes()” to enable attribute routing as sDefine Hown below
public static void RegistearRoutes(RouteCollection routes)
{
routes.IgnoareRoute(“{resource}.axd/{ pathInfo}”);
//enabling attribute routing
routes.MapMvcAttributeRoutes();
//convention-based routing
routes.MapRoute
(
name: “Default”,
url: “{controller}/{action}/{id}”,
defaults: new { controller = “Customer”, action = “GetCustomerList”, id
= UrlParameter.Optional }
);
}
61. Explain JSON Binding?
JavaScript Object Notation (JSON) binding support started from MVC3 onwards via the new JsonValueProviderFactory, which allows the action methods to accept and model-bind data in JSON format. This is useful in Ajax scenarios like client templates and data binding that need to post data back to the server.
62. Explain Dependency Resolution?
Dependency Resolver again has been introduced in MVC3 and it is greatly simplified the use of dependency injection in your applications. This turn to be easier and useful for decoupling the application components and making them easier to test and more configurable.
63. Explain Bundle. Config in MVC4?
“BundleConfig.cs” in MVC4 is used to register the bundles by the bundling and minification system. Many bundles are added by default including jQuery libraries like – jquery. validate, Modernizr, and default CSS references.
64. Define How route table has been created in ASP.NET MVC?
Method – “RegisterRoutes()” is used for registering the routes which will be added in “Application_Start()” method of global.asax file, which is fired when the application is loaded or started.
65. Which are the important namespaces used in MVC?
Below are the important namespaces used in MVC –
System.Web.Mvc
System.Web.Mvc.Ajax
System.Web.Mvc.Html
System.Web.Mvc.Async
67. Define what is ViewData?
Viewdata contains the key, value pairs as dictionary and this is derived from class – “ViewDataDictionary“. In the action method, we are setting the value for viewdata and in view, the value will be fetched by typecasting.
68. Define what is the difference between ViewBag and ViewData in MVC?
ViewBag is a wrapper around ViewData, which allows creating dynamic properties. Advantage of viewbag over viewdata will be –
In ViewBag no need to typecast the objects as in ViewData. ViewBag will take advantage of the dynamic keyword which is introduced in version 4.0. But before using ViewBag we have to keep in mind that ViewBag is slower than ViewData.
69. Can you specify different types of filters in ASP.Net MVC application?
1. Authorization filters (IAuthorizationFilter)
2. Action filters (IActionFilter)
3. Result filters (IResultFilter)
4. Exception filters (IExceptionFilter)
70. If you have already implemented different filters then Define what will be the order of these filters?
1) Authorization filters
2) Action filters
3) Response filters
4) Exception filters
71. Define what are the advantages of using ASP.NET routing?
Answer: Clean URLs is originally brought from Ruby on Rails. http://www.technologycrowds.com?abc=10, now clean URL in MVC ASP.Net will be work like http://www.technologycrowds.com/abc/10
72. Define what is the difference between MVC (Model View Controller) and MVP (Model View Presenter)?
Answer: MVC controller handles all the requests, MVP handles as the handler and also handles the all requests as well.
73. Can we use third-party View Engine using ASP.Net MVC Engine?
Yes, below are the top five alternative ASP.Net MVC View Engines.
1. Spark (Castle MonoRail framework projects), Open Sourced, it is
popular as MVCContrib library.
2. NHaml works like inline page templating.
3. Django uses F# Language.
4. Hasic uses VB.Net, XML.
5. Bellevue for ASP.NEt view, It respects HTML class first.
74. Define what is scaffolding using ASP.Net MVC Engine?
Answer: Scaffolding helps us to write CRUD operations blend using Entity The framework, It helps the developer to write down simply even yet complex business logic.
75. Define what is life cycle in ASP.Net MVC Engine?
Step 1: Fill Route (Global.asax file will hit first).
Step 2: Fetch Route: It will gather information about the controller and action to invoke.
Step 3: Request Context
Step 4: Controller instance: it calls the Controller class and method.
Step 5: Executing Action: It determines which action to be executed
Step 6: Result (View): Now Action method executed and returns back a response to view in differentiating forms like Jason, View Result, File Result, etc.
76. Define what is the significance of ASP.NET routing?
Answer: Default Route Name:“{controller}/{action}/{id}”, // URL with parameters By default, routing is defined under Global.asax file. MVC ASP.Net uses routing to map between incoming browser request to controller action
methods.
77. Can be it possible to share a single view across multiple controllers in MVC?
Answer: We can put the view under the shared folder, it will automatically view them across the multiple controllers.
78. Can you list the main types of result using ASP.Net MVC?
There are total 10 main types of result, ActionResult is main type and others are sub types of results as listed below:
System.Web.Mvc.ActionResult
System.Web.Mvc.ContentResult
System.Web.Mvc.EmptyResult
System.Web.Mvc.FileResult
System.Web.Mvc.HttpStatusCodeResult
System.Web.Mvc.JavaScriptResult
System.Web.Mvc.JsonResult
System.Web.Mvc.RedirectResult
System.Web.Mvc.RedirectToRouteResult
System.Web.Mvc.ViewResultBase
79. Define what are Model Binders in ASP.Net MVC?
For Model Binding we will use a class called: “ModelBinders”, which gives access to all the model binders in an application. We can create a custom model binders by inheriting “IModelBinder”.
