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subclassing QList and operator+ overloading

- by Milen

I would like to be able to add two QList objects. For example: QList<int> b; b.append(10); b.append(20); b.append(30); QList<int> c; c.append(1); c.append(2); c.append(3); QList<int> d; d = b + c; For this reason, I decided to subclass the QList and to overload the operator+. Here is my code: class List : public QList<int> { public: List() : QList<int>() {} // Add QList + QList friend List operator+(const List& a1, const List& a2); }; List operator+(const List& a1, const List& a2) { List myList; myList.append(a1[0] + a2[0]); myList.append(a1[1] + a2[1]); myList.append(a1[2] + a2[2]); return myList; } int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); List b; b.append(10); b.append(20); b.append(30); List c; c.append(1); c.append(2); c.append(3); List d; d = b + c; List::iterator i; for(i = d.begin(); i != d.end(); ++i) qDebug() << *i; return a.exec(); } , the result is correct but I am not sure whether this is a good approach. I would like to ask whether there is better solution?

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why is this rails association loading individually after an eager load?

- by codeman73

I'm trying to avoid the N+1 queries problem with eager loading, but it's not working. The associated models are still being loaded individually. Here are the relevant ActiveRecords and their relationships: class Player < ActiveRecord::Base has_one :tableau end Class Tableau < ActiveRecord::Base belongs_to :player has_many :tableau_cards has_many :deck_cards, :through => :tableau_cards end Class TableauCard < ActiveRecord::Base belongs_to :tableau belongs_to :deck_card, :include => :card end class DeckCard < ActiveRecord::Base belongs_to :card has_many :tableaus, :through => :tableau_cards end class Card < ActiveRecord::Base has_many :deck_cards end and the query I'm using is inside this method of Player: def tableau_contains(card_id) self.tableau.tableau_cards = TableauCard.find :all, :include => [ {:deck_card => (:card)}], :conditions => ['tableau_cards.tableau_id = ?', self.tableau.id] contains = false for tableau_card in self.tableau.tableau_cards # my logic here, looking at attributes of the Card model, with # tableau_card.deck_card.card; # individual loads of related Card models related to tableau_card are done here end return contains end Does it have to do with scope? This tableau_contains method is down a few method calls in a larger loop, where I originally tried doing the eager loading because there are several places where these same objects are looped through and examined. Then I eventually tried the code as it is above, with the load just before the loop, and I'm still seeing the individual SELECT queries for Card inside the tableau_cards loop in the log. I can see the eager-loading query with the IN clause just before the tableau_cards loop as well. EDIT: additional info below with the larger, outer loop Here's the larger loop. It is inside an observer on after_save def after_save(pa) @game = Game.find(turn.game_id, :include => :goals) @game.players = Player.find :all, :include => [ {:tableau => (:tableau_cards)}, :player_goals ], :conditions => ['players.game_id =?', @game.id] for player in @game.players player.tableau.tableau_cards = TableauCard.find :all, :include => [ {:deck_card => (:card)}], :conditions => ['tableau_cards.tableau_id = ?', player.tableau.id] if(player.tableau_contains(card)) ... end end end

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Python multiprocessing global variable updates not returned to parent

- by user1459256

I am trying to return values from subprocesses but these values are unfortunately unpicklable. So I used global variables in threads module with success but have not been able to retrieve updates done in subprocesses when using multiprocessing module. I hope I'm missing something. The results printed at the end are always the same as initial values given the vars dataDV03 and dataDV04. The subprocesses are updating these global variables but these global variables remain unchanged in the parent. import multiprocessing # NOT ABLE to get python to return values in passed variables. ants = ['DV03', 'DV04'] dataDV03 = ['', ''] dataDV04 = {'driver': '', 'status': ''} def getDV03CclDrivers(lib): # call global variable global dataDV03 dataDV03[1] = 1 dataDV03[0] = 0 # eval( 'CCL.' + lib + '.' + lib + '( "DV03" )' ) these are unpicklable instantiations def getDV04CclDrivers(lib, dataDV04): # pass global variable dataDV04['driver'] = 0 # eval( 'CCL.' + lib + '.' + lib + '( "DV04" )' ) if __name__ == "__main__": jobs = [] if 'DV03' in ants: j = multiprocessing.Process(target=getDV03CclDrivers, args=('LORR',)) jobs.append(j) if 'DV04' in ants: j = multiprocessing.Process(target=getDV04CclDrivers, args=('LORR', dataDV04)) jobs.append(j) for j in jobs: j.start() for j in jobs: j.join() print 'Results:\n' print 'DV03', dataDV03 print 'DV04', dataDV04 I cannot post to my question so will try to edit the original. Here is the object that is not picklable: In [1]: from CCL import LORR In [2]: lorr=LORR.LORR('DV20', None) In [3]: lorr Out[3]: <CCL.LORR.LORR instance at 0x94b188c> This is the error returned when I use a multiprocessing.Pool to return the instance back to the parent: Thread getCcl (('DV20', 'LORR'),) Process PoolWorker-1: Traceback (most recent call last): File "/alma/ACS-10.1/casa/lib/python2.6/multiprocessing/process.py", line 232, in _bootstrap self.run() File "/alma/ACS-10.1/casa/lib/python2.6/multiprocessing/process.py", line 88, in run self._target(*self._args, **self._kwargs) File "/alma/ACS-10.1/casa/lib/python2.6/multiprocessing/pool.py", line 71, in worker put((job, i, result)) File "/alma/ACS-10.1/casa/lib/python2.6/multiprocessing/queues.py", line 366, in put return send(obj) UnpickleableError: Cannot pickle <type 'thread.lock'> objects In [5]: dir(lorr) Out[5]: ['GET_AMBIENT_TEMPERATURE', 'GET_CAN_ERROR', 'GET_CAN_ERROR_COUNT', 'GET_CHANNEL_NUMBER', 'GET_COUNT_PER_C_OP', 'GET_COUNT_REMAINING_OP', 'GET_DCM_LOCKED', 'GET_EFC_125_MHZ', 'GET_EFC_COMB_LINE_PLL', 'GET_ERROR_CODE_LAST_CAN_ERROR', 'GET_INTERNAL_SLAVE_ERROR_CODE', 'GET_MAGNITUDE_CELSIUS_OP', 'GET_MAJOR_REV_LEVEL', 'GET_MINOR_REV_LEVEL', 'GET_MODULE_CODES_CDAY', 'GET_MODULE_CODES_CMONTH', 'GET_MODULE_CODES_DIG1', 'GET_MODULE_CODES_DIG2', 'GET_MODULE_CODES_DIG4', 'GET_MODULE_CODES_DIG6', 'GET_MODULE_CODES_SERIAL', 'GET_MODULE_CODES_VERSION_MAJOR', 'GET_MODULE_CODES_VERSION_MINOR', 'GET_MODULE_CODES_YEAR', 'GET_NODE_ADDRESS', 'GET_OPTICAL_POWER_OFF', 'GET_OUTPUT_125MHZ_LOCKED', 'GET_OUTPUT_2GHZ_LOCKED', 'GET_PATCH_LEVEL', 'GET_POWER_SUPPLY_12V_NOT_OK', 'GET_POWER_SUPPLY_15V_NOT_OK', 'GET_PROTOCOL_MAJOR_REV_LEVEL', 'GET_PROTOCOL_MINOR_REV_LEVEL', 'GET_PROTOCOL_PATCH_LEVEL', 'GET_PROTOCOL_REV_LEVEL', 'GET_PWR_125_MHZ', 'GET_PWR_25_MHZ', 'GET_PWR_2_GHZ', 'GET_READ_MODULE_CODES', 'GET_RX_OPT_PWR', 'GET_SERIAL_NUMBER', 'GET_SIGN_OP', 'GET_STATUS', 'GET_SW_REV_LEVEL', 'GET_TE_LENGTH', 'GET_TE_LONG_FLAG_SET', 'GET_TE_OFFSET_COUNTER', 'GET_TE_SHORT_FLAG_SET', 'GET_TRANS_NUM', 'GET_VDC_12', 'GET_VDC_15', 'GET_VDC_7', 'GET_VDC_MINUS_7', 'SET_CLEAR_FLAGS', 'SET_FPGA_LOGIC_RESET', 'SET_RESET_AMBSI', 'SET_RESET_DEVICE', 'SET_RESYNC_TE', 'STATUS', '_HardwareDevice__componentName', '_HardwareDevice__hw', '_HardwareDevice__stickyFlag', '_LORRBase__logger', '__del__', '__doc__', '__init__', '__module__', '_devices', 'clearDeviceCommunicationErrorAlarm', 'getControlList', 'getDeviceCommunicationErrorCounter', 'getErrorMessage', 'getHwState', 'getInternalSlaveCanErrorMsg', 'getLastCanErrorMsg', 'getMonitorList', 'hwConfigure', 'hwDiagnostic', 'hwInitialize', 'hwOperational', 'hwSimulation', 'hwStart', 'hwStop', 'inErrorState', 'isMonitoring', 'isSimulated'] In [6]:

