Search Results

Search found 12001 results on 481 pages for 'naked objects'.

Page 201/481 | < Previous Page | 197 198 199 200 201 202 203 204 205 206 207 208  | Next Page >

• Windows 7 versus Windows XP multithreading - Delphi app not acting right

  - by Robert Oschler

  I'm having a problem with a Delphi Pro 6 application that I wrote on my Windows XP machine when it runs on Windows 7. I don't have Windows 7 to test yet and I'm trying to see if Windows 7 might be the source of the trouble. Is there a fundamental difference between the way Windows 7 handles threads compared to Windows XP? I am seeing things happen out of sequence in my error logs on Windows 7 and it's causing problems. For example, objects that should have been initialized are uninitialized when running on Windows 7, yet those objects are initialized on Windows XP by the time they are needed. Some questions: 1) Are there any core differences that could cause threads/processes to behave differently between the two operating system versions? 2) I know this next question may seem absurd, but does Windows 7 attempt to split/fork threads that aren't split/forked on Windows XP? 3) And lastly, are there any known issues with FPU handling that can cause XP programs trouble when run on Windows 7 due to operational differences in wait state handling or register storage, or perhaps something like Exception mask settings, etc? 4) Any 32-bit versus 64-bit issues that could be creating trouble here? -- roschler

  Read the article

• How should rules for Aggregate Roots be enforced?

  - by MylesRip

  While searching the web, I came across a list of rules from Eric Evans' book that should be enforced for aggregates: The root Entity has global identity and is ultimately responsible for checking invariants Root Entities have global identity. Entities inside the boundary have local identity, unique only within the Aggregate. Nothing outside the Aggregate boundary can hold a reference to anything inside, except to the root Entity. The root Entity can hand references to the internal Entities to other objects, but they can only use them transiently (within a single method or block). Only Aggregate Roots can be obtained directly with database queries. Everything else must be done through traversal. Objects within the Aggregate can hold references to other Aggregate roots. A delete operation must remove everything within the Aggregate boundary all at once When a change to any object within the Aggregate boundary is committed, all invariants of the whole Aggregate must be satisfied. This all seems fine in theory, but I don't see how these rules would be enforced in the real world. Take rule 3 for example. Once the root entity has given an exteral object a reference to an internal entity, what's to keep that external object from holding on to the reference beyond the single method or block? (If the enforcement of this is platform-specific, I would be interested in knowing how this would be enforced within a C#/.NET/NHibernate environment.)

  Read the article

• How can I refactor this to work without breaking the pattern horribly?

  - by SnOrfus

  I've got a base class object that is used for filtering. It's a template method object that looks something like this. public class Filter { public void Process(User u, GeoRegion r, int countNeeded) { List<account> selected = this.Select(u, r, countNeeded); // 1 List<account> filtered = this.Filter(selected, u, r, countNeeded); // 2 if (filtered.Count > 0) { /* do businessy stuff */ } // 3 if (filtered.Count < countNeeded) this.SendToSuccessor(u, r, countNeeded - filtered) // 4 } } Select(...), Filter(...) are protected abstract methods and implemented by the derived classes. Select(...) finds objects in the based on x criteria, Filter(...) filters those selected further. If the remaining filtered collection has more than 1 object in it, we do some business stuff with it (unimportant to the problem here). SendToSuccessor(...) is called if there weren't enough objects found after filtering (it's a composite where the next class in succession will also be derived from Filter but have different filtering criteria) All has been ok, but now I'm building another set of filters, which I was going to subclass from this. The filters I'm building however would require different params and I don't want to just implement those methods and not use the params or just add to the param list the ones I need and have them not used in the existing filters. They still perform the same logical process though. I also don't want to complicated the consumer code for this (which looks like this) Filter f = new Filter1(); Filter f2 = new Filter2(); Filter f3 = new Filter3(); f.Sucessor = f2; f2.Sucessor = f3; /* and so on adding filters as successors to previous ones */ foreach (User u in users) { foreach (GeoRegion r in regions) { f.Process(u, r, ##); } } How should I go about it?

