C#•2y ago

Can't read Json in WPF

I don't think I understand this error. It requires an array? but how? Should I make a loop?

        static List<Persondata> persondata()
        {
            string fileName = @"C:\Users\elko\source\repos\JsonData\JsonData\bin\Debug\net6.0-windows\Persons.json";
            if (File.Exists(fileName))
            {
                var persons = JsonConvert.DeserializeObject<List<Persondata>>
                (File.ReadAllText(fileName));

                return persons;
            }
            return null;
        }
    }

        static List<Persondata> persondata()
        {
            string fileName = @"C:\Users\elko\source\repos\JsonData\JsonData\bin\Debug\net6.0-windows\Persons.json";
            if (File.Exists(fileName))
            {
                var persons = JsonConvert.DeserializeObject<List<Persondata>>
                (File.ReadAllText(fileName));

                return persons;
            }
            return null;
        }
    }

8 Replies

DayKnight•2y ago

So basically, The program runs just fine when Json is empty. But as soon there is something inside the Json it fails, because it isn't an array? I got some help yesterday so I could write to my Json. I can't read it though

ero•2y ago

show the json

DayKnight•2y ago

{"Name":"awrfawf","Address":"awgfaeg","City":"aegae"}

{"Name":"awrfawf","Address":"awgfaeg","City":"aegae"}

I tried that, it worked with Javascript, but c# removes it when I write to Json

            File.WriteAllText(@"C:\Users\elko\source\repos\JsonData\JsonData\bin\Debug\net6.0-windows\Persons.json", JsonConvert.SerializeObject(persondata));

            using (StreamWriter file = File.CreateText(@"C:\Users\elko\source\repos\JsonData\JsonData\bin\Debug\net6.0-windows\Persons.json"))
            {
                JsonSerializer serializer = new JsonSerializer();
                serializer.Serialize(file, persondata);
            }

            File.WriteAllText(@"C:\Users\elko\source\repos\JsonData\JsonData\bin\Debug\net6.0-windows\Persons.json", JsonConvert.SerializeObject(persondata));

            using (StreamWriter file = File.CreateText(@"C:\Users\elko\source\repos\JsonData\JsonData\bin\Debug\net6.0-windows\Persons.json"))
            {
                JsonSerializer serializer = new JsonSerializer();
                serializer.Serialize(file, persondata);
            }

It's just above

            Persondata persondata = new Persondata();
            {
                persondata.Name = name;
                persondata.Address = address;
                persondata.City = city;
            };

            Persondata persondata = new Persondata();
            {
                persondata.Name = name;
                persondata.Address = address;
                persondata.City = city;
            };

ero•2y ago

and show the persondata class

DayKnight•2y ago

The person data class is this

    public class Persondata
    {
        [JsonPropertyName("name")]
        public string Name { get; set; }

        [JsonPropertyName("address ")]
        public string Address { get; set; }

        [JsonPropertyName("city")]
        public string City { get; set; }
        
    }

    public class Persondata
    {
        [JsonPropertyName("name")]
        public string Name { get; set; }

        [JsonPropertyName("address ")]
        public string Address { get; set; }

        [JsonPropertyName("city")]
        public string City { get; set; }
        
    }

Thanks hmm.. That is true, I am only making one object. But should I not be doing that, making a new object foreach click?

private void DataInputButton_Click(object sender, RoutedEventArgs e)

private void DataInputButton_Click(object sender, RoutedEventArgs e)

ero•2y ago

also the names in the json are in a different case

DayKnight•2y ago

I know what you mean now. I am adding one object, and reading it as a list, which it isn't, it is not a list. So I need to find a way to write objects as a list That sounds nice, and easy. Maybe too easy... I'll try that <a:aPES_Think:493353113332219924> Like this right?

        static List<Persondata> persondata()
        {
            string fileName = @"C:\Users\elko\source\repos\JsonData\JsonData\bin\Debug\net6.0-windows\Persons.json";
            if (File.Exists(fileName))
            {
                var persons = JsonConvert.DeserializeObject<List<Persondata>>
                (File.ReadAllText(fileName));

        static List<Persondata> persondata()
        {
            string fileName = @"C:\Users\elko\source\repos\JsonData\JsonData\bin\Debug\net6.0-windows\Persons.json";
            if (File.Exists(fileName))
            {
                var persons = JsonConvert.DeserializeObject<List<Persondata>>
                (File.ReadAllText(fileName));

oh I see yeah, let me do that to the writing method too I tried something, it suddenly dosen't like it though

            List<Persondata> persondata = new List<Persondata>();
            {
               new (persondata.Name = name);
               new (persondata.Address = address);
               new (persondata.City = city);
            };

            List<Persondata> persondata = new List<Persondata>();
            {
               new (persondata.Name = name);
               new (persondata.Address = address);
               new (persondata.City = city);
            };

It says "Does not contain a definition for Name, Address, City" Hm. the error first appeared when I added List. So the name should be fine I guess? I could try to rename everything, just to get a better view Hmm true, I have tried something new

           List<Persondata> persondata = new List<Persondata>();

            var pers = new Persondata
            {
                Name = name,
                Address = address,
                City = city
            };

            string jsonSring = JsonSerializer.Serialize(pers);

           List<Persondata> persondata = new List<Persondata>();

            var pers = new Persondata
            {
                Name = name,
                Address = address,
                City = city
            };

            string jsonSring = JsonSerializer.Serialize(pers);

I have also made a constructor now, I don't know if that is correct though

ero•2y ago

you're only serializing that one persondata you made you never added it to the list, nor are you serializing the list

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Can't read Json in WPF