So, can somebody please help me understand why leveraging the same overload inside of those other methods is failing with that error? Precisely because you’re using a dynamic value (param) as one of the arguments. That means it will use dynamic dispatch… but dynamic dispatch isn’t supported for extension methods. The solution is simple though: … Read more
The only difference between a static and a non-static method is that a non-static method receives an implicit parameter – this. Extension methods are not called in the context of the object on which the method is declared, therefore there is no way to pass them the this reference, therefore they must be static. You … Read more
You can easily extend the label by creating your own LabelFor: Something like this should do what you need public static MvcHtmlString LabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, object htmlAttributes) { return LabelFor(html, expression, new RouteValueDictionary(htmlAttributes)); } public static MvcHtmlString LabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, IDictionary<string, object> htmlAttributes) { ModelMetadata metadata = … Read more
In Rust, you can use extension traits, that is a trait with a generic implementation for all types T that implement the base trait: struct Kaz {} impl Foo for Kaz {} trait Foo { fn sample1(&self) -> isize { 111 } } trait FooExt { fn sample2(&self); } impl<T: Foo> FooExt for T { … Read more
Because of language design: Using static makes extension methods declared in the specified type available for extension method lookup. However, the names of the extension methods are not imported into scope for unqualified reference in code. using Directive
Generally speaking, since you do not specify the class when you use an extension method, the compiler would have no way to know which is the class where the extension method is defined: static class GenStatic<T> { static void ExtMeth(this Class c) {/*…*/} } Class c = new Class(); c.ExtMeth(); // Equivalent to GenStatic<T>.ExtMeth(c); what … Read more
No. In C#, you cannot specify any modifiers (like ‘out’ or ref) other than this for the first parameter of an extension method – you can for the others. Not familiar with the VB Syntax but it seems to be using a declarative approach to mark an extension method. When you call it, you do … Read more
static class Extension { public static string Extend(this Array array) { return “Yes, you can”; } } class Program { static void Main(string[] args) { int[,,,] multiDimArray = new int[10,10,10,10]; Console.WriteLine(multiDimArray.Extend()); } }
var query = someList.Where(a => (someCondition)? a == “something” : true); so, if ‘someCondition’ is false, ‘Where’ will be skipped.
[<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