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  • Problems Expanding an Array in C++

    - by dxq
    I'm writing a simulation for class, and part of it involves the reproduction of organisms. My organisms are kept in an array, and I need to increase the size of the array when they reproduce. Because I have multiple classes for multiple organisms, I used a template: template <class orgType> void expandarray(orgType* oldarray, int& numitems, int reproductioncount) { orgType *newarray = new orgType[numitems+reproductioncount]; for (int i=0; i<numitems; i++) { newarray[i] = oldarray[i]; } numitems += reproductioncount; delete[] oldarray; oldarray = newarray; newarray = NULL; } However, this template seems to be somehow corrupting my data. I can run the program fine without reproduction (commenting out the calls to expandarray), but calling this function causes my program to crash. The program does not crash DURING the expandarray function, but crashes on access violation later on. I've written functions to expand an array hundreds of times, and I have no idea what I screwed up this time. Is there something blatantly wrong in my function? Does it look right to you? EDIT: Thanks for everyone's help. I can't believe I missed something so obvious. In response to using std::vector: we haven't discussed it in class yet, and as silly as it seems, I need to write code using the methods we've been taught.

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  • Is this method a good aproach to get SQL values from C#?

    - by MadBoy
    I have this little method that i use to get stuff from SQL. I either call it with varSearch = "" or varSearch = "something". I would like to know if having method written this way is best or would it be better to split it into two methods (by overloading), or maybe i could somehow parametrize whole WHERE clausule? private void sqlPobierzKontrahentDaneKlienta(ListView varListView, string varSearch) { varListView.BeginUpdate(); varListView.Items.Clear(); string preparedCommand; if (varSearch == "") { preparedCommand = @" SELECT t1.[KlienciID], CASE WHEN t2.[PodmiotRodzaj] = 'Firma' THEN t2.[PodmiotFirmaNazwa] ELSE t2.[PodmiotOsobaNazwisko] + ' ' + t2.[PodmiotOsobaImie] END AS 'Nazwa' FROM [BazaZarzadzanie].[dbo].[Klienci] t1 INNER JOIN [BazaZarzadzanie].[dbo].[Podmioty] t2 ON t1.[PodmiotID] = t2.[PodmiotID] ORDER BY t1.[KlienciID]"; } else { preparedCommand = @" SELECT t1.[KlienciID], CASE WHEN t2.[PodmiotRodzaj] = 'Firma' THEN t2.[PodmiotFirmaNazwa] ELSE t2.[PodmiotOsobaNazwisko] + ' ' + t2.[PodmiotOsobaImie] END AS 'Nazwa' FROM [BazaZarzadzanie].[dbo].[Klienci] t1 INNER JOIN [BazaZarzadzanie].[dbo].[Podmioty] t2 ON t1.[PodmiotID] = t2.[PodmiotID] WHERE t2.[PodmiotOsobaNazwisko] LIKE @searchValue OR t2.[PodmiotFirmaNazwa] LIKE @searchValue OR t2.[PodmiotOsobaImie] LIKE @searchValue ORDER BY t1.[KlienciID]"; } using (var varConnection = Locale.sqlConnectOneTime(Locale.sqlDataConnectionDetails)) using (SqlCommand sqlQuery = new SqlCommand(preparedCommand, varConnection)) { sqlQuery.Parameters.AddWithValue("@searchValue", "%" + varSearch + "%"); using (SqlDataReader sqlQueryResult = sqlQuery.ExecuteReader()) if (sqlQueryResult != null) { while (sqlQueryResult.Read()) { string varKontrahenciID = sqlQueryResult["KlienciID"].ToString(); string varKontrahent = sqlQueryResult["Nazwa"].ToString(); ListViewItem item = new ListViewItem(varKontrahenciID, 0); item.SubItems.Add(varKontrahent); varListView.Items.AddRange(new[] {item}); } } } varListView.EndUpdate(); }

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  • Create SQL parameters programmatically

