private void newCustomerToolStripMenuItem_Click(object sender, EventArgs e)
        {
            frmAddEditCust CList = new frmAddEditCust(-1);

            CList.MdiParent = this;
            CList.Visible   = true;
        }
        private void btnEdit_Click(object sender, EventArgs e)
        {
            frmAddEditCust Edit = new frmAddEditCust(Convert.ToInt32(lstCust.SelectedValue));

            Edit.Visible = true;
        }
        private void btnAdd_Click(object sender, EventArgs e)
        {
            frmAddEditCust Add = new frmAddEditCust(-1);

            Add.Visible = true;
        }