C#•12mo ago

❔ Basic C# Getting Null Result when trying to index attribute of an object.

I need some help here as im not sure what im doing wrong, the first screenshot is the code being run leading to the error, and the second screenshot is a seperate file that is the structure of the object. When i use the JsonUtility to turn the json string into the object i cant index the attribute ServerName. The provided Json string is {"ServerName":"Server","SavedPort":"25555","SavedIP":"127.0.0.1"}. Thanks for the time for looking at this.

27 Replies

SinFluxx•12mo ago

I don't think you can have { get; set; } present on your properties if you're using Unity's JsonUtility.FromJson

ChucklesTheBeard•12mo ago

https://docs.unity3d.com/ScriptReference/JsonUtility.FromJson.html only says it allows fields (as in public string ServerName;), it doesn't mention properties (as in public string ServerName{ ... };) so presumably they're not supported.

D12•12mo ago

thanks this seemed to have solved my issue

D12•12mo ago

I changed it a little bit to allow a list of servers to be sent however now im getting a similar error. From what i've seen this should get me the result im hoping for but it doesnt. Can i not convert a list of objects in a json string to a list of objects using json utility from json?

D12•12mo ago

@chucklesthebeard @sinfluxx

ChucklesTheBeard•12mo ago

googling the error message reveals that it doesn't support arrays as the base type; you'll need to wrap it in something like { "Servers": [{...}] }

D12•12mo ago

ok thanks for the quick answer

D12•12mo ago

I did this so that the json string was {"Servers":[{"ServerName":"Server","SavedPort":"127.0.0.1","SavedIP":"25555"}]} however the count of the list "Servers" is 0 for some reason.

D12•12mo ago

@chucklesthebeard

ChucklesTheBeard•12mo ago

does it work the other way around? (can you feed a ServerInfo into ToJson) If that works, no idea. If it doesn't, also no idea, but you might be able to figure it out. wonder if it just doesn't like the nested class?

D12•12mo ago

when this is done i get the result "{}" @chucklesthebeard

D12•12mo ago

modified this and still get {}

SinFluxx•12mo ago

What about ...Jsonutility.FromJson<List<Server>>(UnserializedData); ?

D12•12mo ago

trying now

D12•12mo ago

D12•12mo ago

still nothing

SinFluxx•12mo ago

Sounds like this may be a better answer https://stackoverflow.com/a/36244111

Stack Overflow

Serialize and Deserialize Json and Json Array in Unity

I have a list of items send from a PHP file to unity using WWW. The WWW.text looks like: [ { "playerId": "1", "playerLoc": "Powai" }, { "playerId": "2", "

D12•12mo ago

ok thanks, i'll check it out

ChucklesTheBeard•12mo ago

Unity's JsonUtility does not support array as it is still new

(answered Mar 27, 2016) apparently still the case eh? when

SinFluxx•12mo ago

Just a small startup

Accord•12mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

D12•12mo ago

    public static class JsonTester {
        public static void Test() {
            List<ServerInfo> playerInstances = new List<ServerInfo>();

            ServerInfo playerInstance1 = new ServerInfo();
            playerInstance1.ServerName = "8484239823";
            playerInstance1.SavedPort = "Powai";
            playerInstance1.SavedIP = "Random Nick";

            ServerInfo playerInstance2 = new ServerInfo();
            playerInstance2.ServerName = "512343283";
            playerInstance2.SavedPort = "User2";
            playerInstance2.SavedIP = "Rand Nick 2";
            playerInstances.Add(playerInstance2);
            playerInstances.Add(playerInstance1);
            Log.Message(playerInstances[0].ServerName);
            // To Json
            string stringListAsJson = JsonUtility.ToJson(new JsonableListWrapper<ServerInfo>(playerInstances));
            Log.Message(stringListAsJson);
            // From Json
            List<ServerInfo> stringListFromJson = JsonUtility.FromJson<JsonableListWrapper<ServerInfo>>(stringListAsJson).list;
            Log.Message("Here");
            //Convert to JSON
            Log.Message(stringListFromJson.Count.ToString());
            //Log.Message(stringListFromJson[0].ServerName);



        }
    
    
    
    
    }

    [System.Serializable]
    public class JsonableListWrapper<T>
    {
        public List<T> list;
        public JsonableListWrapper(List<T> list) => this.list = list;
    }

    public static class JsonTester {
        public static void Test() {
            List<ServerInfo> playerInstances = new List<ServerInfo>();

            ServerInfo playerInstance1 = new ServerInfo();
            playerInstance1.ServerName = "8484239823";
            playerInstance1.SavedPort = "Powai";
            playerInstance1.SavedIP = "Random Nick";

            ServerInfo playerInstance2 = new ServerInfo();
            playerInstance2.ServerName = "512343283";
            playerInstance2.SavedPort = "User2";
            playerInstance2.SavedIP = "Rand Nick 2";
            playerInstances.Add(playerInstance2);
            playerInstances.Add(playerInstance1);
            Log.Message(playerInstances[0].ServerName);
            // To Json
            string stringListAsJson = JsonUtility.ToJson(new JsonableListWrapper<ServerInfo>(playerInstances));
            Log.Message(stringListAsJson);
            // From Json
            List<ServerInfo> stringListFromJson = JsonUtility.FromJson<JsonableListWrapper<ServerInfo>>(stringListAsJson).list;
            Log.Message("Here");
            //Convert to JSON
            Log.Message(stringListFromJson.Count.ToString());
            //Log.Message(stringListFromJson[0].ServerName);



        }
    
    
    
    
    }

    [System.Serializable]
    public class JsonableListWrapper<T>
    {
        public List<T> list;
        public JsonableListWrapper(List<T> list) => this.list = list;
    }

Log:

Requesting Server Info through packet
512343283
{}
Here
[Openworld] Failed to connect to server browser. Full Stack Error:
System.NullReferenceException: Object reference not set to an instance of an object

Requesting Server Info through packet
512343283
{}
Here
[Openworld] Failed to connect to server browser. Full Stack Error:
System.NullReferenceException: Object reference not set to an instance of an object

ServerInfo File

namespace OpenWorldRedux
{
    [System.Serializable]
    public class ServerInfo
    {

        public string ServerName;
        public string SavedPort;
        public string SavedIP;
    }

}

namespace OpenWorldRedux
{
    [System.Serializable]
    public class ServerInfo
    {

        public string ServerName;
        public string SavedPort;
        public string SavedIP;
    }

}

I have tried a bunch of stuff from this solution but it seems nothing works (I have also tried the json helper but i get the same result) so im really not sure what im doing wrong

SinFluxx•12mo ago

I'm not sure myself, is it easier just to try and use newtonsoft or something at this point?

D12•12mo ago

yeah i did try to use newton soft but this is for a rimworld mod and im not really sure what newtonsoft dll im supposed to be using and kept getting errors ah it was this error System.TypeLoadException: Could not resolve type with token 010000a1

Accord•12mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

D12•12mo ago

Accord•12mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Basic C# Getting Null Result when trying to index attribute of an object.