Search Results

Search found 17163 results on 687 pages for 'extension objects'.

Page 298/687 | < Previous Page | 294 295 296 297 298 299 300 301 302 303 304 305  | Next Page >

  • NoSuchMethodError in Java using XStream

    - by Brad Germain
    I'm trying to save a database into a file using XStream and then open it again later using XStream and deserialize it back into the objects it was in previously. The database consists of an arraylist of tables, which consists of an arraylist of a data class where the data class contains an arraylist of objects. I'm basically trying to create an sql compiler. I'm currently getting a java.lang.NoSuchMethodError because of the last line in the load method. Here's what I have: Save Method public void save(Database DB){ File file = new File(DB.getName().toUpperCase() + ".xml"); //Test sample DB.createTable("TBL1(character(a));"); DB.tables.getTable("TBL1").rows.add(new DataList()); DB.tables.getTable("TBL1").rows.getRow(0).add(10); XStream xstream = new XStream(); //Database xstream.alias("Database", Database.class); //Tables xstream.alias("Table", Table.class); //Rows xstream.alias("Row", DataList.class); //Data //xstream.alias("Data", Object.class); //String xml = xstream.toXML(DB); Writer writer = null; try { writer = new FileWriter(file); writer.write(xstream.toXML(DB)); writer.close(); } catch (IOException e) { e.printStackTrace(); } } Load Method public void Load(String dbName){ XStream xstream = new XStream(); BufferedReader br; StringBuffer buff = null; try { br = new BufferedReader(new FileReader(dbName + ".xml")); buff = new StringBuffer(); String line; while((line = br.readLine()) != null){ buff.append(line); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } database = (Database)xstream.fromXML(buff.toString()); }

    Read the article

  • (C#) Get index of current foreach iteration

    - by Graphain
    Hi, Is there some rare language construct I haven't encountered (like the few I've learned recently, some on Stack Overflow) in C# to get a value representing the current iteration of a foreach loop? For instance, I currently do something like this depending on the circumstances: int i=0; foreach (Object o in collection) { ... i++; } Answers: @bryansh: I am setting the class of an element in a view page based on the position in the list. I guess I could add a method that gets the CSSClass for the Objects I am iterating through but that almost feels like a violation of the interface of that class. @Brad Wilson: I really like that - I've often thought about something like that when using the ternary operator but never really given it enough thought. As a bit of food for thought it would be nice if you could do something similar to somehow add (generically to all IEnumerable objects) a handle on the enumerator to increment the value that an extension method returns i.e. inject a method into the IEnumerable interface that returns an iterationindex. Of course this would be blatant hacks and witchcraft... Cool though... @crucible: Awesome I totally forgot to check the LINQ methods. Hmm appears to be a terrible library implementation though. I don't see why people are downvoting you though. You'd expect the method to either use some sort of HashTable of indices or even another SQL call, not an O(N) iteration... (@Jonathan Holland yes you are right, expecting SQL was wrong) @Joseph Daigle: The difficulty is that I assume the foreach casting/retrieval is optimised more than my own code would be. @Jonathan Holland: Ah, cheers for explaining how it works and ha at firing someone for using it.

    Read the article

  • Is there added overhead to looking up a column in a DataTable by name rather than by index?

    - by Ben McCormack
    In a DataTable object, is there added overhead to looking up a column value by name thisRow("ColumnA") rather than by the column index thisRow(0)? In which scenarios might this be an issue. I work on a team that has lots of experience writing VB6 code and I noticed that didn't do column lookups by name for DataTable objects or data grids. Even in .NET code, we use a set of integer constants to reference column names in these types of objects. I asked our team lead why this was so, and he mentioned that in VB6, there was a lot of overhead in looking up data by column name rather than by index. Is this still true for .NET? Example code (in VB.NET, but same applies to C#): Public Sub TestADOData() Dim dt As New DataTable 'Set up the columns in the DataTable ' dt.Columns.Add(New DataColumn("ID", GetType(Integer))) dt.Columns.Add(New DataColumn("Name", GetType(String))) dt.Columns.Add(New DataColumn("Description", GetType(String))) 'Add some data to the data table ' dt.Rows.Add(1, "Fred", "Pitcher") dt.Rows.Add(3, "Hank", "Center Field") 'Method 1: By Column Name ' For Each r As DataRow In dt.Rows Console.WriteLine( _ "{0,-2} {1,-10} {2,-30}", r("ID"), r("Name"), r("Description")) Next Console.WriteLine() 'Method 2: By Column Name ' For Each r As DataRow In dt.Rows Console.WriteLine("{0,-2} {1,-10} {2,-30}", r(0), r(1), r(2)) Next End Sub Is there an case where method 2 provides a performance advantage over method 1?

