private void button4_Click(object sender, EventArgs e)
        {
            int pos = 0;

            try
            {
                pos = dataGridView1.CurrentCell.RowIndex;
                int v = (int)dataGridView1[5, pos].Value;

                EditarCasting cast = new EditarCasting(v, this);
                cast.MdiParent = this.MdiParent;
                cast.Show();
            }
            catch { MessageBox.Show("Seleccione un casting primero"); }
        }//
        private void button4_Click(object sender, EventArgs e)
        {
            int pos = 0;
            try
            {
                pos = dataGridView1.CurrentCell.RowIndex;
                int v = (int)dataGridView1[5, pos].Value;

                EditarCasting cast= new EditarCasting(v, this);
                cast.MdiParent = this.MdiParent;
                cast.Show();
            }
            catch { MessageBox.Show("Seleccione un casting primero"); }
        }