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References between Spring beans when using a NameSpaceHandler

- by teabot

I'm trying to use a Spring context namespace to build some existing configuration objects in an application. I have defined a context and pretty much have if working satisfactorily - however, I'd like one bean defined by my namespace to implicitly reference another: Consider the class named 'Node': public Class Node { private String aField; private Node nextNode; public Node(String aField, Node nextNode) { ... } Now in my Spring context I have something like so: <myns:container> <myns:node aField="nodeOne"/> <myns:node aField="nodeTwo"/> </myns:container> Now I'd like nodeOne.getNode() == nodeTwo to be true. So that nodeOne.getNode() and nodeTwo refer to the same bean instance. These are pretty much the relevant parts I have in my AbstractBeanDefinitionParser: public AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) { ... BeanDefinitionBuilder containerFactory = BeanDefinitionBuilder.rootBeanDefinition(ContainerFactoryBean.class); List<BeanDefinition> containerNodes = Lists.newArrayList(); String previousNodeBeanName; // iterate backwards over the 'node' elements for (int i = nodeElements.size() - 1; i >= 0; --i) { BeanDefinitionBuilder node = BeanDefinitionBuilder.rootBeanDefinition(Node.class); node.setScope(BeanDefinition.SCOPE_SINGLETON); String nodeField = nodeElements.getAttribute("aField"); node.addConstructorArgValue(nodeField); if (previousNodeBeanName != null) { node.addConstructorArgValue(new RuntimeBeanReference(previousNodeBeanName)); } else { node.addConstructorArgValue(null); } BeanDefinition nodeDefinition = node.getBeanDefinition(); previousNodeBeanName = "inner-node-" + nodeField; parserContext.getRegistry().registerBeanDefinition(previousNodeBeanName, nodeDefinition); containerNodes.add(node); } containerFactory.addPropertyValue("nodes", containerNodes); } When the application context is created my Node instances are created and recognized as singletons. Furthermore, the nextNode property is populated with a Node instance with the previous nodes configuration - however, it isn't the same instance. If I output a log message in Node's constructor I see two instances created for each node bean definition. I can think of a few workarounds myself but I'm keen to use the existing model. So can anyone tell me how I can pass these runtime bean references so that I get the correct singleton behaviour for my Node instances?

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Django admin fails when using includes in urlpatterns

- by zenWeasel

I am trying to refactor out my application a little bit to keep it from getting too unwieldily. So I started to move some of the urlpatterns out to sub files as the documentation proposes. Besides that fact that it just doesn't seem to be working (the items are not being rerouted) but when I go to the admin, it says that 'urlpatterns has not been defined'. The urls.py I have at the root of my application is: if settings.ENABLE_SSL: urlpatterns = patterns('', (r'^checkout/orderform/onepage/(\w*)/$','checkout.views.one_page_orderform',{'SSL':True},'commerce.checkout.views.single_product_orderform'), ) else: urlpatterns = patterns('', (r'^checkout/orderform/onepage/(\w*)/$','commerce.checkout.views.single_product_orderform'), ) urlpatterns+= patterns('', (r'^$', 'alchemysites.views.route_to_home'), (r'^%s/' % settings.DAJAXICE_MEDIA_PREFIX, include('dajaxice.urls')), (r'^/checkout/', include('commerce.urls')), (r'^/offers',include('commerce.urls')), (r'^/order/',include('commerce.urls')), (r'^admin/', include(admin.site.urls)), (r'^accounts/login/$', login), (r'^accounts/logout/$', logout), (r'^(?P<path>.*)/$','alchemysites.views.get_path'), (r'^static/(?P<path>.*)$', 'django.views.static.serve', {'document_root':settings.MEDIA_ROOT}), The urls I have moved out so far are the checkout/offers/order which are all subapps of 'commerce' where the urls.py for the apps are so to be clear. /urls.py in questions (included here) /commerce/urls.py where the urls.py I want to include is: order_info = { 'queryset': Order.objects.all(), } urlpatterns+= patterns('', (r'^offers/$','offers.views.start_offers'), (r'^offers/([a-zA-Z0-9-]*)/order/(\d*)/add/([a-zA-Z0-9-]*)/(\w*)/next/([a-zA-Z0-9-)/$','offers.views.show_offer'), (r'^reports/orders/$', list_detail.object_list,order_info), ) and the applications offers lies under commerce. And so the additional problem is that admin will not work at all, so I'm thinking because I killed it somewhere with my includes. Things I have checked for: Is the urlpatterns variable accidentally getting reset somewhere (i.e. urlpatterns = patterns, instead of urlpatterns+= patterns) Are the patterns in commerce.urls valid (yes, when moved back to root they work). So from there I am stumped. I can move everything back into the root, but was trying to get a little decoupled, not just for theoretical reason but for some short terms ones. Lastly if I enter www.domainname/checkout/orderform/onepage/xxxjsd I get the correct page. However, entering www.domainname/checkout/ gets handled by the alchemysites.views.get_path. If not the answer (because this is pretty darn specific), then is there a good way for troubleshoot urls.py? It seems to just be trial and error. Seems there should be some sort of parser that will tell you what your urlpatterns will do.

