c# - Does Linq to Sql close connections automatically? -

this question has answer here:

• c# linq-to-sql - should datacontext disposed using idisposable 1 answer

does linq sql close connections automatically? or should use using?

var db = new datacontext(); // codes 

or

using (var db = new datacontext()) {     // codes } 

when using using statement connection managed automatically.the datacontext class implements idisposable interface, need call dispose on datacontext implementation whenever finished it.

from c# in depth

there few reasons implemented idisposable:

• if application logic needs hold onto entity beyond when datacontext expected used or valid can enforce that
  contract calling dispose. deferred loaders in entity will
  still referencing datacontext , try use if any
  code attempts navigate deferred properties. these attempts
  fail. dispose forces datacontext dump cache of
  materialized entities single cached entity not
  accidentally keep alive entities materialized through that
  datacontext, otherwise cause appears memory
  leak.
• the logic automatically closes datacontext connection can tricked leaving connection open. datacontext relies on application code enumerating results of query since getting end of resultset triggers connection close. if application uses ienumerable's movenext method instead of foreach statement in c# or vb, can exit enumeration prematurely. if application experiences problems connections not closing , suspect automatic closing behavior not working can use dispose pattern work around.