Csharp/CSharp Tutorial/Language Basics/Predefined Exception

Check OverflowException for long

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

 static void Main(string[] args)
 {
   int MyInt = 12345000;
   long MyLong = MyInt;
   
   try
   {
     long c = checked(MyLong * 5000000);
   }
   catch (OverflowException e)
   {
     Console.WriteLine(e);
   }
 }

}</source>

Define exception variable in catch statement: DivideByZeroException

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

  static void Main()
  {
     try
     {
        int y = 0;
        y = 10/y; 
     } catch (DivideByZeroException e) {
        Console.WriteLine("Message: {0}", e.Message);
        Console.WriteLine("Source: {0}", e.Source);
        Console.WriteLine("Stack: {0}", e.StackTrace);
     }
  }

}</source>

Message: Attempted to divide by zero.
Source: main
Stack:    at MainClass.Main()

Generate an index out-of-bounds exception

<source lang="csharp">using System;

class MainClass {

 public static void Main() { 
   int[] nums = new int[4]; 

   try { 
     Console.WriteLine("Before exception is generated."); 

     // Generate an index out-of-bounds exception. 
     for(int i=0; i < 10; i++) { 
       nums[i] = i; 
       Console.WriteLine("nums[{0}]: {1}", i, nums[i]); 
     } 

     Console.WriteLine("this won"t be displayed"); 
   } 
   catch (IndexOutOfRangeException) { 
     // catch the exception 
     Console.WriteLine("Index out-of-bounds!"); 
   } 
   Console.WriteLine("After catch statement."); 
 } 

}</source>

Before exception is generated.
nums[0]: 0
nums[1]: 1
nums[2]: 2
nums[3]: 3
Index out-of-bounds!
After catch statement.

Handle ArgumentOutOfRangeException

<source lang="csharp">using System; using System.Collections; using System.Runtime.rupilerServices; [assembly: RuntimeCompatibility(WrapNonExceptionThrows = false)] public class MainClass {

   static void Main() {
       try {
           ArrayList list = new ArrayList();
           list.Add( 1 );
           Console.WriteLine( "Item 10 = {0}", list[10] );
       }
       catch( ArgumentOutOfRangeException x ) {
           Console.WriteLine( x );
           Console.WriteLine( "ArgumentOutOfRangeException Handler" );
       }
       catch( Exception x ) {
           Console.WriteLine( x );
           Console.WriteLine( "Exception Handler" );
       }
       catch {
           Console.WriteLine( "An exception I was not expecting..." );
           Console.WriteLine( "Unexpected Exception Handler" );
       }
       finally {
           Console.WriteLine( "Cleaning up..." );
       }
   }

}</source>

System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the s
ize of the collection.
Parameter name: index
   at System.Collections.ArrayList.get_Item(Int32 index)
   at MainClass.Main()
ArgumentOutOfRangeException Handler
Cleaning up...

Throwing Exceptions: ArgumentNullException

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

  static void Main()
  {
     string arg = null;
     
     try
     {
        if (arg == null)
        {
           ArgumentNullException MyEx = new ArgumentNullException();
           throw MyEx;
        }
     }
     catch (ArgumentNullException e)
     {
        Console.WriteLine("Message: {0}", e.Message);
     }
  }

}</source>

Message: Value cannot be null.

Use the NullReferenceException.

<source lang="csharp">using System;

class MainClass {

 public static void Main() {   
   try { 
     string str = null;
     Console.WriteLine(str.ToString());
     
   } catch (NullReferenceException) { 
     Console.WriteLine("NullReferenceException!"); 
     Console.WriteLine("fixing...\n"); 

   } 

 }  

}</source>

NullReferenceException!
fixing...