Question

I have defined an extension method in app_code like below.

public static class Extensions
{
    public static string Hi(this object obj)
    {
        return "hi";
    }
}

In the razor page, anything can say Hi 🙂

@Html.Hi();
@Request.Hi();   
@this.Hi();

But @Hi() doesn’t work. Is there a way to make @Hi() work?

Answer 1

C# only allows you to call extension methods qualified by an object instance.
If you have an extension method that extends your type, you can’t call it “directly”; you need to write this.ExtensionMethod().

The only way to do what you’re asking for is to make a class which inherits WebPage (or WebViewPage for MVC views) and change your Razor page to inherit that class (using the @inherits directive)