How to serialize parameter values as JSON property?

Question

I need a JSON string that the JSON key is property value instead of the property name.

I have these classes:

public class Group
{
    public int Id { get; set; } = 1;
    public string Name { get; set; } = "Test Group";

    public IEnumerable<Document> Documents { get; set; }
}

public class Document
{
    public int Id { get; set; } = 1;
    public int GroupId { get; set; } = 1;
    public string Key { get; set; } = "Test Key";
    public string Value { get; set; } = "Test Value";
    public Group Group { get; set; }
}

And my result has to be like that:

{
    "Test Group": {
        "Test Key": "Test Value",
        "Test 2 Key": "Test 2 Value"
    },
    "Group 2": {
        "Key 2": "Value 2"
    }
}

Answer 1

It looks like you want to map a list of Document's to the inner json nodes and map a list of Group's to the outer nodes. Both of these can be mapped to a Dictionary using ToDictionary().

Assuming you have an enumerable of groups: var groups = some IEnumerable<Group>, then the following code produces your desired result:

// use ToDictionary on the groups, and on the Documents
var groupDictionary = groups.ToDictionary(g => g.Name, 
                                 g => g.Documents.ToDictionary(d => d.Key, d => d.Value));

var result = JsonConvert.SerializeObject(groupDictionary, Formatting.Indented);

// output
{
  "Test Group": {
    "Test Key": "Test Value",
    "Test Key 2": "Test 2 Value"
  },
  "Group 2": {
    "Key 2": "Value 2"
  }
}

Where I've used Newtonsoft.Json to serialize. If you're using System.Text.Json instead you can serialize using:

JsonSerializer.Serialize(groupDictionary, new JsonSerializerOptions { WriteIndented = true });

Try the demo online