返回类型

return View(model); 即返回html
return Json("String"); 返回Json格式的数据
return File(new byte[] { }, "application/json"); 返回文件（下载），也可以不使用这种方法下载文件

例子:下载excle

ShopDevelopment. ExportImportUtil
httpContext.Response.BinaryWrite(streamName.ToArray()); 完成下载功能
输入excle的内容为html即可，可以自动转为excle格式
关键类：System.Web. HttpContextBase 也可以采用其他帮助库

public static void ExportExcel(HttpContextBase httpContext, string name, MemoryStream streamName)

{

    httpContext.Response.ContentType = "applicationnd.ms-excel";

    name = HttpUtility.UrlEncode(name,System.Text.Encoding.GetEncoding("UTF-8"));

    httpContext.Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}", name));

    httpContext.Response.Clear();

    httpContext.Response.BinaryWrite(streamName.ToArray());

    httpContext.Response.End();

}