    Read the article

  • Core-data: when accessing a relationship, the count method on NSSet fails

    - by lordsandwich
    I'm trying to access a relationship (one to many) programatically. My Data model contains an NSManagedEntity called language (with a two string attributes) with a relationship to an entity called WordCategory (one-to-many). I use an NSFetchRequest to get all the Language entities. that works fine. I get the valueForKey for the relationship and that works fine. I can work with its objects. However, when I try to send the message count to the NSSet that stores the WordCategory objects I get a In other words, this line works: NSLog(@"word category count %@",[[wordCategory anyObject] valueForKey:@"name"]); This one doesn't: NSLog(@"word category count %@",[wordCategory count] I get a the message: EXC_BAD_ACCESS in the debugger. Here's the rest of the code: NSManagedObjectContext *moc = [myAppDelegate managedObjectContext]; NSFetchRequest *request = [[NSFetchRequest alloc] init]; [request setEntity:[NSEntityDescription entityForName:@"Language" inManagedObjectContext:moc]]; NSError *error = nil; NSArray *results = [moc executeFetchRequest:request error: &error]; if (error) { [NSApp presentError:error]; return; } NSManagedObject *obj = [results objectAtIndex:0]; NSSet *wordCategory = [obj valueForKey:@"category"]; NSLog(@"word category count %@",[wordCategory count]); I'll appreciate any light than anybody can shed in this mystery. Thanks for your help!

    Read the article

  • XNA 2D mouse picking

    - by Corndog
    I'm working on a simple 2D Real time strategy game using XNA. Right now I have reached the point where I need to be able to click on the sprite for a unit or building and be able to reference the object associated with that sprite. From the research I have done over the last three days I have found many references on how to do "Mouse picking" in 3D which does not seem to apply to my situation. I understand that another way to do this is to simply have an array of all "selectable" objects in the world and when the player clicks on a sprite it checks the mouse location against the locations of all the objects in the array. the problem I have with this approach is that it would become rather slow if the number of units and buildings grows to larger numbers. (it also does not seem very elegant) so what are some other ways I could do this. (Please note that I have also worked over the ideas of using a Hash table to associate the object with the sprite location, and using a 2 dimensional array where each location in the array represents one pixel in the world. once again they seem like rather clunky ways of doing things.)

    Read the article

  • Django's self.client.login(...) does not work in unit tests

    - by thebossman
    I have created users for my unit tests in two ways: 1) Create a fixture for "auth.user" that looks roughly like this: { "pk": 1, "model": "auth.user", "fields": { "username": "homer", "is_active": 1, "password": "sha1$72cd3$4935449e2cd7efb8b3723fb9958fe3bb100a30f2", ... } } I've left out the seemingly unimportant parts. 2) Use 'create_user' in the setUp function (although I'd rather keep everything in my fixtures class): def setUp(self): User.objects.create_user('homer', '[email protected]', 'simpson') Note that the password is simpson in both cases. I've verified that this info is correctly being loaded into the test database time and time again. I can grab the User object using User.objects.get. I can verify the password is correct using 'check_password.' The user is active. Yet, invariably, self.client.login(username='homer', password='simpson') FAILS. I'm baffled as to why. I think I've read every single Internet discussion pertaining to this. Can anybody help? The login code in my unit test looks like this: login = self.client.login(username='homer', password='simpson') self.assertTrue(login) Thanks.

    Read the article

  • How to implement properly plugins in C#?

    - by MartyIX
    I'm trying to add plugins to my game and what I'm trying to implement is this: Plugins will be either mine or 3rd party's so I would like a solution where crashing of the plugin would not mean crashing of the main application. Methods of plugins are called very often (for example because of drawing of game objects). What I've found so far: 1) http://www.codeproject.com/KB/cs/pluginsincsharp.aspx - simple concept that seems like it should work nicely. Since plugins are used in my game for every round I would suffice to add the Restart() method and if a plugin is no longer needed Unload() method + GC should take care of that. 2) http://mef.codeplex.com/Wikipage - Managed Extensibility Framework - my program should work on .NET 3.5 and I don't want to add any other framework separately I want to write my plugin system myself. Therefore this solution is out of question. 3) Microsoft provides: http://msdn.microsoft.com/en-us/library/system.addin.aspx but according to a few articles I've read it is very complex. 4) Different AppDomains for plugins. According to Marc Gravell ( http://stackoverflow.com/questions/665668/usage-of-appdomain-in-c ) different AppDomains allow isolation. Unloading of plugins would be easy. What would the performance load be? I need to call methods of plugins very often (to draw objects for example). Using Application Domains - http://msdn.microsoft.com/en-us/library/yb506139.aspx A few tutorials on java2s.com Could you please comment on my findings? New approaches are also welcomed! Thanks!

