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  • Best practice for passing configuration to each GUI object

    - by Laimoncijus
    Hi, I am writing an application, where I do have few different windows implemented, where each window is a separate class. Now I need somehow to pass a single configuration object to all of them. My GUI is designed in way, where I have one main window, which may create some child windows of its own, and these child windows can have their own childs (so there is no possibility to create all windows in initialization part and feed the config object to all of them from the very beginning)... What would be best practice for sharing this configuration object between them? Always passing via constructor or maybe making it somewhere as final public static and let each window object to access it when needed? Thanks

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  • Updating a Database from DataBound Controls

    - by Avatar_Squadron
    Hi. I'm currently creating a WinForm in VB.NET bound to an access database. Basically what i have are two forms: one is a search form used to search the database, and the other is a details form. You run a search on the searchForm and it returns a list of Primary Keys and a few other identifying values. You then double click on the entry you want to view, and it loads the details form. The Details form has a collection of databound controls to display the data: mostly text boxes and checkboxs. The way i've set it up is i used the UI to build the form and then set the DataBindings Property of each control to "TblPropertiesBindingSource - " where value name is one of the values in the table (such as PropertyID or HasWoodFloor). Then, when you double click an entry in the searchform, I handle the event by parsing the Primary Key (PropertyID) out of the selected row and then storing this to the details form: Note: Detail is the details form that is opened to display the info Private Sub propView_CellDoubleClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles propView.CellDoubleClick Dim detail As frmPropertiesDetail = New frmPropertiesDetail detail.id = propView.Rows(e.RowIndex).Cells(0).Value detail.Show() End Sub Then, upon loading the details form, it set's the filter on the BindSource as such: TblPropertiesBindingSource.Filter() = "PropertyID=" & id This works great so far. All the controls on the details form will display the correct info. The problem is updating changes. Scenario: If i have the user load the details for say, property 10001, it will show a description in a textBox named descriptionBox which is identical to the value of the description value of for that entry in the database. I want the user to then be able to change the text of the text box (which they can currently do) and click the save button (saveBut) and have the form update all the values in the controls to the database. Theorectically, it should do this as the controls are DataBound, thus i can avoid writing code that tells each entry in the database row to take the value of the aligned control. I've tried calleding PropertiesTableAdapter.Update(PropertiesBindingSource.DataSource), but that doesnt seem to do it.

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  • What Patterns Should I Consider For a Html Widget Generator?

    - by DaveDev
    I'm looking to see if I can design a HtmlHelper extension method that will generate the Html for different types of widgets I want to produce. Each different type of widget implements functionality to get and prepare any data it needs to render. Can anyone suggest any patterns I could refer to for approaches to take? I know there are probably frameworks available that will do this for me, but I thought I'd give it a try anyway. Any points of advice? Thanks

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  • Return an object after parsing xml with SAX

    - by sentimental_turtle
    I have some large XML files to parse and have created an object class to contain my relevant data. Unfortunately, I am unsure how to return the object for later processing. Right now I pickle my data and moments later depickle the object for access. This seems wasteful, and there surely must be a way of grabbing my data without hitting the disk. def endElement(self, name): if name == "info": # done collecting this iteration self.data.setX(self.x) self.data.setY(self.y) elif name == "lastTagOfInterest": # done with file # want to return my object from here filehandler = open(self.outputname + ".pi", "w") pickle.dump(self.data, filehandler) filehandler.close() I have tried putting a return statement in my endElement tag, but that does not seem to get passed up the chain to where I call the SAX parser. Thanks for any tips.

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  • Modifying object in AfterInsert / AfterUpdate

    - by Jean Barmash
    I have a domain object that holds results of a calculation based on parameters that are properties of the same domain object. I'd like to make sure that any time parameters get changed by the user, it recalculates and gets saved properly into the database. I am trying to do that with afterInsert (to make sure calculation is correct in the first place), and afterUpdate. However, since my calculation is trying to modify the object itself, it's not working - throwing various hibernate exceptions. I tried to put the afterUpdate code into a transaction, but that didn't help. I am afraid I am getting into a circular dependency issues here. The exception I am getting right now is: org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [esc.scorecard.PropertyScorecard#27] Are the GORM events designed for simpler use cases? I am tempted to conclude that modifying the object you are in the middle of saving is not the way to go.