    - by Neo
    Another annoying one for me but probably something simple. I have a number of possible where clauses for a query based on user input, my question is how can I add these programmatically? For instance: wherequery = @"WHERE fieldname = @p_FieldName AND "; if (txtValue.textLength > 0){ wherequery += "fieldname2 = @p_FieldName2 AND "; } query = @"SELECT * FROM tabe" + wherequery; sql = connection.CreateCommand(); sql.CommandText = query; How would I go about doing the parameters for that? I've tried ArrayLists, Dictionaries and a few other methods but can't find a way of doing it. Ideally I'd want to do something like this: SqlParameter[] sqlparams; wherequery = @"WHERE fieldname = @p_FieldName AND "; if (txtValue.textLength > 0){ wherequery += "fieldname2 = @p_FieldName2 AND "; sqlparams.Parameters.Add("@p_FieldName2 ", SqlDbType.VarChar).Value = txtValue.text; } query = @"SELECT * FROM tabe" + wherequery; sql = connection.CreateCommand(); sql.CommandText = query; sql.Parameters.Add(sqlparams);

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  • Easy HTTPS to PHP script

    - by Tom
    Hi, here is my scenario: I have a website with php, mySQL. I have a software application that has a login screen and sends usernames and passwords over the web by http: public String GetWebPageSource(String pURL) { try { byte[] vReceivedBytes = null; using (System.Net.WebClient vWebClient = new System.Net.WebClient()) { vReceivedBytes = vWebClient.DownloadData(pURL); } int vBomLen = 3; byte[] vStrippedBytes = new byte[vReceivedBytes.Length - vBomLen]; Array.Copy(vReceivedBytes, vBomLen, vStrippedBytes, 0, vReceivedBytes.Length - vBomLen); return System.Text.Encoding.UTF8.GetString(vStrippedBytes); } catch (Exception e) { Console.WriteLine(e.Message); return null; } } So to send a username and password I would write: GetWebPageSource("http://mywebsite.com/Login.php?username=stackoverflow&password=iscool") and the php file would spit out some text saying whether the password is accepted or denied. However this is NOT secure. So I want to make it secure... https. How easy is it to integrate https? How much will the code change? How much do I have to handle? What is transparent to me. Do I have to check if a cookie already exists and if not write the methods for authentication or is there librarys already provided that will do it for me?

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  • How do you send an extended-ascii AT-command (CCh) from Android bluetooth to a serial device?

    - by softex
    This one really has me banging my head. I'm sending alphanumeric data from an Android app, through the BluetoothChatService, to a serial bluetooth adaptor connected to the serial input of a radio transceiver. Everything works fine except when I try to configure the radio on-the-fly with its AT-commands. The AT+++ (enter command mode) is received OK, but the problem comes with the extended-ascii characters in the next two commands: Changing the radio destination address (which is what I'm trying to do) requires CCh 10h (plus 3 hex radio address bytes), and exiting the command mode requires CCh ATO. I know the radio can be configured OK because I've done it on an earlier prototype with the serial commands from PIC basic, and it also can be configured by entering the commands directly from hyperterm. Both these methods somehow convert that pesky CCh into a form the radio understands. I've have tried just about everything an Android noob could possibly come up with to finagle the encoding such as: private void command_address() { byte[] addrArray = {(byte) 0xCC, 16, 36, 65, 21, 13}; CharSequence addrvalues = EncodingUtils.getString(addrArray, "UTF-8"); sendMessage((String) addrvalues); } but no matter what, I can't seem to get that high-order byte (CCh/204/-52) to behave as it should. All other (< 127) bytes, command or data, transmit with no problem. Any help here would be greatly appreciated. -Dave

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  • Simple Oracle File repository with folder hierarchy