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Prevent SQL Injection in Dynamic column names

- by Mr Shoubs

I can't get away without writing some dynamic sql conditions in a part of my system (using Postgres). My question is how best to avoid SQL Injection with the method I am currently using. EDIT (Reasoning): There are many of columns in a number of tables (a number which grows (only) and is maintained elsewhere). I need a method of allowing the user to decide which (predefined) column they want to query (and if necessary apply string functions to). The query itself is far too complex for the user to write themselves, nor do they have access to the db. There are 1000's of users with varying requirements and I need to remain as flexible as possible - I shouldn't have to revisit the code unless the main query needs to change - Also, there is no way of knowing what conditions the user will need to use. I have objects (received via web service) that generates a condition (the generation method is below - it isn't perfect yet) for some large sql queries. The _FieldName is user editable (parameter name was, but it didn't need to be) and I am worried it could be an attack vector. I put double quotes (see quoted identifier) around the field name in an attempt to sanitize the string, this way it can never be a key word. I could also look up the field name against a list of fields, but it would be difficult to maintain on a timely basis. Unfortunately the user must enter the condition criteria, I am sure there must be more I can add to the sanatize method? and does quoting the column name make it safe? (my limited testing seems to think so). an example built condition would be "AND upper(brandloaded.make) like 'O%' and upper(brandloaded.make) not like 'OTHERBRAND'" ... Any help or suggestions are appreciated. Public Function GetCondition() As String Dim sb As New Text.StringBuilder 'put quote around the table name in an attempt to prevent some sql injection 'http://www.postgresql.org/docs/8.2/static/sql-syntax-lexical.html sb.AppendFormat(" {0} ""{1}"" ", _LogicOperator.ToString, _FieldName) Select Case _ConditionOperator Case ConditionOperatorOptions.Equals sb.Append(" = ") ... End Select sb.AppendFormat(" {0} ", Me.UniqueParameterName) 'for parameter Return Me.Sanitize(sb) End Function Private Function Sanitize(ByVal sb As Text.StringBuilder) As String 'compare against a similar blacklist mentioned here: http://forums.asp.net/t/1254125.aspx sb.Replace(";", "") sb.Replace("'", "") sb.Replace("\", "") sb.Replace(Chr(8), "") Return sb.ToString End Function Public ReadOnly Property UniqueParameterName() As String Get Return String.Concat(":" _UniqueIdentifier) End Get End Property

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Java: omitting a data member from the equals method.

- by cchampion

public class GamePiece { public GamePiece(char cLetter, int nPointValue) { m_cLetter=cLetter; m_nPointValue=nPointValue; m_nTurnPlaced=0; //has not been placed on game board yet. } public char GetLetter() {return m_cLetter;} public int GetPointValue() {return m_nPointValue;} public int GetTurnPlaced() {return m_nTurnPlaced;} public void SetTurnPlaced(int nTurnPlaced) { m_nTurnPlaced=nTurnPlaced; } @Override public boolean equals(Object obj) { /*NOTE to keep this shorter I omitted some of the null checking and instanceof stuff. */ GamePiece other = (GamePiece) obj; //not case sensitive, and I don`t think we want it to be here. if(m_cLetter != other.m_cLetter) { return false; } if(m_nPointValue != other.m_nPointValue) { return false; } /* NOTICE! m_nPointValue purposely omitted. It does not affect hashcode or equals */ return true; } @Override public int hashCode() { /* NOTICE! m_nPointValue purposely omitted. It should not affect hashcode or equals */ final int prime = 41; return prime * (prime + m_nPointValue + m_cLetter); } private char m_cLetter; private int m_nPointValue; private int m_nTurnPlaced;//turn which the game piece was placed on the game board. Does not affect equals or has code! } Consider the given piece of code. This object has been immutable until the introduction of the m_nTurnPlaced member (which can be modified by the SetTurnPlaced method, so now GamePiece becomes mutable). GamePiece is used in an ArrayList, I call contains and remove methods which both rely on the equals method to be implemented. My question is this, is it ok or common practice in Java for some members to not affect equals and hashcode? How will this affect its use in my ArrayList? What type of java Collections would it NOT be safe to use this object now that it is mutable? I've been told that you're not supposed to override equals on mutable objects because it causes some collections to behave "strangely" (I read that somewhere in the java documentation).

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How do I destruct data associated with an object after the object no longer exists?

- by Phineas

I'm creating a class (say, C) that associates data (say, D) with an object (say, O). When O is destructed, O will notify C that it soon will no longer exist :( ... Later, when C feels it is the right time, C will let go of what belonged to O, namely D. If D can be any type of object, what's the best way for C to be able to execute "delete D;"? And what if D is an array of objects? My solution is to have D derive from a base class that C has knowledge of. When the time comes, C calls delete on a pointer to the base class. I've also considered storing void pointers and calling delete, but I found out that's undefined behavior and doesn't call D's destructor. I considered that templates could be a novel solution, but I couldn't work that idea out. Here's what I have so far for C, minus some details: // This class is C in the above description. There may be many instances of C. class Context { public: // D will inherit from this class class Data { public: virtual ~Data() {} }; Context(); ~Context(); // Associates an owner (O) with its data (D) void add(const void* owner, Data* data); // O calls this when he knows its the end (O's destructor). // All instances of C are now aware that O is gone and its time to get rid // of all associated instances of D. static void purge (const void* owner); // This is called periodically in the application. It checks whether // O has called purge, and calls "delete D;" void refresh(); // Side note: sometimes O needs access to D Data *get (const void *owner); private: // Used for mapping owners (O) to data (D) std::map _data; }; // Here's an example of O class Mesh { public: ~Mesh() { Context::purge(this); } void init(Context& c) const { Data* data = new Data; // GL initialization here c.add(this, new Data); } void render(Context& c) const { Data* data = c.get(this); } private: // And here's an example of D struct Data : public Context::Data { ~Data() { glDeleteBuffers(1, &vbo); glDeleteTextures(1, &texture); } GLint vbo; GLint texture; }; }; P.S. If you're familiar with computer graphics and VR, I'm creating a class that separates an object's per-context data (e.g. OpenGL VBO IDs) from its per-application data (e.g. an array of vertices) and frees the per-context data at the appropriate time (when the matching rendering context is current).

