I was with a customer in Germany this week, and just before I left one of the (rather talented I might say) developers asked me about passing markup into an HtmlHelper extension. It turns out this is pretty easy, as covered by Phil Haack under Templated Razor Delegates. However, I particularly like keeping my HTML markup in cshtml files. It’s just easier to maintain. So I combined Phil’s post with the use of a partial view. The nice simple HtmlHelper extension looks like this;
1: public static MvcHtmlString Region<TModel>(
2: this HtmlHelper<TModel> html,
3: Func<TModel, object> content)
5: var result = content(html.ViewData.Model);
6: return html.Partial("_Region", result);
This accepts a Func<TModel, object> which is the Templated Razor Delegate. This is quite simply a snippet of Razor syntax that is executed to return markup as “result”.
I’ve combined my HtmlHelper extension with a partial view named _Region, stored in the Shared folder;
1: <fieldset class="demoregion">
2: <legend>A Region</legend>
This would be way neater if I could use an @helper under App_Code, but in MVC 3 that feature doesn’t support using HtmlHelper, so you couldn’t use Html.Textbox in the template, for example.
The code is attached – easy huh?