ASP.NET MVC Razor render without encoding using an attribute ie. data annotation

Not that I know of, but it appears that you can change the datatype from a string to an HTMLString. If you use an HTMlString, it should render the HTML in the string.

See Always output raw HTML using MVC3 and Razor

The second response in that thread shows a possible way of using an attribute to display raw html.

Try Html.Raw(yourstring)

This should help.

MVC by default outputs a string as plain string, not HTML.

e.g. in your Action:

public ActionResult Test()
{
    var model = new TestViewModel(); // your view model
    model.Message = "<b>hello</b>";
    return View(model);
}

your View:

@model MyProject.TestViewModel

<div>
    @Model.Message
</div>

This will render as:

<b>hello</b>

If you want to actually render it as HTML, you need to change the above to this:

@MvcHtmlString.Create(Model.Message)

Alternatively, you could create an extension to make it nicer:

    public static MvcHtmlString ToMvcHtmlString(this String str)
    {
        if (string.IsNullOrEmpty(str))
            return MvcHtmlString.Empty;
        else
            return MvcHtmlString.Create(str);
    }

So then to render a string as HTML, in your View, you could write:

@Model.Message.ToMvcHtmlString()

If this is not what you're after, you should provide us with an example of where your code is falling over.