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Django Encoding Issues with MySQL

- by Jordan Reiter

Okay, so I have a MySQL database set up. Most of the tables are latin1 and Django handles them fine. But, some of them are UTF-8 and Django does not handle them. Here's a sample table (these tables are all from django-geonames): DROP TABLE IF EXISTS `geoname`; SET @saved_cs_client = @@character_set_client; SET character_set_client = utf8; CREATE TABLE `geoname` ( `id` int(11) NOT NULL, `name` varchar(200) NOT NULL, `ascii_name` varchar(200) NOT NULL, `latitude` decimal(20,17) NOT NULL, `longitude` decimal(20,17) NOT NULL, `point` point default NULL, `fclass` varchar(1) NOT NULL, `fcode` varchar(7) NOT NULL, `country_id` varchar(2) NOT NULL, `cc2` varchar(60) NOT NULL, `admin1_id` int(11) default NULL, `admin2_id` int(11) default NULL, `admin3_id` int(11) default NULL, `admin4_id` int(11) default NULL, `population` int(11) NOT NULL, `elevation` int(11) NOT NULL, `gtopo30` int(11) NOT NULL, `timezone_id` int(11) default NULL, `moddate` date NOT NULL, PRIMARY KEY (`id`), KEY `country_id_refs_iso_alpha2_e2614807` (`country_id`), KEY `admin1_id_refs_id_a28cd057` (`admin1_id`), KEY `admin2_id_refs_id_4f9a0f7e` (`admin2_id`), KEY `admin3_id_refs_id_f8a5e181` (`admin3_id`), KEY `admin4_id_refs_id_9cc00ec8` (`admin4_id`), KEY `fcode_refs_code_977fe2ec` (`fcode`), KEY `timezone_id_refs_id_5b46c585` (`timezone_id`), KEY `geoname_52094d6e` (`name`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; SET character_set_client = @saved_cs_client; Now, if I try to get data from the table directly using MySQLdb and a cursor, I get the text with the proper encoding: >>> import MySQLdb >>> from django.conf import settings >>> >>> conn = MySQLdb.connect (host = "localhost", ... user = settings.DATABASES['default']['USER'], ... passwd = settings.DATABASES['default']['PASSWORD'], ... db = settings.DATABASES['default']['NAME']) >>> cursor = conn.cursor () >>> cursor.execute("select name from geoname where name like 'Uni%Hidalgo'"); 1L >>> g = cursor.fetchone() >>> g[0] 'Uni\xc3\xb3n Hidalgo' >>> print g[0] Unión Hidalgo However, if I try to use the Geoname model (which is actually a django.contrib.gis.db.models.Model), it fails: >>> from geonames.models import Geoname >>> g = Geoname.objects.get(name__istartswith='Uni',name__icontains='Hidalgo') >>> g.name u'Uni\xc3\xb3n Hidalgo' >>> print g.name UniÃ³n Hidalgo There's pretty clearly an encoding error here. In both cases the database is returning 'Uni\xc3\xb3n Hidalgo' but Django is (incorrectly?) translating the '\xc3\xb3n' to Ã³. What can I do to fix this?

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jQuery: Counter, Tricky problem with effects for brainy people.

- by Marius

Hello there! I made this counter that I think is cool because it only makes visible changes to the numbers being changed between each time it is triggered. This is the code // counter $('a').click(function(){ var u = ''; var newStr = ''; $('.counter').each(function(){ var len = $(this).children('span').length; $(this).children('span').each(function(){ u = u + $(this).text(); }); v = parseInt(u) + 1; v = v + ''; for (i=v.length - 1; i >= 0; i--) { if (v.charAt(i) == u.charAt(i)) { break; } } slce = len - (v.length - (i + 1)) updates = $(this).children('span').slice(slce); $(updates).fadeTo(100,0).delay(100).each(function(index){ f = i + 1 + index; $(this).text(v.charAt(f)); }).fadeTo(100,1); }); }); Markup: <span class="counter"> <span></span><span></span><span></span><span></span><span></span><span></span><span style="margin-right:4px;">9</span><span>9</span><span>9</span><span>9</span> </span> <a href="">Add + 1</a> The problem is that I previously used queue() function to delay() $(this).text(v.charAt(f)); by 100ms, (without queue the text()-function would not be delayed because it isnt in the fx catergory) so that the text would be updated before the object had faded to opacity = 0. That would look stupid. When adding multiple counters, only one of the counters would count. When removing the queue function, both counters would work, but as you can imagine, the delay of the text() would be gone (as it isnt fx-category). It is probably a bit tricky to make out how I can have multiple counters, and still delay the text()-function by 100ms, but I was hoping there is somebody here with spare brain capacity for these things ;) You can see a (NSFW) problem demo here: Just look underneath the sharing icons and you will notice that the text changes WHILE the objects fade out. Looking for some help to sove this problem. I would like to call the text() function once the text has faded to opacity 0, then fade in once the text() has executed. Thank you for your time.

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HTML wrapper div over embedded flash object cannot be "clickable" by jQuery

- by Michael Mao

Hi all: I've been trying to do as the client requested : redirect to campaign page then to destination page once a customer clicks on the top banner in swf format. You can check what's been done at :http://ausdcf.org If you are using Firefox, Chrome or Safari, I suspect you can reach the destination page. However, if you are using IE or Opera, I doubt it. I think to cause of such a weird problem is: The swf ojbects don't have a link to url, SO I have to hack the theme template file like this : <div id="header">'; /* * A quick and dirty way to put some swf into PHP, and rotate among them ... */ //available banners $banners = array( 'http://localhost/smf/flash/banner_fertalign_1.swf', 'http://localhost/smf/flash/banner_fertalign_2.swf', 'http://localhost/smf/flash/banner_fertalign_3.swf' ); //get random banner srand((double) microtime() * 1000000); $rand = rand(0,count($banners)-1); echo '<div id="top_banner_clickable">'; echo '<div id="top_banner_wrapper">'; echo '<object width="400" height="60">'; echo '<param name="wmode" value="transparent">'; echo '<embed wmode="transparent" src="'.$banners[$rand].'" '; echo 'width="400" height="60" type="application/x-shockwave-flash"'; echo 'pluginspage="http://www.macromedia.com/shockwave/download/index.cgi?P1_Prod_Version=ShockwaveFlash" />'; echo '</object>'; echo '</div>'; echo '</div>'; And the related jQuery code is like this: /* master.js */ $(document).ready(function() { $("#top_banner_clickable").click(function() { window.location ="http://ausdcf.org/campaign/"; }); }); I absolutely know nothing about Flash or embedded objects. I guess that's the cause of this problem. Plus, I don't know why it works with some browsers but not all... I even tried to add a z-index to the wrapper div in css like this: #top_banner_clickable { z-index : 100; } No this wouldn't do, either... Is there a way to go around this issue? Many thanks in advance.

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Do Websites need Local Databases Anymore?

