What Are Actions In Asp.net 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 method : "InvokeAction()" called by controller.
What Is Attribute Routing In Asp.net Mvc?
ASP.NET Web API supports this type routing. This is introduced in ASP.Net 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 Action level like
[Route("{action = TestCategoryList}")] - Controller Level
[Route("customers/{TestCategoryId:int:min(10)}")] - Action Level
How To Enable Attribute Routing?
Just add @Model.CustomerName the method : "MapASP.Net MVCAttributeRoutes()" to enable attribute routing as shown below
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
//enabling attribute routing
routes.MapASP.Net MVCAttributeRoutes();
//convention-based routing
routes.MapRoute
(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Customer", action = "GetCustomerList", id = UrlParameter.Optional }
);
}
What Are The Options Can Be Configured In Ajax Helpers?
Below are the options in AJAX helpers
Url : This is the request URL.
Confirm : This is used to specify the message which is to be displayed in confirm box.
OnBegin : Javascript method name to be given here and this will be called before the AJAX request.
OnComplete : Javascript method name to be given here and this will be called at the end of AJAX request.
OnSuccess - Javascript method name to be given here and this will be called when AJAX request is successful.
OnFailure - Javascript method name to be given here and this will be called when AJAX request is failed.
UpdateTargetId : Target element which is populated from the action returning HTML.
What Is Layout In Asp.net Mvc?
Layout pages are similar to master pages in traditional web forms. This is used to set the common look across multiple pages. In each child page we can find : /p>
@{
Layout = "~/Views/Shared/TestLayout1.cshtml";
} This indicates child page uses TestLayout page as it's master page.
Explain Json Binding?
JavaScript Object Notation (JSON) binding support started from ASP.Net 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.
Explain Dependency Resolution?
Dependency Resolver again has been introduced in ASP.Net 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.
Explain Bundle.config In Asp.net Mvc5?
"BundleConfig.cs" in ASP.Net MVC5 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.
How Route Table Has Been Created In Asp.net 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.
Which Are The Important Namespaces Used In Asp.net Mvc?
Below are the important namespaces used in ASP.Net MVC
System.Web.ASP.Net MVC
System.Web.ASP.Net MVC.Ajax
System.Web.ASP.Net MVC.Html
System.Web.ASP.Net MVC.Async
What Is Viewdata?
Viewdata contains the key, value pairs as dictionary and this is derived from class : "ViewDataDictionary". In action method we are setting the value for viewdata and in view the value will be fetched by typecasting.
What Is The Difference Between Viewbag And Viewdata In Asp.net Mvc?
ViewBag is a wrapper around ViewData, which allows to create 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 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.
Explain Tempdata In Asp.net Mvc?
TempData is again a key, value pair as ViewData. This is derived from "TempDataDictionary" class. TempData is used when the data is to be used in two consecutive requests, this could be between the actions or between the controllers. This requires typecasting in view.
What Are Html Helpers In Asp.net Mvc?
HTML Helpers are like controls in traditional web forms. But HTML helpers are more lightweight compared to web controls as it does not hold viewstate and events. HTML Helpers returns the HTML string which can be directly rendered to HTML page. Custom HTML Helpers also can be created by overriding "HtmlHelper" class.
How To Use Jquery Plugins In Asp.net Mvc Validation?
We can use dataannotations 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,
minlength: 2,
messages: {
required: "Please enter name",
minlength: "Minimum length is 2"
}
});
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
}
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 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 we CategoryViewModel has List then @Html.DisplayFor(m => m.Products) works and it renders the template for each item of this list.
Can I Set The Unlimited Length For "maxjsonlength" Property In Config?
No. We can't set unlimited length for property maxJsonLength. Default value is - 102400 and maximum value what we can set would be : 2147483644.
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>
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 !!");
}
What Are Ajax Helpers In Asp.net Mvc?
AJAX Helpers are used to create AJAX enabled elements like as Ajax enabled forms and links which performs the request asynchronously and these are extension methods of AJAXHelper class which exists in namespace - System.Web.ASP.Net MVC.
