Getting data in Json.Net c#-CodePudding

I want to get data from json file correctly. The json data file I modeled for this is as follows:

{
    "Free title 1":[
        {
            "Subject": "a1",
            "Relation": "a2"
        },
        {
            "Subject": "b1",
            "Relation": "b2"
        }
    ],
    "Another free title":[
        {
            "Subject": "z1",
            "Relation": "z2"
        },
        {
            "Subject": "y1",
            "Relation": "y2"
        }
    ],
    "Unordered title":[
        {
            "Subject": "x1",
            "Relation": "x2"
        },
        {
            "Subject": "w1",
            "Relation": "w2"
        }
    ]
}

This is how I create an object class:

public class _Infos_
{
    public List<_Info_> Infos { get; set; }
}
public class _Info_
{
    public string Subject { get; set; }
    public string Relation { get; set; }
}

And finally I'm trying to get the data in a method like this:

var js = JsonConvert.DeserializeObject<_Infos_>(File.ReadAllText("__FILE_PATH__"));
foreach (var j in js.Infos)
{
    MessageBox.Show(j.Subject);
}

I get the error that js is empty. Here I want to get Free title 1, Another free title and Unordered title in a list. Of course, these titles will be constantly changing. Afterwards, I want to get the Subject and Relation data under these titles. But I have no idea how to get it.

CodePudding user response：

This data structure is a dictionary of collections of _Info_s. You need to deserialize it to Dictionary<string, List<_Info_>>.

Here are System.Text.Json and Json.net examples:

var d = System.Text.Json.JsonSerializer.Deserialize<Dictionary<string, List<_Info_>>>(json);

var d2 = Newtonsoft.Json.JsonConvert.DeserializeObject<Dictionary<string, List<_Info_>>>(json);

CodePudding user response：

Your class definition is a little wrong. You can use online tools "json to c#" to generate the correct classes. like this one: https://json2csharp.com

Your "root" of your json for example does not contain an array in your json. The property "Free title 1":[..] is an array, so your root needs a property with the name FreeTitle1 and it has to be an array/list.

public class Root
{
    [JsonProperty("Free title 1")]
    public List<TitleInfo> FreeTitle1 { get; set; }

    [JsonProperty("Another free title")]
    public List<TitleInfo> AnotherFreeTitle { get; set; }

    [JsonProperty("Unordered title")]
    public List<TitleInfo> UnorderedTitle { get; set; }
}

public class TitleInfo
{
    public string Subject { get; set; }
    public string Relation { get; set; }
}

CodePudding user response：

If your object members have dynamic names, you can also manually deserialize the object, e.g. using the general type JObject. E.g.

JObject obj = JObject.Parse(File.ReadAllText("__FILE_PATH__"));

JObject implements IEnumerable<KeyValuePair<string, JToken>> over which you can iterate. Each member will then have JToken Value, which is a JArray in this case, which you can cast to a List of your type.

foreach (var groups in obj)
{
    var infos = groups.Value.ToObject<List<_Info_>>();
    // .. loop over infos
}