    - by Ope
    I have an application that stores large amount of files (XML and binary) in folder hierarchies. Currently the main method is storing them in file system or using a legacy CMS, which we want to get rid of. The CMS supports Oracle and a customer wants to keep the files in Oracle because of enterprise policies (backup etc.) The question is: Is there a simple implementation of file repository with folder hierarchy for Oracle? What I am looking for is a small .Net component or example code (PL/SQL and/or .Net) that would have the following methods: Create, Delete, Exists Folder CRUD file Move and potentially Copy file or directory Access to files and folders with paths like "/root/folder1/folder2/file.xml" Ability to get all the files and folders in a folder and potentially also the entire directory tree Tree traversal, getting the parent, all children etc. needs to be fast. I need the implementation in .Net, but if it was just the stored procedures, I could create the .Net calling code. I have pointers to generic articles for creating hierarchies in DB, so if I need to do it from scratch, I know where to start. What I am asking here, is there already an implementation that I could take without doing this from scratch? It seems like such a generic requirement... If the answer is a CMS, Document management system or such it should be Open Source or at least quite cheap (some hundreds / server) and it should be possible to deploy it XCopy - hopefully only couple of DLL:s. I do not need - or want - a full featured big CMS with dozens of dlls and especially not an msi-installation. I have tried to google this, but the words "repository", "CMS", "file hierarchy" etc. give so many answers, the searches are pretty much useless. Thanks, OPe

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  • Java: How ArrayList memory management

    - by cka3o4nik
    In my Data Structures class we have studies the Java ArrayList class, and how it grows the underlying array when a user adds more elements. That is understood. However, I cannot figure out how exactly this class frees up memory when lots of elements are removed from the list. Looking at the source, there are three methods that remove elements: [code] public E remove(int index) { RangeCheck(index); modCount++; E oldValue = (E) elementData[index]; int numMoved = size - index - 1; if (numMoved 0) System.arraycopy(elementData, index+1, elementData, index, numMoved); elementData[--size] = null; // Let gc do its work return oldValue; } public boolean remove(Object o) { if (o == null) { for (int index = 0; index < size; index++) if (elementData[index] == null) { fastRemove(index); return true; } } else { for (int index = 0; index < size; index++) if (o.equals(elementData[index])) { fastRemove(index); return true; } } return false; } private void fastRemove(int index) { modCount++; int numMoved = size - index - 1; if (numMoved 0) System.arraycopy(elementData, index+1, elementData, index, numMoved); elementData[--size] = null; // Let gc do its work } {/code] None of them reduce the datastore array. I even started questioning if memory free up ever happens, but empirical tests show that it does. So there must be some other way it is done, but where and how? I checked the parent classes as well with no success.

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  • Inheritance concept java..help

    - by max
    Hi everyone. I'd be very grateful if someone could help me to understand the inheritance concept in Java. Is the following code an example of that? I mean the class WavPanel is actually a subclass of JPanel which acts as a superclass. Is that correct? If so it means that "what JPanel has, also WavPanel but it is more specific since through its methods you can do something else". Am I wrong? thank you. Max import javax.swing.JPanel; class WavPanel extends JPanel { List<Byte> audioBytes; List<Line2D.Double> lines; public WavPanel() { super(); setBackground(Color.black); resetWaveform(); } public void resetWaveform() { audioBytes = new ArrayList<Byte>(); lines = new ArrayList<Line2D.Double>(); repaint(); } }

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  • Additional information in ASP.Net MVC View

    - by Max Malmgren
    I am attempting to implement a custom locale service in an MVC 2 webpage. I have an interface IResourceDictionary that provides a couple of methods for accessing resources by culture. This is because I want to avoid the static classes of .Net resources. The problem is accessing the chosen IResourceDictionary from the views. I have contemplated using the ViewDataDictionary given, creating a base controller from which all my controllers inherits that adds my IResourceDictionary to the ViewData before each action executes. Then I could call my resource dictionary this way: (ViewData["Resources"] as IResourceDictionary).GetEntry(params); Admittedly, this is extremely verbose and ugly, especially in inline code as we are encouraged to use in MVC. Right now I am leaning towards static class access ResourceDictionary.GetEntry(params); because it is slightly more elegant. I also thought about adding it to my typed model for each page, which seems more robust than adding it to the ViewData.. What is the preferred way to access my ResourceDictionary from the views? All my views will be using this dictionary.

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  • How to enforce jsf to create new instance of bean instead of throwing NullPointerException?

