Another approach instead of saving the file on the server and retrieving it, is to use .NET 4.0+ ObjectCache with a short expiration until the second Action (at which time it can be definitively dumped). The reason that I want to use JQuery Ajax to do the call, is that it is asynchronous. Building my dynamic PDF file takes quite a bit of time, and I display a busy spinner dialog during that time (it also allows other work to be done). The approach of using the data returned in the "success:" to create a Blob does not work reliably. It depends on the content of the PDF file. It is easily corrupted by data in the response, if it is not completely textual which is all that Ajax can handle.

简而言之，没有更简单的方法了。您需要发出另一个服务器请求来显示PDF文件。尽管有一些替代方案，但它们并不完美，也不能在所有浏览器上运行:

看看数据URI方案。如果二进制数据很小，那么你可以使用javascript在URI中打开窗口传递数据。 Windows/IE唯一的解决方案是使用. net控件或FileSystemObject将数据保存到本地文件系统并从那里打开它。

I know this kind of old, but I think I have come up with a more elegant solution. I had the exact same problem. The issue I was having with the solutions suggested were that they all required the file being saved on the server, but I did not want to save the files on the server, because it introduced other problems (security: the file could then be accessed by non-authenticated users, cleanup: how and when do you get rid of the files). And like you, my data was complex, nested JSON objects that would be hard to put into a form.

What I did was create two server functions. The first validated the data. If there was an error, it would be returned. If it was not an error, I returned all of the parameters serialized/encoded as a base64 string. Then, on the client, I have a form that has only one hidden input and posts to a second server function. I set the hidden input to the base64 string and submit the format. The second server function decodes/deserializes the parameters and generates the file. The form could submit to a new window or an iframe on the page and the file will open up.

这涉及到更多的工作，可能还有更多的处理，但总的来说，使用这个解决方案我感觉好多了。

代码是c# /MVC

    public JsonResult Validate(int reportId, string format, ReportParamModel[] parameters)
    {
        // TODO: do validation

        if (valid)
        {
            GenerateParams generateParams = new GenerateParams(reportId, format, parameters);

            string data = new EntityBase64Converter<GenerateParams>().ToBase64(generateParams);

            return Json(new { State = "Success", Data = data });
        }

        return Json(new { State = "Error", Data = "Error message" });
    }

    public ActionResult Generate(string data)
    {
        GenerateParams generateParams = new EntityBase64Converter<GenerateParams>().ToEntity(data);

        // TODO: Generate file

        return File(bytes, mimeType);
    }

在客户端

    function generate(reportId, format, parameters)
    {
        var data = {
            reportId: reportId,
            format: format,
            params: params
        };

        $.ajax(
        {
            url: "/Validate",
            type: 'POST',
            data: JSON.stringify(data),
            dataType: 'json',
            contentType: 'application/json; charset=utf-8',
            success: generateComplete
        });
    }

    function generateComplete(result)
    {
        if (result.State == "Success")
        {
            // this could/should already be set in the HTML
            formGenerate.action = "/Generate";
            formGenerate.target = iframeFile;

            hidData = result.Data;
            formGenerate.submit();
        }
        else
            // TODO: display error messages
    }

这个问题被问到已经有一段时间了，但我也有同样的挑战，想要分享我的解决方案。它使用了其他答案中的元素，但我无法找到它的全部。它不使用表单或iframe，但它需要post/get请求对。它不是在请求之间保存文件，而是保存post数据。这似乎既简单又有效。

客户端

var apples = new Array(); 
// construct data - replace with your own
$.ajax({
   type: "POST",
   url: '/Home/Download',
   data: JSON.stringify(apples),
   contentType: "application/json",
   dataType: "text",

   success: function (data) {
      var url = '/Home/Download?id=' + data;
      window.location = url;
   });
});

服务器

[HttpPost]
// called first
public ActionResult Download(Apple[] apples)
{
   string json = new JavaScriptSerializer().Serialize(apples);
   string id = Guid.NewGuid().ToString();
   string path = Server.MapPath(string.Format("~/temp/{0}.json", id));
   System.IO.File.WriteAllText(path, json);

   return Content(id);
}

// called next
public ActionResult Download(string id)
{
   string path = Server.MapPath(string.Format("~/temp/{0}.json", id));
   string json = System.IO.File.ReadAllText(path);
   System.IO.File.Delete(path);
   Apple[] apples = new JavaScriptSerializer().Deserialize<Apple[]>(json);

   // work with apples to build your file in memory
   byte[] file = createPdf(apples); 

   Response.AddHeader("Content-Disposition", "attachment; filename=juicy.pdf");
   return File(file, "application/pdf");
}

我一直在尝试使用blobs的另一种选择。我已经设法让它下载文本文档，我下载了PDF文件(但他们是损坏的)。

使用blob API，你可以做以下事情:

$.post(/*...*/,function (result)
{
    var blob=new Blob([result]);
    var link=document.createElement('a');
    link.href=window.URL.createObjectURL(blob);
    link.download="myFileName.txt";
    link.click();

});

这是IE 10+， Chrome 8+， FF 4+。参见https://developer.mozilla.org/en-US/docs/Web/API/URL.createObjectURL

它只能在Chrome、Firefox和Opera中下载文件。它使用锚标记上的下载属性强制浏览器下载它。

我认为最好的方法是结合使用。您的第二种方法似乎是一个优雅的解决方案，其中涉及到浏览器。

这取决于调用的方式。(无论是浏览器还是web服务调用)您可以使用两者的组合，将URL发送到浏览器并将原始数据发送到任何其他web服务客户端。