Can I LINQ a JSON?

问题:

This is the JSON I get from a request on .NET:

{
  "id": "110355660738", 
  "picture": {
    "data": {
      "url": "https://fbcdn-profile-a.akamaihd.net/hprofile-ak-prn2/1027085_12033235063_5234302342947_n.jpg", 
      "is_silhouette": false
    }
  }
}

and I'd like to catch the field "url", using (maybe?) LINQ. I do many request as this, that differents a bit. So I won't to create a C# Class and deserialize it every time.

Is it a way to extract a single field? Thank you!

回答1:

No need for Linq, just use dynamic (using Json.Net)

dynamic obj = JObject.Parse(json);
Console.WriteLine((string)obj.picture.data.url);

Linq version would not be much readable

JObject jObj = JObject.Parse(json);
var url = (string)jObj.Descendants()
                    .OfType<JProperty>()
                    .Where(p => p.Name == "url")
                    .First()
                    .Value;

Documentation: LINQ to JSON

回答2:

I would not recommend LINQ. I would recommend a JSON library such as newtonsoft.json.

So you can do this:

string json = @"{
  ""Name"": ""Apple"",
  ""Expiry"": "2008-12-28T00:00:00",
  ""Price"": 3.99,
  ""Sizes"": [
    ""Small"",
    ""Medium"",
    ""Large""
  ]
}";

JObject o = JObject.Parse(json);

string name = (string)o["Name"];

// Apple
JArray sizes = (JArray)o["Sizes"];
string smallest = (string)sizes[0];

// Small

Note:- this code has been copied from the samples present on the project site http://james.newtonking.com/pages/json-net.aspx

回答3:

In a bind you could always deserialize the JSON and serialize it to XML, and load the XML in a XDocument. Then you can use the classic Linq to XML. When you are done take the XML, deserialize it, and serialize it back to JSON to JSON. We used this technique to add JSON support to an application that was originally built for XML, it allowed near-zero modifications to get up and running.