VINIL.APP/proba/Form/Prodaja.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.Data.SqlClient;
using System.Windows.Forms;

namespace proba
{
    public partial class Form2 : Form
    {
        string id_sale;
        string product;
        string date_sale;
        string employee;
        string summa;
        bool save;
        DataBase dataBase = new DataBase();
        public Form2()
        {
            InitializeComponent();
        }
        private void CreateColumns()
        {
            dataGridView1.Columns.Add("product", "Название товара");
            dataGridView1.Columns.Add("date_sale", "Дата продажи");
            dataGridView1.Columns.Add("employee", "Сотрудник");
            dataGridView1.Columns.Add("summa", "Сумма продажи");
            dataGridView1.Columns.Add("", String.Empty);
        }
        private void ReadSingleRow(DataGridView dgw, IDataRecord record)
        {
            dgw.Rows.Add(record.GetString(0), record.GetString(1), record.GetString(2), record.GetString(3), RowState.ModifiedNew);
        }
        private void RefresDataGird(DataGridView dgw)
        {
            dgw.Rows.Clear();
            dataGridView1.Columns[4].Visible = false;
            string queryString = $"Select P.product, S.date_sale, E.surname, S.summa from Sales S inner join Products P ON P.id_product=S.id_product inner join Employee E ON S.id_employee=E.id_employee";
            SqlCommand command = new SqlCommand(queryString, dataBase.GetConnection());
            dataBase.openConnection();
            SqlDataReader reader = command.ExecuteReader();
            while (reader.Read())
            {
                ReadSingleRow(dgw, reader);
            }
            reader.Close();
        }

        private void button_back_Click(object sender, EventArgs e)
        {
            this.Hide();
            MainMenu mainMenu = new MainMenu();
            mainMenu.ShowDialog();
        }
        public void global_FormClosed(object sender, EventArgs e)
        {
            Application.Exit();
        }
        private void pictureBox2_Click(object sender, EventArgs e)
        {
            RefresDataGird(dataGridView1);
        }
        private void Search(DataGridView dgw)
        {
            dgw.Rows.Clear();
            string searchString = $"Select P.product, S.date_sale, E.surname, S.Summa from Sales S inner join Products P ON P.id_product=S.id_product inner join Employee E ON S.id_employee=E.id_employee Where P.product like '%" + StrokaSearch.Text + "%'";
            SqlCommand com = new SqlCommand(searchString, dataBase.GetConnection());
            dataBase.openConnection();
            SqlDataReader read = com.ExecuteReader();
            while (read.Read())
            {
                ReadSingleRow(dgw, read);
            }
            read.Close();
        }

        private void StrokaSearch_TextChanged(object sender, EventArgs e)
        {
            Search(dataGridView1);
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            CreateColumns();
            RefresDataGird(dataGridView1);
        }

        private void deleteRow()
        {
            int index = dataGridView1.CurrentCell.RowIndex;
            dataGridView1.Rows[index].Visible = false;
            if (dataGridView1.Rows[index].Cells[0].Value.ToString() == String.Empty)
            {
                dataGridView1.Rows[index].Cells[4].Value = RowState.Deleted;
                return;
            }
            dataGridView1.Rows[index].Cells[4].Value = RowState.Deleted;
            id_sale = null;
        }

        private void button_delete_Click(object sender, EventArgs e)
        {
            if (id_sale == null)
            {
                MessageBox.Show("Не выделена запись для удаления!!!");
            }
            else
            {
                deleteRow();
                save = true;
            }
        }

        new private void Update()
        {
            dataBase.openConnection();
            for (int index = 0; index < dataGridView1.Rows.Count; index++)
            {
                var rowState = (RowState)dataGridView1.Rows[index].Cells[4].Value;
                if (rowState == RowState.Existed)
                    continue;
                if (rowState == RowState.Deleted)
                {
                    SqlCommand sqlCommand_product = new SqlCommand($"SELECT id_sale From Sales S inner join Products P ON S.id_product=P.id_product WHERE P.product = '{dataGridView1.Rows[index].Cells[0].Value}'", dataBase.GetConnection());
                    var id = sqlCommand_product.ExecuteScalar().ToString();
                    var deleteQuery = $"delete from Sales where id_sale = {id}";
                    var command = new SqlCommand(deleteQuery, dataBase.GetConnection());
                    command.ExecuteNonQuery();
                }
            }
            dataBase.closeConnection();
        }

        private void buttonSave_Click(object sender, EventArgs e)
        {
            if (save == true)
            {
                Update();
                save = false;
            }
        }

        private void button_insert_Click(object sender, EventArgs e)
        {
            if (id_sale == null)
            {
                MessageBox.Show("Не выделена строчка для изменения");
            }
            else
            {
                this.Hide();
                Prodaja_update prodaja_Update = new Prodaja_update(id_sale, product, date_sale, employee, summa);
                prodaja_Update.ShowDialog();
            }
        }

        private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            var selectedRow = e.RowIndex;
            if (e.RowIndex >= 0)
            {
                DataGridViewRow row = dataGridView1.Rows[selectedRow];
                product = row.Cells[0].Value.ToString();
                date_sale = row.Cells[1].Value.ToString();
                employee = row.Cells[2].Value.ToString();
                summa = row.Cells[3].Value.ToString();
                dataBase.openConnection();
                SqlCommand sqlCommand_product = new SqlCommand($"SELECT id_sale From Sales S inner join Products P ON S.id_product=P.id_product WHERE P.product = '{product}'", dataBase.GetConnection());
                id_sale = sqlCommand_product.ExecuteScalar().ToString();
                dataBase.closeConnection();
            }
        }
        private void pictureBox2_Click_1(object sender, EventArgs e)
        {
            RefresDataGird(dataGridView1);
            save = false;
        }

        private void button_add_Click(object sender, EventArgs e)
        {
            this.Hide();
            Sales sales = new Sales();
            sales.ShowDialog();
        }

        private void button_saleDay_Click(object sender, EventArgs e)
        {
            this.Hide();
            SummaSaleDay summaSaleDay = new SummaSaleDay();
            summaSaleDay.ShowDialog();
        }
    }
}