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  • Ordering by Sum from a separate controller part 2

    - by bgadoci
    Ok, so I had this working just fine before making a few controller additions and the relocation of some code. I feel like I am missing something really simple here but have spent hours trying to figure out what is going on. Here is the situation. class Question < ActiveRecord::Base has_many :sites end and class Sites < ActiveRecord::Base belongs_to :questions end I am trying to display my Sites in order of the sum of the 'like' column in the Sites Table. From my previous StackOverflow question I had this working when the partial was being called in the /views/sites/index.html.erb file. I then moved the partial to being called in the /views/questions/show.html.erb file and it successfully displays the Sites but fails to order them as it did when being called from the Sites view. I am calling the partial from the /views/questions/show.html.erb file as follows: <%= render :partial => @question.sites %> and here is the SitesController#index code class SitesController < ApplicationController def index @sites = @question.sites.all(:select => "sites.*, SUM(likes.like) as like_total", :joins => "LEFT JOIN likes AS likes ON likes.site_id = sites.id", :group => "sites.id", :order => "like_total DESC") respond_to do |format| format.html # index.html.erb format.xml { render :xml => @sites } end end

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  • Ensuring quality of your software and code

    - by Filip Ekberg
    When I usually write code I follow some guidelines to ensure that my code has a certain standard and I as any other developer try to ensure that my code and software is of quality. Try to focus on the programming and not the understanding of the domain or any other pre-programming steps. These are the following steps I live by: Writing unit tests Make it fail ( no code ) Make it Work ( working code ) Analysing abstraction Extracting methods Exteract interfaces Refactoring In addition to the above which is a part of refactoring, I also try to refactor the code with good tools such as ReSharper, CodeRush or others. The question; What is the next step? Commenting the code is trivial and shouldn't even have to be mentioned, but updated comments and xml-comments where it's needed / everywhere is something that I try to have. But all the above helps he ensure that other developers might understand my code, that the code has some sort of quality and follows naming standards. It does however not ensure any product quality. I am looking for tools for post-development quality ensurance, such as profilers and how one would use these tools to increase product quality.

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  • ESXi with software iSCSI

    - by jharley
    Has anyone had any luck using the swiSCSI driver on ESXi? Following the instructions from VMWare.com I get to the point where I have the iSCSI HBA showing up but no LUNs/targets are showing up. The iSCSI target is running on Solaris 10 update 5 and works with other initiators fine. The ESXi initiator (from the logs) sees the targets but just logs in and out of them every 2 - 5 seconds. We're using unauthenticated discovery, and over and over in /var/log/messages I see: iSCSI: bus 0 target 0 trying to establish session 0xb203f90 to portal 0, address 10.1.100.9 port 3260 group 1 iSCSI: bus 0 target 0 establish session 0xb203f90 #4848 to port 0, address 10.1.100.9 port 3260 group 1, alias data/ESXi iSCSI: session 0xb203f90 dropping after receiving unexpected opcode 0x60 iSCSI: session 0xb203f90 to data/ESXi dropped iSCSI: session 0xb203f90 to data/ESXi waiting 2 seconds before next login attempt The only other thing that seems out of wack is that my 'Recent Tasks' pane keeps filling with 'Browse Diagnostic Manager' events and /var/log/vmware/hostd.log is filled with messages like this up to two times per second: [2008-09-19 16:05:57.901 'TaskManager' 196621 info] Task Created: haTask-ha-host-vim.DiagnosticManager.browser-776 [2008-09-19 16:05:57.094 'TaskManager' 196621 info] Task Completed: haTask-ha-host-vim.DiagnosticManager.browser-766 Any help would be appreciated.

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  • File.Move, why do i get a FileNotFoundException? The file exist...

