1

I have the following class structure:

public class JsonModel
{
    public string PropertyName { get; set; }
    public string PropertyValue { get; set; }
}

And I have an instance of this class as follows:

var entry = new JsonModel { PropertyName = "foo", PropertyValue = "bar" };

I want to convert this to json, but I want it to come out like this:

{
    "foo": "bar"
}

How cant his be done?

4
  • Sure, it's quite simple. Fire up a StringBuilder and you're off to the races. But I guess your question is really how to do this automatically? In this case, you'll need to be more specific. Which serialization library are you using? Commented Dec 28, 2021 at 19:55
  • @PeterRuderman I am happy to use any library that can do this easily Commented Dec 28, 2021 at 20:04
  • @Alex Do you have only 2 propertis in class? Commented Dec 28, 2021 at 20:30
  • You are asking how to convert to json, but you've also tagged the question parsing which in this context would be from json. Can you elaborate on whether you need both ways or just object to json? Commented Dec 28, 2021 at 20:36

4 Answers 4

1

If you use Newtonsoft Json.NET you can use a JsonConverter implementation to handle it.

Here's a rather naive implementation:

public class JsonModelConverter : JsonConverter
{
    public override bool CanConvert(Type objectType) => objectType == typeof(JsonModel);

    public override object ReadJson(JsonReader reader, Type objectType,
        object existingValue, JsonSerializer serializer)
    {
        var dict = serializer.Deserialize<Dictionary<string, string>>(reader);
        var item = dict.First();
        return new JsonModel { PropertyName = item.Key, PropertyValue = item.Value };
    }

    public override void WriteJson(JsonWriter writer, object value,
        JsonSerializer serializer)
    {
        var model = (JsonModel)value;
        var dict = new Dictionary<string, string>();
        dict[model.PropertyName] = model.PropertyValue;
        serializer.Serialize(writer, dict);
    }
}

You have to pass this in to the SerializeObject and DeserializeObject<T> methods, here's a usage example with example output:

void Main()
{
    var t = new Test
    {
        Model = new JsonModel { PropertyName = "key", PropertyValue = "some value" }
    };
    string json = JsonConvert.SerializeObject(t, new JsonModelConverter());
    Console.WriteLine(json);

    var t2 = JsonConvert.DeserializeObject<Test>(json, new JsonModelConverter());
    Console.WriteLine($"{t2.Model.PropertyName}: {t2.Model.PropertyValue}");
}

public class Test
{
    public JsonModel Model { get; set; }
}

Output:

{"Model":{"key":"some value"}}
key: some value
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Comments

0

assuming that your class has only 2 properties ( name and value) you can use this

var entry = new JsonModel { PropertyName = "foo", PropertyValue = "bar" };
    
var json=   GetJson(entry);
 
public string GetJson(object obj)
{  
    var prop= obj.GetType().GetProperties();
   
   var prop1=prop[0].GetValue(obj, null).ToString();
   var prop2= prop[1].GetValue(obj, null).ToString();

    return "{\n\"" + $"{prop1}\": \"{prop2}" + "\"\n}";
}

json

{
 "foo": "bar"
}

if you wnat to use a serializer, it can be done like this

public string GetJsonFromParsing(object obj)
{
    var json=JsonConvert.SerializeObject(obj);
    var properties=JObject.Parse(json).Properties().ToArray();

    var prop1 = properties[0].Value;
    var prop2 = properties[1].Value;

    return "{\n\"" + $"{prop1}\": \"{prop2}" + "\"\n}";
}

1 Comment

var entry = new JsonModel { PropertyName = "fo\"o", PropertyValue = "bar" }; will result in { "fo"o": "bar" }, which is not a valid JSON.
-1

To output key value pairs, just specify what the key and value is in an interface. In your case:

public interface IKVP
{
    string PropertyName { get; set; }
    string PropertyValue { get; set; }
}

Then you can output any class that adheres to the interface:

public class JsonModel : IKVP
{
    public string PropertyName { get; set; }
    public string PropertyValue { get; set; }
}

Once that is done, create an extension method which will only take classes that implement the interface:

public static class ClassConverter
{
    public static string ToJson<T>(this T value)  where T : IKVP
      => $"{{ \x22{value.PropertyName}\x22 : \x22{value.PropertyValue}\x22  }}";

}

Once done, output the json string:

var entry = new JsonModel { PropertyName = "foo", PropertyValue = "bar" };

var json = entry.ToJson(); // { "foo" : "bar"  }

Build upon this as needed for more complex situations.

2 Comments

var entry = new JsonModel { PropertyName = "fo\"o", PropertyValue = "bar" }; will result in { "fo"o": "bar" }, which is not a valid JSON.
@RonKlein yes it fails for your edge case. But, most answers on SO imply that error checking and validation are not provided for brevity of answer(s) as to only impart a working suggestion for the happy path. To fix the issue you bring up, a developer should update the setter to catch the extraneous quote as its being set or/as well upon ToJSON above to put in code to validate the json. That is why I put "Build upon this as needed for more complex situations." in my answer.
-2

in most programming languages, including C#, the common way to serialize to JSON would be to take the field's name as the key name, and the field's value as the value.

what you're asking to achieve is to somehow couple between two different fields, which is not a common thing to do.

Comments

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