Method overloading in ASMX service

·         Method overloading (polymorphism) is not supported by default

·         But can be achieved using MessageName property of WebMethod attribute.

·         Reference:  http://forums.asp.net/t/1162934.aspx/1

 

[WebService(Namespace = "http://tempuri.org/")]

//[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

[WebServiceBinding(ConformsTo = WsiProfiles.None)]

// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.

// [System.Web.Script.Services.ScriptService]

public class Service : System.Web.Services.WebService

{

    public Service () {

 

        //Uncomment the following line if using designed components

        //InitializeComponent();

    }

 

    [WebMethod]

    public string HelloWorld()

    {

        return "Hello World";

    }

 

    [WebMethod(MessageName = "HelloWorldwithParam")]

    public string HelloWorld(string message)

    {

        return message;

    }

   

}

 

 

---

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Self join: Employee - Manager

ID   Name        ManagerID

1 Balaji NULL
2 Ashish 1
3 Divya 1
4 Nidhish 2


Write a query to display ManagerName (ManagerID is foreign key to ID)/



SELECT     e.ID, e.Name, mgr.Name AS ManagerName
FROM         Employee AS e LEFT OUTER JOIN
                      Employee AS mgr ON e.ManagerID = mgr.ID

Result:


1 Balaji NULL
2 Ashish Balaji
3 Divya Balaji
4 Nidhish Ashish

SQL Sample question

1.       Find out Name of customer who has maximum number of product?

2.       Find out Name of customer who does not have product.

/*find customer who has maximum product*/

select top 1 c.Name , COUNT(c.ID) as CustomerCount from Customer c left outer join CustomerProduct cp

      on c.ID = cp.CustomerID

            group by c.ID ,c.Name

            order by CustomerCount desc

/*find all customers who does not have any product*/

select c.Name  from Customer c left outer join CustomerProduct cp

      on c.ID = cp.CustomerID

     

            where cp.CustomerID is null

Create a Project plan in 5 easy steps - Microsoft Office Project

http://office.microsoft.com/en-us/project-help/create-a-project-plan-in-5-easy-steps-HA001136153.aspx 

Strategy Pattern

A manufacturing company produces different products, and they sell it with help of distributors. Manufacturing company and distributor makes agreement like 10% rebate for 1000 products. Rebate claim by distributor can be send to company in the form of files (txt, excel1, excel2, excel3). And claim management system processes these files. 


txt         - process directly
excel1 - 4 columns template
excel2 - 8 columns template
excel3 - 9 columns template

Which GoF pattern is ideal in this scenario?

Solution: Strategy pattern

• Strategy is a behavioral pattern
• algorithms can be selected at runtime
• defines a family of algorithms, encapsulates each one, make them interchangable

Reference: 
http://www.dofactory.com/Patterns/PatternStrategy.aspx
http://en.wikipedia.org/wiki/Strategy_pattern

Publisher - Subscriber (optimized)

• Publisher-Subscriber is a messaging pattern. 
• Publisher is the sender of the message. (PUSH)
• Publisher does not have to know about the subscribers.
• Subscribers has the control to subscribe/unsubscribe message

Reference: http://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern 

Scenario: There is a publisher and many subscribers (like Printer, Fax, Web server etc). Whenever Publisher gets file, it should notify the subscribers. And subscriber should have the authority to subscribe/not subscribe. How will you design this approach?

class Program

    {

        static void Main(string[] args)

        {

            //create publisher

            Publisher p = new Publisher();

            //Create subscribers

            Print pr = new Print(p);

            Fax f = new Fax(p);

            Broadcast b = new Broadcast(p);

            //subscribe

            pr.Subscribe();

            b.Subscribe();

            //message

            Console.WriteLine("Message: ");

            string s = Console.ReadLine();

            //push message to subscribers

            p.Publish(s);

            Console.Read();

        }

    }

    class Publisher

    {

        public delegate void NotifyDelegate(string message);

        public event NotifyDelegate NotifyMessageToSubscribers;

        public void Publish(string message)

        {

            NotifyMessageToSubscribers(message);

        }

    }

    class Print

    {

        Publisher _publisher;

        public Print(Publisher p)

