My first programm 2017 year

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp12
{
    public partial class Form1 : Form
    {
        protected static int GenomNum;
        protected static int A;
        protected static int G;
        protected static int C;
        protected static int T;
        protected static char x;
        protected static string DNA;
        protected static string DNA_2;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            string l6 = "Плюс - конец";
            label3.Text = l6;
            string l7 = "Минус - конец";
            label4.Text = l7;
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            DNA = Box1.Text;
        }
        private void Math()
        {
            switch (x)
            {
                case 'A':
                    A = A + 1;
                    break;
                case 'G':
                    G = G + 1;
                    break;
                case 'T':
                    T = T + 1;
                    break;
                case 'C':
                    C = C + 1;
                    break;
                case 'a':
                    A = A + 1;
                    break;
                case 'g':
                    G = G + 1;
                    break;
                case 't':
                    T = T + 1;
                    break;
                case 'c':
                    C = C + 1;
                    break;
            }
        }
        private void button1_Click(object sender, EventArgs e)
        {
            DNA_2 = null;
            try
            {
                char[] n = new char[DNA.Length];
                GenomNum = DNA.Length;
                for (int i = 0; i < GenomNum; i++)
                {
                    //Алгоритм создания комплиментароной цепочки ДНК
                    n[i] = DNA[i];
                    x = n[i];
                    Complementarity();
                }
                Kompli.Visible = true;
            }
            catch
            {
                Form3 error = new Form3();
                error.ShowDialog();
            }
            Kompli.Text = DNA_2;
        }
        private void Complementarity()
        {
            string Base;

            switch (x)
            {
                case 'a':
                    Base = "T";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'c':
                    Base = "G";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 't':
                    Base = "A";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'g':
                    Base = "C";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'A':
                    Base = "T";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'C':
                    Base = "G";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'T':
                    Base = "A";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'G':
                    Base = "C";
                    DNA_2 = DNA_2 + Base;
                    break;
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (String.IsNullOrWhiteSpace(DNA))
            {
                label1.Visible = true;
                A = 0;
                G = 0;
                C = 0;
                T = 0;
                label4.Text = ($"Значения на минус - конце молекулы: Аденин - {A} Гуанин - {G} Тимин - {T} Цитозин - {C}");
                label3.Text = ($"Значения на плюс - конце молекулы: Аденин - {A} Гуанин - {G} Тимин - {T} Цитозин - {C}");
            }
            else
            {
                A = 0;
                G = 0;
                C = 0;
                T = 0;
                label1.Visible = false;
                char[] n = new char[DNA.Length];
                GenomNum = DNA.Length;
                GenomNum = GenomNum / 2;
                for (int i = 0; i < GenomNum; i++)
                {
                    n[i] = DNA[i];
                    x = n[i];
                    Math();
                }
                label4.Text = ($"Значения на минус - конце молекулы: Аденин - {A} Гуанин - {G} Тимин - {T} Цитозин - {C}");
                A = 0;
                G = 0;
                C = 0;
                T = 0;
                for (int i = GenomNum; i < DNA.Length; i++)
                {
                    n[i] = DNA[i];
                    x = n[i];
                    Math();
                }
                label3.Text = ($"Значения на плюс - конце молекулы: Аденин - {A} Гуанин - {G} Тимин - {T} Цитозин - {C}");
            }
        }

        private void RNA_Click(object sender, EventArgs e)
        {
            DNA_2 = null;
            try
            {
                char[] count = new char[DNA.Length];
                GenomNum = DNA.Length / 2;
                for (int i = 0; i < GenomNum; i++)
                {
                    count[i] = DNA[i];
                    x = count[i];
                    RNA_Create();
                }
                Kompli.Visible = true;
            }
            catch
            {
                Form3 error = new Form3();
                error.ShowDialog();
            }
            Kompli.Text = DNA_2;
        }
        private void RNA_Create()
        {
            string Base;
            switch (x)
            {
                case 'a':
                    Base = "U";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'c':
                    Base = "G";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 't':
                    Base = "A";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'g':
                    Base = "C";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'A':
                    Base = "U";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'C':
                    Base = "G";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'T':
                    Base = "A";
                    DNA_2 = DNA_2 + Base;
                    break;
                case 'G':
                    Base = "C";
                    DNA_2 = DNA_2 + Base;
                    break;
            }
        }

        private void DNA_1_Click(object sender, EventArgs e)
        {
            try
            {
                DNA_2 = null;
                char[] countDNA = new char[DNA.Length];
                GenomNum = DNA.Length;
                for (int i = 0; i < GenomNum; i++)
                {
                    x = countDNA[i];
                    DNA_Create();
                }
                Kompli.Visible = true;
                Kompli.Text = DNA_2;
            }
            catch
            {
                Form3 error = new Form3();
                error.ShowDialog();
            }
        }
        private void DNA_Create()
        {
            string Base;
            switch (x)
            {
                case 'u':
                    Base = "T";
                    x = Convert.ToChar(Base);
                    break;
                case 'U':
                    Base = "T";
                    x = Convert.ToChar(Base);
                    break;
            }
            DNA_2 = DNA_2 + Convert.ToString(x);
        }
    }
}