Throw and Throw ex

Question

Hi Difference between Throw and Throw ex?

Jignesh Trivedi · Answer

Hi In Throw Ex the original stack trace info gets overwritten. So you loose original exceptions's stack trace as only the last point from which the exception was thrown is available. Throw on the other hand retains the stack trace with the original point of exception available. Please refer... http://geekswithblogs.net/sdorman/archive/2007/08/20/Difference-between-quotthrowquot-and-quotthrow-exquot-in-.NET.aspx hope this will help you.

Santhosh Kumar Jayaraman · Answer

Throw Ex  the original stack trace info gets overwritten. So you loose original exceptions's stack trace as only the last point from which the exception was thrown is available. Throw  on the other hand retains the stack trace with the original point of exception available. I find a good sample code in the below link. http://stackoverflow.com/questions/730250/is-there-a-difference-between-throw-and-throw-ex static void Main(string[] args) { try { ThrowException1(); // line 19 } catch (Exception x) { Console.WriteLine(Exception 1:); Console.WriteLine(x.StackTrace); } try { ThrowException2(); // line 25 } catch (Exception x) { Console.WriteLine(Exception 2:); Console.WriteLine(x.StackTrace); } } private static void ThrowException1() { try { DivByZero(); // line 34 } catch { throw; // line 36 } } private static void ThrowException2() { try { DivByZero(); // line 41 } catch (Exception ex) { throw ex; // line 43 } } private static void DivByZero() { int x = 0; int y = 1 / x; // line 49 } and here is the output: Exception 1: at UnitTester.Program.DivByZero() in \Dev\UnitTester\Program.cs:line 49 at UnitTester.Program.ThrowException1() in \Dev\UnitTester\Program.cs:line 36 at UnitTester.Program.TestExceptions() in \Dev\UnitTester\Program.cs:line 19 Exception 2: at UnitTester.Program.ThrowException2() in \Dev\UnitTester\Program.cs:line 43 at UnitTester.Program.TestExceptions() in \Dev\UnitTester\Program.cs:line 25 You can see that in Exception 1 the stack trace goes back to the DivByZero() method whereas in Exception 2 it does not. Take note though that the line number shown in ThrowException1() and ThrowException2() is the line number of the throw statement not the line number of the call to DivByZero() which probably makes sense now that I think about it a bit...