    - by Roman
    I'm almost sure that I do something wrong and thus the question's title is a bit incorrect. I have a form with several fields for creating a new User-objects (fields like login, password, birthday etc). And I have 2 buttons - Cancel and Create. I didn't finish Create yet :) , but when I press Cancel I see NullPointerException. Here is simplified code: <f:view> <h:form> <h:panelGroup layout="block"> <h:inputText id="add_login" value="#{userSupport.user.login}"/> <h:inputSecret id="add_password" value="#{userSupport.user.password}"/> <h:inputText id="add_name" value="#{userSupport.user.name}"/> <h:inputText id="add_surname" value="#{userSupport.user.surname}"/> <h:commandButton value="Cancel" action="cancel"/> </h:panelGroup> </h:form> </f:view> UserSupport class has field user with getter and setter and some other methods. It's a Spring bean with Session scope. When I press cancel, I see NPE because jsf tries to save values from inputs in user-object, but user-object is null. What is the correct way of doing this?

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  • sortable list using jquery ui not passing updated list order

    - by Matthew Berman
    I am following the sortable lists railscast and got everything working except when I sort, the same (original) order gets passed to the update method each time, so it doesn't update the true order. Here's the code: In the view: %tbody#lineup{"data-update-url" => sort_lineups_url} - @lineup.pieces.each_with_index do |piece, index| = content_tag_for :tr, piece do = render 'piece', :piece => piece, :index => index and pieces.js.coffee: jQuery -> $('#lineup').sortable( axis: 'y' update: -> $.post($(this).data('update-url'), $(this).sortable('serialize')) ); sort and show methods of lineupscontroller: def show @lineup = Lineup.find_by_user_id(current_user.id) @pieces = @lineup.pieces.order("position") end def sort params[:piece].each_with_index do |id, index| current_user.lineup.pieces.update_all({position: index+1}, {id: id}) end render nothing: true end and the update request: Started POST "/lineups/sort" for 127.0.0.1 at 2012-06-24 20:06:14 -0700 Processing by LineupsController#sort as */* Parameters: {"piece"=>["8", "2", "1", "4", "3", "7"]} User Load (0.4ms) SELECT `users`.* FROM `users` WHERE `users`.`id` = 2 LIMIT 1 Lineup Load (0.6ms) SELECT `lineups`.* FROM `lineups` WHERE `lineups`.`user_id` = 2 LIMIT 1 SQL (2.9ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 1 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 8 SQL (0.6ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 2 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 2 SQL (0.6ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 3 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 1 SQL (0.5ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 4 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 4 SQL (0.6ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 5 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 3 SQL (0.5ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 6 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 7 Rendered text template (0.0ms) so each time i drag+drop the list, it sends the same order again. what am I doing wrong that the params isn't passing the right, updated order? Completed 200 OK in 2757ms (Views: 1.0ms | ActiveRecord: 6.7ms)

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  • License key pattern detection?

    - by Ricket
    This is not a real situation; please ignore legal issues that you might think apply, because they don't. Let's say I have a set of 200 known valid license keys for a hypothetical piece of software's licensing algorithm, and a license key consists of 5 sets of 5 alphanumeric case-insensitive (all uppercase) characters. Example: HXDY6-R3DD7-Y8FRT-UNPVT-JSKON Is it possible (or likely) to extrapolate other possible keys for the system? What if the set was known to be consecutive; how do the methods change for this situation, and what kind of advantage does this give? I have heard of "keygens" before, but I believe they are probably made by decompiling the licensing software rather than examining known valid keys. In this case, I am only given the set of keys and I must determine the algorithm. I'm also told it is an industry standard algorithm, so it's probably not something basic, though the chance is always there I suppose. If you think this doesn't belong in Stack Overflow, please at least suggest an alternate place for me to look or ask the question. I honestly don't know where to begin with a problem like this. I don't even know the terminology for this kind of problem.