  Read the article

• Deserialize json with json.net c#

  - by 76mel

  Hi, am new to Json so a little green. I have a Rest Based Service that returns a json string; {"treeNode":[{"id":"U-2905","pid":"R","userId":"2905"}, {"id":"U-2905","pid":"R","userId":"2905"}]} I have been playing with the Json.net and trying to Deserialize the string into Objects etc. I wrote an extention method to help. public static T DeserializeFromJSON<T>(this Stream jsonStream, Type objectType) { T result; using (StreamReader reader = new StreamReader(jsonStream)) { JsonSerializer serializer = new JsonSerializer(); try { result = (T)serializer.Deserialize(reader, objectType); } catch (Exception e) { throw; } } return result; } I was expecting an array of treeNode[] objects. But its seems that I can only deserialize correctly if treeNode[] property of another object. public class treeNode { public string id { get; set; } public string pid { get; set; } public string userId { get; set; } } I there a way to to just get an straight array from the deserialization ? Cheers

  Read the article

• Animate and form rows, arrays, AS3

  - by VideoDnd

  Question How can I animate and form rows together? Explanation One 'for loop' is for animation, the other 'for loop' is for making rows. I want to understand how to use arrays and create a row of sprite animations. 'for loop' for animation //FRAMES ARRAY //THIS SETS UP MY ANIMATION FOR TIMER EVENT var frames:Array = [ new Frame1(), new Frame2(), new Frame3(), new Frame4(), new Frame5(), new Frame6(), new Frame7(), new Frame8(), new Frame9(), new Frame0(), ]; for each (var frame:Sprite in frames) { addChild(frame); } 'for loop' for rows //THIS MAKES A ROW OF DISPLAY OBJECTS var numberOfClips:Number = 11; var xStart:Number = 0; var yStart:Number = 0; var xVal:Number = xStart; var xOffset:Number = 2; for (var $:Number=0; $<numberOfClips; $++) { //DUDE ARRAY var dude:Array = frames; dude.y = yStart +11; dude.x = xVal +55; xVal = dude.x + dude.width + this.xOffset; } timer var timer:Timer = new Timer(100); timer.addEventListener(TimerEvent.TIMER, countdown); function countdown(event:TimerEvent) { var currentFrame:int = timer.currentCount % frames.length; for (var i:int = 0; i < frames.length; ++i) { frames[i].visible = (i == currentFrame); } } timer.start(); counter experiment My new class I'm working on loops through 10 different display objects that are numbers. For those following, I'm trying to make something like NumbersView.

  Read the article

• object / class methods serialized as well?

  - by Mat90

  I know that data members are saved to disk but I was wondering whether object's/class' methods are saved in binary format as well? Because I found some contradictionary info, for example: Ivor Horton: "Class objects contain function members as well as data members, and all the members, both data and functions, have access specifiers; therefore, to record objects in an external file, the information written to the file must contain complete specifications of all the class structures involved." and: Are methods also serialized along with the data members in .NET? Thus: are method's assembly instructions (opcodes and operands) stored to disk as well? Just like a precompiled LIB or DLL? During the DOS ages I used assembly so now and then. As far as I remember from Delphi and the following site (answer by dan04): Are methods also serialized along with the data members in .NET? sizeof(<OBJECT or CLASS>) will give the size of all data members together (no methods/procedures). Also a nice C example is given there with data and members declared in one class/struct but at runtime these methods are separate procedures acting on a struct of data. However, I think that later class/object implementations like Pascal's VMT may be different in memory.

  Read the article

• How to filter Many2Many / Generic Relations properly with Q?

