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  • actionscript-3: refactor interface inheritance to get rid of ambiguous reference error

    - by maxmc
    hi! imagine there are two interfaces arranged via composite pattern, one of them has a dispose method among other methods: interface IComponent extends ILeaf { ... function dispose() : void; } interface ILeaf { ... } some implementations have some more things in common (say an id) so there are two more interfaces: interface ICommonLeaf extends ILeaf { function get id() : String; } interface ICommonComponent extends ICommonLeaf, IComponent { } so far so good. but there is another interface which also has a dispose method: interface ISomething { ... function dispose() : void; } and ISomething is inherited by ICommonLeaf: interface ICommonLeaf extends ILeaf, ISomething { function get id() : String; } As soon as the dispose method is invoked on an instance which implements the ICommonComponent interface, the compiler fails with an ambiguous reference error because ISomething has a method called dispose and ILeaf also has a dispose method, both living in different interfaces (IComponent, ISomething) within the inheritace tree of ICommonComponent. I wonder how to deal with the situation if the IComponent, the ILeaf and the ISomething can't change. the composite structure must also work for for the ICommonLeaf & ICommonComponent implementations and the ICommonLeaf & ICommonComponent must conform to the ISomething type. this might be an actionscript-3 specific issue. i haven't tested how other languages (for instance java) handle stuff like this.

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  • Problem with setVisible (true)

    - by Jessy
    The two examples shown below are same. Both are supposed to produce same result e.g. generate the coordinates of images displayed on JPanel. Example 1, works perfectly (print the coordinates of images), however example 2 returning 0 for the coordinate. I was wondering why because, I have put the setvisible (true) after adding the panel, in both examples. The only difference is that example 1 used extends JPanel and example 2 extends JFrame EXAMPLE 1: public class Grid extends JPanel{ public static void main(String[] args){ JFrame jf=new JFrame(); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); final Grid grid = new Grid(); jf.add(grid); jf.pack(); Component[] components = grid.getComponents(); for (Component component : components) { System.out.println("Coordinate: "+ component.getBounds()); } jf.setVisible(true); } } EXAMPLE 2: public class Grid extends JFrame { public Grid () { setLayout(new GridBagLayout()); GridBagLayout m = new GridBagLayout(); Container c = getContentPane(); c.setLayout (m); GridBagConstraints con = new GridBagConstraints(); //construct the JPanel pDraw = new JPanel(); ... m.setConstraints(pDraw, con); pDraw.add (new GetCoordinate ()); // call new class to generate the coordinate c.add(pDraw); pack(); setVisible(true); } public static void main(String[] args) { new Grid(); } }

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  • What's the idiomatic way of inheriting data access functionality as well as object properties?

    - by Knut Arne Vedaa
    Suppose the following (slightly pseudo-code for brevity): class Basic { String foo; } class SomeExtension extends Basic { String bar; } class OtherExtension extends Basic { String baz; } class BasicService { Basic getBasic() { } } class SomeExtensionService extends BasicService { SomeExtension getSomeExtension() { } } class OtherExtensionService extends BasicService { OtherExtension getOtherExtension() { } } What would be the most idiomatic, elegant way to implement the get-() service methods with the most possible code reuse? Obviously you could do it like this: class BasicService { Basic getBasic() { Basic basic = new Basic(); basic.setFoo("some kind of foo"); return basic; } } class SomeExtensionService { SomeExtension getSomeExtension() { SomeExtension someExtension = new SomeExtension; Basic basic = getBasic(); someExtension.setFoo(basic.getFoo()); someExtension.setBar("some kind of bar"); return someExtension; } } But this would be ugly if Basic has a lot of properties, and also you only need one object, as SomeExtension already inherits Basic. However, BasicService can obviously not return a SomeExtension object. You could also have the get methods not create the object themselves, but create it at the outermost level and pass it to the method for filling in the properties, but I find that too imperative. (Please let me know if the question is confusingly formulated.)

