ASP.NET & Csharp (C#)

ASP.NET & Csharp (C#) , Here you can find my posts about .NET c# .

Demonstrates the use of a virtual property to override a base class property

Posted on by coder 

   

/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa

Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/

//
// VProp.cs -- Demonstrates the use of a virtual method to override
//             a base class method.
//
//             Compile this program with the following command line:
//                 C:>csc VProp.cs
namespace nsVirtual
{
    using System;
    
    public class VPropclsMain
    {
        static public void Main ()
        {
            clsBase Base = new clsBase();
            clsFirst First = new clsFirst();
            Base.SetString ("This should set the base class property");
            First.SetString ("This should set the derived class property");
            Console.WriteLine();
            Console.WriteLine (Base.GetString());
            Console.WriteLine (First.GetString());
        }
    }
    class clsBase
    {
  public void SetString (string str)
        {
            StrProp = str;
        }
        public string GetString ()
        {
            return (StrProp);
        }
        virtual protected string StrProp
        {
            get
            {
                Console.WriteLine ("Getting Base string");
                return (m_BaseString);
            }
            set
            {
                Console.WriteLine ("Setting Base string");
                m_BaseString = value;
            }
        }
        private string m_BaseString = "";
    }
    class clsFirst : clsBase
    {
        override protected string StrProp
        {
            get
            {
                Console.WriteLine ("Getting derived string");
                return (m_DerivedString);
            }
            set
            {
                Console.WriteLine ("Setting derived string");
                m_DerivedString = value;
            }
        }
        private string m_DerivedString = "";
   }
}

Demonstrates the use of a virtual method to override a base class method

Posted on by coder 

   

/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa

Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/
//
// Virtual.cs -- Demonstrates the use of a virtual method to override
//               a base class method.
//
//               Compile this program with the following command line:
//                   C:>csc Virtual.cs
namespace nsVirtual
{
    using System;
    
    public class VirtualclsMain
    {
        static public void Main ()
        {
            clsBase Base = new clsBase();
            clsFirst First = new clsFirst();
            clsSecond Second = new clsSecond();
            Base.Show();
            First.Show();
            Second.Show ();
        }
    }
    class clsBase
    {
        public void Show ()
        {
            Describe ();
        }
        virtual protected void Describe ()
        {
            Console.WriteLine ("Called the base class Describe() method");
        }
    }
    class clsFirst : clsBase
    {
        override protected void Describe ()
        {
            Console.WriteLine ("Called the derived class Describe() method");
        }
    }
    class clsSecond : clsBase
    {
    }
}

illustrates polymorphism

Posted on by coder 

   

/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy

Publisher: Sybex;
ISBN: 0782129110
*/
/*
  Example7_2.cs illustrates polymorphism
*/

using System;


// declare the MotorVehicle class
class MotorVehicle
{

  // declare the fields
  public string make;
  public string model;

  // define a constructor
  public MotorVehicle(string make, string model)
  {
    this.make = make;
    this.model = model;
  }

  // define the Accelerate() method (may be overridden in a
  // derived class)
  public virtual void Accelerate()
  {
    Console.WriteLine(model + " accelerating");
  }

}


// declare the Car class (derived from MotorVehicle)
class Car : MotorVehicle
{

  // define a constructor
  public Car(string make, string model) :
  base(make, model)
  {
    // do nothing
  }

  // override the base class Accelerate() method
  public override void Accelerate()
  {
    Console.WriteLine("Pushing gas pedal of " + model);
    base.Accelerate();  // calls the Accelerate() method in the base class
  }

}


// declare the Motorcycle class (derived from MotorVehicle)
class Motorcycle : MotorVehicle
{

  // define a constructor
  public Motorcycle(string make, string model) :
  base(make, model)
  {
    // do nothing
  }

  // override the base class Accelerate() method
  public override void Accelerate()
  {
    Console.WriteLine("Twisting throttle of " + model);
    base.Accelerate();  // calls the Accelerate() method in the base class
  }

}


public class Example7_2
{

  public static void Main()
  {

    // create a Car object and call the object's Accelerate() method
    Car myCar = new Car("Toyota", "MR2");
    myCar.Accelerate();

    // create a Motorcycle object and call the object's Accelerate() method
    Motorcycle myMotorcycle = new Motorcycle("Harley-Davidson", "V-Rod");
    myMotorcycle.Accelerate();

  }

}

When a virtual method is not overridden, the base class method is used

Posted on by coder 

   

/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/


/* When a virtual method is not overridden, 
   the base class method is used. */ 
 
using System; 
 
class Base { 
  // Create virtual method in the base class.  
  public virtual void who() { 
    Console.WriteLine("who() in Base"); 
  } 
} 
 
class Derived1 : Base { 
  // Override who() in a derived class. 
  public override void who() { 
    Console.WriteLine("who() in Derived1"); 
  } 
} 
 
class Derived2 : Base { 
  // This class does not override who(). 
} 
 
public class NoOverrideDemo { 
  public static void Main() { 
    Base baseOb = new Base(); 
    Derived1 dOb1 = new Derived1(); 
    Derived2 dOb2 = new Derived2(); 
 