- by viatropos

If there's a better place to ask this, please let me know. Every time I build a new website/blog/shopping-cart/etc., I keep trying to do the following: Extract out common functionality into reusable code (Rubygems and jQuery plugins mostly) If possible, convert that gem into a small service so I never have to deal with a database for the objects involved (by service, I mean something lean and mean, usually built with the Sinatra Web Framework with a few core models). My assumption is, if I can remove dependencies on local databases, that will make it easier and more scalable in the long run (scalable in terms of reusability and manageability, not necessarily database/performance). I'm not sure if that's a good or bad assumption yet. What do you think? I've made this assumption because of the following reason: Most serious database/model functionality has been built on the internet somewhere. Just to name a few: Social Network API: Facebook Messaging API: Twitter Mailing API: Google Event API: Eventbrite Shopping API: Shopify Comment API: Disqus Form API: Wufoo Image API: Picasa Video API: Youtube ... Each of those things are fairly complicated to build from scratch and to make as optimized, simple, and easy to use as those companies have made them. So if I build an app that shows pictures (picasa) on an Event page (eventbrite), and you can see who joined the event (facebook events), and send them emails (google apps api), and have them fill out monthly surveys (wufoo), and watch a video when they're done (youtube), all integrated into a custom, easy to use website, and I can do that without ever creating a local database, is that a good thing? I ask because there's two things missing from the puzzle that keep forcing me to create that local database: Post API RESTful/Pretty Url API While there's plenty of Blogging systems and APIs for them, there is no one place where you can just write content and have it part of some massive thing. For every app, I have to use code for creating pretty/restful urls, and that saves posts. But it seems like that should be a service! Question is, is that what the website is? ...That place to integrate the worlds services for my specific cause... and, sigh, to store posts that only my site has access to. Will everyone always need "their own blog"? Why not just have a profile and write lots of content on an established platform like StackOverflow or Facebook? ... That way I can write apps entirely without a database and know that I'm doing it right. Note: Of course at some point you'd need a database, if you were doing something unique or new. But for the case where you're just rewiring information or creating things like videos, events, and products, is it really necessary anymore??

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Would a Centralized Blogging Service Work?

- by viatropos

If there's a better place to ask this, please let me know. Every time I build a new website/blog/shopping-cart/etc., I keep trying to do the following: Extract out common functionality into reusable code (Rubygems and jQuery plugins mostly) If possible, convert that gem into a small service so I never have to deal with a database for the objects involved (by service, I mean something lean and mean, usually built with the Sinatra Web Framework with a few core models. My assumption is, if I can remove dependencies on local databases, that will make it easier and more scalable in the long run (scalable in terms of reusability and manageability, not necessarily database/performance). I'm not sure if that's a good or bad assumption yet. What do you think? I've made this assumption because of the following reason: Most serious database/model functionality has been built on the internet somewhere. Just to name a few: Social Network API: Facebook Messaging API: Twitter Mailing API: Google Event API: Eventbrite Shopping API: Shopify Comment API: Disqus Form API: Wufoo Image API: Picasa Video API: Youtube ... Each of those things are fairly complicated to build from scratch and to make as optimized, simple, and easy to use as those companies have. So if I build an app that shows pictures (picasa) on an Event page (eventbrite), and you can see who joined the event (facebook events), and send them emails (google apps api), and have them fill out monthly surveys (wufoo), and watch a video when they're done (youtube), all integrated into a custom, easy to use website, and I can do that without ever creating a local database, is that a good thing? I ask because there's two things missing from the puzzle that keep forcing me to create that local database: Post API RESTful/Pretty Url API While there's plenty of Blogging systems and APIs for them, there is no one place where you can just write content and have it part of some massive thing. For every app, I have to use code for creating pretty/restful urls, and that saves posts. But it seems like that should be a service! Question is, is that the main point of a website? Will everyone always need "their own blog"? Why not just have a profile and write lots of content on an established platform like StackOverflow or Facebook?

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Good object/DB set-up for CMS-esque app for managing content and user permissions?

- by sah302

Hi all, so I am writing a big CMS-esque app to allow users to manage web content through web applications, I've got a pretty good db-driven user permission system going, but am having trouble coming up with a good way to handle content groups and pages, I've got a couple options and not sure which one to take. Furthermore, I am not sure how to handle static page updates that have no 'widgets' in them. My current set-up for permissions is this: Objects: User, UserGroup, UserUserGroup, UserGroupType Standard many to many relationship User -> UserUserGroup <- UserGroup each Usergroup has a UserGroupType, which could be anything from Title, Department, to PermissionGroup. PermissionGroup manages the permissions. Right now on a per page basis I check permissions based on their PermissionsGroups. So for a page which has CMS features for a news widget, I check for permission groups of "Site Admin" and "News Admin". Now the issue I am coming to is, the site has many different departments involved. No problem I think, I can just have a EntityContentGroup so any widget app can be used for any departments. So my HR department, each of their news items would be in the EntityContentGroup with the news item ID, and content group of "HR" or "HR News". But maybe this isn't the most efficient way to go about it? I don't want to put the content group simply as a NewsItemType because some news items could apply to multiple areas, so I want to be able to assign them to as many areas as I want. Likewise, all of my widget apps have this, so that's why I decided to choose EntityContentGroup and not just NewsItemContentGroup. I was also thinking well instead of doing a contentGroup do a Page object that says which page some entity should be on. It seems almost like the same thing, but would I want to use Page for something else? I was thinking Page would be used for static pages with no widgets, a simple Rich Text Editor can edit the content of that page and I save that item to a page?? And then instead of doing a page level check for UserGroup permissions, would it be better to associate a usergroup to a contentgroup, and then just depending on what contentGroup content on the page is displayed, determine the permissions through that relationship? Is that better? I am not sure at this point. I guess I am just getting a tad overwhelmed at this is the largest app in scope and size that I have ever written. What is the best approach for this based on my current user permission set-up?

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Python4Delphi: Returning a python object in a function. (DelphiWrapper)

- by Gabriel Fonseca

I am using python4delphi. ow can I return an object from a wrapped Delphi class function? Code Snippet: I have a simple Delphi Class that i wrapped to Python Script, right? TSimple = Class Private function getvar1:string; Public Published property var1:string read getVar1; function getObj:TSimple; end; ... function TSimple.getVar1:string; begin result:='hello'; end; function TSimple.getObj:TSimple; begin result:=self; end; I made the TPySimple like the demo32 to give class access to the python code. My python module name is test. TPyDado = class(TPyDelphiPersistent) // Constructors & Destructors constructor Create( APythonType : TPythonType ); override; constructor CreateWith( PythonType : TPythonType; args : PPyObject ); override; // Basic services function Repr : PPyObject; override; class function DelphiObjectClass : TClass; override; end; ... { TPyDado } constructor TPyDado.Create(APythonType: TPythonType); begin inherited; // we need to set DelphiObject property DelphiObject := TDado.Create; with TDado(DelphiObject) do begin end; Owned := True; // We own the objects we create end; constructor TPyDado.CreateWith(PythonType: TPythonType; args: PPyObject); begin inherited; with GetPythonEngine, DelphiObject as TDado do begin if PyArg_ParseTuple( args, ':CreateDado' ) = 0 then Exit; end; end; class function TPyDado.DelphiObjectClass: TClass; begin Result := TDado; end; function TPyDado.Repr: PPyObject; begin with GetPythonEngine, DelphiObject as TDado do Result := VariantAsPyObject(Format('',[])); // or Result := PyString_FromString( PAnsiChar(Format('(%d, %d)',[x, y])) ); end; And now the python code: import test a = test.Simple() # try access the property var1 and everything is right print a.var1 # work's, but.. b = a.getObj(); # raise a exception that not find any attributes named getObj. # if the function returns a string for example, it's work.

