asp.net - Showing the error "A previous catch clause already catches all exceptions of this or a super type `System.Exception' " in my C# code -


showing error "a previous catch clause catch clause catches exceptions of or super type `system.exception' " in c# code 

using system;    class test {      static void main()  {          try{              int a=10,b=0,c=0;c=a/b ;              console.writeline(c);         }            catch(system.exception e) {              console.writeline(e.message);          }          catch(system.dividebyzeroexception ex) {               console.writeline(ex.message);          }      }  }

exception handlers processed in order top bottom , first matching exception handler invoked. because first handler catches system.exception, , exceptions derive system.exception, it'll catch everything, , second handler never execute.

the best practice multiple exception handlers order them specific general, this:

using system;    class test {      static void main()  {          try{              int a=10,b=0,c=0;c=a/b ;              console.writeline(c);         }            catch(system.dividebyzeroexception ex) {               console.writeline(ex.message);          }          catch(system.exception e) {              console.writeline(e.message);          }      }  }

if absolutely positively have handle system.exception first (although can't think of reason why) write exception filter allow dividebyzero through, this:

using system;    class test {      static void main()  {          try{              int a=10,b=0,c=0;c=a/b ;              console.writeline(c);         }            catch(system.exception e)          when (!(e dividebyzeroexception)){              console.writeline(e.message);          }          catch(system.dividebyzeroexception ex) {               console.writeline(ex.message);          }      }  }

note: per msdn, you should avoid catching general exception types system.exception.


Comments

Post a Comment

Popular posts from this blog

PHP and MySQL WP -

i trying accomplish 2 things here code. writing php directly wp page using insert php plugin. 1) query mysql database , return results 1 column 4 columns. 2) make each result own hyperlink directs user new wp page runs new query on page. i able query show results , turn results dynamic hyperlink, cannot formatting down. right returns result 1 column. here have: [insert_php] $servername = "localhost"; $username = "login"; //edited privacy $password = "password"; //edited privacy $database = "database"; //edited privacy // create connection $conn = new mysqli($servername, $username, $password, $database); // check connection if ($conn->connect_error) { die("connection failed: " . $conn->connect_error); } echo "connected successfully"; //get results database $result = mysqli_query($conn,"select mine mines order mine"); $all_property = array(); //declare array saving property //showing proper...
Read more

android - InAppBilling registering BroadcastReceiver in AndroidManifest -

i'm implementing inapp billing in android app. works well, however, i'm trying decouple broadcast receiver activity manifest. suggestion in android's trivialdrive sample: // important: dynamically register broadcast messages updated purchases. // register receiver here instead of <receiver> in manifest // because call getpurchases() @ startup, therefore can ignore // broadcasts sent while app isn't running. // note: registering listener in activity bad idea, done here // because sample. regardless, receiver must registered after // iabhelper setup, before first call getpurchases(). currently there's class extends broadcastreceiver : public class iabbroadcastreceiver extends broadcastreceiver { /** * intent action receiver should filter for. */ public static final string action = "com.android.vending.billing.purchases_updated"; private final iabbroadcastlistener mlistener; public iabbroadcastreceiver(iabbroadcastlistener listener) { m...
Read more

nginx - phpPgAdmin - log in works but I have to login again after clicking on any links -

i have setup postgres 9.6 , phppgadmin on centos 7 server nginx, i can log in phppgadmin, postgresql server on right of page remains crossed out , link try browse (databases, roles etc) requires log in again. i'm thinking seems sessions problem, unsure how resolve it. any pointers on how fix or should looking @ in order track down problem? solved. turns out owner of /var/lib/php/session apache - needed nginx. sorted changing ownership nginx below: chown -r nginx:nginx /var/lib/php/session/
Read more