如何在C＃中从JSON获取密钥

Question

JSON :

{"From":
{"CHF":{"Rate":0.91640105,"AsAtDate":"2016-04-19T00:00:00"},
"DKK":{"Rate":0.13437824,"AsAtDate":"2016-04-19T00:00:00"},
"EUR":{"Rate":1.0,"AsAtDate":"2016-04-19T00:00:00"},
"GBP":{"Rate":1.25985769,"AsAtDate":"2016-04-19T00:00:00"},
"PLN":{"Rate":0.23213581,"AsAtDate":"2016-04-19T00:00:00"},
"RON":{"Rate":0.22338218,"AsAtDate":"2016-04-19T00:00:00"},
"SEK":{"Rate":0.10868521,"AsAtDate":"2016-04-19T00:00:00"}},
"To":"EUR","RequestedDate":"2016-07-08T00:00:00"}

I want to fetch list of keys under from. Eg. list should return keys all values like DKK, EUR,GBP . C# code is required to deserialize JSON.

I am able to fetch values from JSON but not keys.

Answer 1

You can create classes to match your json Format, and then read the keys:

public class CurrecyConversion
{
    public Dictionary<string, CurrencyRate> From { set; get; }
    public string To { set; get; }
    public DateTime RequestedDate { set; get; }
}

public class CurrencyRate
{
    public decimal Rate { set; get; }
    public DateTime AsAtDate { set; get; }
}

You need to download this Nuget Package (Right Click Project > Manager Nuget Packages)

Usage:

CurrecyConversion result = Newtonsoft.Json.JsonConvert.
                                        DeserializeObject<CurrecyConversion>(jsonText);

List<string> keys = result.From.Keys.ToList();
foreach (var key in keys)
    Console.WriteLine(key);

Result:

CHF
DKK
EUR
GBP
PLN
RON
SEK