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How can I load a file into a DataBag from within a Yahoo PigLatin UDF?

- by Cervo

I have a Pig program where I am trying to compute the minimum center between two bags. In order for it to work, I found I need to COGROUP the bags into a single dataset. The entire operation takes a long time. I want to either open one of the bags from disk within the UDF, or to be able to pass another relation into the UDF without needing to COGROUP...... Code: # **** Load files for iteration **** register myudfs.jar; wordcounts = LOAD 'input/wordcounts.txt' USING PigStorage('\t') AS (PatentNumber:chararray, word:chararray, frequency:double); centerassignments = load 'input/centerassignments/part-*' USING PigStorage('\t') AS (PatentNumber: chararray, oldCenter: chararray, newCenter: chararray); kcenters = LOAD 'input/kcenters/part-*' USING PigStorage('\t') AS (CenterID:chararray, word:chararray, frequency:double); kcentersa1 = CROSS centerassignments, kcenters; kcentersa = FOREACH kcentersa1 GENERATE centerassignments::PatentNumber as PatentNumber, kcenters::CenterID as CenterID, kcenters::word as word, kcenters::frequency as frequency; #***** Assign to nearest k-mean ******* assignpre1 = COGROUP wordcounts by PatentNumber, kcentersa by PatentNumber; assignwork2 = FOREACH assignpre1 GENERATE group as PatentNumber, myudfs.kmeans(wordcounts, kcentersa) as CenterID; basically my issue is that for each patent I need to pass the sub relations (wordcounts, kcenters). In order to do this, I do a cross and then a COGROUP by PatentNumber in order to get the set PatentNumber, {wordcounts}, {kcenters}. If I could figure a way to pass a relation or open up the centers from within the UDF, then I could just GROUP wordcounts by PatentNumber and run myudfs.kmeans(wordcount) which is hopefully much faster without the CROSS/COGROUP. This is an expensive operation. Currently this takes about 20 minutes and appears to tack the CPU/RAM. I was thinking it might be more efficient without the CROSS. I'm not sure it will be faster, so I'd like to experiment. Anyway it looks like calling the Loading functions from within Pig needs a PigContext object which I don't get from an evalfunc. And to use the hadoop file system, I need some initial objects as well, which I don't see how to get. So my question is how can I open a file from the hadoop file system from within a PIG UDF? I also run the UDF via main for debugging. So I need to load from the normal filesystem when in debug mode. Another better idea would be if there was a way to pass a relation into a UDF without needing to CROSS/COGROUP. This would be ideal, particularly if the relation resides in memory.. ie being able to do myudfs.kmeans(wordcounts, kcenters) without needing the CROSS/COGROUP with kcenters... But the basic idea is to trade IO for RAM/CPU cycles. Anyway any help will be much appreciated, the PIG UDFs aren't super well documented beyond the most simple ones, even in the UDF manual.

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Grouping php array items based on user and created time

- by Jim

This is an array of objects showing a user uploading photos: Array ( [12] => stdClass Object ( [type] => photo [created] => 2010-05-14 23:36:41 [user] => stdClass Object ( [id] => 760 [username] => mrsmith ) [photo] => stdClass Object ( [id] => 4181 ) ) [44] => stdClass Object ( [type] => photo [created] => 2010-05-14 23:37:15 [user] => stdClass Object ( [id] => 760 [username] => mrsmith ) [photo] => stdClass Object ( [id] => 4180 ) ) ) However instead of showing: mr smith uploaded one photo mr smith uploaded one photo I'd like to display: mr smith uploaded two photos by grouping similar items, grouping by user ID and them having added them within, let's say 15 minutes of each other. So I'd like to get the array in this sort of shape: Array ( [12] => stdClass Object ( [type] => photo [created] => 2010-05-14 23:36:41 [user] => stdClass Object ( [id] => 760 [username] => mrsmith ) [photos] => Array ( [0] => stdClass Object ( [id] => 4181 ) [1] => stdClass Object ( [id] => 4180 ) ) ) ) preserving the first item of the group and it's created time, and supplementing it with any other groupable photos and then unsetting any items that were grouped (so the final array doesn't have key 44 anymore as it was grouped in with 12). The array contains other actions than just photos, hence the original keys of 12 and 44. I just can't figure out a way to do this efficiently. I used to use MySQL and PHP to do this but am trying to just use pure PHP for caching reasons. Can anyone shed any insights? I thought about going through each item and seeing if I can group it with the previous one in the array but the previous one might not necessarily be relevant or even a photo. I've got total brain freeze :(

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Accessing Content Page elements

- by Abdel Olakara

Hi all, I am facing a strange problem.. may be i am overlooking something and not able to find the silly issue. Need your help! I have a Master page and a Content Page: <form id="AccountForm" runat="server"> <div> <asp:ContentPlaceHolder ID="MenuHolder" runat="server"> </asp:ContentPlaceHolder> </div> <hr /> <div> <asp:ContentPlaceHolder ID="ContentHolder" runat="server"> </asp:ContentPlaceHolder> </div> And my content page has some form elements: <asp:Content ID="Content3" ContentPlaceHolderID="ContentHolder" runat="server"> First Name: <asp:TextBox ID="fName" runat="server"></asp:TextBox> <br /> Middle Name: <asp:TextBox ID="mName" runat="server"></asp:TextBox> <br /> Family Name: <asp:TextBox ID="lName" runat="server"></asp:TextBox> <br /> Birthday: <asp:TextBox ID="birthday" runat="server"></asp:TextBox> <br /> Mobile Phone: <asp:TextBox ID="mobile" runat="server"></asp:TextBox> <br /> Alternate Phone: <asp:TextBox ID="phone" runat="server"></asp:TextBox> <br /> I also have the code for submit button in the content page where i try to retrieve the values from the form elements and persist it into DB. Here is the SubmitButton_Click code: protected void SubmitButton_Click(object sender, EventArgs e) { log.Info("From Submit button: " + customerObject.first_name + " " + customerObject.family_name); if (fName != null) log.Info("First Name is not null"); log.Info("First Name:" + fName.Text); log.Info("Middle Name:" + mName.Text); log.Info("Family Name:" + fName.Text); log.Info("Mobile:" + mobile.Text); log.Info("Phone: " + phone.Text); log.Info("Address:" + bAddressL1.Text + bAddressL2.Text); Strangly.. i don't get any data that is filled into my text fields? Their objects are not null as well!! why is this behaviour happening? I am not trying to access elements in master page or other.. all the fields are in the content page.. only thing is there is no form element in the content page and the form element is in master page! Thanks in advance for your suggestions and answers. Abdel Raoof Olakara

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How to initiate chatting between two clients and two clients only, using applets and servlets?

