C try catch continue execution

Question

I have a question that might seem fairly simple  of course if you know the answer    A certain function I have calls another function but I want to continue execution from the caller even though the callee has thrown an exception   Let me give you an example   something function1         try                 some code         int idNumber   function2              other code that need to execute even if function2 fails         return something            catch Exception e             perhaps something here      EDIT  function1 also has a return statement so nothing can in fact crash on the way  In function2 I need to do stuff but I only need to log if anything fails  example   int function2         try                 dostuff           catch Exception e                  Log stuff to db           ok  now my question is  what should I do if I wanted to continue execution in function1 even if function 2 throws an error   Sometimes I mix up if I should do throw  or throw e  or throw nothing at all  leave catch block empty

User · Answer

Or you can encapsulate the looping logic itself in a try catch e.g.

for(int i = function2(); i < 100 /*where 100 is the end or another function call to get the end*/; i = function2()){

    try{
     //ToDo
    }
    catch { continue; }    

}

Or...

try{ 
    for(int i = function2(); ; ;) {
        try { i = function2(); return; } 
        finally { /*decide to break or not :P*/continue; } }
} catch { /*failed on first try*/ } finally{ /*afterwardz*/ }

User · Answer

Leaving the catch block empty should do the trick  This is almost always a bad idea  though  On one hand  there s a performance penalty  and on the other  and this is more important   you always want to know when there s an error   I would guess that the  callee  function failing  in your case  is actually not necessarily an   error   so to speak  That is  it is expected for it to fail sometimes  If this is the case  there is almost always a better way to handle it than using exceptions   There are  if you ll pardon the pun  exceptions to the  rule   though  For example  if function2 were to call a web service whose results aren t really necessary for your page  this kind of pattern might be ok  Although  in almost 100  of cases  you should at least be logging it somewhere  In this scenario I d log it in a finally block and report whether or not the service returned  Remember that data like that which may not be valuable to you now can become valuable later   Last edit  probably    In a comment I suggested you put the try catch inside function2  Just thought I would elaborate  Function2 would look like this   public Something  function2         try                 all of your function goes here         return anActualObjectOfTypeSomething            catch Exception ex                  logging goes here         return null            That way  since you use a nullable return type  returning null doesn t hurt you

User · Answer

In your second function remove the e variable in the catch block then add throw   This will carry over the generated exception the the final function and output it   Its very common when you dont want your business logic code to throw exception but your UI

User · Answer

Why cant you use the finally block   Like   try      catch  Exception e          THIS WILL EXECUTE IF THERE IS AN EXCEPTION IS THROWN IN THE TRY BLOCK    finally         THIS WILL EXECUTE IRRESPECTIVE OF WHETHER AN EXCEPTION IS THROWN WITHIN THE TRY CATCH OR NOT      EDIT after question amended   You can do    int  returnFromFunction2   null      try           returnFromFunction2   function2            return returnFromFunction2 value            catch  Exception e                  THIS WILL EXECUTE IF THERE IS AN EXCEPTION IS THROWN IN THE TRY BLOCK            finally             if  returnFromFunction2 HasValue       do something with value                THIS WILL EXECUTE IRRESPECTIVE OF WHETHER AN EXCEPTION IS THROWN WITHIN THE TRY CATCH OR NOT

User · Answer

Do you mean you want to execute code in function1 regardless of whether function2 threw an exception or not  Have you looked at the finally-block  http   msdn microsoft com en-us library zwc8s4fz aspx

User · Answer

just do this      try                 some code      try                  int idNumber   function2                 finally               do stuff here                      catch Exception e             perhaps something here    For all intents and purposes the finally block will always execute   Now there are a couple of exceptions where it won t actually execute  task killing the program  and there is a fast fail security exception which kills the application instantly  Other than that  an exception will be thrown in function 2  the finally block will execute the needed code and then catch the exception in the outer catch block

[c#] C# try catch continue execution

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