    - by acidzombie24
    Its extremely weird since the program is iterating the file! outfolder and infolder are both in H:/ my external HD using windows 7. The idea is to move all folders that only contain files with the extention db and svn-base. When i try to move the folder i get an exception. VS2010 tells me it cant find the folder specified in dir. This code is iterating through dir so how can it not find it! this is weird. string []theExt = new string[] { "db", "svn-base" }; foreach (var dir in Directory.GetDirectories(infolder)) { bool hit = false; if (Directory.GetDirectories(dir).Count() > 0) continue; foreach (var f in Directory.GetFiles(dir)) { var ext = Path.GetExtension(f).Substring(1); if(theExt.Contains(ext) == false) { hit = true; break; } } if (!hit) { var dst = outfolder + "\\" + Path.GetFileName(dir); File.Move(dir, outfolder); //FileNotFoundException: Could not find file dir. } } }

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  • Using group_by with fields_for and accepts_nested_attributes_for

    - by Derek
    I have a the following rails models: class Release < ActiveRecord::Base has_many :release_questionnaires, :dependent => :destroy accepts_nested_attributes_for :release_questionnaires ... end class class ReleaseQuestionnaire < ActiveRecord::Base belongs_to :release belongs_to :milestone ... end class In my view code, I have the following form. <% form_for @release, ... do |f| %> ... <table class="questionnaires"> <% f.fields_for :release_questionnaires, @release.release_questionnaires.sort_by{|ra| ra.questionnaire.name} do |builder| %> ... <% end %> </table> <% end %> This works and allows me to view and edit the questionnaires as desired. However, I have an additional requirement to break the questionnaires out into their own tables grouped by the milestone they are associated to, rather than in a single table. It appears as though the group_by method is design to accomplish this, but I cannot get it to work as desired inside the tag. It may be that I'm missing something obvious, as I am a beginner... Any help is appreciated.

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  • Which isolation level should I use for the following insert-if-not-present transaction?

    - by Steve Guidi
    I've written a linq-to-sql program that essentially performs an ETL task, and I've noticed many places where parallelization will improve its performance. However, I'm concerned about preventing uniquness constraint violations when two threads perform the following task (psuedo code). Record CreateRecord(string recordText) { using (MyDataContext database = GetDatabase()) { Record existingRecord = database.MyTable.FirstOrDefault(record.KeyPredicate()); if(existingRecord == null) { existingRecord = CreateRecord(recordText); database.MyTable.InsertOnSubmit(existingRecord); } database.SubmitChanges(); return existingRecord; } } In general, this code executes a SELECT statement to test for record existance, followed by an INSERT statement if the record doesn't exist. It is encapsulated by an implicit transaction. When two threads run this code for the same instance of recordText, I want to prevent them from simultaneously determining that the record doesn't exist, thereby both attempting to create the same record. An isolation level and explicit transaction will work well, except I'm not certain which isolation level I should use -- Serializable should work, but seems too strict. Is there a better choice?

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  • Spring Security ACL: NotFoundException from JDBCMutableAclService.createAcl

    - by user340202
    Hello, I've been working on this task for too long to abandon the idea of using Spring Security to achieve it, but I wish that the community will provide with some support that will help reduce the regret that I have for choosing Spring Security. Enough ranting and now let's get to the point. I'm trying to create an ACL by using JDBCMutableAclService.createAcl as follows: [code] public void addPermission(IWFArtifact securedObject, Sid recipient, Permission permission, Class clazz) { ObjectIdentity oid = new ObjectIdentityImpl(clazz.getCanonicalName(), securedObject.getId()); this.addPermission(oid, recipient, permission); } @Override @Transactional(propagation = Propagation.REQUIRED, isolation = Isolation.READ_UNCOMMITTED, readOnly = false) public void addPermission(ObjectIdentity oid, Sid recipient, Permission permission) { SpringSecurityUtils.assureThreadLocalAuthSet(); MutableAcl acl; try { acl = this.mutableAclService.createAcl(oid); } catch (AlreadyExistsException e) { acl = (MutableAcl) this.mutableAclService.readAclById(oid); } // try { // acl = (MutableAcl) this.mutableAclService.readAclById(oid); // } catch (NotFoundException nfe) { // acl = this.mutableAclService.createAcl(oid); // } acl.insertAce(acl.getEntries().length, permission, recipient, true); this.mutableAclService.updateAcl(acl); } [/code] The call throws a NotFoundException from the line: [code] // Retrieve the ACL via superclass (ensures cache registration, proper retrieval etc) Acl acl = readAclById(objectIdentity); [/code] I believe this is caused by something related to Transactional, and that's why I have tested with many TransactionDefinition attributes. I have also doubted the annotation and tried with declarative transaction definition, but still with no luck. One important point is that I have used the statement used to insert the oid in the database earlier in the method directly on the database and it worked, and also threw a unique constraint exception at me when it tried to insert it in the method. I'm using Spring Security 2.0.8 and IceFaces 1.8 (which doesn't support spring 3.0 but definetely supprorts 2.0.x, specially when I keep caling SpringSecurityUtils.assureThreadLocalAuthSet()). My AppServer is Tomcat 6.0, and my DB Server is MySQL 6.0 I wish to get back a reply soon because I need to get this task off my way

