private void UniteDBF2()
        {
            int result = ExecuteNoneQuery("E:\\tt.dbf", "USE " + "\"" + "E:\\tt.dbf" + "\"");
            if (result == -1) return;
            result = ExecuteNoneQuery("E:\\tb.dbf", "append from " + "\"" + "E:\\tb.dbf" + "\"");
            if (result == -1) return;
            //...
        }
        private int ExecuteNoneQuery(string tbName, string sql)
        {
            System.Data.Odbc.OdbcConnection con = null;
            try
            {
                string connStr = @"Driver={Microsoft Visual FoxPro Driver};SourceType=DBF;SourceDB=" + tbName + ";Exclusive=No;NULL=NO;Collate=Machine;BACKGROUNDFETCH=NO;DELETED=NO";
                con = new System.Data.Odbc.OdbcConnection(connStr);
                System.Data.Odbc.OdbcCommand cmd = new System.Data.Odbc.OdbcCommand(sql, con);
                
                con.Open();
                int result = cmd.ExecuteNonQuery();//执行到这里报错
                return result;
            }
            catch (Exception ex)
            {
                if (con.State != ConnectionState.Closed)
                    con.Close();
                MessageBox.Show(ex.Message, "系统消息", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return -1;
            }
        }