Explain Sections Is Asp.net Mvc?
Section are the part of HTML which is to be rendered in layout page. In Layout page we will use the below syntax for rendering the HTML
@RenderSection("TestSection") And in child pages we are defining these sections as shown below
@section TestSection{
<h1>Test Content<h1>
} If any child page does not have this section defined then error will be thrown so to avoid that we can render the HTML like this
@RenderSection("TestSection", required: false)
How To Change The Action Name In Asp.net Mvc?
"ActionName" attribute can be used for changing the action name.
Below is the sample code snippet to demonstrate more
[ActionName("TestActionNew")]
public ActionResult TestAction()
{
return View();
}
So in the above code snippet "TestAction" is the original action name and in "ActionName" attribute, name - "TestActionNew" is given. So the caller of this action method will use the name "TestActionNew" to call this action.
What Are Code Blocks In Views?
Unlike code expressions that are evaluated and sent to the response, it is the blocks of code that are executed. This is useful for declaring variables which we may be required to be used later.
@{
int x = 123;
string y = "aa";
}
What Is The "helper Page.isajax" Property?
The Helper Page.IsAjax property gets a value that indicates whether Ajax is being used during the request of the Web page.
Can You Explain Renderbody And Renderpage In Asp.net Mvc?
RenderBody is like ContentPlaceHolder in web forms. This will exist in layout page and it will render the child pages/views. Layout page will have only one RenderBody() method. RenderPage also exists in Layout page and multiple RenderPage() can be there in Layout page.
What Is Viewstart Page In Asp.net Mvc?
This page is used to make sure common layout page will be used for multiple views. Code written in this file will be executed first when application is being loaded.
Explain The Methods Used To Render The Views In Asp.net Mvc?
Below are the methods used to render the views from action -
View() : To return the view from action.
PartialView() : To return the partial view from action.
RedirectToAction() : To Redirect to different action which can be in same controller or in different controller.
Redirect() : Similar to "Response.Redirect()" in webforms, used to redirect to specified URL.
RedirectToRoute() : Redirect to action from the specified URL but URL in the route table has been matched.
What Are The Sub Types Of Actionresult?
ActionResult is used to represent the action method result. Below are the subtypes of ActionResult
ViewResult
PartialViewResult
RedirectToRouteResult
RedirectResult
JavascriptResult
JSONResult
FileResult
HTTPStatusCodeResult
What Are Non Action Methods In Asp.net Mvc?
In ASP.Net MVC all public methods have been treated as Actions. So if you are creating a method and if you do not want to use it as an action method then the method has to be decorated with "NonAction" attribute as shown below
[NonAction]
public void TestMethod()
{
// Method logic
}
How We Can Call A Javascript Function On The Change Of A Dropdown List In Asp.net Mvc?
Create a JavaScript method
function DrpIndexChanged() { } Invoke the method
< %:Html.DropDownListFor(x => x.SelectedProduct, new SelectList(Model.Customers, "Value", "Text"), "Please Select a Customer", new { id = "ddlCustomers", onchange=" DrpIndexChanged ()" })%>
What Are Validation Annotations?
Data annotations are attributes which can be found in the "System.ComponentModel.DataAnnotations" namespace. These attributes will be used for server-side validation and client-side validation is also supported. Four attributes - Required, String Length, Regular Expression and Range are used to cover the common validation scenarios.
Why To Use Html.partial In Asp.net Mvc?
This method is used to render the specified partial view as an HTML string. This method does not depend on any action methods.
We can use this like below
@Html.Partial("TestPartialView")
What Is The Need Of Action Filters In Asp.net Mvc?
Action Filters allow us to execute the code before or after action has been executed. This can be done by decorating the action methods of controls with ASP.Net MVC attributes.
Mention Some Action Filters Which Are Used Regularly In Asp.net Mvc?
Below are some action filters used
Authentication
Authorization
HandleError
OutputCache
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 method : "InvokeAction()" called by controller.