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  • C++ Storing variables and inheritance

    - by Kaa
    Hello Everyone, Here is my situation: I have an event driven system, where all my handlers are derived from IHandler class, and implement an onEvent(const Event &event) method. Now, Event is a base class for all events and contains only the enumerated event type. All actual events are derived from it, including the EventKey event, which has 2 fields: (uchar) keyCode and (bool)isDown. Here's the interesting part: I generate an EventKey event using the following syntax: Event evt = EventKey(15, true); and I ship it to the handlers: EventDispatch::sendEvent(evt); // void EventDispatch::sendEvent(const Event &event); (EventDispatch contains a linked list of IHandlers and calls their onEvent(const Event &event) method with the parameter containing the sent event. Now the actual question: Say I want my handlers to poll the events in a queue of type Event, how do I do that? x Dynamic pointers with reference counting sound like too big of a solution. x Making copies is more difficult than it sounds, since I'm only receiving a reference to a base type, therefore each time I would need to check the type of event, upcast to EventKey and then make a copy to store in a queue. Sounds like the only solution - but is unpleasant since I would need to know every single type of event and would have to check that for every event received - sounds like a bad plan. x I could allocate the events dynamically and then send around pointers to those events, enqueue them in the array if wanted - but other than having reference counting - how would I be able to keep track of that memory? Do you know any way to implement a very light reference counter that wouldn't interfere with the user? What do you think would be a good solution to this design? I thank everyone in advance for your time. Sincerely, Kaa

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  • rails xml to active record object

    - by Brian D.
    I've been googling for a while to try and convert and incoming XML request into an active record object. I've tried using the ActiveRecordObject.new.from_xml method but it doesn't seem to handle relationships. For example, say I have the following xml: <blog> <title></title> <blog-pages> <blog-page> <page-number></page-number> <content></content> </blog-page> </blog-pages> </blog> And I have the following model objects: class Blog < ActiveRecord::Base has_many :blog_pages end class BlogPage < ActiveRecord::Base belongs_to :blog end Is there a way to convert the xml into a blog object WITH relationships? Or do I need to manually parse the XML? Thanks in advance.

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  • How do you work on Strategic Development initiatives when Tactical work takes priority?

    - by Shaun F
    My day-to-day job consists of maintaining large volume websites and this has given me exposure to developing better methods to develop and maintain the code. This has also given me a large body of knowledge in the code base in terms of troubleshooting that is beneficial to the company. I'm also the maintainer of an IDE plug in I created to help navigate and generate code that is used. Operationally though, my job is to handle any client requests that come in of that are emergencies and make any enhancements and additions to the code base required. This work, along with the daily managing and feeding of the the project managers will take up my entire day. How does one manage the time between the tactical day job and the strategic initiatives? How does one get and ask for recognition for taking strategic initiatives? Is the 8-9 hour day just not going to cut it? Is there even a job out there for programmers to develop strategic initiatives and solutions for a company? I want to also point out that this isn't a problem with the company at all. I think this is more of a personal-improvement decision. Nobody will say no to the improvements at all. I believe in making the things happen but I don't think I'm going to get time from the company to do it...

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  • In what order should the Python concepts be explained to absolute beginners?

