{"id":11703,"date":"2011-01-21T07:00:00","date_gmt":"2011-01-21T07:00:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/oldnewthing\/2011\/01\/21\/modality-part-9-setting-the-correct-owner-for-modal-ui-practical-exam\/"},"modified":"2011-01-21T07:00:00","modified_gmt":"2011-01-21T07:00:00","slug":"modality-part-9-setting-the-correct-owner-for-modal-ui-practical-exam","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/oldnewthing\/20110121-00\/?p=11703","title":{"rendered":"Modality, part 9: Setting the correct owner for modal UI, practical exam"},"content":{"rendered":"

\nHere’s a question that came from a customer.\nYou can answer it yourself based on what you know about modal UI.\n(If you’re kind of rusty on the topic,\n\nyou can catch up here<\/a>.)\nI’ve left in some irrelevant details\njust to make things interesting.\n<\/p>\n

\n

\nOur program launches a helper program\nto display an Aero Wizard\nto guide the user through submitting a service request.\n<\/p>\n

\ntheWiz.DoModal(hwndMainFrame);\n<\/pre>\n
\nThere are no EnableWindow<\/code> calls leading up to\nor returning from this call.\nthe DoModal<\/code> handles things nicely.\n<\/p>\n
\nWhen the user clicks “Cancel” to cancel the service request,\nwe use a TaskDialog so we can get the new look for our confirmation\nmessage box.\nThe task dialog setup goes like this:\n<\/p>\n
\nTASKDIALOGCONFIG config = { 0 };\nconfig.cbSize = sizeof(config);\nconfig.hwndParent = hwndMainFrame;\n<\/pre>\n
\nWhen the user clicks “Yes” to cancel,\nthen another window instead of our frame becomes active.\n<\/p>\n
\nOn a hunch, I replaced the task dialog with a Win32 message box\n<\/p>\n
\nMessageBox(hwndMainFrame, ...);\n<\/pre>\n
\nand bingo, we get the correct behavior.\nWhen our wizard exits, the main frame receives focus.\n<\/p>\n
\nI believe that the “automatic” modal behavior that comes\nwith DoModal()<\/code> that takes care of disabling\nand reenabling the main frame is somehow getting short-circuited\nby using TaskDialog<\/code> from inside our\nPSM_QUERYCANCEL<\/code> message handler.\n<\/p>\n
\nRight now, we’ve switched to MessageBox<\/code>,\nbut we would much prefer to use the task dialog.\n<\/p>\n<\/blockquote>\n
\nAlthough it’s not common,\nit is legal to have a window’s parent or owner\nbelongs to another thread or process.\nBut it definitely makes things a bit more tricky to manage\nbecause it attaches the input queues of the two threads,\nand you now have two threads coöperating to manage a single\nwindow hierarchy.\n<\/p>\n
\nIs the cross-process window hierarchy a contributing factor\nto the problem, or is it just a red herring?<\/p>\n","protected":false},"excerpt":{"rendered":"
Here’s a question that came from a customer. You can answer it yourself based on what you know about modal UI. (If you’re kind of rusty on the topic, you can catch up here.) I’ve left in some irrelevant details just to make things interesting. Our program launches a helper program to display an Aero […]<\/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-11703","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":"
Here’s a question that came from a customer. You can answer it yourself based on what you know about modal UI. (If you’re kind of rusty on the topic, you can catch up here.) I’ve left in some irrelevant details just to make things interesting. Our program launches a helper program to display an Aero […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/11703","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=11703"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/11703\/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=11703"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=11703"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=11703"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}