EPiserver: ICurrentPage does not have a definition for ContentLink

Question

Our Editors in EPiserver would like to be able to modify the hreflang links of each page as needed. So I would like to modify our pages and enable an override of the default hreflang feature in episerver.

I have started by trying to write my own htmlhelper that will put together the hreflang for me so that I can modify it later.

In the file HtmlHelpers.cs I have started with the following:

public static IHtmlString HrefLangLinks()
{
    var pageLanguagesBranches = ContentRepository.GetLanguageBranches<PageData>(ICurrentPage.ContentLink).ToList();
    var availablePageLanguages = FilterForVisitor.Filter(pageLanguagesBranches).OfType<PageData>();

    // Dictionary<String, String>
    return null;
}

Visual Studio is informing me that ICurrentPage does not have a definition for ContentLink.

I would appreciate any help as I am not that familiar with EPiserver.

Update 1:

The following was suggested:

public static IHtmlString HrefLangLinks(this BasePage currentPage)
        {
            var pageLanguagesBranches = ContentRepository.GetLanguageBranches<PageData>(currentPage.ContentLink).ToList();
            var availablePageLanguages = FilterForVisitor.Filter(pageLanguagesBranches).OfType<PageData>();

            // Dictionary<String, String>
            return null;
        }

Instead of BasePage We have StandardPage which inherits from SitePageData which inherits from PageData. I tried all three but that didn't work, Visual Studio underlines this section ContentRepository.GetLanguageBranches<PageData>with the following message:

Unsupported internal API....

An object reference is required for the non-static field, method or property ContentRepository.GetLanguageBranches<PageData>(ContentReference)

Answer 1

If you have the consept of a BasePage (you should) that all your pages inherit from, you can try the following:

 public static IHtmlString HrefLangLinks(this BasePage currentPage)
    {
        IContentRepository repo = ServiceLocator.Current.GetInstance<IContentRepository>();
        var pageLanguagesBranches = repo.GetLanguageBranches<PageData>(currentPage.ContentLink).ToList();
        var availablePageLanguages = FilterForVisitor.Filter(pageLanguagesBranches).OfType<PageData>();

        // Dictionary<String, String>
        return null;
    }