    - by Tomaž Pisanski
    I am teaching Python to undergraduate math majors. I am interested in the optimal order in which students should be introduced to various Python concepts. In my view, at each stage the students should be able to solve a non-trivial programming problem using only the tools available at that time. Each new tool should enable a simpler solution to a familiar problem. A selection of numerous concepts available in Python is essential in order to keep students focused. They should also motivated and should appreciate each newly mastered tool without too much memorization. Here are some specific questions: For instance, my predecessor introduced lists before strings. I think the opposite is a better solution. Should function definitions be introduced at the very beginning or after mastering basic structured programming ideas, such as decisions (if) and loops (while)? Should sets be introduced before dictionaries? Is it better to introduce reading and writing files early in the course or should one use input and print for most of the course? Any suggestions with explanations are most welcome.

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  • C++ Matrix class hierachy

    - by bpw1621
    Should a matrix software library have a root class (e.g., MatrixBase) from which more specialized (or more constrained) matrix classes (e.g., SparseMatrix, UpperTriangluarMatrix, etc.) derive? If so, should the derived classes be derived publicly/protectively/privately? If not, should they be composed with a implementation class encapsulating common functionality and be otherwise unrelated? Something else? I was having a conversation about this with a software developer colleague (I am not per se) who mentioned that it is a common programming design mistake to derive a more restricted class from a more general one (e.g., he used the example of how it was not a good idea to derive a Circle class from an Ellipse class as similar to the matrix design issue) even when it is true that a SparseMatrix "IS A" MatrixBase. The interface presented by both the base and derived classes should be the same for basic operations; for specialized operations, a derived class would have additional functionality that might not be possible to implement for an arbitrary MatrixBase object. For example, we can compute the cholesky decomposition only for a PositiveDefiniteMatrix class object; however, multiplication by a scalar should work the same way for both the base and derived classes. Also, even if the underlying data storage implementation differs the operator()(int,int) should work as expected for any type of matrix class. I have started looking at a few open-source matrix libraries and it appears like this is kind of a mixed bag (or maybe I'm looking at a mixed bag of libraries). I am planning on helping out with a refactoring of a math library where this has been a point of contention and I'd like to have opinions (that is unless there really is an objective right answer to this question) as to what design philosophy would be best and what are the pros and cons to any reasonable approach.

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  • Getting ellipses function parameters without an initial argument

    - by Tox1k
    So I've been making a custom parser for a scripting language, and I wanted to be able to pass only ellipses arguments. I don't need or want an initial variable, however Microsoft and C seem to want something else. FYI, see bottom for info. I've looked at the va_* definitions #define _crt_va_start(ap,v) ( ap = (va_list)_ADDRESSOF(v) + _INTSIZEOF(v) ) #define _crt_va_arg(ap,t) ( *(t *)((ap += _INTSIZEOF(t)) - _INTSIZEOF(t)) ) #define _crt_va_end(ap) ( ap = (va_list)0 ) and the part I don't want is the v in va_start. As a little background I'm competent in goasm and I know how the stack works so I know what's happening here. I was wondering if there is a way to get the function stack base without having to use inline assembly. Ideas I've had: #define im_va_start(ap) (__asm { mov [ap], ebp }) and etc... but really I feel like that's messy and I'm doing it wrong. struct function_table { const char* fname; (void)(*fptr)(...); unsigned char maxArgs; }; function_table mytable[] = { { "MessageBox", &tMessageBoxA, 4 } }; ... some function that sorts through a const char* passed to it to find the matching function in mytable and calls tMessageBoxA with the params. Also, the maxArgs argument is just so I can check that a valid number of parameters is being sent. I have personal reasons for not wanting to send it in the function, but in the meantime we can just say it's because I'm curious. This is just an example; custom libraries are what I would be implementing so it wouldn't just be calling WinAPI stuff. void tMessageBoxA(...) { // stuff to load args passed MessageBoxA(arg1, arg2, arg3, arg4); } I'm using the __cdecl calling convention and I've looked up ways to reliably get a pointer to the base of the stack (not the top) but I can't seem to find any. Also, I'm not worried about function security or typechecking.