  - by HWM-Rocker

  Hi, I have 3 Models, the TaggedObject has a GenericRelation with the ObjectTagBridge. And the ObjectTagBridge has a ForeignKey to the Tag Model. class TaggedObject(models.Model): """ class that represent a tagged object """ tags = generic.GenericRelation('ObjectTagBridge', blank=True, null=True) class ObjectTagBridge(models.Model): """ Help to connect a generic object to a Tag. """ # pylint: disable-msg=W0232,R0903 content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') tag = models.ForeignKey('Tag') class Tag(models.Model): ... when I am attaching a Tag to an Object, I am creating a new ObjectTagBridge and set its ForeignKey tag to the Tag I want to attach. That is working fine, and I can get all Tags that I attached to my Object very easy. But when I want to get (filter) all Objects that have Tag1 and Tag2 I tried to something like this: query = Q(tags__tag=Tag1) & Q(tags__tag=Tag2) object_list = TaggedObjects.filter(query) but now my object_list is empty, because it is looking for TaggedObjects that have one ObjectTagBridge with 2 tag objects, the first with Tag1 and the second with Tag2. I my application will be more complex Q queries than this one, so I think I need a solution with this Q object. In fact any combination of binary conjunctions, like: (...) and ( (...) or not(...)) How can I filter this correctly? Every answer is welcome, maybe there is also a different way do achieve this. thx for your help!!!

  Read the article

• Getting Outlook calendar items based on subject

  - by EKS

  I'm trying to get a list of calendar objects from exchange and sorting them based on subject. The part of of getting the objects just based on date and sorting out via subject is in "code" is now working, but i want to do a sort on subject in the "sql" first, but im unable to make it work ( Currently getting error from exchange saying the query is wrong. The line I added is: + "AND lcase(\"urn:schemas:calendar:subject\") = 'onsite%' " What I want is the ability to catch all appointments that start with onsite, both in upper and lower case. strQuery = "<?xml version=\"1.0\"?>" + "<g:searchrequest xmlns:g=\"DAV:\">" + "<g:sql>SELECT \"urn:schemas:calendar:location\", \"urn:schemas:httpmail:subject\", " + "\"urn:schemas:calendar:dtstart\", \"urn:schemas:calendar:dtend\", " + "\"urn:schemas:calendar:busystatus\", \"urn:schemas:calendar:instancetype\" " + "FROM Scope('SHALLOW TRAVERSAL OF \"" + strCalendarURI + "\"') " + "WHERE NOT \"urn:schemas:calendar:instancetype\" = 1 " + "AND \"DAV:contentclass\" = 'urn:content-classes:appointment' " + "AND \"urn:schemas:calendar:dtstart\" > '2003/06/01 00:00:00' " //'" + DateString + "'" + "AND lcase(\"urn:schemas:calendar:subject\") = 'onsite' " + "ORDER BY \"urn:schemas:calendar:dtstart\" ASC" + "</g:sql></g:searchrequest>";

  Read the article

• Sync two SqlExpress using NHibernate

  - by Christian

  Hello, I am creating a simple project management system which uses NHibernate for object storage. The underlying database is SQL express (at least currently for development). The client runs on either the desktop or laptop. I know I could use web-services and store the DB only on the desktop, but this would force the desktop to be available all the time. I am currently thinking about duplicating the DB, having two instances with "different data". To clarify, we are not talking about a productive app here, its a prototype. One way to achieve this very simple would be the following process: Client: Check if desktop DB is available (through web service) Client: If yes, use desktop storage, no problem here Client: If not, use own DB as storage Client: Poll desktop regulary, as soon as it comes on, sync Client: Switch to desktop storage ... Desktop: Do not attempt any DB operation before checking for required sync Desktop: If sync needed, do it... My question is now, how would you sync? Assume 4 or 5 types of objects, all have GUID as identifiers. Would you always manually "lazy load" all objects of a certain type and feed them to the DB. Would you always drop the whole desktop DB in case the client DB may be newer and out of sync? Again, I want to stress out, I am not assuming any conflicts or stale data, I basically just want to "copy the whole DB from the client". Would you use NHibernate for this? Or would you separate the copy process? When I think about it, my questions comes down to this: Is there any function from NHibernate: SyncDBs_SourceWins_(SourceDB, TargetDB) Thanks for help, Chris