What Is Attribute Routing In Asp.net Mvc?
ASP.NET Web API supports this type routing. This is introduced in ASP.Net 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 Action level like
[Route("{action = TestCategoryList}")] - Controller Level
[Route("customers/{TestCategoryId:int:min(10)}")] - Action Level
How To Enable Attribute Routing?
Just add @Model.CustomerName the method : "MapASP.Net MVCAttributeRoutes()" to enable attribute routing as shown below
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
//enabling attribute routing
routes.MapASP.Net MVCAttributeRoutes();
//convention-based routing
routes.MapRoute
(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Customer", action = "GetCustomerList", id = UrlParameter.Optional }
);
}
 |
| Samsung SDS Frequently Asked ASP.NET MVC Interview Questions Answers |
What Are The Options Can Be Configured In Ajax Helpers?
Below are the options in AJAX helpers
Url : This is the request URL.
Confirm : This is used to specify the message which is to be displayed in confirm box.
OnBegin : Javascript method name to be given here and this will be called before the AJAX request.
OnComplete : Javascript method name to be given here and this will be called at the end of AJAX request.
OnSuccess - Javascript method name to be given here and this will be called when AJAX request is successful.
OnFailure - Javascript method name to be given here and this will be called when AJAX request is failed.
UpdateTargetId : Target element which is populated from the action returning HTML.
What Is Layout In Asp.net Mvc?
Layout pages are similar to master pages in traditional web forms. This is used to set the common look across multiple pages. In each child page we can find : /p>
@{
Layout = "~/Views/Shared/TestLayout1.cshtml";
} This indicates child page uses TestLayout page as it's master page.
Explain Json Binding?
JavaScript Object Notation (JSON) binding support started from ASP.Net 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.
Explain Dependency Resolution?
Dependency Resolver again has been introduced in ASP.Net 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.
Explain Bundle.config In Asp.net Mvc5?
"BundleConfig.cs" in ASP.Net MVC5 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.
How Route Table Has Been Created In Asp.net 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.
Which Are The Important Namespaces Used In Asp.net Mvc?
Below are the important namespaces used in ASP.Net MVC
System.Web.ASP.Net MVC
System.Web.ASP.Net MVC.Ajax
System.Web.ASP.Net MVC.Html
System.Web.ASP.Net MVC.Async
What Is Viewdata?
Viewdata contains the key, value pairs as dictionary and this is derived from class : "ViewDataDictionary". In action method we are setting the value for viewdata and in view the value will be fetched by typecasting.
What Is The Difference Between Viewbag And Viewdata In Asp.net Mvc?
ViewBag is a wrapper around ViewData, which allows to create 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 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.
Explain Tempdata In Asp.net Mvc?
TempData is again a key, value pair as ViewData. This is derived from "TempDataDictionary" class. TempData is used when the data is to be used in two consecutive requests, this could be between the actions or between the controllers. This requires typecasting in view.
What Are Html Helpers In Asp.net Mvc?
HTML Helpers are like controls in traditional web forms. But HTML helpers are more lightweight compared to web controls as it does not hold viewstate and events. HTML Helpers returns the HTML string which can be directly rendered to HTML page. Custom HTML Helpers also can be created by overriding "HtmlHelper" class.
How To Use Jquery Plugins In Asp.net Mvc Validation?
We can use dataannotations 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,
minlength: 2,
messages: {
required: "Please enter name",
minlength: "Minimum length is 2"
}
});
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
}
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 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 we CategoryViewModel has List then @Html.DisplayFor(m => m.Products) works and it renders the template for each item of this list.
Can I Set The Unlimited Length For "maxjsonlength" Property In Config?
No. We can't set unlimited length for property maxJsonLength. Default value is - 102400 and maximum value what we can set would be : 2147483644.
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>
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 !!");
}
What Are Ajax Helpers In Asp.net Mvc?
AJAX Helpers are used to create AJAX enabled elements like as Ajax enabled forms and links which performs the request asynchronously and these are extension methods of AJAXHelper class which exists in namespace - System.Web.ASP.Net MVC.
