private void btnOK_Click(object sender, EventArgs e)
 {
     using (frmWaitAsyncForm frm = new frmWaitAsyncForm(GetExcelFile))
     {
         frm.ShowDialog(this);
     }
 }
        /// <summary>
        /// 엑셀로 등록하는 이벤트
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnExcel_Click(object sender, EventArgs e)
        {
            openFileDialog1.Filter           = "Excel Files (*.xls)|*.xls";
            openFileDialog1.InitialDirectory = "C:";
            openFileDialog1.Title            = "OpenSalesCost";

            if (this.openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                openFileName = openFileDialog1.FileName;
                if (openFileName.Length > 1)
                {
                    using (frmWaitAsyncForm frm = new frmWaitAsyncForm(GetExcelFile))
                    {
                        frm.ShowDialog(this);
                    }
                }
            }
        }