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  • Approaches for animating a C# property over time?

    - by Mario Fritsch
    I'm currently trying to animate a bunch of public properties on certain objects. Usually they are of type float or vectors of floats (the type is known at compile-time). I want to be able to: assign a static value to them (MyObject.Duration = 10f;) or assign a random value to them by specifying a minimum and maximum value and optionally also a weight (MyObject.Duration = new RandomFloat(5f, 20f, 2f);) or "bind" this property to the property of another object (think of a child object binding some of its properties to its parent object, like its color or size or sth.) or assign sort of a keyframe animation to them, specifying a variable number of keyframes with timecode and the property's value at that specific point in time as well as information about how to interpolate between these frames The keyframes should be able to accept random values for each frame, both for the time and the property's value. What would be a practical approach for this kind of system? Currently I'm thinking about polymorphism: implement a base class or interface with a public Value-property and/or GetValue(float time)-method and then creating different sub classes like StaticValue, RandomValue, BindingValue and AnimatedValue implementing this base class or interface. Doesn't seem very elegant, though, and the initialization of even simple objects becomes a bit tedious. Another idea would be to implement these properties just as regular floats or vectors and create special "Modifier"-types binding to these properties. To retrieve the "real" value of the property, I'd first call any Modifier bound to the property, which would in turn update the actual object's property for me to retrieve later on. That would most likely mean using reflection at some point, which could be quite bad for performance as I'll probably have thousands of properties to update dozens of times per second. Any suggestions on this? Being a novice I'm (hopefully) missing some far more elegant and/or practical solution than I'm already playing around with :( Edit: Probably should have mentioned this earlier, but WPF isn't an option - it's not available on all targetted platforms, so I can't rely on it. I'm aware of its powerful databinding and animation capabilities, but I need to roll my own (or find some other lightweight alternative meeting my needs).

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  • Are ternary operators not valid for linq-to-sql queries?

    - by KallDrexx
    I am trying to display a nullable date time in my JSON response. In my MVC Controller I am running the following query: var requests = (from r in _context.TestRequests where r.scheduled_time == null && r.TestRequestRuns.Count > 0 select new { id = r.id, name = r.name, start = DateAndTimeDisplayString(r.TestRequestRuns.First().start_dt), end = r.TestRequestRuns.First().end_dt.HasValue ? DateAndTimeDisplayString(r.TestRequestRuns.First().end_dt.Value) : string.Empty }); When I run requests.ToArray() I get the following exception: Could not translate expression ' Table(TestRequest) .Where(r => ((r.scheduled_time == null) AndAlso (r.TestRequestRuns.Count > 0))) .Select(r => new <>f__AnonymousType18`4(id = r.id, name = r.name, start = value(QAWebTools.Controllers.TestRequestsController). DateAndTimeDisplayString(r.TestRequestRuns.First().start_dt), end = IIF(r.TestRequestRuns.First().end_dt.HasValue, value(QAWebTools.Controllers.TestRequestsController). DateAndTimeDisplayString(r.TestRequestRuns.First().end_dt.Value), Invoke(value(System.Func`1[System.String])))))' into SQL and could not treat it as a local expression. If I comment out the end = line, everything seems to run correctly, so it doesn't seem to be the use of my local DateAndTimeDisplayString method, so the only thing I can think of is Linq to Sql doesn't like Ternary operators? I think I've used ternary operators before, but I can't remember if I did it in this code base or another code base (that uses EF4 instead of L2S). Is this true, or am I missing some other issue?

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  • php code in FTP to backup db using URL

    - by Giom
    I fund and inserted this code in my FTP in a backup.php that works great but it copy the file into the root folder (homez/) 1- I would like to put these backup files in a homez/backupDB any idea where to put this path? 2- the db backup files (DB.sql.bz2) have always the same name, is it possible to name each one with the date of creation? (I launch this php with the URL link) <? echo "Votre base est en cours de sauvegarde....... "; $db="nom_de_ma_base"; $status=system("mysqldump --host=mysql5-1.perso --user=$_POST[login] --password=$_POST[password] $db > ../$db.sql"); echo $status; echo "Compression du fichier..... "; system("bzip2 -f ../$db.sql"); echo "C'est fini. Vous pouvez récupérer la base par FTP \n "; ?> Thanks!

