Csharp/CSharp Tutorial/Class/Class Instance

Call GetType and ToString on object instance

<source lang="csharp">using System; public class Thing {

   public int i = 2;
   public int j = 3;

}

public class objectTypeApp {

   public static void Main() 
   {
       object a;
       a = 1;
       Console.WriteLine(a);
       Console.WriteLine(a.ToString());
       Console.WriteLine(a.GetType());
       Console.WriteLine();
  
       Thing b = new Thing();
       Console.WriteLine(b);
       Console.WriteLine(b.ToString());
       Console.WriteLine(b.GetType());
   }

}</source>

Creating an array of objects.

<source lang="csharp">using System; class MainClass {

   private int fValue;
   public MainClass() {
       fValue = 0;
   }
   public void setValue(int value) {
       fValue = value;
   }
   public int getValue() {
       return fValue;
   }
   public static void Main() {
       MainClass[] arr = new MainClass[10];
       for (int i = 0; i < 10; ++i)
           arr[i] = new MainClass();
       for (int i = 0; i < 10; ++i)
           arr[i].setValue(i);
       for (int i = 0; i < 10; ++i)
           Console.WriteLine("Object {0}. Value = {1}",
             i, arr[i].getValue());
   }

}</source>

Instance Class Members

<source lang="csharp">using System; class MyClass {

  public int memberVariable;

} class MainClass {

  static void Main()
  {
     MyClass d1 = new MyClass();
     MyClass d2 = new MyClass();
     d1.memberVariable = 10; 
     d2.memberVariable = 28;
     Console.WriteLine("d1 = {0}, d2 = {1}", d1.memberVariable, d2.memberVariable);
  }

}</source>

d1 = 10, d2 = 28

Invoke a method in a class

<source lang="csharp">using System;

class MyClass {

  void PrintDateAndTime()               
  {
     DateTime dt = DateTime.Now;        
     Console.WriteLine("{0}", dt);      
  }
  static void Main()
  {
     MyClass mc = new MyClass();
     mc.PrintDateAndTime();             
  }

}</source>

25/03/2007 2:14:04 PM

public member method

<source lang="csharp">using System; class MyClass {

  public int High, Low;
  
  public int Sum() 
  {
     return High + Low;
  }

} class MainClass {

  static void Main()
  {
     MyClass T1 = new MyClass();
     MyClass T2 = new MyClass();
     T1.High = 76; 
     T1.Low = 57;
     
     T2.High = 75; 
     T2.Low = 53;
     Console.WriteLine("T1: {0}, {1}, {2}", T1.High, T1.Low, T1.Sum ());
     Console.WriteLine("T2: {0}, {1}, {2}", T2.High, T2.Low, T2.Sum ());
  }

}</source>

T1: 76, 57, 133
T2: 75, 53, 128

Try to change static value in different instance

<source lang="csharp">using System; class MyClass {

  int nonStaticVariable;
  static int staticVariable;
  public void SetVars(int v1, int v2) 
  {
     nonStaticVariable = v1;
     staticVariable = v2;
  }
  public void Display()
  {
     Console.WriteLine("nonStaticVariable= {1}, staticVariable= {2}", nonStaticVariable, staticVariable);
  }

} class MainClass {

  static void Main()
  {
     MyClass d1 = new MyClass(), d2 = new MyClass();
     d1.SetVars(2, 4);    
     d1.Display();
     d2.SetVars(15, 17);  
     d2.Display();
  }                       

}</source>