ViewBag return null in Extension Class

Question

I want to use my ViewBag in my _Layout, because all my views have similar data. So here what I do:

In my View:

ViewBag.MetaKeywords = Model.MetaKeywords

I have an extension class binded on the HtmlHelper

public static string MetaKeywords(this HtmlHelper helper)
{
    return helper.ViewContext.Controller.ViewBag.MetaKeyWords;
}

And in my _Layout:

@Html.MetaKeywords()

The problem is my extension method returns null. Why I use an extension method instead of @ViewBag.MetaKeyWords? Because some other functions have logic and we want to share it between ourself.

Thank you for your help.

Answer 1

When using Razor the ViewBag/ViewData properties which were set in the View can be accessed with helper.ViewData instead of helper.ViewContext. ...:

 public static string MetaKeywords(this HtmlHelper helper)
 {
     return (string) helper.ViewData["MetaKeyWords"];
 }

Note: The ViewBag is just a dynamic wrapper around the ViewData dictionary.

Or if you do the ViewBag.MetaKeywords = Model.MetaKeywords in the Controller then your original extension method should also work.