  Read the article

• Style first 2 TextViews in Android ListView differently

  - by Kurtis Nusbaum

  I have a ListView and I want the first two entries in it to be displayed differently than the rest. Nothing fancy, I want them all to just be text views. But the first two entries need to have different sizes and weights than the rest. I tried modifying the ArrayAdapter class like so: private class BusStopAdapter<T> extends ArrayAdapter<T>{ public BusStopAdapter( Context context, int textViewResourceId, List<T> objects) { super(context, textViewResourceId, objects); } public View getView(int position, View convertView, ViewGroup parent) { TextView toReturn = (TextView)super.getView(position, convertView, parent); if(position == 0){ toReturn.setTextSize(12); toReturn.setText("Previous Bus: " + toReturn.getText()); toReturn.setPadding(0,0,0,0); } else if(position == 1){ toReturn.setTextSize(20); toReturn.setPadding( toReturn.getPaddingLeft(), 0, toReturn.getPaddingRight(), 0 ); toReturn.setText("Next Bus: " + toReturn.getText()); toReturn.setGravity(Gravity.CENTER_HORIZONTAL|Gravity.TOP); } return toReturn; } } But this inadvertantly causes some of the other textviews to take on these special attributes. I think it's because cause textviews get "recycled" in the AbsListAdapter class.

  Read the article

• Dynamic Auto updating (to UI, Grid) binding list in C# Winform?

  - by Dhana

  I'm not even sure if i'm doing this correctly. But basically I have a list of objects that are built out of a class/interface. From there, I am binding the list to a datagrid view that is on a Windows Form (C#) Here the list is a Sync list which will auto update the UI, in this case datagridview. Every thing works fine now, but now i would like to have the List should have an dynamic object, that is the object will have by default two static property (ID, Name), and at run time user will select remaining properties. These should be bind to the data grid. Any update on the list should be auto reflected in the grid. I am aware that, we can use dynamic objects, but i would like to know , how to approach for solution, datagridview.DataSource = myData; // myData is AutoUpdateList<IPersonInfo> Now IPersonInfo is the type of object, need to add dynamic properties for this type at runtime. public class AutoUpdateList<T> : System.ComponentModel.BindingList<T> { private System.ComponentModel.ISynchronizeInvoke _SyncObject; private System.Action<System.ComponentModel.ListChangedEventArgs> _FireEventAction; public AutoUpdateList() : this(null) { } public AutoUpdateList(System.ComponentModel.ISynchronizeInvoke syncObject) { _SyncObject = syncObject; _FireEventAction = FireEvent; } protected override void OnListChanged(System.ComponentModel.ListChangedEventArgs args) { try { if (_SyncObject == null) { FireEvent(args); } else { _SyncObject.Invoke(_FireEventAction, new object[] { args }); } } catch (Exception) { // TODO: Log Here } } private void FireEvent(System.ComponentModel.ListChangedEventArgs args) { base.OnListChanged(args); } } Could you help out on this?

  Read the article

• Static Variables somehow maintaining state?

  - by gfoley

  I am working on an existing project, setup by another coder. I'm having some trouble understanding how state is being maintained between pages. There is a Class library which has some helper objects. Mostly these objects are just used for there static methods and rarely instantiated or inherited. This is an example class I'm testing with. public sealed class Application { public static string Test; } Now when i run something like the following in the base class of my page, I would expect the result to be "1: 2:Test" all the time (note that "1" is empty), but strangly its only this way the first time it is run. Then every time afterwards its "1:Test 2:Test". Somehow its maintaining the state of the static variable between pages and being refreshed?? Response.Write("1:" + SharedLibrary.Application.Test); SharedLibrary.Application.Test = "Test"; Response.Write(" 2:" + SharedLibrary.Application.Test); I need to create more classes like this, but want to understand why this is occurring in the first place. Many Thanks

  Read the article

• How to provide an inline model field with a queryset choices without losing field value for inline r