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  • Learn Prolog Now! DCG Practice Example

    - by Timothy
    I have been progressing through Learn Prolog Now! as self-study and am now learning about Definite Clause Grammars. I am having some difficulty with one of the Practical Session's tasks. The task reads: The formal language anb2mc2mdn consists of all strings of the following form: an unbroken block of as followed by an unbroken block of bs followed by an unbroken block of cs followed by an unbroken block of ds, such that the a and d blocks are exactly the same length, and the c and d blocks are also exactly the same length and furthermore consist of an even number of cs and ds respectively. For example, ε, abbccd, and aaabbbbccccddd all belong to anb2mc2mdn. Write a DCG that generates this language. I am able to write rules that generate andn, b2mc2m, and even anb2m and c2mndn... but I can't seem to join all these rules into anb2mc2mdn. The following are my rules that can generate andn and b2mc2m. s1 --> []. s1 --> a,s1,d. a --> [a]. d --> [d]. s2 --> []. s2 --> c,c,s2,d,d. c --> [c]. d --> [d]. Is anb2mc2mdn really a CFG, and is it possible to write a DCG using only what was taught in the lesson (no additional arguments or code, etc)? If so, can anyone offer me some guidance how I can join these so that I can solve the given task?

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  • Protecting sensitive entity data

    - by Andreas
    Hi, I'm looking for some advice on architecture for a client/server solution with some peculiarities. The client is a fairly thick one, leaving the server mostly to peristence, concurrency and infrastructure concerns. The server contains a number of entities which contain both sensitive and public information. Think for example that the entities are persons, assume that social security number and name are sensitive and age is publicly viewable. When starting the client, the user is presented with a number of entities, not disclosing any sensitive information. At any time the user can choose to log in and authenticate against the server, given the authentication is successful the user is granted access to the sensitive information. The client is hosting a domain model and I was thinking of implementing this as some kind of "lazy loading", making the first request instantiating the entities and later refreshing them with sensitive data. The entity getters would throw exceptions on sensitive information when they've not been disclosed, f.e.: class PersonImpl : PersonEntity { private bool undisclosed; public override string SocialSecurityNumber { get { if (undisclosed) throw new UndisclosedDataException(); return base.SocialSecurityNumber; } } } Another more friendly approach could be to have a value object indicating that the value is undisclosed. get { if (undisclosed) return undisclosedValue; return base.SocialSecurityNumber; } Some concerns: What if the user logs in and then out, the sensitive data has been loaded but must be disclosed once again. One could argue that this type of functionality belongs within the domain and not some infrastructural implementation(i.e. repository implementations). As always when dealing with a larger number of properties there's a risk that this type of functionality clutters the code Any insights or discussion is appreciated!

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  • how to sort the items in listbox alphabetically?

    - by user2745378
    i need to sort the items alphabetically in listbox when sort button is clicked. (I have sort button in appbar). But I dunno how to achieve this. here is XAML. All help will be much appreciated. <phone:PhoneApplicationPage.Resources> <DataTemplate x:Key="ProjectTemplate"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="400" /> </Grid.ColumnDefinitions> <TextBlock Grid.Column="1" Text="{Binding Name}" Style="{StaticResource PhoneTextLargeStyle}" /> </Grid> </DataTemplate> </phone:PhoneApplicationPage.Resources> <Grid x:Name="ContentPanel" Grid.Row="1" Margin="0,0,12,0"> <ListBox x:Name="projectList" ItemsSource="{Binding Items}" SelectionChanged="ListBox_SelectionChanged" ItemTemplate="{StaticResource ProjectTemplate}" /> </Grid> Here's my ViewModel namespace PhoneApp.ViewModels { public class ProjectsViewModel: ItemsViewModelBase<Project> { public ProjectsViewModel(TaskDataContext taskDB) : base(taskDB) { } public override void LoadData() { base.LoadData(); var projectsInDB = _taskDB.Projects.ToList(); Items = new ObservableCollection<Project>(projectsInDB); } public override void AddItem(Project item) { _taskDB.Projects.InsertOnSubmit(item); _taskDB.SubmitChanges(); Items.Add(item); } public override void RemoveItem(int id) { var projects = from p in Items where p.Id == id select p; var item = projects.FirstOrDefault(); if (item != null) { var tasks = (from t in App.TasksViewModel.Items where t.ProjectId == item.Id select t).ToList(); foreach (var task in tasks) App.TasksViewModel.RemoveItem(task.Id); Items.Remove(item); _taskDB.Projects.DeleteOnSubmit(item); _taskDB.SubmitChanges(); } } } } I have added the ViewModel C# Code herewith

