private void btmodificar_Click(object sender, EventArgs e)
        {
            suplidores.modificar = true;

            foreach (DataGridViewRow fila in dataGridView1.SelectedRows)
            {
                try
                {
                    suplidores.idmodificar = fila.Cells[0].Value.ToString();
                }
                catch (Exception)
                {
                }
            }
            Form f = new suplidores();

            f.ShowDialog();

            operacion oper = new operacion();
            DataTable dt   = new DataTable();

            dt = oper.ExtraeData("SELECT * FROM suplidores;");
            dataGridView1.DataSource = dt;
            dataGridView1.Refresh();
        }
        private void ConsultaSuplidores_Load(object sender, EventArgs e)
        {
            operacion oper = new operacion();
            DataTable dt   = new DataTable();

            dt = oper.ExtraeData("SELECT * FROM suplidores;");
            dataGridView1.DataSource = dt;
            dataGridView1.Refresh();
            dataGridView1.Columns[0].ReadOnly = true;

            if (mantenimiento)
            {
                Form f = new suplidores();
                this.Hide();
                f.ShowDialog();
                if (!mantenimiento2)
                {
                    this.Close();
                }
                else
                {
                }
                mantenimiento  = false;
                mantenimiento2 = false;
            }
            else
            {
            }
        }