extracting a value from a JSON string

Question

I'm working on a Blazor application and I have a Json string from which I'm trying to extract a value.

Json Data looks like this:

{"a1":"a1234","e1":"e1234}

I'm trying to extract the a1 value from this which is "a1234"

My JSON Data is in a string variable, rawJsonData. I'm trying to use the JsonSerializer.Deserialize, but I'm not sure how to completely use it...

@code 
{
    string rawJsonData = JsonData (this is not the actual data, it's being pulled from elsewhere)
    var x = System.Text.Json.JsonSerializer.Deserialize<???>(rawJsonData)
}

is this the right way to approach this? I'm not sure what to put in place of ??? above. Anyone has experience with this.

you can create a class that represents that... or use the jsondocument way. — Daniel A. White, Aug 21 '20 at 21:24
Make sure that the json is valid, you are missing an ending "" fyi — jaabh, Aug 21 '20 at 21:26
If you only need one value you can parse the json and dig out that one value. no need for a class that way. Gobs and gobs of posts here on both deserializing and parsing. — Ňɏssa Pøngjǣrdenlarp, Aug 21 '20 at 22:11

score 2 · Accepted Answer · answered Aug 21 '20 at 22:58

2

If you use Newtonsoft, as suggested in another answer, you don't even have to create a class.

JObject temp = JObject.Parse(rawJsonData);
var a1 = temp["a1"];

answered Aug 21 '20 at 22:58

Lex

6,758
2
27
42

jaabh · Answer 2 · 2020-08-21T22:06:32.867

1

Create a class:

public class Root
{
   public string a1 { get; set; }
   public string e1 { get; set; }
}

Then Deserialize it into that class:

var x = System.Text.JsonSerializer.Deserialize<Root>(rawJsonData);

Or use Newtonsoft.Json:

var x = Newtonsoft.Json.JsonConvert.DeserializeObject<Root>(rawJsonData);

To retrieve the value of a1 just call: x.a1

edited Aug 21 '20 at 22:06

answered Aug 21 '20 at 21:25

jaabh

815
6
22

score 1 · Answer 3 · answered Aug 23 '20 at 10:55

If you want to stick with System.Text.Json and don't want to create a class/struct for the data (why not?), as suggested in comments, you can

var jsonData = "{\"a1\":\"a1234\",\"e1\":\"e1234\"}";
var doc = JsonDocument.Parse(jsonData);
var a1 = doc?.RootElement.GetProperty("a1").GetString();

Of course, a try catch around the conversion would help.

extracting a value from a JSON string

3 Answers3