What is mvc 2 web application

DefaultValueAttribute class allows a default value to be supplied for the argument parameter to an action method. For example, assume that the following default route is defined:. Any of the following request URLs will invoke the View action method that is defined in the preceding example. Without the DefaultValueAttribute attribute, the first URL from the preceding list would not work, because the page argument is a non-nullable value type whose value has not been provided. If your code is written in Visual Basic or Visual C , you can use optional parameters instead of the DefaultValueAttribute attribute, as shown in the following example:.

There are two new overloads of the Html. Hidden helper that encode binary values as baseencoded strings:. A typical use is to embed a timestamp for an object in the view. For example, your application might include the following Product object:. This markup renders a hidden input element with the timestamp value as a baseencoded string that resembles the following example:. This form might be posted to an action method that has an argument of type Product, as shown in the following example:.

In the action method, the TimeStamp property is populated correctly because the posted baseencoded string is converted to a byte array. The ModelMetadataProvider class provides an abstraction for obtaining metadata for the model within a view.

MVC 2 includes a default provider that makes available the metadata that is exposed by the attributes in the System. DataAnnotations namespace. It is possible to create metadata providers that provide metadata from other data stores, such as databases or XML files. The ViewDataDictionary class exposes a ModelMetadata object that contains the metadata that is extracted from the model by the ModelMetadataProvider class. This enables the templated helpers to consume this metadata and adjust their output accordingly.

DataAnnotations namespace when you bind to a model in order to provide input validation. The model-validation provider class represents an abstraction that provides validation logic for the model. You can also create your own validation providers that define custom validation rules and custom mappings of validation rules to the model. For more information, see the documentation for the ModelValidatorProvider class. The model-validator provider class exposes validation metadata to the browser in the form of JSON-serialized data that can be consumed by a client-side validation library.

NET MVC 2 includes a client validation library and adapter that supports the DataAnnotations namespace validation attributes noted earlier.

The provider class also enables you to use other client-validation libraries by writing an adapter that processes the JSON data and calls into the alternate library. To view a list of these snippets, in the Tools menu, select Code Snippets Manager. For more information about how to use code snippets, see the Visual Studio documentation.

NET MVC 2 includes new attributes that you can apply to action methods and that feature compact syntax. These attributes enable ASP.

In earlier versions of ASP. Thus it is not possible to natively support all RESTful requests. This method renders a hidden input element that causes the form to effectively emulate any HTTP method. The behavior of HttpMethodOverride affects the following attributes:.

The override can only be used when the real request is a POST request. The override value will be ignored for requests that use any other HTTP verb.

You can apply the new HiddenInputAttribute attribute to a model property to indicate whether a hidden input element should be rendered when displaying the model in an editor template.

The attribute's DisplayValue property lets you specify whether the value is displayed in editor and display modes. The default value for DisplayValue is true. Thus many subsequent requests can be easily handled by servlet. Problem in Servlet technology Servlet needs to recompile if any designing code is modified. It doesn't provide separation of concern. Presentation and Business logic are mixed up.

JSP overcomes almost all the problems of Servlet. It provides better separation of concern, now presentation and business logic can be easily separated. You don't need to redeploy the application if JSP page is modified. As you can see in the above figure, there is picture which show the flow of the model1 architecture. The MVC design pattern consists of three modules model, view and controller.

Model The model represents the state data and business logic of the application. View The view module is responsible to display data i. Controller The controller module acts as an interface between view and model. It intercepts all the requests i. It uses the declarative approach for defining view components, request mapping etc. It resolves the problem of Model 2 architecture. The Struts framework provides the configurable MVC support.

In struts 2, we define all the action classes and view components in struts. JavaTpoint offers too many high quality services. Mail us on [email protected] , to get more information about given services. Please mail your requirement at [email protected] Duration: 1 week to 2 week. Struts Tutorial Struts2 Introduction. Struts 2 Architecture. Struts2 Configuration. Custom Interceptor params interceptor execAndWait prepare interceptor modelDriven interceptor exception interceptor fileUpload interceptor.

Some other action results redirect to another controller, return a JSON object or return a file stream. Typically you do not return an ActionResult directly; instead you use a helper method to construct the ActionResult. One example is calling the View method to create a ViewResult object. Views are responsible for displaying the current state of the application to a user.

Views are associated with controllers and actions based on specific folder and file names. In ASP. They can greatly reduce the amount of HTML markup and script that you need to produce. The controller ViewData property is used to pass information from the controller to the View. Example 1 above shows the string value "Welcome to ASP.

Example 2 above is displaying the value that was assigned. In contrast to the Controller and Views, the Model is not a defined set of classes or interfaces. The Model can be implemented using whatever means best suit the application. If the Model is part of the main application, it is recommended to put the Model classes under the Model folder in the project.

In larger systems the Model objects are often contained in separate assemblies so they can be reused in other projects. The Controller typically interfaces with the Model by instantiating the Model classes in the Controller Action and calling methods to manipulate the Model and then passing information from the Model to a View for display.

It is also available as a download for Visual Studio , and an upgrade wizard is provided to update ASP.