  - by Judith Boonstra

  The code displayed below is providing the choices I need for the app field, and the choices I need for the attr field when using Admin. I am having a problem with the attr field on the inline form for already saved records. The attr selected for these saved does show in small print above the field, but not within the field itself. # MODELS: Class Vocab(models.Model): entity = models.Charfield, max_length = 40, unique = True) Class App(models.Model): name = models.ForeignKey(Vocab, related_name = 'vocab_appname', unique = True) app = SelfForeignKey('self, verbose_name = 'parent', blank = True, null = True) attr = models.ManyToManyField(Vocab, related_name = 'vocab_appattr', through ='AppAttr' def parqs(self): a method that provides a queryset consisting of available apps from vocab, excluding self and any apps within the current app's dependent line. def attrqs(self): a method that provides a queryset consisting of available attr from vocab excluding those already selected by current app, 2) those already selected by any apps within the current app's parent line, and 3) those selected by any apps within the current app's dependent line. Class AppAttr(models.Model): app = models.ForeignKey(App) attr = models.ForeignKey(Vocab) # FORMS: from models import AppAttr def appattr_form_callback(instance, field, *args, **kwargs) if field.name = 'attr': if instance: return field.formfield(queryset = instance.attrqs(), *kwargs) return field.formfield(*kwargs) # ADMIN: necessary imports class AppAttrInline(admin.TabularInline): model = AppAttr def get_formset(self, request, obj = None, **kwargs): kwargs['formfield_callback'] = curry(appattr_form_callback, obj) return super(AppAttrInline, self).get_formset(request, obj, **kwargs) class AppForm(forms.ModelForm): class Meta: model = App def __init__(self, *args, **kwargs): super(AppForm, self).__init__(*args, **kwargs) if self.instance.id is None: working = App.objects.all() else: thisrec = App.objects.get(id = self.instance.id) working = thisrec.parqs() self.fields['par'].queryset = working class AppAdmin(admin.ModelAdmin): form = AppForm inlines = [AppAttrInline,] fieldsets = .......... necessary register statements

  Read the article

• Are there any downsides in using C++ for network daemons?

  - by badcat

  Hey guys! I've been writing a number of network daemons in different languages over the past years, and now I'm about to start a new project which requires a new custom implementation of a properitary network protocol. The said protocol is pretty simple - some basic JSON formatted messages which are transmitted in some basic frame wrapping to have clients know that a message arrived completely and is ready to be parsed. The daemon will need to handle a number of connections (about 200 at the same time) and do some management of them and pass messages along, like in a chat room. In the past I've been using mostly C++ to write my daemons. Often with the Qt4 framework (the network parts, not the GUI parts!), because that's what I also used for the rest of the projects and it was simple to do and very portable. This usually worked just fine, and I didn't have much trouble. Being a Linux administrator for a good while now, I noticed that most of the network daemons in the wild are written in plain C (of course some are written in other languages, too, but I get the feeling that 80% of the daemons are written in plain C). Now I wonder why that is. Is this due to a pure historic UNIX background (like KISS) or for plain portability or reduction of bloat? What are the reasons to not use C++ or any "higher level" languages for things like daemons? Thanks in advance! Update 1: For me using C++ usually is more convenient because of the fact that I have objects which have getter and setter methods and such. Plain C's "context" objects can be a real pain at some point - especially when you are used to object oriented programming. Yes, I'm aware that C++ is a superset of C, and that C code is basically C++. But that's not the point. ;)

  Read the article

• Sending a JSON object to an ASP.NET web service using JQUERY ajax function

  - by uzay95

  I want to create object on the client side of aspx page. And i want to add functions to these javascript classes to make easier the life. Actually i can get and use the objects (derived from the server side classes) which returns from the services. When i wanted to send objects from the client by jquery ajax methods, i couldn't do it :) This is my javascript object: function ClassAndMark(_mark, _lesson){ this.Lesson = _lesson; this.Mark = _mark; } function Student(_name, _surname, _classAndMark){ this.Name = _name; this.SurName = _surname; this.ClassAndMark = _classAndMark; } JSClass.prototype.fSaveToDB(){ $.ajax({ type: "POST", contentType: "application/json; charset=utf-8", url: "/WS/SaveObject.asmx/fSaveToDB"), data: ????????????, dataType: "json" }); } Actually i don't know what should be definition of classes and methods on the Server side but i think: class ClassAndMark{ public string Lesson ; public string Mark ; } class Student{ public string Name ; public string SurName ; public ClassAndMark ClassAndMark ; } Web service is below but again i couldn't get what should be instead of the ???? : [WebMethod()] public void fSaveToDB(???? _obj) { // How can i convert input parameter/parameters // of method in the server side object? }