    Read the article

  • How can I stop an auto-generated Linq to SQL class from loading ALL data?

    - by Gary McGill
    I have an ASP.NET MVC project, much like the NerdDinner tutorial example. (I'm using MVC 2, but followed the NerdDinner tutorial in order to create it). As per the instructions in part 3 of the tutorial, I've created a Linq-to-SQL model of my database by creating a "Linq to SQL Classes" (.dbml) surface, and dropping my database tables onto it. The designer has automatically added relationships between the generated classes based on my database tables. Let's say that my classes are as per the NerdDinner example, so I have Dinner and RSVP tables, where each Dinner record is associated with many RSVP records - hence in the generated classes, the Dinner object has a RSVPs property which is a list of RSVP objects. My problem is this: it appears (and I'd be gladly proved wrong on this) that as soon as I access a Dinner object, it's loading all of the corresponding RSVP objects, even if I don't use the RSVPs member. First question: is this really the default behavior for the generated classes? In my particular situation, the object graph contains many more tables (which have an order of magnitude more records), and so this is disastrous behaviour - I'd be loading tons of data when all I want to do is show the details of a single parent record. Second question: are there any properties exposed through the designer UI that would let me modify this behavior? (I can't find any). Third question: I've seen a description of how to control the loading of related records in a DataContext by using a DataShape object associated with the DataContext. Is that what I'm meant to do, and if so are there any tutorials like the NerdDinner one that would show not only how to do it, but also suggest a 'pattern' for normal use?

    Read the article

  • How can I stop an auto-generated Linq to SQL class from loading ALL data?

    - by Gary McGill
    DUPLICATE of http://stackoverflow.com/questions/2433422/how-can-i-stop-an-auto-generated-linq-to-sql-class-from-loading-all-data post answers there! I have an ASP.NET MVC project, much like the NerdDinner tutorial example. (I'm using MVC 2, but followed the NerdDinner tutorial in order to create it). As per the instructions in part 3 of the tutorial, I've created a Linq-to-SQL model of my database by creating a "Linq to SQL Classes" (.dbml) surface, and dropping my database tables onto it. The designer has automatically added relationships between the generated classes based on my database tables. Let's say that my classes are as per the NerdDinner example, so I have Dinner and RSVP tables, where each Dinner record is associated with many RSVP records - hence in the generated classes, the Dinner object has a RSVPs property which is a list of RSVP objects. My problem is this: it appears (and I'd be gladly proved wrong on this) that as soon as I access a Dinner object, it's loading all of the corresponding RSVP objects, even if I don't use the RSVPs member. First question: is this really the default behavior for the generated classes? In my particular situation, the object graph contains many more tables (which have an order of magnitude more records), and so this is disastrous behaviour - I'd be loading tons of data when all I want to do is show the details of a single parent record. Second question: are there any properties exposed through the designer UI that would let me modify this behavior? (I can't find any). Third question: I've seen a description of how to control the loading of related records in a DataContext by using a DataShape object associated with the DataContext. Is that what I'm meant to do, and if so are there any tutorials like the NerdDinner one that would show not only how to do it, but also suggest a 'pattern' for normal use?

    Read the article

  • Application connection with database persist after sucessfull transaction also.

    - by anupam3m
    Hi , I am using Spring.Data.NHibernate12 on my database level.my application connection with database is not getting released. Underneath given is Dataconfiguration.xml < ?xml version="1.0" encoding="utf-8" ? < objects xmlns="http://www.springframework.net" xmlns:db="http://www.springframework.net/database" < object id="AuditLogger" type="Risco.Rsp.Ac.Audit.AuditLogger, Risco.Rsp.Ac.Audit" singleton="false" < property name="CacheSettings" ref="CacheSettings"/ < /object < object id="CacheSettings" type="Risco.Rsp.Ac.AMAC.CacheMgmt.Utilities.UpdateEntityCacheHelper, Risco.Rsp.Ac.AMAC.CacheMgmt.Utilities" singleton="false"/ < object type="Spring.Objects.Factory.Config.PropertyPlaceholderConfigurer, Spring.Core" < <property name="ConfigSections" value="databaseSettings"/> < < db:provider id="AMACDbProvider" provider="OracleClient-2.0" connectionString="Data Source=RISCODEVDB;User ID=amsbvt; Password=amsuser1234;"/ Risco.Rsp.Ac.AMAC.Mapping Risco.Rsp.Ac.Logging.Appenders Risco.Rsp.Ac.AMAC.CacheMappings --

