Question

I am trying to create controller actions which will return either JSON or partial html depending upon a parameter. What is the best way to get the result returned to an MVC page asynchronously?

Answer 1

In your action method, return Json(object) to return JSON to your page.

public ActionResult SomeActionMethod() {   return Json(new {foo='bar', baz='Blech'}); } 

Then just call the action method using Ajax. You could use one of the helper methods from the ViewPage such as

<%= Ajax.ActionLink('SomeActionMethod', new AjaxOptions {OnSuccess='somemethod'}) %> 

SomeMethod would be a javascript method that then evaluates the Json object returned.

If you want to return a plain string, you can just use the ContentResult:

public ActionResult SomeActionMethod() {     return Content('hello world!'); } 

ContentResult by default returns a text/plain as its contentType.
This is overloadable so you can also do:

return Content('<xml>This is poorly formatted xml.</xml>', 'text/xml');