c# - Possible consequences of duplicate ProgId for different classes -


in software i'm maintaining i've observed com classes marked identical [progid]s.

afaik progid human readable identifier component , should map 1-to-1 component's clsid.

so i'm wondering:

  • is there reason have same progid different classes?

  • what possible consequences? (except not being able reach component using convenient way)

thanks in advance.

a progid provides friendly name clsid guid of coclass. important scripting languages, no way know guid. used languages support late binding, vb.net , c#. conversion string guid happens @ runtime. usual name of factory function createobject(), language runtime implements looking @ registry entry stored in hklm\software\classes.

which cue go wrong when duplicate them. actual object client program creates random. whichever 1 happened registered last. client program calls different method 1 intended call. might trigger disp_e_xxxx error return that's no guarantee. in general nasty , quite undebuggable mishap.

the way can not have problem when client code uses binding , uses type library know guids. that's not unusual not in control. if know client code doesn't use them omit [progid] attribute no accidents can happen.


Comments

Post a Comment

Popular posts from this blog

Magento/PHP - Get phones on all members in a customer group -

i working on custom magento extension. working around adminhtml part , i've created custom form there. here form code: <?php class vivasindustries_smsnotification_block_adminhtml_sms_sendmass_edit_form extends mage_adminhtml_block_widget_form { public function _preparelayout() { $extensionpath = mage::getmoduledir('js', 'vivasindustries_smsnotification'); $head = $this->getlayout()->getblock('head'); $head->addjs('jquery.js'); $head->addjs('vivas.js'); return parent::_preparelayout(); } protected function _prepareform() { $form = new varien_data_form(array( 'id' => 'edit_form', 'action' => $this->geturl('*/*/save', array('id' => $this->getrequest()->get
Read more

php - .htaccess mod_rewrite for dynamic url which has domain names -

i want convert url ex:( example.com/link.php?url=facebook.com ) ( example.com/facebook.com.php ) how can using .htaccess. or there other process make job easier ? i tried adding script .htaccess file options +followsymlinks rewriteengine on rewriterule url-(.*)\.htm$ link.php?url=$1 but converting url adding "url-" ( example.com/url-facebook.com.php ) i want remove "url-" , want make ( example.com/facebook.com.php ) rewriteengine on rewritecond %{the_request} ^get.*link\.php\?url\= [nc] rewritecond %{request_uri} !/system/.* [nc] rewriterule (.*?)link\.php\?url\=/*(.*) /$1$2 [r=301,ne,l] not sure how above work edit of used use remove index.php url
Read more

Website Login Issue developed in magento -

i have website developed using magento . able login. right now, login failed. infact operations interacts user table failing. need know issue. how figure out? first clear try clear log file second make sure have not upgraded magento and 3rd make sure db accessible in magento -harry p
Read more