  Read the article

• Android: CustomListAdapter

  - by primal

  Hi, I have implemented a custom list view which looks like the twitter timeline. adapter = new MyClickableListAdapter(this, R.layout.timeline, mObjectList); setListAdapter(adapter); The constructor for MyClickableListAdapter is as follows private class MyClickableListAdapter extends ClickableListAdapter{ public MyClickableListAdapter(Context context, int viewId, List objects) { super(context, viewId, objects); } ClickableListAdapter extends BaseAdapter and implements the necessary methods. The xml code for the list view is as follows <ListView android:id="@+id/android:list" android:layout_width="fill_parent" android:layout_height="wrap_content" /> This is what it looks like. I have 3 questions 1) I tried registering a context menu for the list view by adding the line after setting the list adapter registerforContextMenu(getListView()); But on long-click the menu doesnt get displayed. I cannot understand what I am doing wrong! 2) Is it possible to display a textview above the listview? I tried it by adding the code for textview above the listview. But then, only the textview gets displayed. 3) I have seen in many twitter clients that on clicking post a window pops up from the top covering only some portion of the screen and rest of the timeline is visible. How can this be done possibly without starting a new activity? Any help would be much appreciated..

  Read the article

• What's the difference between DI and factory patterns?

  - by Anthony Short

  I have a class which depends on 3 classes, all 3 of which have other classes they rely on. Currently, I'm using a container class to build up all the required classes, inject them into one another and return the application. The simplified version of the container looks something like this: class Builder { private $_options; public function __construct($options) { $this->_options = $options; } public function build() { $cache = $this->getCache(); $response = $this->getResponse(); $engine = $this->getEngine(); return new Application($cache,$response,$engine); } public function getResponse() { $encoder = $this->getResponseEncoder(); $cache = $this->getResponseCache(); return new Response($encoder,$cache); } // Methods for building each object } I'm not sure if this would be classified as FactoryMethod or a DI Container. They both seem to solve the same problem in the same way - They build objects and inject dependencies. This container has some more complicated building methods, like loading observers and attaching them to observable objects. Should factories be doing all the building (loading extensions etc) and the DI container should use these factories to inject dependencies? That way the sub-packages, like Cache, Response etc, can each have their own specialised factories.

  Read the article

• c++ struct size

  - by kiokko89

  struct CExample { int a; } int main(int argc, char* argv[]) { CExample ce; CExample ce2; cout << "Size:" << sizeof(ce)<< " Address: "<< &ce<< endl; cout << "Size:" << sizeof(ce2)<< " Address: "<< &ce2 << endl; CExample ceArr[2]; cout << "Size:" << sizeof(ceArr[0])<< " Address: "<<&ceArr[0]<<endl; cout << "Size:" << sizeof(ceArr[1])<< " Address: "<<&ceArr[1]<<endl; return 0; } Excuse me I'm just a beginner but i'd like to know why with this code, there is a difference of 12 bytes between the addresses of the first two objects(ce and ce2) (i thought about data allignment), but there is only a difference of 4 bytes between the two objects in the array. Sorry for my bad English...

  Read the article

• Returning XML natively in a .NET (C#) webservice?

  - by James McMahon

  I realize that SOAP webservices in .NET return XML representation of whatever object the web method returns, but if I want to return data formatting in XML what is the best object to store it in? I am using the answer to this question to write my XML, here is the code: XmlWriter writer = XmlWriter.Create(pathToOutput); writer.WriteStartDocument(); writer.WriteStartElement("People"); writer.WriteStartElement("Person"); writer.WriteAttributeString("Name", "Nick"); writer.WriteEndElement(); writer.WriteStartElement("Person"); writer.WriteStartAttribute("Name"); writer.WriteValue("Nick"); writer.WriteEndAttribute(); writer.WriteEndElement(); writer.WriteEndElement(); writer.WriteEndDocument(); writer.Flush(); Now I can return this output as a String to my calling webmethod, but it shows up as <string> XML HERE </string>, is there anyway to just return the full xml? Please in your answer, give an example of how to use said object with either XmlWriter or another internal object (if you consider XmlWriter to be a poor choice). The System.Xml package (namespace) has many objects, but I haven't been able to uncover decent documentation on how to use the objects together, or what to use for what situations.

