Question

How to re-throw an exception in C#

Answer 1

using System;

public class Test {
    string s;

    public Test(string _s) {
        s = _s;
    }
    public char GetFirstCharacter() {
        try {
            return s[0];
        }
        catch (NullReferenceException ex) {
            Console.WriteLine($"ex: {ex}");
            throw; // re-throw
        }
   }
}

public class Program
{
   public static void Main()
   {
      var o = new Test(null);
      
      Console.WriteLine(o.GetFirstCharacter());
   }
}




/*
run

ex: System.NullReferenceException: Object reference not set to an instance of an object
  at Test.GetFirstCharacter () [0x00000] in <1b733234f3474553a7af0285f4dd26a9>:0 


Unhandled Exception:
System.NullReferenceException: Object reference not set to an instance of an object
  at Test.GetFirstCharacter () [0x00023] in <1b733234f3474553a7af0285f4dd26a9>:0 
  at Program.Main () [0x00007] in <1b733234f3474553a7af0285f4dd26a9>:0 
[ERROR] FATAL UNHANDLED EXCEPTION: System.NullReferenceException: Object reference not set to an instance of an object
  at Test.GetFirstCharacter () [0x00023] in <1b733234f3474553a7af0285f4dd26a9>:0 
  at Program.Main () [0x00007] in <1b733234f3474553a7af0285f4dd26a9>:0 

*/

 

70+ SQL courses for beginners and professionals