Newtonsoft.Json SerializeObject without escape backslashes

If this happens to you while returning the value from a WebApi method, try returning the object itself, instead of serializing the object and returning the json string. WebApi will serialize objects to json in the response by default; if you return a string, it will escape any double quotes it finds.

So instead of:

public string Get()
{
    ExpandoObject foo = new ExpandoObject();
    foo.Bar = "something";
    string json = Newtonsoft.Json.JsonConvert.SerializeObject(foo);
    return json;
}

Try:

public ExpandoObject Get()
{
    ExpandoObject foo = new ExpandoObject();
    foo.Bar = "something";
    return foo;
}

Try the JToken.Parse method. I've found that even though when I view JSON objects in the debugger and they are correct, when I go to manipulate them they end up being converted to literals (i.e. backslashes are added). The JToken.Parse method seems to avoid this.

var token = JToken.Parse(text);

So in the case of the original question it would be something like:

dynamic foo = new ExpandoObject();
foo.Bar = "something";
string json = Newtonsoft.Json.JsonConvert.SerializeObject(foo);
var token = JToken.Parse(json);
//Do stuff with token -- not json string

In my case specifically the issue was that using JObject.Add(json) would not recognize that my string was json and just insert the entire string as a single property. Once converted into a Jtoken however the JSON was interpreted correctly.

Old question but I found this,

In my case, I was looking at the JSON string in a debugger and I found that was adding the escaping.

And when I printed JSON to console, it was without escape characters. Hope it helps.

What you see in debugger when looking at the json value is the string value that you should use in a C# file to obtain the same value.

Indeed you could replace

dynamic foo = new ExpandoObject();
foo.Bar = "something";
string json = Newtonsoft.Json.JsonConvert.SerializeObject(foo);

with

string json = "{\"Bar\":\"something\"}";

without changing the program's behaviour.

Thus, to obtain a different value, you should change how JsonConvert works, but JsonConvert conforms to the JSON standard, thus forget it!

If you are not actually serializing ExpandoObject (nor any other sealed class out of your control), you can use the DebuggerDisplayAttribute on the types that you are serializing in json, to define how the object will be shown during debug (in your code, the foo instance).

But a string is a string and VisualStudio is right: double-quotes must be escaped.