Use a custom Exception : Custom Exception « Language Basics « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Language Basics
3. Custom Exception

using System;  
  
class RangeArrayException : ApplicationException { 
  public RangeArrayException() : base() { } 
  public RangeArrayException(string str) : base(str) { }  
 
  public override string ToString() { 
    return Message; 
  } 
} 
 
      
class MainClass {   
  public static void Main() {   
    try { 
         throw new RangeArrayException("Low index not less than high.");  
    } catch (RangeArrayException exc) { 
       Console.WriteLine(exc); 
    } 
  }  
}

Low index not less than high.