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  • Java Generics Class Type Parameter Inference

    - by Pindatjuh
    Given the interface: public interface BasedOnOther<T, U extends BasedList<T>> { public T getOther(); public void staticStatisfied(final U list); } The BasedOnOther<T, U extends BasedList<T>> looks very ugly in my use-cases. It is because the T type parameter is already defined in the BasedList<T> part, so the "uglyness" comes from that T needs to be typed twice. Problem: is it possible to let the Java compiler infer the generic T type from BasedList<T> in a generic class/interface definition? Ultimately, I'd like to use the interface like: class X extends BasedOnOther<BasedList<SomeType>> { public SomeType getOther() { ... } public void staticStatisfied(final BasedList<SomeType> list) { ... } } Instead: class X extends BasedOnOther<SomeType, BasedList<SomeType>> { public SomeType getOther() { ... } public void staticStatisfied(final BasedList<SomeType> list) { ... } }

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  • Scala: Correcting type inference of representation type over if statement

    - by drhagen
    This is a follow-up to two questions on representation types, which are type parameters of a trait designed to represent the type underlying a bounded type member (or something like that). I've had success creating instances of classes, e.g ConcreteGarage, that have instances cars of bounded type members CarType. trait Garage { type CarType <: Car[CarType] def cars: Seq[CarType] def copy(cars: Seq[CarType]): Garage def refuel(car: CarType, fuel: CarType#FuelType): Garage = copy( cars.map { case `car` => car.refuel(fuel) case other => other }) } class ConcreteGarage[C <: Car[C]](val cars: Seq[C]) extends Garage { type CarType = C def copy(cars: Seq[C]) = new ConcreteGarage(cars) } trait Car[C <: Car[C]] { type FuelType <: Fuel def fuel: FuelType def copy(fuel: C#FuelType): C def refuel(fuel: C#FuelType): C = copy(fuel) } class Ferrari(val fuel: Benzin) extends Car[Ferrari] { type FuelType = Benzin def copy(fuel: Benzin) = new Ferrari(fuel) } class Mustang(val fuel: Benzin) extends Car[Mustang] { type FuelType = Benzin def copy(fuel: Benzin) = new Mustang(fuel) } trait Fuel case class Benzin() extends Fuel I can easily create instances of Cars like Ferraris and Mustangs and put them into a ConcreteGarage, as long as it's simple: val newFerrari = new Ferrari(Benzin()) val newMustang = new Mustang(Benzin()) val ferrariGarage = new ConcreteGarage(Seq(newFerrari)) val mustangGarage = new ConcreteGarage(Seq(newMustang)) However, if I merely return one or the other, based on a flag, and try to put the result into a garage, it fails: val likesFord = true val new_car = if (likesFord) newFerrari else newMustang val switchedGarage = new ConcreteGarage(Seq(new_car)) // Fails here The switch alone works fine, it is the call to ConcreteGarage constructor that fails with the rather mystical error: error: inferred type arguments [this.Car[_ >: this.Ferrari with this.Mustang <: this.Car[_ >: this.Ferrari with this.Mustang <: ScalaObject]{def fuel: this.Benzin; type FuelType<: this.Benzin}]{def fuel: this.Benzin; type FuelType<: this.Benzin}] do not conform to class ConcreteGarage's type parameter bounds [C <: this.Car[C]] val switchedGarage = new ConcreteGarage(Seq(new_car)) // Fails here ^ I have tried putting those magic [C <: Car[C]] representation type parameters everywhere, but without success in finding the magic spot.

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  • Cache layer for MVC - Model or controller?

    - by Industrial
    Hi everyone, I am having some second thoughts about where to implement the caching part. Where is the most appropriate place to implement it, you think? Inside every model, or in the controller? Approach 1 (psuedo-code): // mycontroller.php MyController extends Controller_class { function index () { $data = $this->model->getData(); echo $data; } } // myModel.php MyModel extends Model_Class{ function getData() { $data = memcached->get('data'); if (!$data) { $query->SQL_QUERY("Do query!"); } return $data; } } Approach 2: // mycontroller.php MyController extends Controller_class { function index () { $dataArray = $this->memcached->getMulti('data','data2'); foreach ($dataArray as $key) { if (!$key) { $data = $this->model->getData(); $this->memcached->set($key, $data); } } echo $data; } } // myModel.php MyModel extends Model_Class{ function getData() { $query->SQL_QUERY("Do query!"); return $data; } } Thoughts: Approach 1: No multiget/multi-set. If a high number of keys would be returned, overhead would be caused. Easier to maintain, all database/cache handling is in each model Approach 2: Better performancewise - multiset/multiget is used More code required Harder to maintain Tell me what you think!

