Passing JSON, deserialization failed because of backslashs

Question

Trying to pass this object between two modules:

public class Transaction
{
    public string ID { get; set; }
    public string ErrorMessage { get; set; }
    public int ErrorCode { get; set; }
}

Serialization:

transaction.ErrorMessage = "temptemptemp";
transaction.ErrorCode = 123;
transaction.ID = "0";
return Ok(JsonConvert.SerializeObject(transaction));

Deserialization:

using (WebClient webClient = new WebClient())
{
    string json = webClient.DownloadString(url);
    Transaction transaction = JsonConvert.DeserializeObject<Transaction>(json);
}

in the debug window, I see the two strings like this:

• after serialization - {"ID":"0","ErrorMessage":"temptemptemp","ErrorCode":123}
• before deserialization - "{\"ID\":\"0\",\"ErrorMessage\":\"temptemptemp\",\"ErrorCode\":123}"

and so I'm getting the following exception:

Error converting value "{"ID":"0","ErrorMessage":"temptemptemp","ErrorCode":123}" to type 'WebService.Transaction'. Path '', line 1, position 75.

Answer 1

You are double-serializing your transaction object. First you serialize it to a JSON string by manually calling

var jsonString = JsonConvert.SerializeObject(transaction);

Then you pass it to Ok<T>(T content) which also serializes its incoming value:

return Ok(jsonString);

Since the incoming value is a string, Ok() escapes it as a required by the JSON standard for representation of a string literal.

Instead, let asp.net serialize it for you:

return Ok(transaction);

If you want to force JSON to be returned, you can use Json<T>(T content):

return Json(transaction);