Try, catch statement in C# -

i have following c# code calculating each file's hash in certain, user specified directory. point works fine, until encounters file cannot access. when finds this, throws error message , exits program. want instead is, throw error message name of file cannot accessed, write there error in accessing file, , continue executing program other files in directory. if can me edit code , achieve things glad.

    private void sha256directory(string directory)     {         try         {             sha256 directorysha256 = sha256managed.create();             byte[] hashvalue;              directoryinfo dir = new directoryinfo(directory);             fileinfo[] files = dir.getfiles();              foreach (fileinfo finfo in files)             {                 filestream fstream = finfo.open(filemode.open);                 fstream.position = 0;                 hashvalue = directorysha256.computehash(fstream);                  console.writeline(finfo.name);                 miscellaneous.bytearraytohex(hashvalue);                 miscellaneous.bytearraytobase64(hashvalue);                 console.writeline();                  fstream.close();             }              return;         }         catch(directorynotfoundexception)         {             console.writeline("error: directory specified not found.");         }         catch(ioexception)         {             console.writeline("error: file in directory not accessed.");         }         catch(argumentnullexception)         {             console.writeline("error: argument cannot null or empty.");         }      } 

move try/catch inside foreach. haven't explained in post, i'm guessing that's encounter exception.

in doing so, exception caused code in there caught , allow loop continue.

careful, though -- these 2 lines still not exception-safe:

directoryinfo dir = new directoryinfo(directory); fileinfo[] files = dir.getfiles(); 

you'll want account well.

if want show file/directory caused issue, tostring exception, example:

catch(directorynotfoundexception ex) {     console.writeline("error: directory specified not found: " + ex.tostring()); } 

if tostring doesn't give desired output, try ex.message. use tostring though.

edit credit ken henderson

when using kind of stream, should put in using block. garbage collector close stream eventually, practice this, using block close stream you're done using it:

using (filestream fstream = finfo.open(filemode.open))  {     fstream.position = 0;     hashvalue = directorysha256.computehash(fstream);      console.writeline(finfo.name);     miscellaneous.bytearraytohex(hashvalue);     miscellaneous.bytearraytobase64(hashvalue);     console.writeline(); } // no need fstream.close() more, using block take care of