80. Define How we can handle the exception at controller level in ASP.Net MVC?
Exception Handling is made simple in ASP.Net MVC and it can be done by just overriding “OnException” and set the result property of the filter context object (as define Hown below) to the view detail, which is to be returned in case of exception.
protected overrides void OnException(ExceptionContext filterContext)
{
}
81. Define what are Scaffold templates in ASP.Net MVC?
Scaffolding in ASP.NET ASP.Net MVC is used to generate the Controllers, Model, and Views for creating read update and delete (CRUD) functionality in an application. The scaffolding will be knowing the naming conventions used for models and controllers and views.
82. Does Tempdata hold the data for other requests in ASP.Net MVC?
If Tempdata is assigned in the current request then it will be available for the current request and the subsequent request and it depends whether data in TempData read or not. If data in Tempdata is read then it would not be available for the subsequent requests.
83. Explain Keep method in Tempdata in ASP.Net MVC?
As explained above in case data in Tempdata has been read in the current request only then “Keep” method has been used to make it available for the subsequent request.
@TempData[“TestData”];
TempData.Keep(“TestData”);
84. Explain Peek method in Tempdata in ASP.Net MVC?
Similar to Keep method we have one more method called “Peek” which is used for the same purpose. This method used to read data in Tempdata and it maintains the data for the subsequent request.
string A4str = TempData.Peek(“TT”).ToString();
85. Define what is Area in ASP.Net MVC?
The area is used to store the details of the modules of our project. This is really helpful for big applications, where controllers, views, and models are all in the main controller, view and model folders and it is very difficult to manage.
86. Define How we can register the Area in ASP.Net MVC?
When we have created an area make sure this will be registered in “Application_Start” event in Global.asax. Below is the code snippet where area registration is done :
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
}
87. Define what are child actions in ASP.Net MVC?
To create reusable widgets child actions are used and this will be embedded into the parent views. In ASP.Net MVC Partial views are used to have reusability in the application. Child action mainly returns partial views.
88. Define How we can invoke child actions in ASP.Net MVC?
“ChildActionOnly” attribute is decorated over action methods to indicate that the action method is a child actor. Below is the code snippet used to denote the child action :
{
//Logic here
return PartialView();
}
89. Define what is Dependency Injection in ASP.Net MVC?
it’s a design pattern and is used for developing loosely coupled code. This is greatly used in software projects. This will reduce the coding in case of changes in project design so this is vastly used.
90. Explain the advantages of Dependency Injection (DI) in ASP.Net MVC?
Below are the advantages of DI :
Reduces class coupling
Increases code reusing
Improves code maintainability
Improves application testing
y TDD is a methodology which says, write your tests first before you write your code. In TDD, tests drive your application design and development cycles. You do not do the check-in of your code into the source control until all of your unit tests pass.
92. Explain the tools used for unit testing in ASP.Net MVC?
Below are the tools used for unit testing :
1. NUnit
2. xUnit.NET
3. Ninject 2
4. Moq
93. Define what is Representational State Transfer (REST) mean?
REST is an architectural style which uses HTTP protocol methods like GET, POST, PUT, and DELETE to access the data. ASP.Net MVC works in this style. In ASP.Net MVC 4 there is support for Web API which uses to build the service using HTTP verbs.
94. Define How to use Jquery Plugins in ASP.Net MVC validation?
We can use data annotations for validation in ASP.Net MVC. If we want to use validation during runtime using Jquery then we can use Jquery plugins for validation. Eg: If validation is to be done on customer name textbox then we can do as :
$(‘#CustomerName’).rules(“add”, {
required: true,
min length: 2,
messages: {
required: “Please enter the name”,
min length: “Minimum length is 2”
}
});
95. Define How we can multiple submit buttons in ASP.Net MVC?
Below is the scenario and the solution to solve multiple submit buttons
issue. Scenario :
@using (Html.BeginForm(“MyTestAction”,”MyTestController”)
{
<input type=”submit” value=”MySave” />
<input type=”submit” value=”MyEdit” />
} Solution :
Public ActionResult MyTestAction(string submit) //submit will have value
either “MySave” or “MyEdit”
{
// Write code here
}
96. Define what are the differences between Partial View and Display
Template and Edit Templates in ASP.Net MVC?
Display Templates: These are model-centric. Meaning it depends on the properties of the view model used. It uses a convention that will only display like divs or labels.
Edit Templates: These are also model-centric but will have editable controls like Textboxes.
Partial View: These are view-centric. These will differ from templates by the way they render the properties (Id’s) Eg: CategoryViewModel has Product class property then it will be rendered as Model.Product.ProductName but in case of templates if weCategoryViewModel has List then @Html.DisplayFor(m => m.Products) works and it renders the template for each item of this list.
97. Can I set the unlimited length for “maxJsonLength” property in the config?
No. We can’t set unlimited length for property maxJsonLength. The default value is – 102400 and maximum value Define what we can set would be: 2147483644.
98. Can I use Razor code in Javascript in ASP.Net MVC?
Yes. We can use the razor code in javascript in cshtml by using <text>
element.
< script type=”text/javascript”>
@foreach (var item in Model) {
< text >
//javascript goes here which uses the server values
< text >
}
< script>
99. Define How can I return string result from Action in ASP.Net MVC?
Below is the code snippet to return string from action method :
public ActionResult TestAction() {
return Content(“Hello Test !!”);
}
100. Define How to return the JSON from action method in ASP.Net MVC?
Below is the code snippet to return string from action method :
public ActionResult TestAction() {
return JSON(new { prop1 = “Test1”, prop2 = “Test2” });
}