private void btnadd_Click(object sender, EventArgs e)
 {
     if (txt_catname.Text == "")
     {
         PL.FRM_ERRORINSERT FError = new FRM_ERRORINSERT();
         FError.Show();
     }
     else
     {
         if (ID == 0)
         {
             BL.CLS_CAT BLCAT = new BL.CLS_CAT();
             BLCAT.Insert(txt_catname.Text);
             PL.FRM_DADD fadd = new FRM_DADD();
             fadd.Show();
             this.Close();
         }
         else
         {
             BL.CLS_CAT BLCAT = new BL.CLS_CAT();
             BLCAT.Update(txt_catname.Text, ID);
             PL.FRM_DEDIT fedit = new FRM_DEDIT();
             fedit.Show();
             this.Close();
         }
     }
 }