{"id":13963,"date":"2010-05-21T07:00:00","date_gmt":"2010-05-21T07:00:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/oldnewthing\/2010\/05\/21\/shautocomplete-giveth-and-shautocomplete-taketh-away\/"},"modified":"2010-05-21T07:00:00","modified_gmt":"2010-05-21T07:00:00","slug":"shautocomplete-giveth-and-shautocomplete-taketh-away","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/oldnewthing\/20100521-00\/?p=13963","title":{"rendered":"SHAutoComplete giveth, and SHAutoComplete taketh away"},"content":{"rendered":"

\nThe SH­Auto­Complete<\/code> function lets you attach\nautocomplete functionality to an edit control,\nand there are flags that describe what sources you want\nthe autocomplete to draw from.\nIf you call SH­Auto­Complete<\/code> a second time,\nthe second set of flags replace the original flags.\nThe flags do not accumulate.\nFor example, if you first call\nSH­Auto­Complete(SHACF_FILESYS_ONLY)<\/code>, and then\nyou later call\nSH­Auto­Complete(SHACF_URLHISTORY)<\/code>,\nthe result is that the autocompletion uses only the URL history.\n<\/p>\n

\nThis replacement behavior (as opposed to accumulation behavior)\nis handy if you want to remove<\/i> an autocompletion that you\npreviously added.\nYou just call SH­Auto­Complete<\/code> a second time\nand leave off the flags for autocomplete sources you don’t want.\nThere’s a catch, though:\nIf you want to turn off everything, then you cannot pass zero,\nbecause that gets interpreted as SHACF_DEFAULT<\/code>.\nYou have to pass a nonzero value,\nand fortunately there’s a handy nonzero value which means\nTurn off everything<\/i>:\nSHACF_AUTOSUGGEST_FORCE_OFF<\/code>.\n<\/p>\n

\nLet’s illustrate this technique by disabling autocomplete\nin the common dialog, a problem which\ncommenter Ian mistakenly\n\nsolved by modifying a global setting<\/a>.\n<\/p>\n

\n#include <windows.h>\n#include <shlwapi.h>\n#include <commctrl.h>\n#include <commdlg.h>\n#include <dlgs.h>\nUINT_PTR CALLBACK HookProc(HWND hdlg, UINT uMsg,\n                           WPARAM wParam, LPARAM lParam)\n{\n    switch (uMsg) {\n    case WM_INITDIALOG:\n        PostMessage(hdlg, WM_APP, 0, 0);\n        break;\n    case WM_APP:\n        SHAutoComplete(\n          (HWND)SendDlgItemMessage(GetParent(hdlg), cmb13,\n                                   CBEM_GETEDITCONTROL, 0, 0),\n          SHACF_AUTOSUGGEST_FORCE_OFF);\n        break;\n    }\n    return 0;\n}\nint WINAPI WinMain(HINSTANCE hinst, HINSTANCE hinstPrev,\n                   LPSTR lpCmdLine, int nShowCmd)\n{\n    TCHAR szFile[MAX_PATH];\n    szFile[0] = TEXT('\\0');\n    OPENFILENAME ofn = { sizeof(ofn) };\n    ofn.hInstance = hinst;\n    ofn.lpstrFilter = TEXT(\"All files\\0*.*\\0\");\n    ofn.lpstrFile = szFile;\n    ofn.nMaxFile = MAX_PATH;\n    ofn.Flags = OFN_ENABLEHOOK | OFN_EXPLORER;\n    ofn.lpfnHook = HookProc;\n    GetOpenFileName(&ofn);\n    return 0;\n}\n<\/pre>\n
\nThe hook procedure uses the SH­Auto­Complete<\/code>\nfunction to turn off autocompletion on the file name\nedit control in the common dialog.\nThere are a few annoying bits that I have to get through\nbefore I finally make that SH­Auto­Complete<\/code>\ncall:\nFirst I have to find the edit control,\nwhich means finding the combo box and then asking the combo box\nfor the interior edit control.\n(Fortunately, this is already called out in the documentation\nfor SH­Auto­Complete<\/code>, so I didn’t have to puzzle over\nit for long.)\nAnd second,\nI couldn’t disable autocomplete directly in WM_INITDIALOG<\/code>\nbecause that happens too early in the common file dialog\ninitialization process.\nInstead, I post myself a message and do the “final initialization”\nlater.\n(This I discovered by trial and error.)\n<\/p>\n
\nAnd there you have it, a common dialog box with no autocomplete.\n<\/p>\n
\nUpdate<\/b>:\n\nJoylon Smith<\/a>\npoints out that\n\nthe documentation for SHAutoComplete<\/code> explicitly\ncautions against calling it more than once on the same window<\/a>\nbecause it results in a memory leak.\n<\/p>\n
\nThat caution was written based on information I provided\nback in Windows XP.\nThe memory leak was fixed in Windows Vista, but the documentation\nwas not updated to match.\nSo please mentally insert\n“On versions of Windows prior to Windows Vista (and versions\nof Windows Server prior to Windows Server 2008)” at the start of\nthat paragraph.\nA doc change request has also been submitted, so hopefully the\nrevised documentation will appear soon.<\/p>\n","protected":false},"excerpt":{"rendered":"
The SH­Auto­Complete function lets you attach autocomplete functionality to an edit control, and there are flags that describe what sources you want the autocomplete to draw from. If you call SH­Auto­Complete a second time, the second set of flags replace the original flags. The flags do not accumulate. For example, if you first call SH­Auto­Complete(SHACF_FILESYS_ONLY), […]<\/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-13963","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":"
The SH­Auto­Complete function lets you attach autocomplete functionality to an edit control, and there are flags that describe what sources you want the autocomplete to draw from. If you call SH­Auto­Complete a second time, the second set of flags replace the original flags. The flags do not accumulate. For example, if you first call SH­Auto­Complete(SHACF_FILESYS_ONLY), […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/13963","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=13963"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/13963\/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=13963"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=13963"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=13963"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}