AccountSystem.DeleteRecord.btnSearchRecord_Click C# (CSharp) Method

        private void btnSearchRecord_Click(object sender, EventArgs e)
        {
            DateTime dt = dtpDate.Value;
            string dtStr = dt.ToString("yyyy-MM-dd");
            cmbID.Items.Clear();
            try
            {
                string connectstring = "provider=Microsoft.jet.OLEDB.4.0;Data Source=accountsystem.mdb;Jet OleDb:Database Password=lxw618";
                string sqlcommand = "select [ID] as 数据号,[username] as 用户名,[date] as 收支日期,[money] as 金额,[item] as 收支项目,[type] as 收支类型,[memo] as 备注 from [Money] where [username]='" + cmbUsername.Text + "' and [date]=#" + dtStr + "# order by [ID]";
                OleDbConnection aConnection = new OleDbConnection(connectstring);
                aConnection.Open();
                OleDbDataAdapter adp = new OleDbDataAdapter(sqlcommand, connectstring);
                DataSet ds = new DataSet();
                adp.Fill(ds, "Money");
                dgvChangeRecord.DataSource = ds.Tables["Money"];
                OleDbCommandBuilder cbMoney = new OleDbCommandBuilder(adp);

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "系统错误");
            }
            try
            {
                string connectstring = "provider=Microsoft.jet.OLEDB.4.0;Data Source=accountsystem.mdb;Jet OleDb:Database Password=lxw618";
                string sqlcommand = "select [ID] from [Money] where [username]='" + cmbUsername.Text + "' and [date]=#" + dtStr + "# order by [ID]";
                OleDbConnection aConnection = new OleDbConnection(connectstring);
                aConnection.Open();
                OleDbCommand aCommand = new OleDbCommand(sqlcommand, aConnection);
                OleDbDataReader reader = aCommand.ExecuteReader();
                while (reader.Read())
                {
                    cmbID.Items.Add(reader.GetInt32(0));
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "系统错误");
            }
        }