How to call Ajax.BeginForm from a custom helper method?

Can I call Ajax.BeginFrom from a custom helper method ?

AjaxHelper is not available in a custom helper method, so I tried to pass the "Ajax" available 开发者_如何学JAVAin ViewPage to Helper method while calling it, but then in method, BeginForm is not available on that passed "Ajax" parameter.

You could instantiate it:

public static class HtmlExtensions
{
    public static MvcHtmlString Foo(this HtmlHelper htmlHelper)
    {
        var ajaxHelper = new AjaxHelper(htmlHelper.ViewContext, htmlHelper.ViewDataContainer);

        var form = ajaxHelper.BeginForm();
        // ... use the ajaxHelper and htmlHelper
    }
}

or if you are writing an extension method on AjaxHelper:

public static class AjaxExtensions
{
    public static MvcHtmlString Foo(this AjaxHelper AjaxHelper)
    {
        var htmlHelper = new HtmlHelper(AjaxHelper.ViewContext, AjaxHelper.ViewDataContainer);
        // ... use the ajaxHelper and htmlHelper
    }
}

And don't forget the proper usings if you want to bring other extension methods into scope:

using System.Web.Mvc;
using System.Web.Mvc.Html;
using System.Web.Mvc.Ajax;