private void toolStripButton1_Click_1(object sender, EventArgs e)
        {
            //создать новую тему
            tema_add ta = new tema_add();

            DialogResult res = ta.ShowDialog();

            if (res == DialogResult.Cancel)
            {
                return;
            }

            string tm = "", cnt = "";

            tm  = Normalize(ta.tema.Text.Trim());
            cnt = Normalize(ta.cont.Text.Trim());

            ta.Dispose();

            string q = string.Format(
                "insert into tema_rabota(name, content, predmet_id, vid_rabota_id) " +
                " values('{0}','{1}',{2},{3})",
                tm, cnt, predmet_id, vid_rab_id);

            main.global_command = new SqlCommand(q, main.global_connection);

            try
            {
                main.global_command.ExecuteNonQuery();
            }
            catch (Exception exx)
            {
                MessageBox.Show("Невозможно выполнить операцию вследствие сетевой ошибки. Повторите попытку позднее.",
                                "Ошибка операции", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                return;
            }

            fill_temas();

            q = "select @@identity";
            main.global_command = new SqlCommand(q, main.global_connection);
            SqlDataReader r = main.global_command.ExecuteReader();

            r.Read();
            new_tema_id = Convert.ToInt32(r[0]);
            select_by_id(new_tema_id);
        }
        private void toolStripButton2_Click(object sender, EventArgs e)
        {
            //редактирование темы
            int row = 0;

            if (table.CurrentCell != null)
            {
                row = table.CurrentCell.RowIndex;
            }
            else
            {
                return;
            }


            string tm  = "";
            string cnt = "";
            int    id  = 0;

            if (!Filtered)
            {
                tm  = temas.Rows[row][0].ToString();
                cnt = temas.Rows[row][1].ToString();
                id  = Convert.ToInt32(temas.Rows[row][2]);
            }
            else
            {
                tm  = filteredtema[row][0].ToString();
                cnt = filteredtema[row][1].ToString();
                id  = Convert.ToInt32(filteredtema[row][2]);
            }

            tema_add ta = new tema_add();

            ta.tema.Text = tm;
            ta.cont.Text = cnt;

            DialogResult res = ta.ShowDialog();

            if (res == DialogResult.Cancel)
            {
                return;
            }

            tm  = Normalize(ta.tema.Text.Trim());
            cnt = Normalize(ta.cont.Text.Trim());

            string q = string.Format(
                "update tema_rabota set name = '{0}', content = '{1}', predmet_id = {2}, vid_rabota_id = {3} " +
                " where id = {4}", tm, cnt, predmet_id, vid_rab_id, id);

            main.global_command = new SqlCommand(q, main.global_connection);

            try
            {
                main.global_command.ExecuteNonQuery();
            }
            catch (Exception exx)
            {
                MessageBox.Show("Невозможно выполнить операцию вследствие сетевой ошибки. Повторите попытку позднее.",
                                "Ошибка операции", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                return;
            }

            fill_temas();
            if (Filtered)
            {
                toolStripTextBox1_KeyUp(sender, new KeyEventArgs(Keys.Enter));
            }

            //select_by_id(id);
            ta.Dispose();
        }