public FRM_PRODUCTS()
 {
     InitializeComponent();
     if (frm == null)
     {
         frm = this;
     }
     this.dataGridView1.DataSource = prd.GET_ALL_PRODUCTS();
 }
        private void beecCusubToolStripMenuItem_Click(object sender, EventArgs e)
        {
            FRM_PRODUCTS frm = new FRM_PRODUCTS();

            frm.ShowDialog();
        }
 static void frm_FormClosed(object sender, FormClosedEventArgs e)
 {
     frm = null;
 }