    Read the article

  • Add data to Django form class using modelformset_factory

    - by dean
    I have a problem where I need to display a lot of forms for detail data for a hierarchical data set. I want to display some relational fields as labels for the forms and I'm struggling with a way to do this in a more robust way. Here is the code... class Category(models.Model): name = models.CharField(max_length=160) class Item(models.Model): category = models.ForeignKey('Category') name = models.CharField(max_length=160) weight = models.IntegerField(default=0) class Meta: ordering = ('category','weight','name') class BudgetValue(models.Model): value = models.IntegerField() plan = models.ForeignKey('Plan') item = models.ForeignKey('Item') I use the modelformset_factory to create a formset of budgetvalue forms for a particular plan. What I'd like is item name and category name for each BudgetValue. When I iterate through the forms each one will be labeled properly. class BudgetValueForm(forms.ModelForm): item = forms.ModelChoiceField(queryset=Item.objects.all(),widget=forms.HiddenInput()) plan = forms.ModelChoiceField(queryset=Plan.objects.all(),widget=forms.HiddenInput()) category = "" < assign dynamically on form creation > item = "" < assign dynamically on form creation > class Meta: model = BudgetValue fields = ('item','plan','value') What I started out with is just creating a dictionary of budgetvalue.item.category.name, budgetvalue.item.name, and the form for each budget value. This gets passed to the template and I render it as I intended. I'm assuming that the ordering of the forms in the formset and the querset used to genererate the formset keep the budgetvalues in the same order and the dictionary is created correctly. That is the budgetvalue.item.name is associated with the correct form. This scares me and I'm thinking there has to be a better way. Any help would be greatly appreciated.

    Read the article

  • TDD test data loading methods

    - by Dave Hanson
    I am a TDD newb and I would like to figure out how to test the following code. I am trying to write my tests first, but I am having trouble for creating a test that touches my DataAccessor. I can't figure out how to fake it. I've done the extend the shipment class and override the Load() method; to continue testing the object. I feel as though I end up unit testing my Mock objects/stubs and not my real objects. I thought in TDD the unit tests were supposed to hit ALL of the methods on the object; however I can never seem to test that Load() code only the overriden Mock Load My tests were write an object that contains a list of orders based off of shipment number. I have an object that loads itself from the database. public class Shipment { //member variables protected List<string> _listOfOrders = new List<string>(); protected string _id = "" //public properties public List<string> ListOrders { get{ return _listOfOrders; } } public Shipment(string id) { _id = id; Load(); } //PROBLEM METHOD // whenever I write code that needs this Shipment object, this method tries // to hit the DB and fubars my tests // the only way to get around is to have all my tests run on a fake Shipment object. protected void Load() { _listOfOrders = DataAccessor.GetOrders(_id); } } I create my fake shipment class to test the rest of the classes methods .I can't ever test the Real load method without having an actual DB connection public class FakeShipment : Shipment { protected new void Load() { _listOfOrders = new List<string>(); } } Any thoughts? Please advise. Dave

    Read the article

  • Frameworks to manage dates (effective date and expiry dates)

    - by user214626
    Hello, We have an object that can has an effective date and expiry date.(Ex. i want to maintain the price of a commodity for a time period) Business Rules - Effective date is always a valid date (a datestamp) but, expiry date can be null to indicate that the object is active throughout. Also, both effective and expiry date can be set to some valid dates. Are there any frameworks that manage objects such that the objects are consistent,i.e there are no overlaps of the validity periods ? Ex. class XBOX { double price; Date effectiveDate; Date expiryDate; } XBOX x1 = new XBOX(400$, '2007-01-01','2008-12-31' ); XBOX x2 = new XBOX(200$, '2009-01-01',null ); Assume that we get a new rate from '2010-01-01' and a new XBOX object has to be created (to persist). Is there a framework/pattern that can do the following, so that the XBOX is consistent. x2.setExpiryDate('2009-12-31') XBOX x3 = new XBOX(150$, '2010-01-01',null ); Thanks in advance.