        {

            _publisher = p;

        }

        public void Subscribe()

        {

            _publisher.NotifyMessageToSubscribers += doPrint;

        }

        public void doPrint(string message)

        {

            Console.WriteLine("Printing: " + message);

        }

    }

    class Fax

    {

        Publisher _publisher;

        public Fax(Publisher p)

        {

            _publisher = p;

        }

        public void Subscribe()

        {

            _publisher.NotifyMessageToSubscribers += doFax;

        }

        public void doFax(string message)

        {

            Console.WriteLine("Faxing: " + message);

        }

    }

    class Broadcast

    {

        Publisher _publisher;

        public Broadcast(Publisher p)

        {

            _publisher = p;

        }

        public void Subscribe()

        {

            _publisher.NotifyMessageToSubscribers += doBroadcast;

        }

        public void doBroadcast(string message)

        {

            Console.WriteLine("Broadcasting: " + message);

        }

    }

is a and has a relationship

http://it.toolbox.com/wiki/index.php/%27is_a%27_relationship_and_a_%27has_a%27_relationship_in_Java

House is a building (inheritance)

House has bathroom (composition)

Publisher - Subscriber

Scenario: There is a publisher and many subscribers (like Printer, Fax, Web server etc). Whenever Publisher gets file, it should notify the subscribers. And subscriber should have the authority to subscribe/not subscribe. How will you design this approach?

Solution:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace PublisherSubscriber

{

    class Program

    {

        static void Main(string[] args)

        {

            Publisher p = new Publisher();

            Console.WriteLine("Message: ");

            string s = Console.ReadLine();

            p.Publish(s);

            Console.Read();           

        }

    }

    class Publisher

    {

        public delegate void NotifyDelegate(string message);

        public event NotifyDelegate NotifyMessageToSubscribers;

        Print p ;

        Fax f ;

        Broadcast b ;

        public Publisher()

        {

             p = new Print(this);

             f = new Fax(this);

             b = new Broadcast(this);

        }

       

        public void Publish(string message)

        {

            NotifyMessageToSubscribers(message);

        }

    }

    class Print

    {

        Publisher _publisher;

        public Print(Publisher p)

        {

            _publisher = p;

            //Subscribe to publisher event

            Subscribe();

        }

        public void Subscribe()

        {

            _publisher.NotifyMessageToSubscribers += doPrint;

        }

       

        public void doPrint(string message)

        {

            Console.WriteLine("Printing: " + message);

        }

    }

    class Fax

    {

        Publisher _publisher;

        public Fax(Publisher p)

        {

            _publisher = p;

            //Subscribe to publisher event

            Subscribe();

        }

        public void Subscribe()

        {

            _publisher.NotifyMessageToSubscribers += doFax;

        }

        public void doFax(string message)

        {

            Console.WriteLine("Faxing: " + message);

        }

    }

    class Broadcast

    {

        Publisher _publisher;

        public Broadcast(Publisher p)

        {

            _publisher = p;

            //Subscribe to publisher event

            Subscribe();

           

        }

        public void Subscribe()

        {

            //Publisher.NotifyMessageToSubscribers += doBroadcast;

        }

        public void doBroadcast(string message)

        {

            Console.WriteLine("Broadcasting: " + message);

        }

    }

}

WCF

1. FaultContract

2. MessageContract

3. Duplex

4. Hosting

5. Transactions

6. Session management

7. Polymorphism

8. tcpbinding

1. FaultContract

• FaultContract helps to do Exception handling in WCF service
• convert .NET exceptions into Fault
• Service client does not have to be built by using .NET framework
• SOAP protocol provides a standard mechanism to report faults within SOAP message.
• So client can recognize it as fault from the SOAP message

• Types of error:
• Domain error: (eg: NoFunds)
• Technical error:  (Expected and                 unexpected technical errors(eg: divide by zero))
• These errors should be mapped to one of the defined faults.
• Structure of SOAP fault is an XML representation of error information.
• SOAP fault contains

