C# 设置响应消息内容，但我无法检索它

我有一个服务器方法，它获取并编码字符串列表，因为IE9不读取json格式，所以我想在http响应消息的内容中设置字符串。我似乎做得很好，但当我得到响应时，我无法在身体上找到响应，我能看到的只是我在响应消息中设置的长度

代码如下：

public HttpResponseMessage Upload()
    {
        HttpResponseMessage m = new HttpResponseMessage(HttpStatusCode.OK);
        List<string> returnlist = new List<string>();
        for (int i = 0; i < Request.Files.Count; i++)
        {
                   //string treatment        
        }

        HttpResponseMessage response = new HttpResponseMessage();

        response.Content = new StringContent(string.Join(",", returnlist));
        return response;
    }

如何设置并获取响应消息

如有需要，js在此提供：

self.uploadfiles = function () {
        //startSpinner();

        if (!self.isOldIE()) {
            var loc = window.location;
            base_url = loc.protocol + "//" + loc.host;
            baseUrl = base_url + "/";

            var save = true;

            var xhr = new XMLHttpRequest();
            xhr.open('POST', baseUrl + 'Home/Upload');
            xhr.send(formdata);
            xhr.onreadystatechange = function (data) {
                //The responseText is the same as above
                if (xhr.responseText.length > 0) {  

                   //do stuff
      }
    };

---

尝试使用Javascript获取响应：

var xhr = new XMLHttpRequest();

xhr.open('POST', baseUrl + 'Home/Upload', true);
xhr.onreadystatechange = function() {

    if (xhr.readyState === 4 && xhr.status === 200)  { 
        alert(xhr.responseText);
    } else {
        // do something about the error
    }
};
xhr.send(formdata);

请注意用于异步获取的open方法的第三个布尔参数。

请尝试此代码

        var response = Request.CreateResponse(HttpStatusCode.OK, string.Join(",", returnlist));
        return response;

---

由于某些原因，浏览器没有显示http响应的整个主体。因此，我的解决方案是编写响应的标题并从js获取标题。 也许有人知道为什么浏览器不显示主体，或者有更好的解决方案

这是我的控制器：

public HttpResponseMessage Upload()
    {
        HttpResponseMessage m = new HttpResponseMessage(HttpStatusCode.OK);
        List<string> returnlist = new List<string>();


        for (int i = 0; i < Request.Files.Count; i++)
        {
            HttpPostedFileBase file = Request.Files[i]; //Uploaded file
            //Use the following properties to get file's name, size and MIMEType
            int fileSize = file.ContentLength;

            if (file.FileName != "")
            {
                string fileName = string.Format("{0}.{1}", Guid.NewGuid().ToString(), file.FileName.ToString().Split('.')[1].ToString());
                returnlist.Add(fileName);

            }

        }


//Here I write the response message headers
        HttpResponseMessage response = new HttpResponseMessage();

        response.Content = new StringContent(string.Join(",", returnlist), Encoding.UTF8, "text/html");

        response.Headers.Add("data", string.Join(",", returnlist));

        return response;
    }

---

状态说明一切。。。错误404：您请求的页面不存在。。。您在这里显示的代码可能永远不会被击中……这是因为我在js ajax中像处理json一样处理响应，我编辑了这个问题。我假设您在ApicController中工作，但听起来可能不是这样。保留您的原始代码并尝试使用新的答案来获得响应。我使用的是Controller类，但我需要的是创建一个不是json的响应以在ie9中使用，并使用js从客户端检索它。客户端已解析，但我在响应中没有看到我发送的http消息中的字符串。您还可以粘贴javascript吗？

public HttpResponseMessage Upload()
    {
        HttpResponseMessage m = new HttpResponseMessage(HttpStatusCode.OK);
        List<string> returnlist = new List<string>();


        for (int i = 0; i < Request.Files.Count; i++)
        {
            HttpPostedFileBase file = Request.Files[i]; //Uploaded file
            //Use the following properties to get file's name, size and MIMEType
            int fileSize = file.ContentLength;

            if (file.FileName != "")
            {
                string fileName = string.Format("{0}.{1}", Guid.NewGuid().ToString(), file.FileName.ToString().Split('.')[1].ToString());
                returnlist.Add(fileName);

            }

        }


//Here I write the response message headers
        HttpResponseMessage response = new HttpResponseMessage();

        response.Content = new StringContent(string.Join(",", returnlist), Encoding.UTF8, "text/html");

        response.Headers.Add("data", string.Join(",", returnlist));

        return response;
    }

var xhr = new XMLHttpRequest();
            xhr.open('POST', baseUrl + 'Home/Upload');
            xhr.send(formdata);
            xhr.onreadystatechange = function (data) {
                if (xhr.responseText.length > 0) {
//header response
                    var response = xhr.responseText;
                 }