  Read the article

• Django: Determining if a user has voted or not

  - by TheLizardKing

  I have a long list of links that I spit out using the below code, total votes, submitted by, the usual stuff but I am not 100% on how to determine if the currently logged in user has voted on a link or not. I know how to do this from within my view but do I need to alter my below view code or can I make use of the way templates work to determine it? I have read http://stackoverflow.com/questions/1528583/django-vote-up-down-method but I don't quite understand what's going on ( and don't need any ofjavascriptery). Models (snippet): class Link(models.Model): category = models.ForeignKey(Category, blank=False, default=1) user = models.ForeignKey(User) created = models.DateTimeField(auto_now_add=True) modified = models.DateTimeField(auto_now=True) url = models.URLField(max_length=1024, unique=True, verify_exists=True) name = models.CharField(max_length=512) def __unicode__(self): return u'%s (%s)' % (self.name, self.url) class Vote(models.Model): link = models.ForeignKey(Link) user = models.ForeignKey(User) created = models.DateTimeField(auto_now_add=True) def __unicode__(self): return u'%s vote for %s' % (self.user, self.link) Views (snippet): def hot(request): links = Link.objects.select_related().annotate(votes=Count('vote')).order_by('-created') for link in links: delta_in_hours = (int(datetime.now().strftime("%s")) - int(link.created.strftime("%s"))) / 3600 link.popularity = ((link.votes - 1) / (delta_in_hours + 2)**1.5) if request.user.is_authenticated(): try: link.voted = Vote.objects.get(link=link, user=request.user) except Vote.DoesNotExist: link.voted = None links = sorted(links, key=lambda x: x.popularity, reverse=True) links = paginate(request, links, 15) return direct_to_template( request, template = 'links/link_list.html', extra_context = { 'links': links, }) The above view actually accomplishes what I need but in what I believe to be a horribly inefficient way. This causes the dreaded n+1 queries, as it stands that's 33 queries for a page containing just 29 links while originally I got away with just 4 queries. I would really prefer to do this using Django's ORM or at least .extra(). Any advice?

  Read the article

• Is there a way to automatically load navigational property using the .NET Entity Framework?

  - by René Wolferink

  Stepping away more and more from writing SQL for my applications, I decided to give the Entity Framework a try. However, I've run into something I believe is causing me to write more code than I think is strictly necessary. When I accessed some navigational properties, I discovered that all many-to-one relations (simple references) were null and all one-to-many and many-to-many relations (EntityCollections) were empty. For example: I have a User with a reference to a Group. When I have retieved a User, by using a simple select-by-id, the Group property is null. If I want to access the Group I have to manually load it (using User.GroupReference.Load()). So I added a GetGroup() method in User which checks whether the Group is loaded already and, if not, does so and then returns the Group. Now this will result in a lot of highly similar methods for all navigational properties. And it all results in the navigational properties not being used, only my custom-made Get"PropertyName"() method's are now being used. I don't want to expand my queries (linq to entities) to immediately load all these properties, because it's not always known at first what is needed. And besides, it would cause a lot of queries to have to be made. Is there a way to configure the Entity Framework to load these objects when they happen to not be present? So when I access User.Group and the group is not loaded yet, it is loaded automatically? Or am I stuck using my own Get"PropertyName"() method's as long as I'm trying to load objects only on demand (or "just-in-time")? Some extra info: I'm using VS2008 SP1 with .NET 3.5 SP1. The Entity Framework I'm using is the one that got shipped with it.

