ActionMethod to return excel application content

What's the correct method to return application/ms-excel content type from an action method in MVC?

I've tried creating a controller action method and pass开发者_如何学编程ing the controller context, such as;

public void ExportToExcel(MyViewModel model, ControllerContext context)
{
    .... build up html or xml excel output in Writer

    context.HttpContext.Response.Clear();
    context.HttpContext.Response.ContentType = "applicaton/vnd.ms-excel";
    context.HttpContext.Response.AddHeader(.. etc.);
    context.HttpContext.Response.Write(Writer.ToString());
    context.HttpContext.Response.End();
}

When trying to use the controller context as above I get a method or operation not implemented exception when calling any method of the Response object.

I've also tried returning a FileResult, FileContentResult and ContentResult action result types which seem to just throw my content to the browser.

EDIT: Here's my code for the ExcelResult class;

public class ExcelResult : ActionResult
{
    private string _content = String.Empty;
    public string Content
    {
        get {

            return _content;
        }

        set {

            _content = value;
        }
    }



    public ExcelResult(string content)
    {
        this.Content = content;
    }



    public override void ExecuteResult(ControllerContext context)
    {
        context.HttpContext.Response.Clear();
        context.HttpContext.Response.ContentType = "application/vnd.ms-excel";
        context.HttpContext.Response.Charset = "iso-8859-1";
        context.HttpContext.Response.BufferOutput = true;
        context.HttpContext.Response.AddHeader("content-disposition", "attachment; filename = exportdata.xls");
        context.HttpContext.Response.Write(this.Content);
        context.HttpContext.Response.End();
    }


}

FYI. My problem was due to the fact I was trying to change content-type from an AJAX callback. Always ensure you are submitting a form before changing the content-type.