VINIL.APP/proba/Form/Performer_update.cs

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;
using System.Data.SqlClient;

namespace proba
{
    public partial class Performer_update : Form
    {
        string id_performer;
        public int razmer = 0;
        public static string[] update_performer = new string[1];
        DataBase dataBase = new DataBase();
        public Performer_update(string id_performer, string performer)
        {
            InitializeComponent();
            textBox1.Text = performer;
            this.id_performer = id_performer;
        }

        private void button_save_Click(object sender, EventArgs e)
        {
            if (textBox1.Text.Replace(" ", "") == "") MessageBox.Show("Поле исполнитель не может быть пустым");
            else
            {
                dataBase.openConnection();
                var addQuery = $"update Performer set performer = '{textBox1.Text}' where id_performer = '{id_performer}'";
                var command = new SqlCommand(addQuery, dataBase.GetConnection());
                command.ExecuteNonQuery();
                MessageBox.Show("Запись успешно изменена");
                update_performer[razmer] = textBox1.Text;
                Array.Resize(ref update_performer, update_performer.Length + 1);
                razmer++;
                dataBase.closeConnection();
                this.Hide();
                Performer performer = new Performer();
                performer.ShowDialog();
            }
        }

        private void button_back_Click(object sender, EventArgs e)
        {
            this.Hide();
            Performer performer = new Performer();
            performer.ShowDialog();
        }
        public void global_FormClosed(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}