ASP.NET - .NET Interview Questions and Answers Part 3

61. What do you understand by aggregate dependency?

Aggregate dependency allows multiple dependencies to be aggregated for content that depends on more than one resource. In such type of dependency, you need to depend on the sum of all the defined dependencies to remove a data item from the cache.

62. How can you ensure that no one has tampered with ViewState in a Web page?

To ensure that no one has tampered with ViewState in a Web page, set the EnableViewStateMac property to True.

63. What is the difference between adding items into cache through the Add() method and through theInsert() method?

Both methods work in a similar way except that the Cache.Add() function returns an object that represents the item you added in the cache. The Cache.Insert() function can replace an existing item in the cache, which is not possible using the Cache.Add() method.

64. Explain the cookie less session and its working.

ASP.NET manages the session state in the same process that processes the request and does not create a cookie. It is known as a cookie less session. If cookies are not available, a session is tracked by adding a session identifier to the URL. The cookie less session is enabled using the following code snippet:<sessionState cookieless="true" />

65. What is a round trip?

The trip of a Web page from the client to the server and then back to the client is known as a round trip.

66. What are the major built-in objects in ASP.NET?

The major built-in objects in ASP.NET are as follows:

• Application
• Request
• Response
• Server
• Session
• Context
• Trace

67. Where should the data validations be performed-at the client side or at the server side and why?

Data validations should be done primarily at the client side and the server-side validation should be avoided because it makes server task overloaded. If the client-side validation is not available, you can use server-side validation. When a user sends a request to the server, the validation controls are invoked to check the user input one by one.

68. Why do we need nested master pages in a Web site?

When we have several hierarchical levels in a Web site, then we use nested master pages in the Web site.

69. How can you dynamically add user controls to a page?

User controls can be dynamically loaded by adding a Web User Control page in the application and adding the control on this page.

70. What is the appSettings Section in the web.config file?

The web.config file sets the configuration for a Web project. The appSettings block in configuration file sets the user-defined values for the whole application.

For example, in the following code snippet, the specified ConnectionString section is used throughout the project for database connection:

<configuration>
<appSettings>
<add key="ConnectionString" value="server=indiabixserver; pwd=dbpassword; database=indiabix" />
</appSettings>
...

71. What type of code, client-side or server-side, is found in a code-behind file of a Web page?

A code-behind file contains the server-side code, which means that the code contained in a code-behind file is executed at the server.

72. To which class a Web form belongs to in the .NET Framework class hierarchy?

A Web form belongs to the System.Web.UI.Page class.

73. What does the "EnableViewState" property do? Why do we want it On or Off?

The EnableViewState property enables the ViewState property on the page. It is set to On to allow the page to save the users input between postback requests of a Web page; that is, between the Request and corresponding Response objects. When this property is set to Off, the page does not store the users input during postback.

74. Which event determines that all the controls are completely loaded into memory?

The Page_Load event determines that all the controls on the page are fully loaded. You can also access the controls in the Page_Init event; however, the ViewState property does not load completely during this event.

75. What is the function of the CustomValidator control?

It provides the customize validation code to perform both client-side and server-side validation.

76. What is Role-based security?

In the Role-based security, you can assign a role to every user and grant the privilege according to that role. A role is a group of principal that restricts a user's privileges. Therefore, all the organization and applications use role-based security model to determine whether a user has enough privileges to perform a requested task.

77. Which data type does the RangeValidator control support?

The data types supported by the RangeValidator control are Integer, Double, String, Currency, and Date.

78. What are the HTML server controls in ASP.NET?

HTML server controls are similar to the standard HTML elements, which are normally used in HTML pages. They expose properties and events that can be used programmatically. To make these controls programmatically accessible, you need to specify that the HTML controls act as a server control by adding the runat="server"attribute.

79. Why a SiteMapPath control is referred to as breadcrumb or eyebrow navigation control?

The SiteMapPath control displays a hierarchical path to the root Web page of the Web site. Therefore, it is known as the breadcrumb or eyebrow navigation control.

80. Where is the ViewState information stored?

The ViewState information is stored in the HTML hidden fields.

81. Which namespaces are necessary to create a localized application?

The System.Globalization and System.Resources namespaces are essential to develop a localized application.

82. What is the difference between an HtmlInputCheckBox control and an HtmlInputRadioButton control?

You can select more than one HtmlInputCheckBox control from a group of HtmlInputCheckBox controls; whereas, you can select only a single HtmllnputRadioButton control from a group ofHtmlInputRadioButton controls.

83. What is the difference between HTML and Web server controls?

HTML controls are client-side controls; therefore, all the validations for HTML controls are performed at the client side. On the other hand, Web server controls are server-side controls; therefore, all the validations for Web server controls are performed at the server side.

84. Explain the AdRotator Control.

The AdRotator is an ASP.NET control that is used to provide advertisements to Web pages. The AdRotatorcontrol associates with one or many advertisements, which randomly displays one by one at a time when the Web page is refreshed. The AdRotator control advertisements are associated with links; therefore, when you click on an advertisement, it redirects you to other pages.

The AdRotator control is associated with a data source, which is normally an xml file or a database table. A data source contains all the information, such as advertisement graphics reference, link, and alternate text. Therefore, when you use the AdRotator control, you should first create a data source and then associate it with the AdRotator control.

85. What do you understand by the culture?

The culture denotes a combination of a language and optionally a region or a country. The contents of a Web page of a multilingual Web site are changed according to the culture defined in the operating system of the user accessing the Web page.

86. What is the difference between absolute expiration and sliding-time expiration?

The absolute expiration expires a cached item after the provided expiration time. The sliding time does not expire the cached items because it increments the specified time.

87. What is the code-behind feature in ASP.NET?

The code-behind feature of ASP.NET enables you to divide an ASP.NET page into two files - one consisting of the presentation data, and the second, which is also called the code-behind file, consisting of all the business logic. The presentation data contains the interface elements, such as HTML controls and Web server controls, and the code-behind contains the event-handling process to handle the events that are fired by these controls. The file that contains the presentation data has the .aspx extension. The code behind file has either the .cs extension (if you are using the programming language C#) or the .vb (if you are using the programming language Visual Basic .NET) extension.

88. How can you check if all the validation controls on a Web page are valid and proper?

You can determine that all the validation controls on a Web page are properly working by writing code in the source file of the Web page using a scripting language, such as VBScript or JavaScript. To do this task, you have to loop across validators collection of pages and check the IsValid property of each validation control on the Web page to check whether or not the validation test is successful.

89. Explain the validation controls. How many validation controls in ASP.NET 4.0?

Validation controls are responsible to validate the data of an input control. Whenever you provide any input to an application, it performs the validation and displays an error message to user, in case the validation fails.

ASP.NET 4.0 contains the following six types of validation controls:

• CompareValidator - Performs a comparison between the values contained in two controls.
• CustomValidator - Writes your own method to perform extra validation.
• RangeValidator- Checks value according to the range of value.
• RegularExpressionValidator - Ensures that input is according to the specified pattern or not.
• RequiredFieldValidator - Checks either a control is empty or not.
• ValidationSummary - Displays a summary of all validation error in a central location.

90. What is difference between a Label control and a Literal control?

The Label control's final html code has an HTML tag; whereas, the Literal control's final html code contains only text, which is not surrounded by any HTML tag.