  Read the article

• WPF DataGrid populating blank rows on TreeView's SelectedItemChanged

  - by jes9582

  When my DataGrid populates on the TreeView's SelectedItemChanged event it finds the objects and creates the rows accordingly but the rows populate with no text or are just blank. So I know it is finding my objects but it is not displaying them properly. Does anyone see where I made an error or suggest any changes or fixes? Thank you in advance! Here is the CSharp code that is setting the DataGrid's ItemsSource (I am using .dbml and LINQ with Lambda expressions): dgSystemSettings.ItemsSource = (tvSystemConfiguration.SelectedItem as SYSTEM_SETTINGS_GROUP).SYSTEM_SETTINGS_NAMEs.Join(ssdc.SYSTEM_SETTINGS_VALUEs, x => x.SSN_ID, y => y.SSV_SSN_ID, (x, y) => new { SYSTEM_SETTINGS_NAME = x, SYSTEM_SETTINGS_VALUE = y }); And here is the .xaml: <DataGrid Name="dgSystemSettings" AutoGenerateColumns="False" Height="447" Width="513" DockPanel.Dock="Right" ItemsSource="{Binding}" VerticalAlignment="Top" Margin="10,10,0,0"> <DataGrid.Columns> <DataGridTextColumn x:Name="colDisplayName" Header="Name" Binding="{Binding SSN_DISPLAY_NAME}"></DataGridTextColumn> <DataGridTextColumn x:Name="colValue" Header="Value" Binding="{Binding SSV_VALUE}"></DataGridTextColumn> </DataGrid.Columns> </DataGrid>

  Read the article

• 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).

  Read the article

• Which class should store the lookup table?

  - by max

  The world contains agents at different locations, with only a single agent at any location. Each agent knows where he's at, but I also need to quickly check if there's an agent at a given location. Hence, I also maintain a map from locations to agents. I have a problem deciding where this map belongs to: class World, class Agent (as a class attribute) or elsewhere. In the following I put the lookup table, agent_locations, in class World. But now agents have to call world.update_agent_location every time they move. This is very annoying; what if I decide later to track other things about the agents, apart from their locations - would I need to add calls back to the world object all across the Agent code? class World: def __init__(self, n_agents): # ... self.agents = {} self.agent_locations = {} for id in range(n_agents): x, y = self.find_location() agent = Agent(self,x,y) self.agents.append(agent) self.agent_locations[x,y] = agent def update_agent_location(self, agent, x, y): del self.agent_locations[agent.x, agent.y] self.agent_locations[x, y] = agent def update(self): # next step in the simulation for agent in self.agents: agent.update() # next step for this agent # ... class Agent: def __init__(self, world, x, y): self.world = world self.x, self.y = x, y def move(self, x1, y1): self.world.update_agent_location(self, x1, y1) self.x, self.y = x1, y1 def update(): # find a good location that is not occupied and move there for x, y in self.valid_locations(): if not self.location_is_good(x, y): continue if self.world.agent_locations[x, y]: # location occupied continue self.move(x, y) I can instead put agent_locations in class Agent as a class attribute. But that only works when I have a single World object. If I later decide to instantiate multiple World objects, the lookup tables would need to be world-specific. I am sure there's a better solution... EDIT: I added a few lines to the code to show how agent_locations is used. Note that it's only used from inside Agent objects, but I don't know if that would remain the case forever.

  Read the article

• Sharing same properties of ViewController for iPhone Stroryboard and iPad Story Board

  - by Ruhul Amin

  I'm developing a universal application. in the first view, I have the login screen for the user. In iPhone storyBoard, I have added 2 text field and one button( login check). I have added properties in ViewController.h file by dragging those objects(Ctrl key + Dragg) to .h file. I have added code for login check and it is working fine for iPhone. This is the code in ViewController.h @property (strong, nonatomic) IBOutlet UITextField *txtUserId; @property (strong, nonatomic) IBOutlet UITextField *txtUserPwd; @property (strong, nonatomic) IBOutlet UIButton *btnLogin; In the iPad storyBoard, I have added 2 text field( userid and password) and i button for login. So now, I want to bind those objects with the veriable which I declared already in ViewController.h file in case of iPhone. My questions: 1. What is the right way to bind properties for both storyboard? 2. Am I on the right direction or should I think in a different way to do it? I am new with iPhone development. Please help. Thanks. --Amin

  Read the article

< Previous Page | 197 198 199 200 201 202 203 204 205 206 207 208  | Next Page >