DataTable to JSON- lose extra formatting? - json

Question

I'm sure this has been answered somewhere, but I've read dozens of articles and pages with no joy. I need to pass a DataTable from a windows service to an asp.net page. It seemed that serializing to Json seemed a good idea, so I have this:
[ServiceContract(Namespace = "DataGrabber")]
public interface IDataGrabber
{
[OperationContract]
[WebInvoke(Method="GET", BodyStyle=WebMessageBodyStyle.Bare, UriTemplate = "/Tables/{tablename}", ResponseFormat=WebMessageFormat.Json)]
string GetData(string tablename);
}
public class DataGrabber : IDataGrabber
{
public string GetData(string TableName)
{
DataTable result;
switch (TableName)
{
case "firstTable":
result = Grabber.firstTable;
break;
//SNIP MORE
}
return GetJson(result);
}
public string GetJson(DataTable dt)
{
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;
foreach (DataRow dr in dt.Rows)
{
row = new Dictionary<string, object>();
foreach (DataColumn col in dt.Columns)
{
row.Add(col.ColumnName.Trim(), dr[col]);
}
rows.Add(row);
}
return serializer.Serialize(rows);
}
And my config:
<?xml version="1.0"?>
<configuration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
</startup>
<system.serviceModel>
<services>
<service behaviorConfiguration="DefaultBehavior" name="DataGrabber">
<endpoint address="http://localhost:9001/DataGrabber"
binding="webHttpBinding" bindingConfiguration="WebBinding" name="Rest"
contract="DataGrabber.IDataGrabber" />
</service>
</services>
<bindings>
<webHttpBinding>
<binding name="WebBinding">
<security mode="None" />
</binding>
</webHttpBinding>
</bindings>
<behaviors>
<serviceBehaviors>
<behavior name="DefaultBehavior">
<serviceMetadata httpGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="true"/>
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>
</configuration>
This works OK, but my resulting JSON has lots of escaped quotes, like this:
"[{\"lat\":51.75,\"lng\":-1.25,\"score\":7},{\"lat\":31.780001,\"lng\":35.23,\"score\":7},{\"lat\":47.717999,\"lng\":-116.951599,\"score\":9},{\"lat\":33.990799,\"lng\":-118.460098,\"score\":1},{\"lat\":34.746498,\"lng\":-92.289597,\"score\":10},{\"lat\":-31.9522,...
This is rejected by online parsers, and won't serialize back to a DataTable in my client application. If I strip out all the extra stuff by using the "htmlviewer" instead of "textviewer" while debugging in VS, it's fine for the parsers. I tried using the Newtonsoft library too, and it resulted in similar output- so what am I missing?

Answer 1

Typical. Straight after posting I found the answer.
So because I was converting to a string, it was getting double encoded. Instead, I needed to output a stream.
So both my interface and method are now set to return a System.IO.Stream, and the output is generated thus:
return new MemoryStream(Encoding.UTF8.GetBytes(GetJson(result)));