    Read the article

  • "select * from table" vs "select colA,colB,etc from table" interesting behaviour in SqlServer2005

    - by kristof
    Apology for a lengthy post but I needed to post some code to illustrate the problem. Inspired by the question What is the reason not to use select * ? posted a few minutes ago, I decided to point out some observations of the select * behaviour that I noticed some time ago. So let's the code speak for itself: IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[starTest]') AND type in (N'U')) DROP TABLE [dbo].[starTest] CREATE TABLE [dbo].[starTest]( [id] [int] IDENTITY(1,1) NOT NULL, [A] [varchar](50) NULL, [B] [varchar](50) NULL, [C] [varchar](50) NULL ) ON [PRIMARY] GO insert into dbo.starTest(a,b,c) select 'a1','b1','c1' union all select 'a2','b2','c2' union all select 'a3','b3','c3' go IF EXISTS (SELECT * FROM sys.views WHERE object_id = OBJECT_ID(N'[dbo].[vStartest]')) DROP VIEW [dbo].[vStartest] go create view dbo.vStartest as select * from dbo.starTest go go IF EXISTS (SELECT * FROM sys.views WHERE object_id = OBJECT_ID(N'[dbo].[vExplicittest]')) DROP VIEW [dbo].[vExplicittest] go create view dbo.[vExplicittest] as select a,b,c from dbo.starTest go select a,b,c from dbo.vStartest select a,b,c from dbo.vExplicitTest IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[starTest]') AND type in (N'U')) DROP TABLE [dbo].[starTest] CREATE TABLE [dbo].[starTest]( [id] [int] IDENTITY(1,1) NOT NULL, [A] [varchar](50) NULL, [B] [varchar](50) NULL, [D] [varchar](50) NULL, [C] [varchar](50) NULL ) ON [PRIMARY] GO insert into dbo.starTest(a,b,d,c) select 'a1','b1','d1','c1' union all select 'a2','b2','d2','c2' union all select 'a3','b3','d3','c3' select a,b,c from dbo.vExplicittest select a,b,c from dbo.vStartest If you execute the following query and look at the results of last 2 select statements, the results that you will see will be as follows: select a,b,c from dbo.vExplicittest a1 b1 c1 a2 b2 c2 a3 b3 c3 select a,b,c from dbo.vStartest a1 b1 d1 a2 b2 d2 a3 b3 d3 As you can see in the results of select a,b,c from dbo.vStartest the data of column c has been replaced with the data from colum d. I believe that is related to the way the views are compiled, my understanding is that the columns are mapped by column indexes (1,2,3,4) as apposed to names. I though I would post it as a warning for people using select * in their sql and experiencing unexpected behaviour. Note: If you rebuild the view that uses select * each time after you modify the table it will work as expected

    Read the article

  • How do I implement repository pattern and unit of work when dealing with multiple data stores?

    - by Jason
    I have a unique situation where I am building a DDD based system that needs to access both Active Directory and a SQL database as persistence. Initially this wasnt a problem because our design was setup where we had a unit of work that looked like this: public interface IUnitOfWork { void BeginTransaction() void Commit() } and our repositories looked like this: public interface IRepository<T> { T GetByID() void Save(T entity) void Delete(T entity) } In this setup our load and save would handle the mapping between both data stores because we wrote it ourselves. The unit of work would handle transactions and would contain the Linq To SQL data context that the repositories would use for persistence. The active directory part was handled by a domain service implemented in infrastructure and consumed by the repositories in each Save() method. Save() was responsible with interacting with the data context to do all the database operations. Now we are trying to adapt it to entity framework and take advantage of POCO. Ideally we would not need the Save() method because the domain objects are being tracked by the object context and we would just need to add a Save() method on the unit of work to have the object context save the changes, and a way to register new objects with the context. The new proposed design looks more like this: public interface IUnitOfWork { void BeginTransaction() void Save() void Commit() } public interface IRepository<T> { T GetByID() void Add(T entity) void Delete(T entity) } This solves the data access problem with entity framework, but does not solve the problem with our active directory integration. Before, it was in the Save() method on the repository, but now it has no home. The unit of work knows nothing other than the entity framework data context. Where should this logic go? I argue this design only works if you only have one data store using entity framework. Any ideas how to best approach this issue? Where should I put this logic?

    Read the article

  • Delphi 2009 dbExpress and Interbase: Unicode migration steps and risks?

    - by mjustin
    Currently, our database uses Win1252 as the only character encoding. We will have to support Unicode in the database tables soon, which means we have to perform this migration for four databases and around 80 Delphi applications which run in-house in a 24/7 environment. Are there recommendations for database migrations to UTF-8 (or UNICODE_FSS) for Delphi applications? Some questions listed below. Many thanks in advance for your answers! are there tools which help with the migration of the existing databases (sizes between 250 MB and 2 GB, no Blob fields), by dumping the data, recreating the database with UNICODE_FSS or UTF-8, and loading the data back? are there known problems with Delphi 2009, dbExpress and Interbase 7.5 related to Unicode character sets? would you recommend to upgrade the databases to Interbase 2009 first? (This upgrade is planned but does not have a high priority) can we simply migrate the database and Delphi will handle the Unicode character sets automatically, or will we have to change all character field types in every Datamodule (dfm and source code) too? which strategy would you recommend to work on the migration in parallel with the normal development and maintenance of the existing application? The application runs in-house so development and database administration is done internally. Update: one problem I found now is that there are two different persistent field types for Unicode and non Unicode character fields. For the existing database, dbExpress creates TStringField objects. For the Unicode database fields, dbExpress creates (or expects!) TWideStringField objects. This looks like a lot of work lies ahead. While we could try to avoid persistent fields (and add calculated fields at run time), Of course we would prefer a solution which does not require so many changes in existing units and DFM files.

