extension-methods

FindAll vs Where extension-method

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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

Impossible to use ref and out for first (“this”) parameter in Extension methods?

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You have to specify ref and out explicitly. How would you do this with an extension method? Moreover, would you really want to? TestClass x = new TestClass(); (ref x).ChangeWithExtensionMethod(otherTestClass); // And now x has changed? Or would you want to not have to specify the ref part, just for the first parameter in extension … Read more

Extension methods on a struct

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Yes, you can add extension methods on structs. As per the definition of extension method, you can easily achieve it. Below is example of extension method on int namespace ExtensionMethods { public static class IntExtensions { public static bool IsGreaterEqualThan(this int i, int value) { return i >= value; } } }

F# extension methods in C#

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[<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 … Read more

The operation cannot be completed because the DbContext has been disposed error

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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