extension-methods

I've tried to code a class to avoid a method like "RaisePropertyChanged". I know that I can inherit from a class that has that implementation but in some cases I can't. I've tried with a Extension Method but Visual Studio complain. public static class Extension { public static void RaisePropertyChanged(this INotifyPropertyChanged predicate, string propertyName) { if (predicate.PropertyChanged != null) { predicate.PropertyChanged(propertyName, new PropertyChangedEventArgs(propertyName)); } } } It said: "The event ' System.ComponentModel.INotifyPropertyChanged.PropertyChanged' can only appear on

I am trying to create a PredicateBuilder<T> class which wraps an Expression<Func<T, bool>> and provides some methods to easily build up an expression with various And and Or methods. I thought it would be cool if I could use this PredicateBuilder<T> as an Expression<Func<T, bool>> directly, and thought this could be done by having an implicit operator method thing. Stripped down version of the class looks like this: class PredicateBuilder<T> { public Expression<Func<T, bool>> Predicate { get; protected set; } public PredicateBuilder(bool initialPredicate) { Predicate = initialPredicate ?

I'm a bit confused about how extension methods work. If I'm reading this correctly http://msdn.microsoft.com/en-us/library/bb383977.aspx and this If an extension method has the same signature as a method in the sealed class, what is the call precedence? . Then the following should write out "Instance", but instead it writes "Extension method". interface IFoo { } class Foo : IFoo { public void Say() { Console.WriteLine("Instance"); } } static class FooExts { public static void Say(this IFoo foo) { Console.WriteLine("Extension method"); } } class Program { static void Main(string[] args) { IFoo

I'm reading the book 'C# in Depth, 2nd Edition' of Jon Skeet. He said that we can call extension methods with dynamic arguments using two workarounds, just as dynamic size = 5; var numbers = Enumerable.Range(10, 10); var error = numbers.Take(size); var workaround1 = numbers.Take((int) size); var workaround2 = Enumerable.Take(numbers, size); Then he said "Both approaches will work if you want to call the extension method with the dynamic value as the implicit this value". I don't know how to achieve it. Thanks a lot. Like this: dynamic numbers = Enumerable.Range(10, 10); var firstFive =

Let's say I have a need for a simple private helper method, and intuitively in the code it would make sense as an extension method. Is there any way to encapsulate that helper to the only class that actually needs to use it? For example, I try this: class Program { static void Main(string[] args) { var value = 0; value = value.GetNext(); // Compiler error } static int GetNext(this int i) { return i + 1; } } The compiler doesn't "see" the GetNext() extension method. The error is: Extension method must be defined in a non-generic static class Fair enough, so I wrap it in its own class, but still

I was wondering if it's possible to use an extension method with asp.net webforms and nvelocity. I would like to set some defaults if the string value is null or empty. Example of .vm file: Example of my email body... Billable Status: $billableStatus.Evaluate() rest of my email body... Attempted extension method: public static class Helper { public static string Evaluate(this string value) { if (String.IsNullOrEmpty(value)) return "Not Provided"; else return value; } } Or is there an alternative to what I'm tryting to accomplish? I don't think NVelocity can resolve extension methods with C#/VB

I use a custom extension for my ActionLinks. I have added an attribute data_url which is meant to be translated to an attribute of data-url . This is, replacing the underscaore with a dash. Here is link 1 using my custom extension: @Ajax.ActionLink("Add", MyRoutes.GetAdd(), new AjaxOptions() , new { data_url = Url.Action(...)}) Result: data_url Here is link 2 using the framework ActionLink: @Ajax.ActionLink("Add 2", "x", "x", null, new AjaxOptions() , new { data_url = Url.Action(...) }) Result: data-url Here is the extension, simple enough, except that the only way to pass the htmlAttributes