Checking for empty or null JToken in a JObject
You can proceed as follows to check whether a JToken Value is null
JToken token = jObject["key"];
if(token.Type == JTokenType.Null)
{
// Do your logic
}
To check whether a property exists on a JObject
, you can use the square bracket syntax and see whether the result is null or not. If the property exists, a JToken
will be always be returned (even if it has the value null
in the JSON).
JToken token = jObject["param"];
if (token != null)
{
// the "param" property exists
}
If you have a JToken
in hand and you want to see if it is non-empty, well, that depends on what type of JToken
it is and how you define "empty". I usually use an extension method like this:
public static class JsonExtensions
{
public static bool IsNullOrEmpty(this JToken token)
{
return (token == null) ||
(token.Type == JTokenType.Array && !token.HasValues) ||
(token.Type == JTokenType.Object && !token.HasValues) ||
(token.Type == JTokenType.String && token.ToString() == String.Empty) ||
(token.Type == JTokenType.Null);
}
}
There is also a type - JTokenType.Undefined.
This check must be included in @Brian Rogers answer.
token.Type == JTokenType.Undefined