c++ - Can I get all instances of some class in Qt? -

-

i have implemented qabstractitemmodel , qsortfilterproxymodel source model. have 1 itemmodel instance , several filtermodel instances. in each filtermodel have variable value of calculated based on filtered data itemmodel. when itemmodel recreated (all items removed , new ones inserted back) value of variable should set default (or recalculated after filtering done).

the problem don't have list of pointers filtermodel instances iterate them. sure can create such static list in constructor. moc did instead of me , saved such list inside of qmetaobject of class?

your filter proxy implementation broken. proxies informed of each , every change model - that's why models qobjects , emit change signals! there's nothing preventing changing "some variable" appropriate, when source model indicates has changed.

you need think of "some variable" depending on data (and structure!) source model. every time source model indicates changes dependent data or structure, proxy must recompute value - or @ least set flag value might recomputed lazily when needed.


Comments

Post a Comment

Popular posts from this blog

html - Firefox flex bug applied to buttons? -

-
i'm trying apply flex button on firefox i'm having problem on chrome doesn't happens. this css: .button { display: inline-flex; align-items: center; } as can see in fiddle, "caret" word moved new line, happens if element <button> tag, <div> works expected. http://codepen.io/anon/pen/xblmgx is firefox bug or there css i'm missing? nevermind, looks "mr firefox" doesn't idea... <button> not implementable (by browsers) in pure css, bit of black box, perspective of css. means don't react in same way e.g. <div> would. this isn't specific flexbox -- e.g. don't render scrollbars if put "overflow:scroll" on button, , don't render table if put "display:table" on it. stepping further, isn't specific <button> . consider <fieldset> , <table> have special rendering behavior: data:text/html,<fieldset style="d
Read more

html - Missing border-right in select on Firefox -

-
Image
when put select div width , padding-left, options have no border on right. more, happend if select have width 118px , parent have 15px of padding left! have idea, going on? my code: <!doctype html> <html> <head lang="en"> </head> <body> <div style="width: 1000px; padding-left: 15px;"> <select style="width: 118px;"> <option>a</option> <option>b</option> <option>c</option> </select> </div> </body> </html> and result: here plunker: click it happend on firefox on windows. tested on 40.0.2 version -webkit-box-sizing: border-box; -moz-box-sizing: border-box; -ms-box-sizing: border-box; box-sizing: border-box; source: https://stackoverflow.com/a/11390432/4431269 source of problem: https://bugzilla.mozilla.org/show_bug.cgi?id=924068 and use of google ! edit: (source of problem, explained) after rea
Read more

c# - two queries in same method -

-
i trying execute 2 queries in same method gives me exception. can red of exception declaring new command there way use same command? string id="hi"; connection.open(); oledbcommand command1 = new oledbcommand(); command1.connection = connection; string query1 = "select * products category='" + combobox1.text + "' , subcategory = '" + combobox2.text + "' , sizes='" + combobox3.text + "'"; command1.commandtext = query1; oledbdatareader reader = command1.executereader(); while (reader.read()) { id = reader[0].tostring(); } textbox1.text = id; string query = "insert category_in (category_id,amount,amount_in) values ('"+ id+"' ,500,300)"; command1.commandtext = query; command1.executenonquery(); messagebox.show("saved"); connection.close();
Read more