ASP.NET - .NET Interview Questions and Answers

115. What are the various ways of authentication techniques in ASP.NET?

There are various techniques in ASP.NET to authenticate a user. You can use one of the following ways of authentication to select a built-in authentication provider:

• Windows Authentication - This mode works as the default authentication technique. It can work with any form of Microsoft Internet Information Services (IIS) authentication, such as Basic, Integrated Windows authentication (NTLM/Kerberos), Digest, and certificates. The syntax of Windows authentication mode is given as follows: <authentication mode="windows" />
• Forms Authentication - You can specify this mode as a default authentication mode by using the following code snippet: <authentication mode="Forms"/>
• Passport - This mode works with Microsoft Passport authentication, as shown in the following code snippet: <authentication mode = "Passport"/>

116. What are the different ways to send data across pages in ASP.NET?

The following two ways are used to send data across pages in ASP.NET:

• Session
• Public properties

117. What does the WebpartListUserControlPath property of a DeclarativeCatalogPart control do?

The WebpartListUserControlPath property sets the route of the user defined control to a DeclarativeCatalogPart control.

118. What do you mean by the Web Part controls in ASP.NET?

The Web Part controls are the integrated controls, which are used to create a Web site. These controls allow the users to change the content, outlook, and state of Web pages in a Web browser.

119. What type of the CatalogPart control enables users to restore the Web Parts that have been removed earlier by the user?

The PageCatalogPart control.

120. What is the use of web.config? What is the difference between machine.config and web.config?

ASP.NET configuration files are XML-based text files for application-level settings and are saved with the name web.config. These files are present in multiple directories on an ASP.NET Web application server. The web.config file sets the configuration settings to the directory it is placed in and to all the virtual sub folders under it. The settings in sub directories can optionally override or change the settings specified in the base directory.

The difference between the web.config and machine.config files is given as follows:

• <WinDir>\Microsoft.NET\Framework\<version>\config\machine.config provides default configuration settings for the entire machine. ASP.NET configures IIS to prohibit the browser directly from accessing the web.config files to make sure that their values cannot be public. Attempts to access those files cause ASP.NET to return the 403: Access Forbidden error.
• ASP.NET uses these web.config configuration files at runtime to compute hierarchically a sole collection of settings for every URL target request. These settings compute only once and cached across further requests. ASP.NET automatically checks for changing file settings and do not validate the cache if any of the configuration changes made.
  121. Explain the concept of states in ASP.NET.

  State is quite an innovative concept in Web development because it eliminates the drawback of losing state data due to reloading of a Web page. By using states in a Web application, you can preserve the state of the application either at the server or client end. The state of a Web application helps you to store the runtime changes that have been made to the Web application. For example, as already described earlier, a change in the data source of the Web application might be initiated by a user when he/she selects and saves some products in the shopping cart.
  
  If you are not using states, these changes are discarded and are not saved. You may think that the whole concept of storing states is optional. However, under certain circumstances, using states with applications is imperative. For example, it is necessary to store states for Web applications, such as an e-commerce shopping site or an Intranet site of a company, to keep track of the requests of the users for the items they have selected on the shopping site or the days requested for vacation on the Intranet site.
  122. Can we validate a DropDownList by RequiredFieldValidator?

  Yes, we can validate a DropDownList by RequiredFieldValidator. To perform this validation, we have to set the InitialValue property of RequiredFieldValidator control.
  123. List the features of the Chart control.
  The following are the features of the Chart control:
  
• Bounds a chart with any data source.
• Simple manipulation of chart data, such as copying, merging, grouping, sorting, searching, and filtering.
• Support many statistical and financial formulas for data analysis.
• Provide advanced chart outlook, such as 2-D, 3-D, lighting, and perspective.
• Support events and customizations.
• Includes interactivity with Microsoft AJAX.
• Supports AJAX Content Delivery Network (CDN).