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  • Transfering a set with a Wildcarded Generic to a List in Java

    - by Daniel Bingham
    I have a data type that contains a set and a method that expects List<? extends MyClass>. The data type has Set<? extends MyClass>. I need to be able to move the stuff out of the set and into the List. The order it goes into the list doesn't matter, it just needs to start keeping track of it so that it can be reordered when displayed. Suffice to say that changing the Set into a List in the data type is out of the question here. This seems pretty easy at first. Create a new method that takes a Set instead of a List, changes it into a list and then passes it on to the old method that just took a list. The problem comes in changing the set to a list. public void setData(Set<? extends MyClass> data) { List<? extends Myclass> newData = ArrayList< /* What goes here? */ >(); for(ConcordaEntityBean o : data) { newData.add(o); } setData(newData); } Obviously, I can't instantiate an ArrayList with a wildcard, it chokes. I don't know the type at that point. Is there some way to pull the type out of data and pass it to ArrayList? Can I just instantiate it with MyClass? Is there some other way to do this?

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  • I want a function to return a type of the subclass its invoked from

    - by Jay
    I want to have a function defined in a superclass that returns a value of the type of the subclass that is used to invoke the function. That is, say I have class A with a function plugh. Then I create subclasses B and C that extend A. I want B.plugh to return a B and C.plugh to return a C. Yes, they could return an A, but then the caller would have to either cast it to the right subtype, which is a pain when used a lot, or declare the receiving variable to be of the supertype, which loses type safety. So I was trying to do this with generics, writing something like this: class A<T extends A> { private T foo; public T getFoo() { return foo; } } class B extends A<B> { public void calcFoo() { foo=... whatever ... } } class C extends A<C> { public void calcFoo() { foo=... whatever ... } } This appears to work but it looks pretty ugly. For one thing, I get warnings on "class A". The compiler says that A is generic and I should specify the type. I guess it wants me to say "class A". But what would I put in for x? I think I could get stuck in an infinite loop here. It seems weird to write "class B extends A", but this causes no complaints, so maybe that's just fine. Is this the right way to do it? Is there a better way?

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  • Error when running a basic Hadoop code

    - by Abhishek Shivkumar
    I am running a hadoop code that has a partitioner class inside the job. But, when I run the command hadoop jar Sort.jar SecondarySort inputdir outputdir I am getting a runtime error that says class KeyPartitioner not org.apache.hadoop.mapred.Partitioner. I have ensured that the KeyPartitioner class has extended the Partitioner class, but why am I getting this error? Here is the driver code: JobConf conf = new JobConf(getConf(), SecondarySort.class); conf.setJobName(SecondarySort.class.getName()); conf.setJarByClass(SecondarySort.class); conf.setInputFormat(TextInputFormat.class); conf.setOutputFormat(TextOutputFormat.class); conf.setMapOutputKeyClass(StockKey.class); conf.setMapOutputValueClass(Text.class); conf.setPartitionerClass((Class<? extends Partitioner<StockKey, DoubleWritable>>) KeyPartitioner.class); conf.setMapperClass((Class<? extends Mapper<LongWritable, Text, StockKey, DoubleWritable>>) StockMapper.class); conf.setReducerClass((Class<? extends Reducer<StockKey, DoubleWritable, Text, Text>>) StockReducer.class); and here is the code of the partitioner class: public class KeyPartitioner extends Partitioner<StockKey, Text> { @Override public int getPartition(StockKey arg0, Text arg1, int arg2) { int partition = arg0.name.hashCode() % arg2; return partition; } }

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  • Can't referr to my get method

    - by chility
    I have this amazing and good looking class: public class SayingsHolder extends Application{ ArrayList<String> SayingsList = new ArrayList<String>(){{ SayingsList.add("1"); SayingsList.add("2"); }}; public ArrayList<String> getSayingsList() { return SayingsList; } } Now I'm trying to call the getSayingsList method inside of my activity's FragmentStatePagerAdapter by: private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter { final SayingsHolder holder = (SayingsHolder).getApplication(); } Everything fine for now, but when I make my code like this: private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter { final SayingsHolder holder = (SayingsHolder).getApplication(); holder.getSayingsList(); } it says: Syntax error on token "getSayingsList", Identifier expected after this token The problem is that holder is not functional at all. What I mean is that when i type the this holder. the getSayingsList is not showing at all. What am I missing here? I know that it is an extremely small issue, but it seems that I can't spot it. My activity extends FragmentActivity if it's important It seems that I'm missing something here. I can't call my method anywhere in my activity. I'm starting a bounty, because I need an example.

