extension-methods

问题 I'm writing windows store app (8.1) and I have sample (probably for win 8.0): private WriteableBitmap WriteableBitmap; … WriteableBitmap = new WriteableBitmap(500,500); … using (Stream stream = WriteableBitmap.PixelBuffer.AsStream()) { … } So I have created new win 8.1 project and trying to do it same way, but when I get to: using (Stream stream = WriteableBitmap.PixelBuffer.AsStream()) My project dont recognize *.AsStream() method, can anyone tell me why? 回答1: using System.Runtime

问题 Consider my Event class, and that i store DateTime 's in the DB as UTC dates. I simply want to return a filtered range based on the current date in a particular time zone - easy right? This works fine: IQueryable<Event> test1 = this.GetSortedEvents().Where(e => e.FinishDateTime.Date >= DateTime.UtcNow.Date); This also works fine: IQueryable<Event> test2 = this.GetSortedEvents().Where(e => e.FinishDateTime.AddHours(3).Date >= DateTime.UtcNow.AddHours(3).Date); .. and additionally meets my time

问题 This question already has answers here : How do I use reflection to call a generic method? (7 answers) Closed last year . I'm trying to execute an extension method that returns and object of type T, but I'm trying to have type T dynamic based on a Header/Detail dynamic generic type. This maybe a bit verbose... using System; using System.Collections.Generic; namespace Blah { public interface IHeader { string Name { get; set; } IDetail Detail { get; set; } } public interface IDetail { //Nothing

问题 I'm looking for an extension method or any other suggestion that can help me make this code as concise as possible. foreach( Layer lyr in this.ProgramLayers ) foreach( UWBCEvent evt in this.BcEvents.IncludedEvents ) EventGroupLayerLosses[new EventGroupIDLayerTuple(evt.EventGroupID, lyr)] += GetEL(evt.AsIfs, lyr.LimitInMillions, lyr.AttachmentInMillions); The above code has a fairly clear purpose, I'm bucketing values into groups with a compound key. However, this code will fail because the

问题 A resource extension I've been using for a few years now stopped working at design time in a new .Net 4 project with the following error: Markup extension 'StaticResourceExtension' requires 'IXamlSchemaContextProvider' be implemented in the IServiceProvider for ProvideValue. The relevant method from the extension is the following: public override object ProvideValue(IServiceProvider serviceProvider) { Style resultStyle = new Style(); foreach (string currentResourceKey in resourceKeys) {

问题 I want to override ToString() on IEnumerable<Int32> . I was thinking to use Extension methods. But when I do this below, it still calls the ToString() on System.Object . When I rename my method, then it calls my method. As my extension method is in a static class, I am not able to override. How can I achieve this so that my ToString() implementation is called when I call .ToString() on List<Int32> for example? public static class ExtensionMethods { public static new string ToString(this

问题 Let's say I have an interface, like this: public interface ILoggable { void Log(Func<string> message, Logger.Type type); } And some extension methods, like this: public static class Logger { public static void Log(this ILoggable loggable, Func<string> message) { loggable.Log(message, Type.Information); } public static void Log(this ILoggable loggable, string prefix, byte[] data, int len) { /* snip */ } public static void Log(this ILoggable loggable, Exception ex) { /* snip */ } // And so on..

问题 I created an extension method called HasContentPermission on the System.Security.Principal.IIdentity : namespace System.Security.Principal { public static class IdentityExtensions { public static bool HasContentPermission (this IIdentity identity, int contentID) { // I do stuff here return result; } } } And I call it like this: bool hasPermission = User.Identity.HasPermission(contentID); Works like a charm. Now I want to unit test it. To do that, all I really need to do is call the extension

问题 Background this post explains how one can consume extension methods in Powershell http://community.bartdesmet.net/blogs/bart/archive/2007/09/06/extension-methods-in-windows-powershell.aspx Compare this to what someone does in C# - they add a "using SomeAssembly" and all the extension methods are loaded. My questions Did this get simpler Powershell 2.0. And if so, what does one do to use extension methods in Powershell 2.0? I have checked the publically available documentation and installed

问题 Can someone explain to me why the EF Engine is failing in the following scenario? It works fine with the following expression: var data = context.Programs .Select(d => new MyDataDto { ProgramId = d.ProgramId, ProgramName = d.ProgramName, ClientId = d.ClientId, Protocols = d.Protocols.Where(p => p.UserProtocols.Any(u => u.UserId == userId)) .Count(pr => pr.Programs.Any(pg => pg.ProgramId == d.ProgramId)) }) .ToList(); But if I encapsulate some into an extension method: public static IQueryable