- by mithun1538

Hello everyone, I first need to apologize for my earlier questions. (You can check my profile for them)They seemed to ask more questions than give answers. Hence, I am laying down the actual question that started all them absurd questions. I am trying to design a chat applet. Till now, I have coded the applet, servlet and communication between the applet and the servlet. The code in the servlet side is such that I was able to establish chatting between clients using the applets, but the code was more like a broadcast all feature, i.e. all clients would be chatting with each other. That was my first objective when I started designing the chat applet. The second step is chatting between only two specific users, much like any other chat application we have. So this was my idea for it: I create an instance of the servlet that has the 'broadcast-all' code. I then pass the address of this instance to the respective clients. 2 client applets use the address to then chat. Technically the code is 'broadcast-all', but since only 2 clients are connected to it, it gives the chatting between two clients feature. Thus, groups of 2 clients have different instances of the same servlet, and each instance handles chatting between two clients at a max. However, as predicted, the idea didn't materialize! I tried to create an instance of the servlet but the only solution for that was using sessions on the servlet side, and I don't know how to use this session for later communications. I then tried to modify my broadcast-all code. In that code, I was using classes that implemented Observer and Observable interfaces. So the next idea that I got was: Create a new object of the Observable class(say class_1). This object be common to 2 clients. 2 clients that wish to chat will use same object of the class_1. 2 other clients will use a different object of class_1. But the problem here lies with the class that implements the Observer interface(say class_2). Since this has observers monitoring the same type of class, namely class_1, how do I establish an observer monitoring one object of class_1 and another observer monitoring another object of the same class class_1 (Because notifyObservers() would notify all the observers and I can't assign a particular observer to a particular object)? I first decided to ask individual problems, like how to create instances of servlets, using objects of observable and observer and so on in stackoverflow... but I got confused even more. Can anyone give me an idea how to establish chatting between two clients only?(I am using Http and not sockets or RMI). Regards, Mithun. P.S. Thanks to all who replied to my previous (absurd) queries. I should have stated the purpose earlier so that you guys could help me better.

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IQueryable and lazy loading

- by Nelson

I'm having a hard time determining the best way to handle this... With Entity Framework (and L2S), LINQ queries return IQueryable. I have read various opinions on whether the DAL/BLL should return IQueryable, IEnumerable or IList. Assuming we go with IList, then the query is run immediately and that control is not passed on to the next layer. This makes it easier to unit test, etc. You lose the ability to refine the query at higher levels, but you could simply create another method that allows you to refine the query and still return IList. And there are many more pros/cons. So far so good. Now comes Entity Framework and lazy loading. I am using POCO objects with proxies in .NET 4/VS 2010. In the presentation layer I do: foreach (Order order in bll.GetOrders()) { foreach (OrderLine orderLine in order.OrderLines) { // Do something } } In this case, GetOrders() returns IList so it executes immediately before returning to the PL. But in the next foreach, you have lazy loading which executes multiple SQL queries as it gets all the OrderLines. So basically, the PL is running SQL queries "on demand" in the wrong layer. Is there any sensible way to avoid this? I could turn lazy loading off, but then what's the point of having this "feature" that everyone was complaining EF1 didn't have? And I'll admit it is very useful in many scenarios. So I see several options: Somehow remove all associations in the entities and add methods to return them. This goes against the default EF behavior/code generation and makes it harder to do some composite (multiple entity) LINQ queries. It seems like a step backwards. I vote no. If we have lazy loading anyway which makes it hard to unit test, then go all the way and return IQueryable. You'll have more control farther up the layers. I still don't think this is a good option because IQueryable ties you to L2S, L2E, or your own full implementation of IQueryable. Lazy loading may run queries "on demand", but doesn't tie you to any specific interface. I vote no. Turn off lazy loading. You'll have to handle your associations manually. This could be with eager loading's .Include(). I vote yes in some specific cases. Keep IList and lazy loading. I vote yes in many cases, only due to the troubles with the others. Any other options or suggestions? I haven't found an option that really convinces me.

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how to pass data when using MenuItem.ItemContainerStyle

- by black sensei

Hello Experts! i've been trying to have a dynamic ContextMenu to show the name property of each of the object in its collection of objects. here is concrete example ,i'm connecting to a webservice to pull contacts and groups of a particular account.so i have those as global variables.i display the contacts in a listbox and i want to show on right click of a contact in the listbox the list of groups that it can be added to. to be able to add a contact to a group i need the id of the contact(which i have) and the id of the group which i'm looking for here is my code. xmlns:serviceAdmin="clr-namespace:MyWpfApp.serviceAdmin" ...... <ListBox.ContextMenu> <ContextMenu> <MenuItem Header="Refresh" Click="RefreshContact_Click"></MenuItem> <MenuItem Header="Add New Contact" Click="ContactNew_Click"></MenuItem> <MenuItem Header="Add to Group" Name="groupMenus"> // <MenuItem.ItemContainerStyle> <Style> <Setter Property="MenuItem.Header" Value="{Binding name}"/> <Setter Property="MenuItem.Tag" Value="{Binding id}" /> </Style> </MenuItem.ItemContainerStyle> </MenuItem> <MenuItem Header="Delete Selected" Click="ContactDelete_Click"></MenuItem> </ContextMenu> </ListBox.ContextMenu> ...... and on xaml.cs //this code is in the method that loads the groups loadedgroup = service.getGroups(session.key, null); groupListBox.ItemsSource = loadedgroup; groupMenus.ItemsSource = loadedgroup.ToList(); this code is showing the name of the groups alright but i need the id of the group clicked on. If you've noticed i commented a portion of the xaml code. with that i could bind(with ease) the id to the tag.But it won't work and the MenuItem.ItemContainerStyle is the one working but then i'm lost: Question 1 : how do i create a handler method for a click event of a submenu that has the names of the groups? Question 2 : how do i get the clicked group id to work with? thanks for reading and kindly help me in this

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Issues with LINQ (to Entity) [adding records]

- by Mario

I am using LINQ to Entity in a project, where I pull a bunch of data (from the database) and organize it into a bunch of objects and save those to the database. I have not had problems writing to the db before using LINQ to Entity, but I have run into a snag with this particular one. Here's the error I get (this is the "InnerException", the exception itself is useless!): New transaction is not allowed because there are other threads running in the session. I have seen that before, when I was trying to save my changes inside a loop. In this case, the loop finishes, and it tries to make that call, only to give me the exception. Here's the current code: try { //finalResult is a list of the keys to match on for the records being pulled foreach (int i in finalResult) { var queryEff = (from eff in dbMRI.MemberEligibility where eff.Member_Key == i && eff.EffDate >= DateTime.Now select eff.EffDate).Min(); if (queryEff != null) { //Add a record to the Process table Process prRecord = new Process(); prRecord.GroupData = qa; prRecord.Member_Key = i; prRecord.ProcessDate = DateTime.Now; prRecord.RecordType = "F"; prRecord.UsernameMarkedBy = "Autocard"; prRecord.GroupsId = qa.GroupsID; prRecord.Quantity = 2; prRecord.EffectiveDate = queryEff; dbMRI.AddObject("Process", prRecord); } } dbMRI.SaveChanges(); //<-- Crashes here foreach (int i in finalResult) { var queryProc = from pro in dbMRI.Process where pro.Member_Key == i && pro.UsernameMarkedBy == "Autocard" select pro; foreach (var qp in queryProc) { Audit aud = new Audit(); aud.Member_Key = i; aud.ProcessId = qp.ProcessId; aud.MarkDate = DateTime.Now; aud.MarkedByUsername = "Autocard"; aud.GroupData = qa; dbMRI.AddObject("Audit", aud); } } dbMRI.SaveChanges(); //<-- AND here (if the first one is commented out) } catch (Exception e) { //Do Something here } Basically, I need it to insert a record, get the identity for that inserted record and insert a record into another table with the identity from the first record. Given some other constraints, it is not possible to create a FK relationship between the two (I've tried, but some other parts of the app won't allow it, AND my DBA team for whatever reason hates FK's, but that's for a different topic :)) Any ideas what might be causing this? Thank!