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  • Domain Trust 2008 to 2003

    - by nick3216
    I'm having trouble setting up the trust relationship between a Windows Server 2003 and a Windows Server 2008 AD. Domain a is Windows Server 2003 Forest functional level. Domain b is a Windows Server 2008 Forest functional level. I can set up the incoming side of the trust relationship on domain "a" so that it trusts domain "b". Try as I might on domain "b" I can't set up the outgoing side of the trust relationship to domain "a". The GUI interface gives an unhelpful 'The request is not supported'. I'm not sure netdom is being more or less helpful as it refers me to FilterSIDs netdom trust /add b /uo:b\admin /po:* /d:a /ud:a\admin /pd:* /oneside:trusting To improve the security of this external trust, security identifier (SID) filtering is enabled, however, if users have been migrated to the trusted domain and their SID histories have been preserved, you may choose to turn off this feature. For more information about SID filtering and how to turn it off, see the help for netdom trust /FilterSids or see Help and Support. The request is not supported. The command failed to complete succesfully. I say 'less helpful' because Windows Server 2008 doesn't support the /FilterSIDs option. How can we force creation of this trust? Edit: Just to clarify I've checked that the [Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options] "Network access: Allow anonymous SID/Name translation” is enabled on both sides of the trust as per http://social.technet.microsoft.com/Forums/en/winserverDS/thread/cc61fc25-3569-4413-bbfd-92390eb31118

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  • Questions a bout "interrupt"

    - by smwikipedia
    Could someone help me clarify the following conecpts, and the relationship among them? Maskable interrupt Unmaskable interrupt Hardware interrupt Software interrupt CPU INTR pin the IF bit of EFlags register Some specific questions: What's the relationship between Maskable/Unmaskable interrupt and Hardware/Software interrupt? What kind of interrupts does INTR pin detect? What kind of interrupts are enabled/disabled by IF bit of EFlags register? What kind of interrupts need the presence of an interrupt controller? Many thanks.

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  • full text search on multiple fields in diferrent tables

    - by crisgomez
    Hi, I want to create a a full text search usng ms sql 2005. here is the structure of my table User-contains fields of Id, fname,lname,email,alternativeemail Attachment-contains fields of id, name,category,filenameorurl Certification-contains of fileds of id, title,school,sdate,edate EducationalBackground-contain of fields of, id,qualification,sdate,edate,school,fieldofstudy EmploymentDetails-contain of fields position, positionlevelid,specializationid,description now the relationship of user to the other table is one to many relationship. now how can I create an effective query to have quick full text search and return the values of the different tables?any help please

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  • Mapping a ER model to Rails

    - by Thiago
    Hi there, I want to map the following ER schema to rails: I have an entity called "user" which has a self relationship called "has friend", which has an attribute called "status". In code, I would like to run: User.friends and it should return me an array of users, containing the users that I'm friend of. It shouldn't matter in which side of the relationship I am (i.e. whether I'm the friender or the friendee). Any thoughts?

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  • mysql query for getting all messages that belong to user's contacts

    - by aharon
    So I have a database that is setup sort of like this (simplified, and in terms of the tables, all are InnoDBs): Users: contains based user authentication information (uid, username, encrypted password, et cetera) Contacts: contains two rows per relationship that exists between users as (uid1, uid2), (uid2, uid1) to allow for a good 1:1 relationship (must be mutual) between users Messages: has messages that consist of a blob, owner-id, message-id (auto_increment) So my question is, what's the best MySQL query to get all messages that belong to all the contacts of a specific user? Is there an efficient way to do this?

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  • Setting SQL Relationships For LINQ Queries

    - by Soo
    I have two tables that I'm trying to create a relationship between so I can write nice LINQ queries that don't require join. Widgets WidgetId WidgetDescription Orders OrderId WidgetId OrderDate What I want to be able to do is create a LINQ query that does something similar to: var result = from x in db.Widgets Where x.Orders.OrderDate == "5/11/2010" select x; I can't seem to get intellitext to pick up the other database despite creating a relationship in SQL server. Are there any additional steps I need to take to make this work?

