c# - When Control.ParentChanged Event occurs? -


i read control.parentchanged event on msdn http://msdn.microsoft.com/en-us/library/system.windows.forms.control.parentchanged(vs.71).aspx

but don't understand sample code: there's no parentchanged @ appearing in source code ?

private void currencytextbox_textchanged(object sender, eventargs e) {    try    {       // convert text double , determine if negative number.       if(double.parse(currencytextbox.text) < 0)       {          // if number negative, display in red.          currencytextbox.forecolor = color.red;       }       else       {          // if number not negative, display in black.          currencytextbox.forecolor = color.black;       }    }    catch    {       // if there error, display text using system colors.       currencytextbox.forecolor = systemcolors.controltext;    } }

so don't understand control.parentchanged event or does.

hehe, couldn't come example. , punted showing generic foochanged event handler instead. yeah, useless.

it quite unusual implement parentchanged event handler yourself. it's big deal in winforms internals, properties backcolor, forecolor, font 'ambient' properties. if not overridden default they'll value of parent. of course means really important notice parent changed. winforms code takes care of it, have worry it. unless create own ambient property of course.


Comments

Post a Comment

Popular posts from this blog

asp.net - repeatedly call AddImageUrl(url) to assemble pdf document -

i'm using abcpdf , i'm curious if can recursively call addimageurl() function assemble pdf document compile multiple urls? something like: int pagecount = 0; int theid = thedoc.addimageurl("http://stackoverflow.com/search?q=abcpdf+footer+page+x+out+of+", true, 0, true); //assemble document while (thedoc.chainable(theid)) { thedoc.page = thedoc.addpage(); theid = thedoc.addimagetochain(theid); } pagecount = thedoc.pagecount; console.writeline("1 document page count:" + pagecount); //flatten document (int = 1; <= pagecount; i++) { thedoc.pagenumber = i; thedoc.flatten(); } //now try again theid = thedoc.addimageurl("http://stackoverflow.com/questions/1980890/pdf-report-generation", true, 0, true); //assemble document while (thedoc.chainable(theid)) { thedoc.page = thedoc.addpage(); theid = thedoc.addimagetoc
Read more

java - Android recognize cell phone with keyboard or not? -

in android app, want detect user's device if device has keyboard(like motorola milestone) , show corresponding user interface. guys know how that? ! regards justicepenny http://developer.android.com/reference/android/content/res/configuration.html public int keyboard the kind of keyboard attached device. 1 of: keyboard_nokeys, keyboard_qwerty, keyboard_12key. that's it!
Read more

iphone - How would you achieve a LED Scrolling effect? -

how achieve led scrolling effect example below? led sign - led ticker emulator iphone , ipad http://img.skitch.com/20101201-rsfh4p1bajb1wp94k466pdpiuj.preview.jpg sometimes remunerates comment in other posts :) have put code you, should implement font '8pin matrix' realistic feeling. uilabel *label; - (void)viewdidload { [super viewdidload]; label = [[uilabel alloc]initwithframe:cgrectmake(10, 50, 300, 20)]; label.font = [uifont fontwithname:@"courier-bold" size:16.0]; label.backgroundcolor = [uicolor blackcolor]; label.textcolor = [uicolor greencolor]; label.linebreakmode = uilinebreakmodecharacterwrap; // otherwise "…" label.text = @"this led text scrolled "; // blanks space between [self.view addsubview:label]; [nstimer scheduledtimerwithtimeinterval:0.12f target:self selector:@selector(scrolllabel) use
Read more