ASP.NET MVC Helpers, Merging two object htmlAttributes together

Question

I have a situation where I need to write an HTML Helper to extend another html helper. Normally, the helper would look like this.

@Html.TextAreaFo

Answer 1

When I've to do that, I usually create a partial view Then I use RenderPartial:

@Html.Partial(MVC.Shared.MyPartialView_cshtml, new ViewDataDictionary() {  
       { "Content", model.Content},
       { "Css", "some_other_css"},
});

I usually also create a Model class to avoid using magic string ( and ViewDataDictionary) like in the sample above. In your view you can

• use the Content: @ViewBag.Content
• test and use the default css if a custom one is not specified (@ViewBag.Css)

A small note: it's also possible to change the default template used when calling TextAreaFor (or other similar method). For this, have a look at http://bradwilson.typepad.com/blog/2009/10/aspnet-mvc-2-templates-part-3-default-templates.html