    Read the article

  • Django Cannot set values on a ManyToManyField which specifies an intermediary model

    - by dana
    i am using a m2m and a through table, and when i was trying to save, my error was: Cannot set values on a ManyToManyField which specifies an intermediary model so, i've modified my code, so that when i save the form, to insert data into the 'through' table too.But now, i'm having another error. (i've bolded the lines where i think i am wrong) i have in models.py: class Classroom(models.Model): user = models.ForeignKey(User, related_name = 'classroom_creator') classname = models.CharField(max_length=140, unique = True) date = models.DateTimeField(auto_now=True) open_class = models.BooleanField(default=True) members = models.ManyToManyField(User,related_name="list of invited members", through = 'Membership') class Membership(models.Model): accept = models.BooleanField(User) date = models.DateTimeField(auto_now = True) classroom = models.ForeignKey(Classroom, related_name = 'classroom_membership') member = models.ForeignKey(User, related_name = 'user_membership') and in def save_classroom(request): if request.method == 'POST': form = ClassroomForm(request.POST, request.FILES, user = request.user) **classroom_instance = Classroom member_instance = Membership** if form.is_valid(): new_obj = form.save(commit=False) new_obj.user = request.user r = Relations.objects.filter(initiated_by = request.user) membership = Membership.objects.create(**classroom = classroom_instance, member = member_instance,date=datetime.datetime.now())** new_obj.save() form.save_m2m() return HttpResponseRedirect('/classroom/classroom_view/{{user}}/') else: form = ClassroomForm(user = request.user) return render_to_response('classroom/classroom_form.html', { 'form': form, }, context_instance=RequestContext(request)) but i don't seem to initialise okay the classroom_instance and menber_instance.My error os: Cannot assign "": "Membership.classroom" must be a "Classroom" instance. Thanks!

    Read the article

  • Solving problems involving more complex data structures with CUDA

    - by Nils
    So I read a bit about CUDA and GPU programming. I noticed a few things such that access to global memory is slow (therefore shared memory should be used) and that the execution path of threads in a warp should not diverge. I also looked at the (dense) matrix multiplication example, described in the programmers manual and the nbody problem. And the trick with the implementation seems to be the same: Arrange the calculation in a grid (which it already is in case of the matrix mul); then subdivide the grid into smaller tiles; fetch the tiles into shared memory and let the threads calculate as long as possible, until it needs to reload data from the global memory into shared memory. In case of the nbody problem the calculation for each body-body interaction is exactly the same (page 682): bodyBodyInteraction(float4 bi, float4 bj, float3 ai) It takes two bodies and an acceleration vectors. The body vector has four components it's position and the weight. When reading the paper, the calculation is understood easily. But what is if we have a more complex object, with a dynamic data structure? For now just assume that we have an object (similar to the body object presented in the paper) which has a list of other objects attached and the number of objects attached is different in each thread. How could I implement that without having the execution paths of the threads to diverge? I'm also looking for literature which explains how different algorithms involving more complex data structures can be effectively implemented in CUDA.

    Read the article

  • WPF - Setting ComboBox.SelectedItem in XAML based on matching object

    - by Andy T
    Hi, so, I have templated combobox that is basically acting as a simple colour palette. It is populated with a list of SolidColorBrush objects. Fine. Now, I have some data that holds the hex value of the current colour. I have a converter that converts the hex into a SolidColorBrush. Also fine. Now, I want to set the SelectedItem property of the combobox based on the colour from my datasource. Since my combo is populated with objects of type SolidColourBrush, and my binding converter is returning a SolidColorBrush, I assumed it would be as simple as saying: SelectedItem="{Binding Color, Converter={StaticResource StringToBrush}}" However... it doesn't work :( I've tested that the binding is working behind the scenes by using the exact same value for the Background property of the combobox. It works fine. So, clearly I can't just say SelectedItem = [something] where that [something] is basically an object equal to the item I want to be selected. What is the right way to do this? Surely it's possible in a XAML-only styley using binding, and I don't have to do some nasty C# iterating through all items in the combobox trying to find a match (that seems awfully old-school)...? Any help appreciated. Many thanks! AT

