ASP.NET Service使用xml标头返回JSON数据

Question

I have this code in service

 [WebMethod]        
 [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
 public string GetJson(int nNumResults)
 System.Web.Script.Serialization.JavaScriptSerializer serializer = new
        System.Web.Script.Serialization.JavaScriptSerializer();
        List<Dictionary<string, object>> rows =
          new List<Dictionary<string, object>>();
        Dictionary<string, object> row = null;

    // load dataset from sql query (source not posted here)

        DataSet dset = new DataSet();
        dadapter.Fill(dset);

        if (dset.Tables[0].Rows.Count < 1)
        {
            conn1.Close();
            return null;
        }
        conn1.Close();            

        foreach (DataRow dr in dset.Tables[0].Rows)
        {
            row = new Dictionary<string, object>();
            foreach (DataColumn col in dset.Tables[0].Columns)
            {
                row.Add(col.ColumnName.Trim(), dr[col]);
            }
            rows.Add(row);
        }
        return serializer.Serialize(rows);
    }

Everything is ok, except that the returned string is json with

<string xmlns="http://www.mysite.com/service"> 

and

</string> 

at the end. If I remove these tags the json can be parsed without any problems.

How can I get the json string without the xml tag at the beginning and end?

I use this request from Android which does not read a valid JSON:

 Map<String, Object> params = new HashMap<String, Object>();
    params.put("nNumQuotes", "100");                                   

    aq.ajax(url, params, JSONObject.class, new AjaxCallback<JSONObject>() {

        @Override
        public void callback(String url, JSONObject json, AjaxStatus status) {

            try {
        String aJsonString = json.getString("Id");
    } catch (JSONException e) {
    // TODO Auto-generated catch block
        e.printStackTrace();
    }

        }
    });

And also tested from browser with the integrated service test and the same result.

Answer 1

您是否在请求中包含content-type标题？

contentType: "application/json; charset=utf-8"

Answer 2

You should add " accept: application/json; " to your header to make sure the server knows you want your data back as JSON, as long as your web service can actually return data in JSON format.

When you test the REST web service in your browser (at least in chrome), it sets the 'accept-type' in the header to this:

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8

By testing using something like Fiddler, you can change this to something like:

Accept: application/json

That can tell a web service to return data in JSON format. The android code you are using may not be specifying that it wants JSON data. Again, you can use fiddler to see what the android code request looks like.

I just came across this post about a similar issue: ASP.NET JSON web service always return the JSON response wrapped in XML