求一条事件结束语句!

Question

 private void button1_Click(object sender, EventArgs e)
        {
            Globals.Sheet1.namedRange1.Validation.Delete();
            System.Text.StringBuilder  Sql = new StringBuilder ("");
            string Sqlcheck="";
            CheckBox[] myCheck = new CheckBox[8];
            myCheck[0] = chcek50;
            myCheck[1] = checkALUK;
            myCheck[2] = checkHL828;
            myCheck[3] = checkDQ;
            myCheck[7] = checkHJ;
            myCheck[5] = checkXY802;
            myCheck[6] = checkXY828;
            myCheck[4] = checkBox7;
            for (int i = 0; i < 8; i++)
            {
                if (myCheck[i].Checked )
                {
                    Sql.Append("(xilie = '" + myCheck[i].Text + "')  OR ");
                
                                       
                }
                           }
            try
            {
                Sqlcheck = Sql.ToString().Substring(0, Sql.Length - 3);
            }            catch
            {
                MessageBox.Show("定料提醒框", "数据有效性已成功清除");                //需要在这里加一条事件结束语句,不在执以下语句直接跳出此事件过程,不要GOTO,.Exit().Close()试过不行,谢谢
            }         
                                StringBuilder sItem = new StringBuilder();
            OleDbConnectionStringBuilder connectStringBuilder = new OleDbConnectionStringBuilder();
            connectStringBuilder.DataSource = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase + "\\db1.mdb";
            connectStringBuilder.Provider = "Microsoft.Jet.OLEDB.4.0";
            OleDbConnection con = new OleDbConnection(connectStringBuilder.ConnectionString);
            con.Open();
            OleDbCommand com = con.CreateCommand();
            com.CommandText =
                "SELECT xincaiID FROM [型材列表] WHERE"+Sqlcheck  ;            OleDbDataReader thisReader = com.ExecuteReader();
            while (thisReader.Read())
            {
                sItem.Append(thisReader.GetValue(0));
                sItem.Append(",");
            }
           
            String s1 = sItem.ToString().TrimEnd(',');                       Globals.Sheet1.namedRange1.Validation.Add(Excel.XlDVType.xlValidateList, Excel.XlDVAlertStyle.xlValidAlertStop, Excel.XlFormatConditionOperator.xlBetween, s1, Type.Missing);            thisReader.Close();
            con.Close();
        }
    }
}