What is the difference between throw and throw new in net?

Answer 1

an exception object must follow the throw statement. That exception object must be created by new-operator initially. One can throw the same exception instance again without creating a new one (throw new) later.

Just for fun and as an example: Let's on purposely cause 2 operations to throw exception. A third method will determine which operation produce the shorter exception message length, and throw the shorter one.

public void Operation1() { throw new SystemException("From Operation 1"); }

public void Operation2() { throw new SystemException("From Op2"); }

public void GetShorter() {

SystemException e1;

SystemException e2;

try { Operation1(); } catch (Exception e) { e1 = e; }

try { Operation2(); } catch (Exception e) { e2 = e; }

if (e1.Message.Length < e2.Message.Length) {

throw e1; // an example of not using new-operator

} else {

throw e2;

}

}