{"id":92341,"date":"2015-12-07T07:00:00","date_gmt":"2015-12-07T22:00:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/oldnewthing\/20151207-00\/?p=92341\/"},"modified":"2019-03-13T12:22:34","modified_gmt":"2019-03-13T19:22:34","slug":"20151207-00","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/oldnewthing\/20151207-00\/?p=92341","title":{"rendered":"Enumerating all the programs that can launch a particular protocol"},"content":{"rendered":"

Today’s Little Program is a variation on the one from last time<\/a>. This time, instead of enumerating all the handlers for a file extension, we enumerate all the handlers for a protocol. We then open a Web site with that chosen program. <\/p>\n

Start with the program from last time and make these changes: <\/p>\n

\nstd::vector<CComPtr<IAssocHandler>> LoadHandlers(\n  PCWSTR extension)\n  \/\/ ASSOC_FILTER filter<\/strike><\/font>\n  )\n{\n  std::vector<CComPtr<IAssocHandler>> handlers;\n  CComPtr<IEnumAssocHandlers> enumerator;\n  SHAssocEnumHandlersForProtocolByApplication(\n    L\"http\", IID_PPV_ARGS(&enumerator));<\/font>\n  for (CComPtr<IAssocHandler> handler;\n       enumerator->Next(1, &handler, nullptr) == S_OK;\n       handler.Release()) {\n       handlers.push_back(handler);\n  }\n  return handlers;\n}\n<\/pre>\n
The SHAssoc­Enum­Handlers­ForProtocol­By­Application<\/code> function does not have a filter option, so we delete that parameter from Load­Handlers<\/code>. <\/p>\n
The Choose­Handler<\/code> function is unchanged. <\/p>\n
\nint __cdecl main(int, char**)\n{\n  CCoInitialize init;\n  ProcessReference ref;\n\n  auto handlers = LoadHandlers(L\"http\");\n  auto selection = ChooseHandler(handlers, false);<\/font>\n\n  if (selection < handlers.size()) {\n    CComPtr<IDataObject> dobj;\n    GetUIObjectOfFile(nullptr, L\"http:\/\/www.microsoft.com\/\"<\/font>,\n                      IID_PPV_ARGS(&dobj));\n    handlers[selection]->Invoke(dobj);\n  }\n  return 0;\n}\n<\/pre>\n
This version is shorter because there is no filter option, so we just load up all the handlers, pick one, and invoke it. <\/p>\n
Notice that we are using Get­UI­Object­Of­File<\/code> for something that isn’t a file. If you go back to that function, you’ll see that there’s nothing in it that actually requires a file. It can accept any parseable name. A more accurate name for the function would have been Get­UI­Object­Of­Parsing­Name<\/code>, but it’s too late now. <\/p>\n","protected":false},"excerpt":{"rendered":"
SHAssocEnumHandlersForProtocolByApplication<\/p>\n","protected":false},"author":1069,"featured_media":111744,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[25],"class_list":["post-92341","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":"
SHAssocEnumHandlersForProtocolByApplication<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/92341","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/users\/1069"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/comments?post=92341"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/92341\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media\/111744"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media?parent=92341"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=92341"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=92341"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}