    Read the article

  • XCTest.framework build error

    - by user2703123
    I am using the DropBox Core API in my app and therefore, I must include the XCTest framework, because, when I haven't added the XCTest framework, my app can't connect to dropbox, however when I do add the framework, I get an error while building for the simulator. There is nothing wrong with my code! Here is the error: Ld /Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Products/Debug-iphonesimulator/SnapDrop!.app/SnapDrop! normal i386 cd "/Users/Zach/Desktop/SnapDrop!" setenv IPHONEOS_DEPLOYMENT_TARGET 6.1 setenv PATH "/Applications/Xcode5-DP6.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode5-DP6.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin" /Applications/Xcode5-DP6.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Applications/Xcode5-DP6.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator7.0.sdk -L/Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Products/Debug-iphonesimulator -F/Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Products/Debug-iphonesimulator -F/Users/Zach/Downloads/dropbox-ios-sdk-1.3.5 -F/Users/Zach/Downloads/dropbox-ios-sync-sdk-1-1.1.0 -F/Applications/Xcode5-DP6.app/Contents/Developer/Library/Frameworks -F/Users/Zach/Desktop -filelist /Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Intermediates/SnapDrop!.build/Debug-iphonesimulator/SnapDrop!.build/Objects-normal/i386/SnapDrop!.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=6.1 -framework iAd -framework AssetsLibrary -framework QuartzCore -framework SystemConfiguration -framework Security -framework CFNetwork -framework XCTest -framework Dropbox -framework DropboxSDK -framework CoreGraphics -framework UIKit -framework Foundation -Xlinker -dependency_info -Xlinker /Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Intermediates/SnapDrop!.build/Debug-iphonesimulator/SnapDrop!.build/Objects-normal/i386/SnapDrop!_dependency_info.dat -o /Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Products/Debug-iphonesimulator/SnapDrop!.app/SnapDrop! ld: building for iOS Simulator, but linking against dylib built for MacOSX file '/Applications/Xcode5-DP6.app/Contents/Developer/Library/Frameworks/XCTest.framework/XCTest' for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation) What should I do? If my framework is corrupt, can you tell me how to reinstall it? I have tried deleting and reinstalling Xcode with no luck.

    Read the article

  • Django's post_save signal behaves weirdly with models using multi-table inheritance

    - by hekevintran
    Django's post_save signal behaves weirdly with models using multi-table inheritance I am noticing an odd behavior in the way Django's post_save signal works when using a model that has multi-table inheritance. I have these two models: class Animal(models.Model): category = models.CharField(max_length=20) class Dog(Animal): color = models.CharField(max_length=10) I have a post save callback called echo_category: def echo_category(sender, **kwargs): print "category: '%s'" % kwargs['instance'].category post_save.connect(echo_category, sender=Dog) I have this fixture: [ { "pk": 1, "model": "animal.animal", "fields": { "category": "omnivore" } }, { "pk": 1, "model": "animal.dog", "fields": { "color": "brown" } } ] In every part of the program except for in the post_save callback the following is true: from animal.models import Dog Dog.objects.get(pk=1).category == u'omnivore' # True When I run syncdb and the fixture is installed, the echo_category function is run. The output from syncdb is: $ python manage.py syncdb --noinput Installing json fixture 'initial_data' from '~/my_proj/animal/fixtures'. category: '' Installed 2 object(s) from 1 fixture(s) The weird thing here is that the dog object's category attribute is an empty string. Why is it not 'omnivore' like it is everywhere else? As a temporary (hopefully) workaround I reload the object from the database in the post_save callback: def echo_category(sender, **kwargs): instance = kwargs['instance'] instance = sender.objects.get(pk=instance.pk) print "category: '%s'" % instance.category post_save.connect(echo_category, sender=Dog) This works but it is not something I like because I must remember to do it when the model inherits from another model and it must hit the database again. The other weird thing is that I must do instance.pk to get the primary key. The normal 'id' attribute does not work (I cannot use instance.id). I do not know why this is. Maybe this is related to the reason why the category attribute is not doing the right thing?

