how to get the key from json object and convert into an array?

Question

{
 \"Date\": \"2016-12-15\",
 \"Data\": {
   \"A\": 4.4023,
   \"AB\": 1.6403,
   \"ABC\": 2.3457
 }
}

how can i get my keys A,Ab,ABC into an array

Answer 1

You could install json.net and use LINQ to JSON to query the properties:

var jsonString = @"{
     ""Date"": ""2016-12-15"",
     ""Data"": {
       ""A"": 4.4023,
       ""AB"": 1.6403,
       ""ABC"": 2.3457
     }
}";

var root = JToken.Parse(jsonString);

var properties = root
    // Select nested Data object
    .SelectTokens("Data")
    // Iterate through its children, return property names.
    .SelectMany(t => t.Children().OfType<JProperty>().Select(p => p.Name))
    .ToArray();

Console.WriteLine(String.Join(",", properties)); // Prints A,AB,ABC

Sample fiddle.

Answer 2

You could use the built-in JavaScriptSerializer to deserialize to an object. In this case, any JSON object will actually get deserialized to an IDictionary<string, object>. Then you can cast the returned object to such a dictionary and (recursively) query its contents including its keys and values:

var jsonString = @"{
     ""Date"": ""2016-12-15"",
     ""Data"": {
       ""A"": 4.4023,
       ""AB"": 1.6403,
       ""ABC"": 2.3457
     }
}";

var root = new JavaScriptSerializer().Deserialize<object>(jsonString);

var properties = root
    // Select nested Data object
    .JsonPropertyValue("Data")
    // Iterate through its children, return property names.
    .JsonPropertyNames()
    .ToArray();

Console.WriteLine(String.Join(",", properties)); // Prints A,AB,ABC

Using the extension methods:

public static class JavaScriptSerializerObjectExtensions
{
    public static object JsonPropertyValue(this object obj, string key)
    {
        var dict = obj as IDictionary<string, object>;
        if (dict == null)
            return null;
        object val;
        if (!dict.TryGetValue(key, out val))
            return null;
        return val;
    }

    public static IEnumerable<string> JsonPropertyNames(this object obj)
    {
        var dict = obj as IDictionary<string, object>;
        if (dict == null)
            return null;
        return dict.Keys;
    }
}