This is probably one of those rare cases where it makes sense to use an extern alias. In the properties page for the reference to System.Core (i.e. under References, select System.Core, right-click and select “Properties”), change the “Aliases” value to “global,SystemCore” (or just “SystemCore” if it’s blank to start with). Then in your code, write: … Read more
I just used the Reference Source to look into the code for Last and it checks to see if it is a IList<T> first and performs the appropriate O(1) call: public static TSource Last < TSource > (this IEnumerable < TSource > source) { if (source == null) throw Error.ArgumentNull(“source”); IList < TSource > list … Read more
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