.net - How to seal an overridden property -


suppose have pair of contrived c# classes this:

public abstract class foo {     public abstract int[] legalvalues { get; }     public virtual bool isvaluelegal(int val) {         return array.indexof(legalvalues, val) >= 0;     } }

and this:

public class bar : foo {     static int[] _legalvalues = new int[] { 0, 1 }; // whatever     public sealed override int[] legalvalues          { { return _legalvalues; } }     public sealed override bool isvaluelegal(int val)         { return base.isvaluelegal(val); } }

how do in f#? obvious code properties:

[<sealed>] override this.legalvalues get() = // ...  [<sealed>] override this.isvaluelegal value = // ...

triggers error because sealedattribute apparently can't applied members. can, of course, seal entire class , thereby seal members, (and really important but) have goal of matching existing class signature exactly , base class has other virtual/abstract members should, ideally, remain overridable.

there several limitations f#'s support oo, should not expect able produce f# class hierarchy identical arbitrary c# class hierarchy. far know, there no way override , seal virtual method.


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