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  • Unit Tests Architecture Question

    - by Tom Tresansky
    So I've started to layout unit tests for the following bit of code: public interface MyInterface { void MyInterfaceMethod1(); void MyInterfaceMethod2(); } public class MyImplementation1 implements MyInterface { void MyInterfaceMethod1() { // do something } void MyInterfaceMethod2() { // do something else } void SubRoutineP() { // other functionality specific to this implementation } } public class MyImplementation2 implements MyInterface { void MyInterfaceMethod1() { // do a 3rd thing } void MyInterfaceMethod2() { // do something completely different } void SubRoutineQ() { // other functionality specific to this implementation } } with several implementations and the expectation of more to come. My initial thought was to save myself time re-writing unit tests with something like this: public abstract class MyInterfaceTester { protected MyInterface m_object; @Setup public void setUp() { m_object = getTestedImplementation(); } public abstract MyInterface getTestedImplementation(); @Test public void testMyInterfaceMethod1() { // use m_object to run tests } @Test public void testMyInterfaceMethod2() { // use m_object to run tests } } which I could then subclass easily to test the implementation specific additional methods like so: public class MyImplementation1Tester extends MyInterfaceTester { public MyInterface getTestedImplementation() { return new MyImplementation1(); } @Test public void testSubRoutineP() { // use m_object to run tests } } and likewise for implmentation 2 onwards. So my question really is: is there any reason not to do this? JUnit seems to like it just fine, and it serves my needs, but I haven't really seen anything like it in any of the unit testing books and examples I've been reading. Is there some best practice I'm unwittingly violating? Am I setting myself up for heartache down the road? Is there simply a much better way out there I haven't considered? Thanks for any help.

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  • initialize jquery slider with hidden input value from database.

    - by ludwigs3rd
    I'm using a slider as user input for a screen. Basically it's a bulk update screen where there is a table with multiple rows, thus multiple sliders. I created it so that the hidden value is what gets posted in the form. <td> <input class="percentageProvidedHidden" type="hidden" name='<%= "Values[" + i + "].Percentage" %>' value='<%=item.Percentage %>' /> <div class="percentageProvidedSlider"></div> </td> I have the update working just fine (move slider changes hidden input value, submit, values are updated in db), however, I can't get the damn thing to initialize with the value of the hidden input (note the "value: " parameter below). In this case I think $(this) isn't actually $('percentageProvidedSlider') but the page itself. Can someone help me get the slider value to initialize with the hidden input field? I'm using ASP .Net MVC 2 so if there are any methods I should try with that I welcome them as well. $('.percentageProvidedSlider').slider( { min: 0, max: 100, step: 25, value: $(this).parents('tr').find('input.percentageProvidedHidden').val(), slide: function(e, ui) { var mypos = ui.value; $(this).find('.ui-slider-handle').text(ui.value); }, change: function(event, ui) { var myVal = $(this).slider("option", "value"); $(this).parents('tr').find('input.percentageProvidedHidden').val(myVal); var myDropDown = $(this).parents('tr').find('select.verified'); } });

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  • Manipulate method functionality call

    - by danrichardson
    Hello, is it possibly in c# to have some sort of base class functionality which is manipulated slightly based on the class. For instance say i have the following code (which will quite obviously not compile it's meant to only be for demonstrative purposes) class BaseFunctionality { public virtual bool adminCall public static string MethodName(int id, string parameter) { if (adminCall) return dbcall.Execute(); else return dbcall.ExecuteMe(); } } class Admin : BaseFunctionality { override bool adminCall = true; } class Front : BaseFunctionality { override bool adminCall = false; } Now what i would like to be able to do is; string AdminCall = Admin.MethodName(1, "foo"); string FrontCall = Front.MethodName(2, "bar"); Is their any way to do something like this? I'm trying to do everything with static methods so i do not have to instantiate classes all the time, and have nice clean code which is only being manipulated in one place. The idea behind this is so that there is minimal code repeating and makes things easier to expand on, so for instance another class could implement the BaseFunctionality later on. Thanks Dan

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  • Scope of Groovy's ExpandoMetaClass?

