Question

I am attempting to make a dynamically typed extension HtmlHelper, but I am getting and error. For example, if I try this:

public static string DropDownWithAdder<T>(this HtmlHelper helper)
{
    return "Test Worked";
}

And this in the View:

@Html.DropDownWithAdder<Code>()

I get the error

CS1061:
‘System.Web.Mvc.HtmlHelper’
does not contain a definition for
‘DropDownWithAdder’ and no extension
method ‘DropDownWithAdder’ accepting a
first argument of type
‘System.Web.Mvc.HtmlHelper’
could be found (are you missing a
using directive or an assembly
reference?)

But if I simply remove the <T> it works just fine. My question is can you use a generic typing in an Html extension method?

Answer 1

The extension method needs to take the Html helper object as its first parameter

public static string DropDownWithAdder<T>(this HtmlHelper helper)
{
    return "Test Worked";
}

Edit:

You also need to surround the call in brackets to prevent Razor interpreting the < as the start of an html tag:

@(Html.DropDownWithAdder())