    Base baseRef; // a base-class reference 
 
    baseRef = baseOb;  
    baseRef.who(); 
 
    baseRef = dOb1;  
    baseRef.who(); 
 
    baseRef = dOb2;  
    baseRef.who(); // calls Base's who() 
  } 
}

Demonstrate a virtual method

Posted on by coder 

   

/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/


// Demonstrate a virtual method. 
 
using System; 
 
class Base { 
  // Create virtual method in the base class.  
  public virtual void who() { 
    Console.WriteLine("who() in Base"); 
  } 
} 
 
class Derived1 : Base { 
  // Override who() in a derived class. 
  public override void who() { 
    Console.WriteLine("who() in Derived1"); 
  } 
} 
 
class Derived2 : Base { 
  // Override who() again in another derived class. 
  public override void who() { 
    Console.WriteLine("who() in Derived2"); 
  } 
} 
 
public class OverrideDemo { 
  public static void Main() { 
    Base baseOb = new Base(); 
    Derived1 dOb1 = new Derived1(); 
    Derived2 dOb2 = new Derived2(); 
 
    Base baseRef; // a base-class reference 
 
    baseRef = baseOb;  
    baseRef.who(); 
 
    baseRef = dOb1;  
    baseRef.who(); 
 
    baseRef = dOb2;  
    baseRef.who(); 
  } 
}

Use virtual methods and polymorphism

Posted on by coder

/*
C#: The Complete Reference
by Herbert Schildt

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/

// Use virtual methods and polymorphism.

using System;

class TwoDShape {
double pri_width; // private
double pri_height; // private
string pri_name; // private

// A default constructor.
public TwoDShape() {
width = height = 0.0;
name = “null”;
}

// Parameterized constructor.
public TwoDShape(double w, double h, string n) {
width = w;
height = h;
name = n;
}

// Construct object with equal width and height.
public TwoDShape(double x, string n) {
width = height = x;
name = n;
}

// Construct an object from an object.
public TwoDShape(TwoDShape ob) {
width = ob.width;
height = ob.height;
name = ob.name;
}

// Properties for width, height, and name
public double width {
get { return pri_width; }
set { pri_width = value; }
}

public double height {
get { return pri_height; }
set { pri_height = value; }
}

public string name {
get { return pri_name; }
set { pri_name = value; }
}

public void showDim() {
Console.WriteLine(“Width and height are ” +
width + ” and ” + height);
}

public virtual double area() {
Console.WriteLine(“area() must be overridden”);
return 0.0;
}
}

// A derived class of TwoDShape for triangles.
class Triangle : TwoDShape {
string style; // private

// A default constructor.
public Triangle() {
style = “null”;
}

// Constructor for Triangle.
public Triangle(string s, double w, double h) :
base(w, h, “triangle”) {
style = s;
}

// Construct an isosceles triangle.
public Triangle(double x) : base(x, “triangle”) {
style = “isosceles”;
}

// Construct an object from an object.
public Triangle(Triangle ob) : base(ob) {
style = ob.style;
}

// Override area() for Triangle.
public override double area() {
return width * height / 2;
}

// Display a triangle's style.
public void showStyle() {
Console.WriteLine(“Triangle is ” + style);
}
}

// A derived class of TwoDShape for rectangles.
class Rectangle : TwoDShape {
// Constructor for Rectangle.
public Rectangle(double w, double h) :
base(w, h, “rectangle”){ }

// Construct a square.
public Rectangle(double x) :
base(x, “rectangle”) { }

// Construct an object from an object.
public Rectangle(Rectangle ob) : base(ob) { }

// Return true if the rectangle is square.
public bool isSquare() {
if(width == height) return true;
return false;
}

// Override area() for Rectangle.
public override double area() {
return width * height;
}
}

public class DynShapes {
public static void Main() {
TwoDShape[] shapes = new TwoDShape[5];

shapes[0] = new Triangle(“right”, 8.0, 12.0);
shapes[1] = new Rectangle(10);
shapes[2] = new Rectangle(10, 4);
shapes[3] = new Triangle(7.0);
shapes[4] = new TwoDShape(10, 20, “generic”);

for(int i=0; i < shapes.Length; i++) { Console.WriteLine("object is " + shapes[i].name); Console.WriteLine("Area is " + shapes[i].area()); Console.WriteLine(); } } } [/csharp]

Class hierarchy: override and virtual

Posted on by coder 
   

/*
 * C# Programmers Pocket Consultant
 * Author: Gregory S. MacBeth
 * Email: gmacbeth@comporium.net
 * Create Date: June 27, 2003
 * Last Modified Date:
 */
using System;

namespace Client.Chapter_5___Building_Your_Own_Classes
{
  public class MyMainClass13
  {
    static void Main(string[] args)
    {
      //The function called is based
      //upon the type called by new.
      B MyB = new C();

      MyB.Display();    //Calls C&#039;s Display
    }
  }
  abstract class A
  {
    public abstract void Display();
  }
  class B: A
  {
    public override void Display()
    {
      Console.WriteLine("Class B&#039;s Display Method");
    }
  }
  class C: B
  {
    public override void Display()
    {
      Console.WriteLine("Class C&#039;s Display Method");
    }
  }
  class D: C
  {
    public override void Display()
    {
      Console.WriteLine("Class D&#039;s Display Method");
    }
  }

}