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  • Full text search on multiple fields in different tables

    - by crisgomez
    Hi, I want to create a a full text search usng ms sql 2005. here is the structure of my table User-contains fields of Id, fname,lname,email,alternativeemail Attachment-contains fields of id, name,category,filenameorurl Certification-contains of fileds of id, title,school,sdate,edate EducationalBackground-contain of fields of, id,qualification,sdate,edate,school,fieldofstudy EmploymentDetails-contain of fields position, positionlevelid,specializationid,description now the relationship of user to the other table is one to many relationship. now how can I create an effective query to have quick full text search and return the values of the different tables?any help please

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  • Need help with joins in sqlalchemy

    - by Steve
    I'm new to Python, as well as SQL Alchemy, but not the underlying development and database concepts. I know what I want to do and how I'd do it manually, but I'm trying to learn how an ORM works. I have two tables, Images and Keywords. The Images table contains an id column that is its primary key, as well as some other metadata. The Keywords table contains only an id column (foreign key to Images) and a keyword column. I'm trying to properly declare this relationship using the declarative syntax, which I think I've done correctly. Base = declarative_base() class Keyword(Base): __tablename__ = 'Keywords' __table_args__ = {'mysql_engine' : 'InnoDB'} id = Column(Integer, ForeignKey('Images.id', ondelete='CASCADE'), primary_key=True) keyword = Column(String(32), primary_key=True) class Image(Base): __tablename__ = 'Images' __table_args__ = {'mysql_engine' : 'InnoDB'} id = Column(Integer, primary_key=True, autoincrement=True) name = Column(String(256), nullable=False) keywords = relationship(Keyword, backref='image') This represents a many-to-many relationship. One image can have many keywords, and one keyword can relate back to many images. I want to do a keyword search of my images. I've tried the following with no luck. Conceptually this would've been nice, but I understand why it doesn't work. image = session.query(Image).filter(Image.keywords.contains('boy')) I keep getting errors about no foreign key relationship, which seems clearly defined to me. I saw something about making sure I get the right 'join', and I'm using 'from sqlalchemy.orm import join', but still no luck. image = session.query(Image).select_from(join(Image, Keyword)).\ filter(Keyword.keyword == 'boy') I added the specific join clause to the query to help it along, though as I understand it, I shouldn't have to do this. image = session.query(Image).select_from(join(Image, Keyword, Image.id==Keyword.id)).filter(Keyword.keyword == 'boy') So finally I switched tactics and tried querying the keywords and then using the backreference. However, when I try to use the '.images' iterating over the result, I get an error that the 'image' property doesn't exist, even though I did declare it as a backref. result = session.query(Keyword).filter(Keyword.keyword == 'boy').all() I want to be able to query a unique set of image matches on a set of keywords. I just can't guess my way to the syntax, and I've spent days reading the SQL Alchemy documentation trying to piece this out myself. I would very much appreciate anyone who can point out what I'm missing.

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  • Entity Framework Polymorphism

    - by Chubbs
    Hey guys, I wanted some help with trying to implement a simple polymorphic relationship using Entity Framework. An example of a relationship I would like to implement: Comment table ItemType ('Video', 'User') ItemID Body Video has many Comments User has many Comments No idea the best way to do this, I come from a Ruby on Rails way of thinking.

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  • Which Oracle table uses a sequence?

    - by Jaú
    Having a sequence, I need to find out which table.column gets its values. As far as I know, Oracle doesn't keep track of this relationship. So, looking up for the sequence in source code would be the only way. Is that right? Anyone knows of some way to find out this sequence-table relationship?

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  • MVC pattern implementation. What is the n-relation between its components

    - by Srodriguez
    Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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  • MVC pattern implementation. What is the n-relation between its components

    - by Srodriguez
    Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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  • Is there a way to add extra fields to an association in the ADO.NET Entity Framework?

    - by bigbird1040
    I would like to be able to model a many-to-many relationship that has extra details about the relationship. For example: Person: int id, String name Project: int id, String name ProjectPerson: Person.id, Project.id, String role Whenever I create the ProjectPerson association in the EF, I am unable to add the role attribute to the association. If I create the tables in my DB and then import it into the model, I lose the extra properties.

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  • Select most recent record in sub child

    - by Omar
    I have the following tables/columns: Parent: ParentID Child: ChildID ParentID SubChild: SubChildID ChildID Date Parent has 1 to Many relationship with Child Child has 1 to Many relationship with SubChild For every Parent, I need to get the SubChild with the most recent Date value. How can I do this using SQL. I've tried using MAX(Date), but I can't seem to figure out how to join Parent and Child successfully. The ideal result set would contain all the Parents joined with all the SubChild columns of the latest record. Note: using MS SQL 2005+

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