    - by TicketMonster
    Groovy exposes an ExpandoMetaClass that allows you to dynamically add instance and class methods/properties to a POJO. I would like to use it to add an instance method to one of my Java classes: public class Fizz { // ...etc. } Fizz fizz = new Fizz(); fizz.metaClass.doStuff = { String blah -> fizz.buzz(blah) } This would be the equivalent to refactoring the Fizz class to have: public class Fizz { // ctors, getters/setters, etc... public void doStuff(String blah) { buzz(blah); } } My question: Does this add doStuff(String blah) to only this particular instance of Fizz? Or do all instances of Fizz now have a doStuff(String blah) instance method? If the former, how do I get all instances of Fizz to have the doStuff instance method? I know that if I made the Groovy: fizz.metaClass.doStuff << { String blah -> fizz.buzz(blah) } Then that would add a static class method to Fizz, such as Fizz.doStuff(String blah), but that's not what I want. I just want all instances of Fizz to now have an instance method called doStuff. Ideas?

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  • C# / this. and List<T>

    - by user3533030
    I am having trouble understanding how to initialize a List of objects and use it with methods inside of a class. I understand the mechanics of the List, but not how to initialize it inside a method and use it later. For example, I want to have a class that creates the List when it is constructed. Then, I want to use a method of that class to add elements to the list. The elements in the list are objects defined by the SolidWorks API. So, to construct the List, I used... public class ExportPoints : Exporter { public List<SldWorks.SketchPoint> listOfSketchPoints; public ExportPoints(SldWorks.SldWorks swApp, string nameSuffix) : base(swApp, nameSuffix) { List<SldWorks.SketchPoint> listOfSketchPoints = new List<SldWorks.SketchPoint>(); } public void createListOfFreePoints() { try { [imagine more code here] this.listOfSketchPoints.Add(pointTest); } catch (Exception e) { Debug.Print(e.ToString()); return; } } This fails during execution as if the listOfSketchPoints was never initialized as a List. So, I tried a hack and this worked: public ExportPoints(SldWorks.SldWorks swApp, string nameSuffix) : base(swApp, nameSuffix) { List<SldWorks.SketchPoint> listOfSketchPoints = new List<SldWorks.SketchPoint>(); this.listOfSketchPoints = listOfSketchPoints; } This approach creates the behavior that I want. However, it seems that I lack some understanding as to why this is necessary. Shouldn't it be possible to "initialize" a List that is a property of your object with a constructor? Why would you need to create the list, then assign the pointer of that new List to your property?

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  • EF 4 Query - Issue with Multiple Parameters

    - by Brian
    Hello, A trick to avoiding filtering by nullable parameters in SQL was something like the following: select * from customers where (@CustomerName is null or CustomerName = @CustomerName) This worked well for me in LINQ to SQL: string customerName = "XYZ"; var results = (from c in ctx.Customers where (customerName == null || (customerName != null && c.CustomerName == customerName)) select c); But that above query, when in ADO.NET EF, doesn't work for me; it should filter by customer name because it exists, but it doesn't. Instead, it's querying all the customer records. Now, this is a simplified example, because I have many fields that I'm utilizing this kind of logic with. But it never actually filters, queries all the records, and causes a timeout exception. But the wierd thing is another query does something similarly, with no issues. Any ideas why? Seems like a bug to me, or is there a workaround for this? I've since switched to extension methods which works. Thanks.

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  • Comparing lists of field-hashes with equivalent AR-objects.

    - by Tim Snowhite
    I have a list of hashes, as such: incoming_links = [ {:title => 'blah1', :url => "http://blah.com/post/1"}, {:title => 'blah2', :url => "http://blah.com/post/2"}, {:title => 'blah3', :url => "http://blah.com/post/3"}] And an ActiveRecord model which has fields in the database with some matching rows, say: Link.all => [<Link#2 @title='blah2' @url='...post/2'>, <Link#3 @title='blah3' @url='...post/3'>, <Link#4 @title='blah4' @url='...post/4'>] I'd like to do set operations on Link.all with incoming_links so that I can figure out that <Link#4 ...> is not in the set of incoming_links, and {:title => 'blah1', :url =>'http://blah.com/post/1'} is not in the Link.all set, like so: #pseudocode #incoming_links = as above links = Link.all expired_links = links - incoming_links missing_links = incoming_links - links expired_links.destroy missing_links.each{|link| Link.create(link)} One route I've tried: I'd rather not rewrite Array#- and such, and I'm okay with converting incoming_links to a set of unsaved Link objects; so I've tried overwriting hash eql? and so on in Link so that it ignored the id equality that AR::Base provides by default. But this is the only place this sort of equality should be considered in the application - in other places the Link#id default identity is required. Is there some way I could subclass Link and apply the hash, eql?, etc overwriting there? The other route I've tried is to pull out the attributes hash for each Link and doing a .slice('id',...etc) to prune the hashes down. But this requires writing seperate methods for keeping track of the Link objects while doing set operations on the hashes, or writing seperate Collection classes to wrap the incoming_links hash-list and Link-list which seems a bit overkill. What is the best way to design this interaction? Extra credit for cleanliness.