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Constructor or Explicit cast

- by Felan

In working with Linq to Sql I create a seperate class to ferry data to a web page. To simplify creating these ferry objects I either use a specialized constructor or an explicit conversion operator. I have two questions. First which approach is better from a readibility perspective? Second while the clr code that is generated appeared to be the same to me, are there situations where one would be treated different than the other by the compiler (in lambda's or such). Example code (DatabaseFoo uses specialized constructor and BusinessFoo uses explicit operator): public class DatabaseFoo { private static int idCounter; // just to help with generating data public int Id { get; set; } public string Name { get; set; } public DatabaseFoo() { Id = idCounter++; Name = string.Format("Test{0}", Id); } public DatabaseFoo(BusinessFoo foo) { this.Id = foo.Id; this.Name = foo.Name; } } public class BusinessFoo { public int Id { get; set; } public string Name { get; set; } public static explicit operator BusinessFoo(DatabaseFoo foo) { return FromDatabaseFoo(foo); } public static BusinessFoo FromDatabaseFoo(DatabaseFoo foo) { return new BusinessFoo {Id = foo.Id, Name = foo.Name}; } } public class Program { static void Main(string[] args) { Console.WriteLine("Creating the initial list of DatabaseFoo"); IEnumerable<DatabaseFoo> dafoos = new List<DatabaseFoo>() { new DatabaseFoo(), new DatabaseFoo(), new DatabaseFoo(), new DatabaseFoo(), new DatabaseFoo(), new DatabaseFoo()}; foreach(DatabaseFoo dafoo in dafoos) Console.WriteLine(string.Format("{0}\t{1}", dafoo.Id, dafoo.Name)); Console.WriteLine("Casting the list of DatabaseFoo to a list of BusinessFoo"); IEnumerable<BusinessFoo> bufoos = from x in dafoos select (BusinessFoo) x; foreach (BusinessFoo bufoo in bufoos) Console.WriteLine(string.Format("{0}\t{1}", bufoo.Id, bufoo.Name)); Console.WriteLine("Creating a new list of DatabaseFoo by calling the constructor taking BusinessFoo"); IEnumerable<DatabaseFoo> fufoos = from x in bufoos select new DatabaseFoo(x); foreach(DatabaseFoo fufoo in fufoos) Console.WriteLine(string.Format("{0}\t{1}", fufoo.Id, fufoo.Name)); } }

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Web Services Primer for a WinForms Developer?

- by Unicorns

I've been writing client/server applications with Winforms for about six years now, but I have yet to venture into the web space (neither ASP.NET nor web services). Given the direction that the job market has been heading for some time and the fact that I have a basic curiosity, I'd like to get involved with writing web services, but I don't know where to start. I've read about various options (XML/SOAP vs. JSON, REST vs...well, actually I don't know what it's called, etc.), but I'm not sure what sort of criteria are in play when making the determination to use one or the other. Obviously, I'd like to leverage the tools that I have (Visual Studio, the .NET framework, etc.) without hamstringing myself into only targeting a particular audience (i.e. writing the service in such a way as to make it difficult to consume from a Windows Mobile/Android/iPhone client, for example). For the record, my plan--for now--is to use WCF for my web service development, but I'm open to using another .NET approach if that's advisable. I realize that this question is pretty open-ended so it may get closed, but here are some things I'm wondering: What are some things to consider when choosing the type of web service (REST, etc.) I intend to write? Is it possible (and, if so, feasible) to move from one approach to another? Can web services be written in an event-driven way? As I said I'm a Winforms developer, so I'm used to objects raising events for me to react to. For instance, if I have two clients connected to my service, is there a way for me to "push" information to one of them as a result of an action by the other? If this is possible, is this advisable or am I just not thinking about it correctly? What authentication mechanisms seem to work best for public-facing services? What about if I plan to have different types of OS'es and clients connecting to the service? Is there a generally accepted platform-agnostic approach? In the line of authentication, is this something that I should be doing myself (authenticating an managing sessions, etc.) or is this something should be handled at the framework level and I just define exactly how it should work? If that's the case, how do I tell who the requester has authenticated themselves as? I started writing an authentication mechanism (simple username/password combinations stored in the database and a corresponding session table with a GUID key) within my service and just requiring that key to be passed with every operation (other than logging in, of course), but I want to make sure that I'm not reinventing the wheel here. However, I also don't want to clutter up the server with a bunch of machine user accounts just to use Basic authentication. I'm also under the impression that Digest (and of course Windows) authentication requires a machine (or AD) user account.

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c#: Design advice. Using DataTable or List<MyObject> for a generic rule checker

- by Andrew White

Hi, I have about 100,000 lines of generic data. Columns/Properties of this data are user definable and are of the usual data types (string, int, double, date). There will be about 50 columns/properties. I have 2 needs: To be able to calculate new columns/properties using an expression e.g. Column3 = Column1 * Column2. Ultimately I would like to be able to use external data using a callback, e.g. Column3 = Column1 * GetTemperature The expression is relatively simple, maths operations, sum, count & IF are the only necessary functions. To be able to filter/group the data and perform aggregations e.g. Sum(Data.Column1) Where(Data.Column2 == "blah") As far as I can see I have two options: 1. Using a DataTable. = Point 1 above is achieved by using DataColumn.Expression = Point 2 above is acheived by using DataTable.DefaultView.RowFilter & C# code 2. Using a List of generic Objects each with a Dictionary< string, object to store the values. = Point 1 could be achieved by something like NCalc = Point 2 is achieved using LINQ DataTable: Pros: DataColumn.Expression is inbuilt Cons: RowFilter & coding c# is not as "nice" as LINQ, DataColumn.Expression does not support callbacks(?) = workaround could be to get & replace external value when creating the calculated column GenericList: Pros: LINQ syntax, NCalc supports callbacks Cons: Implementing NCalc/generic calc engine Based on the above I would think a GenericList approach would win, but something I have not factored in is the performance which for some reason I think would be better with a datatable. Does anyone have a gut feeling / experience with LINQ vs. DataTable performance? How about NCalc? As I said there are about 100,000 rows of data, with 50 columns, of which maybe 20 are calculated. In total about 50 rules will be run against the data, so in total there will be 5 million row/object scans. Would really appreciate any insights. Thx. ps. Of course using a database + SQL & Views etc. would be the easiest solution, but for various reasons can't be implemented.

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