Interview Questions Answers
1. What are the asp.net page life cycle, name cycle?
2. What are the different Types of ASP.Net Validation Controls?
RequireFieldValidator: validates for requiring filed or user input
RangeValidator: it validates the range of input filed like (0-9), (A-Z), (100-2000)
CompareValidator: it is used to compare the input control value with certain fixed value or another control value.
RegularExpressionValidator: it is used to express the input value as in required format or expression i.e. for formatting of phone number (e.g. 402-345-2344), date time format etc.
CustomValidator: it is used to customize the validation logic as needs of application logic.
Validation Summary: displays all error message of validation controls on the page.
3. What are the various ways to send content from one page to another page?
4. What is difference between Server.Transfer() and Response.Redirect() and which is best?
In case of Response.Redirect(), a new request is generated from client-side for the redirected page. It’s a kind of additional round trip. As the new request is generated from a client, so the new URL is visible to the user in a browser after redirection.
While in case of Server.Transfer(), a request is transferred from one page to another without making a round trip from the client. For the end user, URL remains the same in a browser even after transferring to another page.
5. Why Html Helper prefer than Asp Control?
Answer: The reason for preferring Html helper is lightweight though these are like ASP Controls.
6. What is the difference between Custom Control and User Control?
Custom control is compiled code e.g: DLL. These are complex to create than User Controls and can easily be added in the toolbox. These can be used in multiple projects with drag and drop approach.
The user controls i.e. (ascx) are like design pages i.e. (aspx). These are comparatively easy to create than custom control and are tightly coupled with respect to code and UserInterface. These can be used in multiple projects with copy and paste method.
7. What is Global.aspx file and purpose of it?
Global.asax is Asp.net Application File. It is located under App_Start Folder.
Main Purpose of it is to place the Application Level code such as Application start, Application End, Session Start, Session End and Application Error handle.
Main Events fired in Global.asax file is
Application_Init: fires for application initialization for the very first time.
Application_Start: fires when the application starts.
Session_Start: fires when the user session starts.
Application_Error: fire when there occurs the error in application.
Session_End: fire when the user session ends.
Application_End: fire at the time of application end or timeout
8. What are the Types of Authentication available in ASP.net?
9. What are Session State Modes in Asp.net?
10. What are session state management processes in Asp.net?
In-Proc: Store the session in Web server Memory.
Out Proc: store the session in different external server either in State Server or SQL Server.
11. What is Difference between Session.Abandon() and Session.Clear()?
Session.Abandon(): Session.Abandon() destroy the running session with the firing of Session_End event from the Global.asax file. It releases the Session State Object and its items to free resources.
Seesion.Clear(): It only clears the session data and set the value to null without killing the session. A resource becomes reserved with a null value.
12. What are the different Types of Catching inAsp.net?
There are 3 types of catching.
13. Can we have the web application running without web.config file?
14. Can we have multiple webconfig files in Asp.net Application?
15. Is it possible to create the web application with Asp.net web forms and MVC?
We can create the hybrid application of Web forms and MVC by using following assembly references.
16. Write a sample code to send email from Asp.net Application.
MailMessage mailMsg=new MailMessage();
mailMsg.Subject=”Email sending test”;
17. What is the good practice for implementation of validation in Asp.net?
Client Side validation is the best way to validate data in Asp.net application. Its Benefits are.
-Low network traffic.
-Save Server Resources.
18. What are the differences between WebConfig and Machine Config file?
WebConfig File: It is specific to the web application. There can have multiple web config file into an application.
MachineConfig File: It is Specific to machine or server. There can be only one MachineConfig File into an application.
1.Write the script to create Table.
CREATE TABLE Test
2. What is Primary Key Constraint?
The PRIMARY KEY constraint uniquely identifies each record in a database table. It must contain unique values and must not contain null values. Most of the tables should have a Primary key but there exists only one Primary Key for one table.
- What is Foreign Key Constraint?
A FOREIGN KEY in one table points to a PRIMARY KEY in another table. There can exist multiple Foreign Key and Foreign Key may have null values. The FOREIGN KEY constraint prevents invalid data from being inserted into the foreign key column because it has to be one of the values contained in the table it points to.
- What is Unique Constraint?
The UNIQUE constraint uniquely identifies each record in a database table. Unique Constraint and Primary Key both provides the uniqueness of data in database table. There can be multiple Unique Key in Table but only One Primary Key. Primary Key itself has automatically defined Unique Constraint on it.
- How Union and Union All works in SQL server?
Union gives the record only once if it occurs several times but Union All gives the record as several time that occurs in the table.
e.g. Table 1
Union All Result
- What are SQL Join?
Inner Join: If we need Common records from both the tables we use Inner Join.
Outer Join: when we need a common and uncommon record from both the table outer join is used. The outer join is of two types on the basis of the unmatching record of which table is needed.
Left Outer Join: This gives all the record of the Left table and common record of the right table. Right Outer Join: This gives all the record of the Right table and common record of the left table.
Full Join: It gives all the record of both tables.
7. Suppose you have the script of one database for one client and you need to create the same database for another client for same project deployment. How you ensure there is the exactly same database, there is no mismatch of the table, table name, columns and constraints in both the Database?
By checking the Number of Tables, Number of Columns, Number of Constraints, Table Name etc we can ensure that there is no mismatch of database creation if there is anything missed we can find out what is missing with the help of it.
Query for Number of Table Count
select COUNT(* ) from INFORMATION_SCHEMA.TABLES
Query for Number of Column count
select COUNT(* ) from INFORMATION_SCHEMA.COLUMNS
Query for Number of Constraint Count
select COUNT(* ) from INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE
If there is one table creation missing then running following below query in both database and comparing each other, we can find out which table is missing. This will give the name list of table in the database.
select TABLE_NAME from INFORMATION_SCHEMA.TABLES
- How many types of Function exists in SQL server explain with example?
There are two types of SQL Function
- SQL Aggregate Functions
It returns a single value, calculated from values in a column.
Some of the Aggregate SQL Function are
AVG() – Returns the average value
COUNT() – Returns the number of rows
FIRST() – Returns the first value
LAST() – Returns the last value
MAX() – Returns the largest value
MIN() – Returns the smallest value
SUM() – Returns the sum
- SQL Scalar functions
SQL Scalar functions return a single value, based on the input value.
Some of the SQL Scalar Functions are
UCASE() – Converts a field to upper case
LCASE() – Converts a field to lower case
MID() – Extract characters from a text field
LEN() – Returns the length of a text field
ROUND() – Rounds a numeric field to the number of decimals specified
NOW() – Returns the current system date and time
FORMAT() – Formats how a field is to be displayed
- What is Difference Between Store Procedure and Function?
– A Stored Procedure can return zero, single or multiple values. But, a function must return a single value.
– A Stored Procedure can have both input and output parameters whereas Functions can have only input parameters.
– Functions allow only a SELECT command whereas a Stored Procedure allows SELECT and other DML commands (INSERT, UPDATE and DELETE).
– A Stored Procedure can call a function, but a function can’t call a Stored Procedure.
– A Stored Procedure can use the try-catch block to handle exceptions. But try-catch is not allowed in functions.
– SQL transactions can be used in Stored Procedures but not in Functions.
- What is SQL Aliases?
Aliases are used to give database Table Name or Table Column Name as Temporary Name. It is used to make column Name more readable.
SELECT ColumnName AS AliasName