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  • Type contraint problem of C#

    - by user351565
    I meet a problem about type contraint of c# now. I wrote a pair of methods that can convert object to string and convert string to object. ex. static string ConvertToString(Type type, object val) { if (type == typeof(string)) return (string)val; if (type == typeof(int)) return val.ToString(); if (type.InSubclassOf(typeof(CodeObject))) return ((CodeObject)val).Code; } static T ConvertToObject<T>(string str) { Type type = typeof(T); if (type == typeof(string)) return (T)(object)val; if (type == typeof(int)) return (T)(object)int.Parse(val); if (type.InSubclassOf(typeof(CodeObject))) return Codes.Get<T>(val); } where CodeObject is a base class of Employees, Offices ..., which can fetch by static method Godes.Get where T: CodeObject but the code above cannot be compiled because error #CS0314 the generic type T of method ConvertToObject have no any constraint but Codes.Get request T must be subclass of CodeObject i tried use overloading to solve the problem but not ok. is there any way to clear up the problem? like reflection?

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  • Heapsort not working in Python for list of strings using heapq module

    - by VSN
    I was reading the python 2.7 documentation when I came across the heapq module. I was interested in the heapify() and the heappop() methods. So, I decided to write a simple heapsort program for integers: from heapq import heapify, heappop user_input = raw_input("Enter numbers to be sorted: ") data = map (int, user_input.split(",")) new_data = [] for i in range(len(data)): heapify(data) new_data.append(heappop(data)) print new_data This worked like a charm. To make it more interesting, I thought I would take away the integer conversion and leave it as a string. Logically, it should make no difference and the code should work as it did for integers: from heapq import heapify, heappop user_input = raw_input("Enter numbers to be sorted: ") data = user_input.split(",") new_data = [] for i in range(len(data)): heapify(data) print data new_data.append(heappop(data)) print new_data Note: I added a print statement in the for loop to see the heapified list. Here's the output when I ran the script: `$ python heapsort.py Enter numbers to be sorted: 4, 3, 1, 9, 6, 2 [' 1', ' 3', ' 2', ' 9', ' 6', '4'] [' 2', ' 3', '4', ' 9', ' 6'] [' 3', ' 6', '4', ' 9'] [' 6', ' 9', '4'] [' 9', '4'] ['4'] [' 1', ' 2', ' 3', ' 6', ' 9', '4']` The reasoning I applied was that since the strings are being compared, the tree should be the same if they were numbers. As is evident, the heapify didn't work correctly after the third iteration. Could someone help me figure out if I am missing something here? I'm running Python 2.4.5 on RedHat 3.4.6-9. Thanks, VSN

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  • Entityframework duplicate record on second insert

