Throw your own exception from class constructor : Constructor « Class « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Class
3. Constructor

using System;

  public class HelloWorld 
  {
    public static void Main() 
    {
      try
      {
        Discount big_discount = new Discount(56);
      }
      catch (MyException ex) 
      {
        Console.WriteLine("Exception Caught");
        Console.WriteLine(ex.Message);
      }
    }
  }
  public class Discount
  {
    private int percent;
    public Discount(int percent)
    {
      this.percent = percent;
      if (percent > 50)
        throw new MyException("Discount > 50%");
    }
  }
  public class MyException : Exception 
  {
    public MyException(String msg) : base (msg)
    {
    }
  }