c# - order of execution of try catch and finally block -
i having big confusion order of try, catch , block execution.
i want know when should use try catch block , should put in try catch block, want know if exception comes in try block if action taken corresponding try block 1 executed first catch or (which executed), , after execution of these 2 does control return try block or abandon forever.
if have (note: not valid c#, see below valid example):
try { // ... code: } catch(...) { // ... exception code: b } { // code: c } code going executed. if goes (i.e. no exceptions thrown while executing), going go finally, code c going executed. if exception thrown while executed, go b , c.
as example, here's valid c# code block http://msdn.microsoft.com/en-us/library/dszsf989.aspx:
public class ehclass { void readfile(int index) { // run code, substitute valid path local machine string path = @"c:\users\public\test.txt"; system.io.streamreader file = new system.io.streamreader(path); char[] buffer = new char[10]; try { file.readblock(buffer, index, buffer.length); } catch (system.io.ioexception e) { console.writeline("error reading {0}. message = {1}", path, e.message); } { if (file != null) { file.close(); } } // buffer... } } the reason use try/catch/finally prevent program fail if there error in code (a in above example). if there problem, can use catch part catch problem , useful, such inform user, log exception log file, try again or try different suppose might work instead of tried originally.
finally used ensure cleanup performed. e.g. in might try open file , read it. if opening succeeds, read fails, have open file dangling. in case have closed, in finally block - block gets executed, guaranteeing closing of file.
take here more info:
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