    Read the article

  • WPF DataGrid binding difficulties

    - by Jasmin Pvvlovic
    This is the class: public class TrainingData { public string Training { get; set; } } And this is the rest of the code in MainWindow: Excel.Workbook xlWorkbook = xlApp.Workbooks.Open("D:/excel.xlsx"); Excel._Worksheet xlWorksheet = xlWorkbook.Sheets[1]; Excel.Range xlRange = xlWorksheet.UsedRange; List <TrainingData> tData= new List <TrainingData>(); int rowCount = xlRange.Rows.Count; int colCount = xlRange.Columns.Count; //int k = 0; for (int i = 1; i <= rowCount; i++) { tData.Add(new TrainingData() { Training = xlRange.Cells[i, 1].Value2.ToString() }); //MessageBox.Show(tData[k].Training); //k++; } Prikaz.ItemsSource = tData; DataGrid: <DataGrid AutoGenerateColumns="False" Height="120" HorizontalAlignment="Left" Margin="12,12,0,0" Name="Prikaz" VerticalAlignment="Top" Width="105" ItemsSource="{Binding}"> <DataGrid.Columns> <DataGridTextColumn Header="Header" /> </DataGrid.Columns> </DataGrid>` So, Prikaz is my DataGrid. tData is List of TrainingData objects. If I uncomment these three lines I can test if I have imported information from excel file correctly, and yes, that works just fine. So why am I getting empty DataGrid? It has right number of rows and only one column, that's ok, but there are no data in it. I used this line: Prikaz.ItemsSource = tData; to bind my objects list and DataGrid. Training is declared public so it should be present in DataGrid. What could be causing the problem?

    Read the article

  • In ParallelPython, a method of an object ( object.func() ) fails to manipulate a variable of an object ( object.value )

    - by mehmet.ali.anil
    With parallelpython, I am trying to convert my old serial code to parallel, which heavily relies on objects that have methods that change that object's variables. A stripped example in which I omit the syntax in favor of simplicity: class Network: self.adjacency_matrix = [ ... ] self.state = [ ... ] self.equilibria = [ ... ] ... def populate_equilibria(self): # this function takes every possible value that self.state can be in # runs the boolean dynamical system # and writes an integer within self.equilibria for each self.state # doesn't return anything I call this method as: Code: j1 = jobserver.submit(net2.populate_equilibria,(),(),("numpy as num")) The job is sumbitted, and I know that a long computation takes place, so I speculate that my code is ran. The problem is, i am new to parallelpython , I was expecting that, when the method is called, the variable net2.equilibria would be written accordingly, and I would get a revised object (net2) . That is how my code works, independent objects with methods that act upon the object's variables. Rather, though the computation is apparent, and reasonably timed, the variable net2.equilibria remains unchanged. As if PP only takes the function and the object, computes it elsewhere, but never returns the object, so I am left with the old one. What do I miss? Thanks in advance.

    Read the article

  • Proper way to validate model in ASP.NET MVC 2 and ViewModel apporach

    - by adrin
    I am writing an ASP.NET MVC 2 application using NHibernate and repository pattern. I have an assembly that contains my model (business entities), moreover in my web project I want to use flattened objects (possibly with additional properties/logic) as ViewModels. These VMs contain UI-specific metadata (eg. DisplayAttribute used by Html.LabelFor() method). The problem is that I don't know how to implement validation so that I don't repeat myself throughout various tiers (specifically validation rules are written once in Model and propagated to ViewModel). I am using DataAnnotations on my ViewModel but this means no validation rules are imposed on the Model itself. One approach I am considering is deriving ViewModel objects from business entities adding new properties/overriding old ones, thus preserving validation metadata between the two however this is an ugly workaround. I have seen Automapper project which helps to map properties, but I am not sure if it can handle ASP.NET MVC 2 validation metadata properly. Is it difficult to use custom validation framework in asp.net mvc 2? Do you have any patterns that help to preserve DRY in regard to validation?

    Read the article

  • How to invalidate the OutputCache in a webfarm?

    - by Pure.Krome
    Hi folks, i've got a website that uses OutputCache attribute to cache pages. Works great. Now, I'm in the middle of R&D'ing scaling up this site to be in a web farm. Along with the usual suspects for webfarm pain ... I've noticed (pretty quickly/obviously) that the OutputCache from Server_A doesn't invalidate the OutputCache from Server_B .. if a try and invalidate a single server's OutputCache. This makes total sense - how can S_A 'tell' S_B to invalidate when they are physically 2 seperate machines, etc? So - what are our options? Velocity? I understand this will move the caching to a different layer .. which means that the final result (output) will always be required to be determined .. as opposed to the OutputCache whic remembers the final output content (yes, varby gives different versions, etc.. which is totally fine). So even though the poco or business objects are all sync'd, there's still that last rendering effort required (even if it's tiny .. compared to the effort to generate/sync business objects). So yeah .. not sure of the options here and what other people do?

    Read the article

< Previous Page | 294 295 296 297 298 299 300 301 302 303 304 305  | Next Page >