Problems sending and receiving JSON between ASP.net web service and ASP.Net web client - asp.net

Question

You would think with all the posts here that this would be easy to figure out. :| Well here is what should be a simple example. NOTE The web service is VB and the client is c#. The wb service sends and receives fine when called from JQuery. From .NET There is a problem,
If the service asks for a parameter as show below then the client's getresponse method gets error 500 Internal server error
The Web Service
<WebMethod()> _
<ScriptMethod(ResponseFormat:=ResponseFormat.Json, XmlSerializeString:=False)> _
Public Function Test(WebInfo As GetUserID) As Person
Dim Someone As New Person
Someone.Name = "Bob"
Someone.FavoriteColor = "Green"
Someone.ID = WebInfo.WebUserID.ToString()
Return Someone
End Function
The Web Client (set up to be send and receive JSON)
public Person Test(int UserID, string url) {
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(url + "test.asmx/Test");
webRequest.Method = "POST";
webRequest.ContentType = "application/json; charset=utf-8";
StreamWriter sw = new StreamWriter(webRequest.GetRequestStream());
sw.Write("{'WebInfo':{'WebUserID':1}}"); // this works from JQuery
HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse();
Stream responseStream = webResponse.GetResponseStream();
DataContractJsonSerializer jsonSerializer = new DataContractJsonSerializer(typeof(Person));
Person someone = (Person)jsonSerializer.ReadObject(responseStream);
return someone;
}
Has anyone out there done this successfully?
Thanks

Answer 1

Here is a method that makes calls to a JSON web service, allowing the developer to both send and receive complext data types. The object passed in can be any data type or class. The result is a JSON string, and or any error message the methods type is shown below
public class WebServiceCallReturn {
public string JSONResponse { get; set; }
public string SimpleResponse { get; set; }
public string Error { get; set; }
}
public WebServiceCallReturn WebServiceJSONCall(string uri, string requestType, object postData = null) {
WebServiceCallReturn result = new WebServiceCallReturn();
// create request
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(uri);
webRequest.ContentType = "application/json; charset=utf-8";
webRequest.Method = requestType;
webRequest.Accept = "application/json; charset=utf-8";
// add json data object to send
if (requestType == "POST") {
string json = "{ }";
if (postData != null) {
try { // the serializer is fairly robust when used this way
DataContractJsonSerializer ser = new DataContractJsonSerializer(postData.GetType());
MemoryStream ms = new MemoryStream();
ser.WriteObject(ms, postData);
json = Encoding.UTF8.GetString(ms.ToArray());
} catch {
result.Error = "Error serializing post";
}
}
webRequest.ContentLength = json.Length;
StreamWriter sw;
try {
sw = new StreamWriter(webRequest.GetRequestStream());
} catch (Exception ex) {
// the remote name could not be resolved
result.Error = ex.Message;
return result;
}
sw.Write(json);
sw.Close();
}
// read response
HttpWebResponse webResponse;
try {
webResponse = (HttpWebResponse)webRequest.GetResponse();
} catch (Exception ex) {
// The remote server returned an error...
// (400) Bad Request
// (403) Access forbidden (check the application pool)
// (404) Not Found
// (405) Method not allowed
// (415) ...not the expected type
// (500) Internal Server Error (problem with IIS or unhandled error in web service)
result.Error = ex.Message;
return result;
}
Stream responseStream = webResponse.GetResponseStream();
StreamReader sr = new StreamReader(responseStream, Encoding.UTF8);
string resultString = sr.ReadToEnd();
sr.Close();
responseStream.Close();
result.JSONResponse = resultString;
return result;
}
This method could be used as follows
public SomeCustomDataClass Getsomeinformation(int userID) {
UserInfoClass postData = new UserInfoClass();
postData.WebUserID = userID;
SomeCustomDataClass result = new SomeCustomDataClass();
string uri = URL + "SomeServices.svc/GetSomething";
WebServiceCallReturn webReturn = WebServiceJSONCall(uri, "POST", postData);
if (webReturn.Error == null) {
//resultString = CleanJSON(resultString);
JavaScriptSerializer serializer = new JavaScriptSerializer();
try {
result = serializer.Deserialize<SomeCustomDataClass>(webReturn.JSONResponse);
} catch {
result.Error = "Error deserializing";
}
} else {
result.Error = webReturn.Error;
}
return result;
}
Hope that helps someone