Question:What are the primary types of Custom Control? Explain each in short. 

ASP.NET custom controls are more flexible than user controls. We can create a custom control that inherits from another server-side control and then extend that control. We can also share a custom control among projects.

Question:What are Web Parts? What they are use for? 

Web Parts are components of a webpage that can be personalized and rearranged. You can use Web Parts to improve a site’s consistency while still allowing users to customize 
content to their specific needs. Forms or Windows

Question:What is Validation Summary control? 

The ValidationSummary control allows you to summarize the error messages from all validation controls on a Web page in a single location. The summary can be displayed as a list, a bulleted list, or a single paragraph

Question:Why HTTP is used? 

An ASP.NET HTTP handler is the process that runs in response to a request made to an ASP.NET Web application. The most common handler is an ASP.NET page handler that processes .aspx files

Question:What is cookies? 

A cookieis a small amount of data that you write to the client to be stored and then passed with requests to your site. You write persistent cookies to a text file on the client machine.

Question:What is Querystrings? 

The query string is a collection of key–value pairs, separated by an ampersand (&) character. The start of the query string is indicated by a question mark (?). 
The following provides an example.
GET /getCustomer.aspx?Id=123&color=blue

Question:What is ASP.NET Theme? 

An ASP.NET theme is a collection of styles, property settings, and graphics that define the appearance of pages and controls on your website. A theme can include skin files, which define property settings for ASP.NET web server controls; cascading style sheet (.css) filesthat define colors, graphics, the size and placement of controls.

Question:What is user control? 

A user control is a file we create that contains a set of other ASP.NET controls and code grouped together to provide common functionality. The user control can then be used on different pages within a website.

Question:Define Web service? 

A web service is a web application which is basically a class consisting of methods that could be used by other applications.