    - by Delysid
    I am building an application for recipe/meal planning, and i have come across a problem i cant seem to figure out. i have a table for units of measure, where i keep the used units in, i only want unique units in here (for grocery list calculation and so forth) but if i use a unit from the table on a recipe, the first time it is okay, nothing is inserted in units of measure, but the second time i get a "duplicate". i suspect it has something to do with entitykey, because the primary key is identity column on the sql server (2008 r2) for some reason it works to change the objectstate on some objects (courses, see code) and that does not generate a duplicate, but that does not work on the unit of measure my insert methods looks like this : public recipe Create(recipe recipe) { using (RecipeDataContext ctx = new RecipeDataContext()) { foreach (recipe_ingredient rec_ing in recipe.recipe_ingredient) { if (rec_ing.ingredient.ingredient_id == 0) { ingredient ing = (from _ing in ctx.ingredients where _ing.name == rec_ing.ingredient.name select _ing).FirstOrDefault(); if (ing != null) { rec_ing.ingredient_id = ing.ingredient_id; rec_ing.ingredient = null; } } if (rec_ing.unit_of_measure.unit_of_measure_id == 0) { unit_of_measure _uom = (from dbUom in ctx.unit_of_measure where dbUom.unit == rec_ing.unit_of_measure.unit select dbUom).FirstOrDefault(); if (_uom != null) { rec_ing.unit_of_measure_id = _uom.unit_of_measure_id; rec_ing.unit_of_measure = null; } } ctx.Recipes.AddObject(recipe); //for some reason it works to change object state of this, and not generate a duplicate ctx.ObjectStateManager.ChangeObjectState(recipe.courses[0], EntityState.Unchanged); } ctx.SaveChanges(); } return recipe; } My datamodel looks like this : http://i.imgur.com/NMwZv.png

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  • Allow login from another site

    - by tunmise fasipe
    I have web application where I store users' password and username. If you logon to this site, you can login with the password and username to have access to your profile. There is another option that requires you to login to my site from your site and have your profile within your site. This is because you might already have a site that your clients know you with. This latter part is what I don't know to implement. I have these ideas: Have a fixed IFrame within your site to contain my site: but I am concerned about size/layout since different clients have different layout/size for their content section. I am thinking of how to maintain session too A webservice: I don't know how feasible this is since the Password and ID are on my server. You may have to send them back and forth. It means client would have to code with my API. But I am not just returning data, I have to show them a page that contains the profile details OpenID, Single-SignOn: Just guessing - but the authentication and data resides on my server. there is nothing to access on your side in this case Any other methods/better approach Examples: like login into facebook within my site and still be able to do post updates, receive notifications Facebook implement some of these with IFrame e.g. the Like button

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  • Hibernate 1:M relationship ,row order, constant values table and concurrency

    - by EugeneP
    table A and B need to have 1:M relationship a and b are added during application runtime, so A created, then say 4 B's created. Each B instance has to come in order, so that I could later extract them in the same order as I added them. The app will be a web-app running on Tomcat, so 10 instances may work simultaneously. So my question are: 1) How to preserve inserting order, so that I could extract B instances that A references in the same order as I persisted them. That's tricky, because we add to a Collection and then it gets saved (am I right?). So, it depends on how Hibernate saves it, what if it changes the order in what we added instances? I've seen something like LIST instead of SET when describing relationships, is that what I need? 2) How to add a 3-rd column to B so that I could differentiate the instances, something like SEX(M,F,U) in B table. Do I need a special table, or there's and easy way to describe constants in Hibernate. What do you recommend? 3) Talking about concurrency, what methods do you recommend to use? There should be no collisions in the db and as you see, there might easily be some if rows are not inserted (PK added) right where it is invoked without delays ?

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  • [Processing/Java]Visibility/Layering Issue

    - by nnash
    I'm working on a small sketch in processing where I am making a "clock" using the time functions and drawing ellipses across the canvas based on milliseconds, seconds and minutes. I'm using a for loop to draw all of the ellipses and each for loop is inside its own method. I'm calling each of these methods in the draw function. However for some reason only the first method that is called is being drawn, when ideally I would like to have them all being visibly rendered. //setup program void setup() { size(800, 600); frameRate(30); background(#eeeeee); smooth(); } void draw(){ milliParticles(); secParticles(); minParticles(); } //time based particles void milliParticles(){ for(int i = int(millis()); i >= 0; i++) { ellipse(random(800), random(600), 5, 5 ); fill(255); } } void secParticles() { for(int i = int(second()); i >= 0; i++) { fill(0); ellipse(random(800), random(600), 10, 10 ); background(#eeeeee); } } void minParticles(){ for(int i = int(minute()); i >= 0; i++) { fill(50); ellipse(random(800), random(600), 20, 20 ); } }

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