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  • how do I best create a set of list classes to match my business objects

    - by ken-forslund
    I'm a bit fuzzy on the best way to solve the problem of needing a list for each of my business objects that implements some overridden functions. Here's the setup: I have a baseObject that sets up database, and has its proper Dispose() method All my other business objects inherit from it, and if necessary, override Dispose() Some of these classes also contain arrays (lists) of other objects. So I create a class that holds a List of these. I'm aware I could just use the generic List, but that doesn't let me add extra features like Dispose() so it will loop through and clean up. So if I had objects called User, Project and Schedule, I would create UserList, ProjectList, ScheduleList. In the past, I have simply had these inherit from List< with the appropriate class named and then written the pile of common functions I wanted it to have, like Dispose(). this meant I would verify by hand, that each of these List classes had the same set of methods. Some of these classes had pretty simple versions of these methods that could have been inherited from a base list class. I could write an interface, to force me to ensure that each of my List classes has the same functions, but interfaces don't let me write common base functions that SOME of the lists might override. I had tried to write a baseObjectList that inherited from List, and then make my other Lists inherit from that, but there are issues with that (which is really why I came here). One of which was trying to use the Find() method with a predicate. I've simplified the problem down to just a discussion of Dispose() method on the list that loops through and disposes its contents, but in reality, I have several other common functions that I want all my lists to have. What's the best practice to solve this organizational matter?

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  • Will a Ph. D. in Computer Science help?

    - by Francisco Garcia
    I am close to my 30s and still learning about programming and software engineering. Like most people who like their profession I truly believe that I should aim to improve and keep updated. One of the things I do is reading technical papers from professional publications (IEEE and ACM) but I admit there are very good bloggers out there too. Lately I started to think (should I say realize?) that Ph. D people actually are expected to expand constantly their knowledge, but little is expected from lower classes once they know enough This made me think that maybe having a Ph. D will help to have more... respect? but I also believe that I am already getting old for that. Futhermore I see many master and doctor programs that does not seem to add any value over hard experience and self learning. I belive that a degree in computer science, althought not necessary, can lay out a good base for programming work. However: What can a Ph. D. degree give you that you cannot learn on your own? (if you are not into something VERY specific and want to work in a non academic environment)

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  • xmldocument and nested schemas

    - by Stuart
    Using c# and .net 3.5 I'm trying to validate an xml document against a schema that has includes. The schemas and there includes are as below Schema1.xsd - include another.xsd another.xsd - include base.xsd When i try to add the Schema1.xsd to the XmlDocument i get the following error. Type 'YesNoType' is not declared or is not a simple type. I believe i'm getting this error because the base.xsd file is not being included when i load the Schema1.xsd schema. I'm trying to use the XmlSchemaSet class and I'm setting the XmlResolver uri to the location of the schemas. NOTE : All schemas live under the same directory E:\Dev\Main\XmlSchemas Here is the code string schemaPath = "E:\\Dev\\Main\\XmlSchemas"; XmlDocument xmlDocSchema = new XmlDocument(); XmlSchemaSet s = new XmlSchemaSet(); XmlUrlResolver resolver = new XmlUrlResolver(); Uri baseUri = new Uri(schemaPath); resolver.ResolveUri(null, schemaPath); s.XmlResolver = resolver; s.Add(null, XmlReader.Create(new System.IO.StreamReader(schemaPath + "\\Schema1.xsd"), new XmlReaderSettings { ValidationType = ValidationType.Schema, XmlResolver = resolver }, new Uri(schemaPath).ToString())); xmlDocSchema.Schemas.Add(s); ValidationEventHandler valEventHandler = new ValidationEventHandler (ValidateNinoDobEvent); try { xmlDocSchema.LoadXml(xml); xmlDocSchema.Validate(valEventHandler); } catch (XmlSchemaValidationException xmlValidationError) { // need to interogate the Validation Exception, for possible further // processing. string message = xmlValidationError.Message; return false; } Can anyone point me in the right direction regarding validating an xmldocument against a schema with nested includes.