§ Code

§ Reason

§ Detail

• Using Fault in service

• Typed and Untyped fault

• Handling service Exceptions at client

2. MessageContract
1. WCF allow you to control SOAP message structure with MessageContract
2. You can modify message by

·   Define custom header

·   Adding elements to SOAP body

·   Altering namespace in SOAP body

3. Message exchange patterns
1. Request response
2. Simplex (one way)
3. Duplex

·         Request  response

o  default message exchange pattern in WCF

o Synchronous remote procedure call(RPC)

·         One way

o Client send message to service, but service does not send message back

o Return type of one-way operation must be void

o Drawback- no way to detect operation failure

o Advantage – performance – as client does not have to wait for response

[OperationContract(IsOneWay = true)]

void MakeDeposit(string account, decimal amount);

·         Duplex

o This pattern consists of 2 separate contracts

o One contract implemented by service, other by client

o 2 one-way messages

4. Polymorphism

·         Operation overloading - Operation with same name, but different parameters

·         Use Name property in OperationContract.

[OperationContract(Name="DepositLocalCurrency")]

void Deposit(string account, decimal amount);

[OperationContract(Name="DepositAnyCurrency")]

void Deposit(string account, Currency amount);

5. Transactions

@server:

1. Select a transaction aware binding

o NetTcpBinding

o NetNamedPipeBinding

o wsHttpBinding

o wsDualHttpBinding

o wsFederationHttpBinding

2. Enable TransactionFlow property of binding in configuration file.

 

   

         transactionProtocol="WSAtomicTransactionOctober2004"/>

 

3. Transactional requirement of operation

@client

1.       Enable transaction flow on binding in configuration file.

2.       Use TransactionScope block at client code

ASP.NET MVC FAQ

1. Can you have viewstate in ASP.NET MVC?

• Ans: No

2. Can you do unit testing of view in ASP.NET MVC?

• Ans: Yes

3. Is routing happens every time a page request or only first time?

• Ans: - Only first time
• - Shared Sub RegisterRoutes(ByVal routes As RouteCollection)

http://jinaldesai.net/asp-net-mvc-3-interview-questions/

Datastructures in .NET

a.       Stack:

·   FILO (first in last out)

·   Push(object o) – insert an object at top of stack

·   POP() – removes object at top of stack

·   Peek() – returns object at top of stack without removing

·   One of the classic examples of stack in .net framework is in memory management of value types.

·   There are non generic collection stack object (System.Collections.Stack) and generic collection stack object (System.Collections.Generic.Stack)

b.      Queue:

·   FIFO

·   Enqueue(object o) – add an object at end of queue

·   Dequeue() – remove object at beginning of queue

·   Peek() - return object at beginning of queue

·   First object entering to the Queue, exits first

·   One of the classic example of queue implementation in MSMQ

·   Queue is used in the highly reliable communication scenarios. Even if the message channel not available, messages are stored in the queue and transmitted once the channel is up.

·   There are non generic collection object (System.Collections.Queue) and generic collection object (System.Collections.Generic. Queue)

c.       Hashtable           

·   Hashtable stores key – value pair

·   Is organized based on the hash code of the key

·   Each element in hashtable is stored as DictionaryEntry object

·   A key cannot be null, but value can be

·   It is a non generic collection System.Collections type

·   Hashtable stores types of object

·   There is a type conversion required every time when we use hashtable

IDictionary, ICollection, IEnumerable, ISerializable, IDeserializationCallback, ICloneable

d.      Dictionary

·   Dictionary is similar to Hashtable (key-value pair storage)

·   It is a generic collection (System.Collections.Generics)

·   Type of the object to store in the dictionary should specify at compile time

·   Performance wise,  Dictionary is better option that Hashtable

IDictionary, ICollection<KeyValuePair>, IEnumerable<KeyValuePair>, IDictionary, ICollection, IEnumerable, ISerializable, IDeserializationCallback

e.      List

·   It is generics collection (System.Collections. Generics)

·   It represents strongly typed list of objects

·   Consider a scenario to store all the employee names of Satyam, then use List

·   No type conversion required hence preferred over ArrayList

IList, ICollection, IEnumerable, IList, ICollection, IEnumerable

f.        ArrayList

·   ArrayList is a non generic collection (System.Collections)

·   Size can be dynamically increase

·   ArrayList stores objects

·   Type conversion required every time when use AL
·  This affects the performance