Why cant Newtonsoft.Json deserialize a Dictionary

Question

nvlst declared here then populated

Dictionary<string, string> nvlst = new Dictionary<string, string>();

When the service is finished, it returns

JsonConvert.SerializeObject(nvlst, Formatting.Indented)

When the client attempts to deserialize, it throws an error

alst = JsonConvert.DeserializeObject<Dictionary<string, string>>(sb.ToString());

here is the error message:

Error converting value "{
  "Status": "SUCCESS:",
  "CustomerId": "1",
  "LicenseKey": "03bad945-37c0-4fa0-8126-fb4935df396d",
  "MachineFingerPrint": "9B82-A8ED-3DE9-0D8C-26DD-2D83-C17F-C2E3",
  "ExpirationDate": "11/18/2014",
  "LicenseDate": "11/18/2013",
  "LicenseGraceDay": "7",
  "RequireRenewal": "Y",
  "BaseUrl": "http://www.xxx-xxxxxxx.com",
  "HelpUrl": "http://www.xxx-xxxxxxx.com/help",
  "APIUrl": "http://localhost:63583/api/Ajax/runGenericMethodFromApp",
  "CoName": "TestCustomer1",
  "Addr1": "123 Any Street",
  "Addr2": "",
  "City": "Louisville",
  "State": "KY",
  "Zip": "40245"
}" to type 'System.Collections.Generic.Dictionary`2[System.String,System.String]'. Path '', line 1, position 704.

the actual value of the sb.ToString() is below

"\"{\\r\\n  \\\"Status\\\": \\\"SUCCESS:\\\",\\r\\n  \\\"CustomerId\\\": \\\"1\\\",\\r\\n  \\\"LicenseKey\\\": \\\"03bad945-37c0-4fa0-8126-fb4935df396d\\\",\\r\\n  \\\"MachineFingerPrint\\\": \\\"9B82-A8ED-3DE9-0D8C-26DD-2D83-C17F-C2E3\\\",\\r\\n  \\\"ExpirationDate\\\": \\\"11/18/2014\\\",\\r\\n  \\\"LicenseDate\\\": \\\"11/18/2013\\\",\\r\\n  \\\"LicenseGraceDay\\\": \\\"7\\\",\\r\\n  \\\"RequireRenewal\\\": \\\"Y\\\",\\r\\n  \\\"BaseUrl\\\": \\\"http://www.xxx-xxxxxxx.com\\\",\\r\\n  \\\"HelpUrl\\\": \\\"http://www.xxx-xxxxxxx.com/help\\\",\\r\\n  \\\"APIUrl\\\": \\\"http://localhost:63583/api/Ajax/runGenericMethodFromApp\\\",\\r\\n  \\\"CoName\\\": \\\"TestCustomer1\\\",\\r\\n  \\\"Addr1\\\": \\\"123 Any Street\\\",\\r\\n  \\\"Addr2\\\": \\\"\\\",\\r\\n  \\\"City\\\": \\\"Louisville\\\",\\r\\n  \\\"State\\\": \\\"KY\\\",\\r\\n  \\\"Zip\\\": \\\"40245\\\"\\r\\n}\""

Answer 1

It looks like your string is getting double-serialized, so that is why it is not deserializing properly. If you are using a framework like WebAPI, it handles serialization for you, so you don't need to call JsonConvert.SerializeObject(). Instead, change your ApiController method to return the object directly (note that you'll need to change the method signature as well). For example:

public class FooController : ApiController
{
    [HttpPost]
    public Dictionary<string, string> runGenericMethodFromApp()
    {
        Dictionary<string, string> dict = new Dictionary<string, string>();
        dict.Add("Status", "SUCCESS,");
        dict.Add("CustomerId", "1");
        dict.Add("LicenseKey", "03bad945-37c0-4fa0-8126-fb4935df396d");
        dict.Add("MachineFingerPrint", "9B82-A8ED-3DE9-0D8C-26DD-2D83-C17F-C2E3");
        dict.Add("ExpirationDate", "11/18/2014");
        dict.Add("LicenseDate", "11/18/2013");
        dict.Add("LicenseGraceDay", "7");
        dict.Add("RequireRenewal", "Y");
        dict.Add("BaseUrl", "http://www.xxx-xxxxxxx.com");
        dict.Add("HelpUrl", "http://www.xxx-xxxxxxx.com/help");
        dict.Add("APIUrl", "http://localhost:63583/api/Ajax/runGenericMethodFromApp");
        dict.Add("CoName", "TestCustomer1");
        dict.Add("Addr1", "123 Any Street");
        dict.Add("Addr2", "");
        dict.Add("City", "Louisville");
        dict.Add("State", "KY");
        dict.Add("Zip", "40245");
        return dict;
    }
}