Explain Sections Is Asp.net Mvc?
Section are the part of HTML which is to be rendered in layout page. In Layout page we will use the below syntax for rendering the HTML
@RenderSection("TestSection") And in child pages we are defining these sections as shown below
@section TestSection{
<h1>Test Content<h1>
} If any child page does not have this section defined then error will be thrown so to avoid that we can render the HTML like this
@RenderSection("TestSection", required: false)
How To Change The Action Name In Asp.net Mvc?
"ActionName" attribute can be used for changing the action name.
Below is the sample code snippet to demonstrate more
[ActionName("TestActionNew")]
public ActionResult TestAction()
{
return View();
}
So in the above code snippet "TestAction" is the original action name and in "ActionName" attribute, name - "TestActionNew" is given. So the caller of this action method will use the name "TestActionNew" to call this action.
What Are Code Blocks In Views?
Unlike code expressions that are evaluated and sent to the response, it is the blocks of code that are executed. This is useful for declaring variables which we may be required to be used later.
@{
int x = 123;
string y = "aa";
}
What Is The "helper Page.isajax" Property?
The Helper Page.IsAjax property gets a value that indicates whether Ajax is being used during the request of the Web page.
Can You Explain Renderbody And Renderpage In Asp.net Mvc?
RenderBody is like ContentPlaceHolder in web forms. This will exist in layout page and it will render the child pages/views. Layout page will have only one RenderBody() method. RenderPage also exists in Layout page and multiple RenderPage() can be there in Layout page.
What Is Viewstart Page In Asp.net Mvc?
This page is used to make sure common layout page will be used for multiple views. Code written in this file will be executed first when application is being loaded.
Explain The Methods Used To Render The Views In Asp.net Mvc?
Below are the methods used to render the views from action -
View() : To return the view from action.
PartialView() : To return the partial view from action.
RedirectToAction() : To Redirect to different action which can be in same controller or in different controller.
Redirect() : Similar to "Response.Redirect()" in webforms, used to redirect to specified URL.
RedirectToRoute() : Redirect to action from the specified URL but URL in the route table has been matched.
What Are The Sub Types Of Actionresult?
ActionResult is used to represent the action method result. Below are the subtypes of ActionResult
ViewResult
PartialViewResult
RedirectToRouteResult
RedirectResult
JavascriptResult
JSONResult
FileResult
HTTPStatusCodeResult
What Are Non Action Methods In Asp.net Mvc?
In ASP.Net MVC all public methods have been treated as Actions. So if you are creating a method and if you do not want to use it as an action method then the method has to be decorated with "NonAction" attribute as shown below
[NonAction]
public void TestMethod()
{
// Method logic
}
How We Can Call A Javascript Function On The Change Of A Dropdown List In Asp.net Mvc?
Create a JavaScript method
function DrpIndexChanged() { } Invoke the method
< %:Html.DropDownListFor(x => x.SelectedProduct, new SelectList(Model.Customers, "Value", "Text"), "Please Select a Customer", new { id = "ddlCustomers", onchange=" DrpIndexChanged ()" })%>
What Are Validation Annotations?
Data annotations are attributes which can be found in the "System.ComponentModel.DataAnnotations" namespace. These attributes will be used for server-side validation and client-side validation is also supported. Four attributes - Required, String Length, Regular Expression and Range are used to cover the common validation scenarios.
Why To Use Html.partial In Asp.net Mvc?
This method is used to render the specified partial view as an HTML string. This method does not depend on any action methods.
We can use this like below
@Html.Partial("TestPartialView")
What Is The Need Of Action Filters In Asp.net Mvc?
Action Filters allow us to execute the code before or after action has been executed. This can be done by decorating the action methods of controls with ASP.Net MVC attributes.
Mention Some Action Filters Which Are Used Regularly In Asp.net Mvc?
Below are some action filters used
Authentication
Authorization
HandleError
OutputCache
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