OOPS

Difference between Abstract class and Interface in C# .Net

Interfaces are essentially having all method prototypes no definition but Abstract class can contain method definations also.

In short Interface is a abstract class having all methods abstract.

If you create a abstract class writing the abstract keyword in the declaration part then You only can inherit the class. You can not create an instance of this abstract class but can inherit the class and with creating the instance of the derived class you can access the method of the abstract class.

If you use a virtual keyword in a method then you can override this method in the subclass if you wish..

If you create a abstract method then you must override this method in the subclass other wise it shows error in the program.

You cannot instantiate Abstract Classes and Interfaces

An interface has all public members

 You can inherit abstract classes to other class

Abstract :
=========================================
1. Abstract class cannot be instantiated.
2. Abstract class may contain abstract methods and accessors.
3. Abstract modifier can be used with classes, methods and properties.
4. A non-abstract class derived from an abstract class must include actual implementations of all inherited abstract methods and accessors.
5. Abstract method declarations are only permitted in abstract classes.

6.Abstract class can contain abstract methods, abstract property as well as other members (just like normal class).

7.Interface can be used to achieve multiple inheritance; abstract class can be used as a single inheritance

8.Abstract class are known as partial abstract class whereas interface is known as fully abstract class
***********************************************************
Interface :
=========================================
1.Interfaces are similar to classes.
2.They can have member properties and methods.
3.All the properties and methods of interfaces are abstract.
4.They have no body, just the declaration.
5.Public, Protected, Private, Friend, Shared, Overrides, MustOverride, NotOverridable are permitted inside an interface.

6.It’s a pure abstract class.

Runtime polymorphism

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
A objA = new A();
B objB = new B();
sendmsg(objA);
sendmsg(objB);
Console.ReadLine();
}
public static void sendmsg(imsg objmsg)
{
objmsg.displaymessage();
}
}

interface imsg
{
void displaymessage();
}
class A : imsg
{
public void displaymessage()
{
Console.WriteLine("this is class A displaymsg()");
}
}

class B : imsg
{
public void displaymessage()
{
Console.WriteLine("this is class B displaymsg()");
}
}
}

WCF OverView PPT

WCF OverView

WCF: Step-by-Step Tutorial

This is a getting started tutorial to Windows Communication Foundation (WCF) Services. I have discussed a simple service to calculate the area of a rectangle; yup, very simple 

1. First you need to download and install Visual Studio 2005 extensions for .NET Framework 3.0 (Windows Workflow Foundation).

Oops, looks like it needs a windows validation (bit of a problem if you have a pirate copy  )

2. Once the installation is complete, start Visual Studio to create the project.

Goto File->New->Web Site, and you’ll see a new template called WFC Service.

Click OK to create an empty WCF Service.

3. Time to get started with the coding

Service.svc

<% @ServiceHost Language=C# Debug="true" Service="GeometryService" CodeBehind="~/App_Code/Service.cs" %>

Only a small change here – the name of the service

Web.config

<?xml version="1.0"?>

 

<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">

  <system.serviceModel>

    <services>

      <!-- Before deployment, you should remove the returnFaults behavior configuration to avoid disclosing information in exception messages -->

      <service name="GeometryService" behaviorConfiguration="GeometryServiceBehavior">

        <endpoint contract="IGeometryService" binding="wsHttpBinding"/>

      </service>

    </services>

    <behaviors>

      <serviceBehaviors>

        <behavior name="GeometryServiceBehavior" >

          <serviceDebug includeExceptionDetailInFaults="true" />

          <serviceMetadata httpGetEnabled="true" />

        </behavior>

      </serviceBehaviors>

    </behaviors>

  </system.serviceModel>

 

  <system.web>

    <compilation debug="true"/>

  </system.web>

 

 </configuration>

Enable metadata publishing and change the name of the service.

Service.cs

using System;

using System.ServiceModel;

using System.Runtime.Serialization;

 

// A WCF service consists of a contract (defined below as IMyService, DataContract1), 

// a class which implements that interface (see MyService), 

// and configuration entries that specify behaviors associated with 

// that implementation (see <system.serviceModel> in web.config)

 

[ServiceContract()]

public interface IGeometryService

{

 [OperationContract]

 int GetArea(Rectangle rect);

 [OperationContract]

 int GetPerimeter(int width, int height);

}

 

public class GeometryService : IGeometryService

{

 public int GetArea(Rectangle rect)

 {

  return rect.Area();

 }

 

 public int GetPerimeter(int width, int height)

 {

  Rectangle rect = new Rectangle(width, height);

  return rect.Perimeter();

 }

}

 

[DataContract]

public class Rectangle

{

 int width;

 int height;

 

 public Rectangle(int width, int height)

 {

  Width = width;

  Height = height;

 }

 

 [DataMember]

 public int Width

 {

  get { return width; }

  set { width = value < 0 ? 0 : value; }

 }

 

 [DataMember]

 public int Height

 {

  get { return height; }

  set { height = value < 0 ? 0 : value; }

 }

 

 public int Area()

 {

  return Height * Width;

 }

 

 public int Perimeter()

 {

  return 2 * (Height + Width);

 }

}

This is the code for the service.

4. Run the service – click F5 

This is what you get on the browser. So, lets do what they want.

5. Run the following on you command on Visual Studio Command Prompt

svcutil.exe http://localhost:1479/GeoWFCService/Service.svc?wsdl

Watch out, the path might be different  . And if you don’t know what Visual Studio command prompt is

6. Let’s create the client

Create (or rather add) a new project; this could even be a website

7. Then run the service – Ctrl + F5

8. Add a web reference to the service

8. Copy the GeometryService.cs created by svcutil in step 5 to the clients working (main) folder and add them to the project

You should also copy the configurations of output.config created by svcutil to app.config

9. Again time for coding

Form1.cs

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

 

namespace GeoWFCClient

{

 public partial class Form1 : Form

 {

  public Form1()

  {

   InitializeComponent();

  }

 

  private void calculateButton_Click(object sender, EventArgs e)

  {

   GeometryServiceClient gsclient = new GeometryServiceClient();

 

   /* The overloaded constructor of Rectangle is not present here */

   Rectangle rect = new Rectangle();

 

   rect.Width = Int32.Parse(widthTextBox.Text);

   rect.Height = Int32.Parse(heightTextBox.Text);

 

   areaTextBox.Text = gsclient.GetArea(rect).ToString();

   perimeterTextBox.Text = gsclient.GetPerimeter(rect.Width, rect.Height).ToString();

  }

 }

}

Set the textboxes and labels with appropriate names.

10. When you compile you’ll get a set of error because some assemblies are not referenced. Add references to them

11. Now see how it works

Start the service if haven’t done so already, and run the client

Wow! It works 

Ok, hope you learned something with this and I got to go study for exam