extension-methods

We're all familiar with the horror that is C# event declaration. To ensure thread-safety, the standard is to write something like this : public event EventHandler SomethingHappened; protected virtual void OnSomethingHappened(EventArgs e) { var handler = SomethingHappened; if (handler != null) handler(this, e); } Recently in some other question on this board (which I can't find now), someone pointed out that extension methods could be used nicely in this scenario. Here's one way to do it: static public class EventExtensions { static public void RaiseEvent(this EventHandler @event, object sender

If you were to define some extension methods, properties in an assembly written in F#, and then use that assembly in C#, would you see the defined extensions in C#? If so, that would be so cool. [<System.Runtime.CompilerServices.Extension>] module Methods = [<System.Runtime.CompilerServices.Extension>] let Exists(opt : string option) = match opt with | Some _ -> true | None -> false This method could be used in C# only by adding the namespace (using using) to the file where it will be used. if (p2.Description.Exists()) { ...} Here is a link to the original blogpost. Answering question in

Consider two extension methods: public static T MyExtension<T>(this T o) where T:class public static T MyExtension<T>(this T o) where T:struct And a class: class MyClass() { ... } Now call the extension method on a instance of the above class: var o = new MyClass(...); o.MyExtension(); //compiler error here.. o.MyExtension<MyClass>(); //tried this as well - still compiler error.. The compiler says that calling the method is an ambiguous call when I call it on a class. I would have thought that it could determine which extension method to call, as MyClass is a class, not a struct? Jon Skeet

Greetings everyone... I need to Trim a String . But I want to remove all the repeated blank spaces within the String itself, not only at the end or at the start of it. I could do it with a method like: public static string ConvertWhitespacesToSingleSpaces(string value) { value = Regex.Replace(value, @"\s+", " "); } Which I got from here . But I want this piece of code to be called within the String.Trim() itself, so I think I need to extend or overload or override the Trim method... Is there a way to do that? Thanks in advance. JoeyRobichaud Since you cannot extend string.Trim(). You could

I'm starting to really love extension methods... I was wondering if anyone her has stumbled upon one that really blew their mind, or just found clever. An example I wrote today: Edited due to other users' comments: public static IEnumerable<int> To(this int fromNumber, int toNumber) { while (fromNumber < toNumber) { yield return fromNumber; fromNumber++; } } This allows a for loop to be written as a foreach loop: foreach (int x in 0.To(16)) { Console.WriteLine(Math.Pow(2, x).ToString()); } I can't wait to see other examples! Enjoy! The full solution is too large to put here, but I wrote a

Compile Error 'System.Data.SqlClient.SqlConnection' has no applicable method named 'Query' but appears to have an extension method by that name. Extension methods cannot be dynamically dispatched. Consider casting the dynamic arguments or calling the extension method without the extension method syntax. Now, I know how to work around the problem, but I'm trying to get a better understanding of the error itself. I have class that I'm building to leverage Dapper. In the end I'm going to provide some more custom functionality to make our type of data access a lot more streamlined. In particular

I'm new to EF and I'm trying to use an extension method which converts from my Database type User to my info class UserInfo . I'm using database first if that makes a difference? My code below gives the error The operation cannot be completed because the DbContext has been disposed. 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; } } return users.Select(x => x.ToInfo()).ToList(); // this line is the problem } catch (Exception ex) { //... } I