CODEWITHSUNDEEP
c#jsonbindingdeserialization
Andreas
Andreas

Reputation: 1279

How to check if property exist in JSON string when deserializing

I have this code that deserializes a JSON string.
Now we can see that the JSON string has for example this property: (Please notice that the CORS property exist under the "has" property so we need to check if "has" also exist before I beleive)

CORS

My question is. Sometimes it do happens that this property could be missing in the JSON string. As seen I use the below code where I use the try/catch block. Because if the CORS property is missing, I get an exception but exceptions are very performance expensive and now I use the try/catch block on 30 properties.

I then wonder how can we check with code if the CORS property exists first? Below line of code WITHOUT try/catch gives this error when CORS does not exist:

Cannot perform runtime binding on a null reference

String corsvalue = "";
try { corsvalue = deserializedTicker.has.CORS.ToLower(); } catch { }

JSON string:

{ 
  "id": "hello", 
  "name": "Hello",
  "has": { 
    "CORS": false,
    "CORS2": true
  },
  "has2": { 
    "CORS3": false,
    "CORS4": true
  }
}

Complete code:

String JSONstring = "{ \"id\": \"hello\", \"name\": \"Hello\", \"has\": { \"CORS\": false, \"CORS2\": true }, \"has2\": { \"CORS3\": false, \"CORS4\": true } }\";"

var deserializedTicker = JsonConvert.DeserializeObject<JsonInfo>(JSONstring);

String corsvalue = "";
try { corsvalue = deserializedTicker.has.CORS.ToLower(); } catch { }


public class JsonInfo 
{
  public string id { get; set; }
  public string name { get; set; }
  public JsonHasInfo has { get; set; }
  public JsonHas2Info has2 { get; set; }
}

public class JsonHasInfo
{
  public bool CORS { get; set; }
  public bool CORS2 { get; set; }
}

public class JsonHas2Info
{
  public bool CORS3 { get; set; }
  public bool CORS4 { get; set; }
}

Upvotes: 1

Views: 4203

Answers (1)

Aldert
Aldert

Reputation: 4313

Here you go:

String JSONstring = "{ \"id\": \"hello\", \"name\": \"Hello\", \"has\": { \"CORS\": false, \"CORS2\": true }, \"has2\": { \"CORS3\": false, \"CORS4\": true }}";

            JObject jobject = JObject.Parse(JSONstring);

            JToken cors = jobject.SelectToken("has.CORS");
            if (cors != null)
            {
                JsonInfo myEvent = jobject.ToObject<JsonInfo>();
            }

Upvotes: 2

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