Well, FindAll copies the matching elements to a new list, whereas Where just returns a lazily evaluated sequence – no copying is required. I’d therefore expect Where to be slightly faster than FindAll even when the resulting sequence is fully evaluated – and of course the lazy evaluation strategy of Where means that if you … Read more
It really depends on what you mean by “mixin” – everyone seems to have a slightly different idea. The kind of mixin I’d like to see (but which isn’t available in C#) is making implementation-through-composition simple: public class Mixin : ISomeInterface { private SomeImplementation impl implements ISomeInterface; public void OneMethod() { // Specialise just this … Read more
Since using Rails should handle this automatically I’m going to assume you’re trying to add Active Support to a non-Rails script. Read “How to Load Core Extensions”. Active Support’s methods got broken into smaller groups in Rails 3, so we don’t end up loading a lot of unneeded stuff with a simple require ‘activesupport’. Now … Read more
No, this seems perfectly reasonable. There is a List<T>.AddRange() method that basically does just this, but requires your collection to be a concrete List<T>.
Like so: // you need this once (only), and it must be in this namespace namespace System.Runtime.CompilerServices { [AttributeUsage(AttributeTargets.Assembly | AttributeTargets.Class | AttributeTargets.Method)] public sealed class ExtensionAttribute : Attribute {} } // you can have as many of these as you like, in any namespaces public static class MyExtensionMethods { public static int MeasureDisplayStringWidth ( … Read more
It seems there are two use-cases of why you may want to do what you are doing. In the first use-case, Swift will allow you to do what you want, but not very cleanly in the second use-case. I’m guessing you fall into the second category, but I’ll go through both. Extending the functionality of … Read more
This question & answer lead me to believe that IQueryable require an active context for its operation. That means you should try this instead: try { IQueryable<User> users; using (var dataContext = new dataContext()) { users = dataContext.Users.Where(x => x.AccountID == accountId && x.IsAdmin == false); if(users.Any() == false) { return null; } else { … Read more
Extension methods only work on instances, so it can’t be done, but with some well-chosen class/method names and generics, you can produce a result that looks just as good: public class SelectList { // Normal SelectList properties/methods go here public static SelectList Of<T>() { Type t = typeof(T); if (t.IsEnum) { var values = from … Read more
EDIT: I’ve now blogged about this in more detail. My original (and I now believe incorrect) thought: generic constraints aren’t taken into account during the overload resolution and type inference phases – they’re only used to validate the result of the overload resolution. EDIT: Okay, after a lot of going round on this, I think … Read more
Creating an extension Add a new swift file with File > New > File… > iOS > Source > Swift File. You can call it what you want. The general naming convention is to call it TypeName+NewFunctionality.swift. Example 1 – Double Double+Conversions.swift import Swift // or Foundation extension Double { func celsiusToFahrenheit() -> Double { … Read more