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  • Organising UI code in .NET forms

    - by sb3700
    Hi I'm someone who has taught myself programming, and haven't had any formal training in .NET programming. A while back, I started C# in order to develop a GUI program to control sensors, and the project has blossomed. I was just wondering how best to organise the code, particularly UI code, in my forms. My forms currently are a mess, or at least seem a mess to me. I have a constructor which initialises all the parameters and creates events. I have a giant State property, which updates the Enabled state of all my form control as users progress through the application (ie: disconnected, connected, setup, scanning) controlled by a States enum. I have 3-10 private variables accessed through properties, some of which have side-effects in changing the values of form elements. I have a lot of "UpdateXXX" functions to handle UI elements that depend on other UI elements - ie: if a sensor is changed, then change the baud rate drop down list. They are separated into regions I have a lot of events calling these Update functions I have a background worker which does all the scanning and analysis. My problem is this seems like a mess, particularly the State property, and is getting unmaintainable. Also, my application logic code and UI code are in the same file and to some degree, intermingled which seems wrong and means I need to do a lot of scrolling to find what I need. How do you structure your .net forms? Thanks

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  • Should we retire the term "Context"?

    - by MrGumbe
    I'm not sure if there is a more abused term in the world of programming than "Context." A word that has a very clear meaning in the English language has somehow morphed into a hot mess in software development, where the definition where the connotation can be completely different based on what library you happen to be developing in. Tomcat uses the word context to mean the configuration of a web application. Java applets, on the other hand, use an AppletContext to define attributes of the browser and HTML tag that launched it, but the BeanContext is defined as a container. ASP.NET uses the HttpContext object as a grab bag of state - containing information about the current request / response, session, user, server, and application objects. Context Oriented Programming defines the term as "Any information which is computationally accessible may form part of the context upon which behavioral variations depend," which I translate as "anything in the world." The innards of the Windows OS uses the CONTEXT structure to define properties about the hardware environment. The .NET installation classes, however, use the InstallContext property to represent the command line arguments entered to the installation class. The above doesn't even touch how all of us non-framework developers have used the term. I've seen plenty of developers fall into the subconscious trap of "I can't think of anything else to call this class, so I'll name it 'WidgetContext.'" Do you all agree that before naming our class a "Context," we may want to first consider some more descriptive terms? "Environment", "Configuraton", and "ExecutionState" come readily to mind.

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  • Find the order among tasks in a company by using prolog?

    - by Cem
    First of all,I wish a happy new year for everyone.I searched more and worked a lot but I could not solve this question.I am quite a new in prolog and I must do this homework. In my homework,the question is like this: Write a prolog program that determines a valid order for the tasks to be carried out in a company. The prolog program will consist of a set of "before" predicates which denotes the order between task pairs. Here is an example; before(a,b). before(a,e). before(d,c). before(b,c). before(c,e). Here, task a should be carried before tasks b and e, d before c and so on. Hence a valid ordering of the tasks would be [a, b, d, c, e]. The order predicate in your program will be queried as follows. ?- order([a,b,c,d,e],X). X = [a, b, d, c, e] ; X = [a, d, b, c, e] ; X = [d, a, b, c, e] ; false. Hint: Try to generate different orders for the tasks (permutation) and then check if the order is consistent with the "before" relationships given. Even if you can generate a single valid order, you will get reasonable partial credits.

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