JSON Program

 using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.IO;
    using System.Linq;
    using System.Runtime.Serialization.Json;
    using System.Text;
    using System.Threading.Tasks;
    using System.Windows.Forms;

    namespace Demo
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
            List<MyModel> data;
            private void Form1_Load(object sender, EventArgs e)
            {
                data = GetJsonFromFile(@"MyData.json");
            }
            private List<MyModel> GetJsonFromFile(string path)
            {
                using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(File.ReadAllText(path))))
                {
                    DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(List<MyModel>));
                    List<MyModel> data = (List<MyModel>)serializer.ReadObject(stream);
                    return data;
                }
            }

            private void button_Click(object sender, EventArgs e)
            {
                CustomMessage frm = new CustomMessage();
                frm.ShowDialog();

                MyModel model = data[0];
                Button btn = sender as Button;
                switch (btn.Text.ToString())
                {
                    //A
                    case "A":
                        List<string> A = model.a5;
                        button5.Text = A[0];
                        break;
                    case "A1":
                        string A1 = model.a1;
                        button1.Text = A1;
                        break;
                    case "A2":
                        string A2 = model.a2;
                        button2.Text = A2;
                        break;
                    case "A3":
                        string A3 = model.a3;
                        button3.Text = A3;
                        break;
                    case "A4":
                        string A4 = model.a4;
                        button4.Text = A4;
                        break;
                    //B
                    case "B":
                        List<string> B = model.b5;
                        button12.Text = B[0];
                        break;
                    case "B1":
                        string B1 = model.b1;
                        button13.Text = B1;
                        break;
                    case "B2":
                        string B2 = model.b2;
                        button14.Text = B2;
                        break;
                    case "B3":
                        string B3 = model.b3;
                        button15.Text = B3;
                        break;
                    case "B4":
                        string B4 = model.b4;
                        button16.Text = B4;
                        break;
                    //C
                    case "C":
                        List<string> C = model.c5;
                        button17.Text = C[0];
                        break;
                    case "C1":
                        string C1 = model.c1;
                        button18.Text = C1;
                        break;
                    case "C2":
                        string C2 = model.c2;
                        button19.Text = C2;
                        break;
                    case "C3":
                        string C3 = model.c3;
                        button20.Text = C3;
                        break;
                    case "C4":
                        string C4 = model.c4;
                        button21.Text = C4;
                        break;
                    //D
                    case "D":
                        List<string> D = model.d5;
                        button7.Text = D[0];
                        break;
                    case "D1":
                        string D1 = model.d1;
                        button8.Text = D1;
                        break;
                    case "D2":
                        string D2 = model.d2;
                        button9.Text = D2;
                        break;
                    case "D3":
                        string D3 = model.d3;
                        button10.Text = D3;
                        break;
                    case "D4":
                        string D4 = model.d4;
                        button11.Text = D4;
                        break;
                    //???
                    case "???":
                        List<string> RR = model.rr;
                        button6.Text = RR[0];
                        break;

                }
            }

    [DataContract]
        public class MyModel
        {
            [DataMember]
            public string a1 { get; set; }
            [DataMember]
            public string a2 { get; set; }
            [DataMember]
            public string a3 { get; set; }
            [DataMember]
            public string a4 { get; set; }
            [DataMember]
            public List<string> a5 { get; set; }
            [DataMember]
            public string b1 { get; set; }
            [DataMember]
            public string b2 { get; set; }
            [DataMember]
            public string b3 { get; set; }
            [DataMember]
            public string b4 { get; set; }
            [DataMember]
            public List<string> b5 { get; set; }
            [DataMember]
            public string c1 { get; set; }
            [DataMember]
            public string c2 { get; set; }
            [DataMember]
            public string c3 { get; set; }
            [DataMember]
            public string c4 { get; set; }
            [DataMember]
            public List<string> c5 { get; set; }
            [DataMember]
            public string d1 { get; set; }
            [DataMember]
            public string d2 { get; set; }
            [DataMember]
            public string d3 { get; set; }
            [DataMember]
            public string d4 { get; set; }
            [DataMember]
            public List<string> d5 { get; set; }
            [DataMember]
            public List<string> rr { get; set; }
        }