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  • Database Design Question: GUID + Natural Numbers

    - by Alan
    For a database I'm building, I've decided to use natural numbers as the primary key. I'm aware of the advantages that GUID's allow, but looking at the data, the bulk of row's data were GUID keys. I want to generate XML records from the database data, and one problem with natural numbers is that I don't want to expose my database key's to the outside world, and allow users to guess "keys." I believe GUID's solve this problem. So, I think the solution is to generate a sparse, unique iD derived from the natural ID (hopefully it would be 2-way), or just add an extra column in the database and store a guid (or some other multibyte id) The derived value is nicer because there is no storage penalty, but it would be easier to reverse and guess compared to a GUID. I'm (buy) curious as to what others on SO have done, and what insights they have.

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  • Inheritence and usage of dynamic_cast

    - by Mewzer
    Hello, Suppose I have 3 classes as follows (as this is an example, it will not compile!): class Base { public: Base(){} virtual ~Base(){} virtual void DoSomething() = 0; virtual void DoSomethingElse() = 0; }; class Derived1 { public: Derived1(){} virtual ~Derived1(){} virtual void DoSomething(){ ... } virtual void DoSomethingElse(){ ... } virtual void SpecialD1DoSomething{ ... } }; class Derived2 { public: Derived2(){} virtual ~Derived2(){} virtual void DoSomething(){ ... } virtual void DoSomethingElse(){ ... } virtual void SpecialD2DoSomething{ ... } }; I want to create an instance of Derived1 or Derived2 depending on some setting that is not available until run-time. As I cannot determine the derived type until run-time, then do you think the following is bad practice?... class X { public: .... void GetConfigurationValue() { .... // Get configuration setting, I need a "Derived1" b = new Derived1(); // Now I want to call the special DoSomething for Derived1 (dynamic_cast<Derived1*>(b))->SpecialD1DoSomething(); } private: Base* b; }; I have generally read that usage of dynamic_cast is bad, but as I said, I don't know which type to create until run-time. Please help!

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  • Why doesn't Java Map extends Collection?

    - by polygenelubricants
    I was surprised by the fact that Map<?,?> is not a Collection<?>. I thought it'd make a LOT of sense if it was declared as such: public interface Map<K,V> extends Collection<Map.Entry<K,V>> After all, a Map<K,V> is a collection of Map.Entry<K,V>, isn't it? So is there a good reason why it's not implemented as such?

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  • Domain object validation vs view model validation

    - by Brendan Vogt
    I am using ASP.NET MVC 3 and I am using FluentValidation to validate my view models. I am just a little concerned that I might not be on the correct track. As far as what I know, model validation should be done on the domain object. Now with MVC you might have multiple view models that are similar that needs validation. What happens if a property from a domain object occurs in more than one view model? Now you are validating the same property twice, and they might not even be in sync. So if I have a User domain object then I would like to do validation on this object. Now what happens if I have UserAViewModel and UserBViewModel, so now it is multiple validations that needs to be done. The scenario above is just an example, so please don't critise on it.

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  • help troubleshooting deadlocks in sql server database

    - by Makach
    I've got two database servers, (1) production (2) test on the production database I get frequent deadlocks and I'm trying to find out what is causing it. I take a backup of the database in production and restore it in test and when I perform the exact same scenario that yields deadlocks on the production server I am unable to reproduce in test. any ideas/tips/hints would be much appreciated.

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  • SEO Url Redirect/Rewrite Using Database Managed Links

    - by user204245
    I have searched left and right. And i am trying to find a script or a method on how I can store links in database and use them for redirection. This is an E-commerce project and I am looking for something to manage Product and system URL from database. Something Similar like magneto dose. Basically anything after the domain say like domain.com/demo/12/my_iphone so now demo/12/my_iphone will be sent to database for querry and in databases there will be a destination URL which could be productlisting.php?searchstring=iphones so the user will see link domain.com/demo/12/my_iphone but actualy he will be seeing productlisting.php?searchstring=iphones basically demo/12/my_iphone = productlisting.php?searchstring=iphones and tomorrow if the user want to edit demo/12/my_iphone to demo/12/myiphone he can just do so using simple form which will update in the database. How can i achieve this ?

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  • When should I use a struct instead of a class?

    - by Esteban Araya
    MSDN says that you should use structs when you need lightweight objects. Are there any other scenarios when a struct is preferable over a class? Edit: Some people have forgotten that: 1. structs can have methods! 2. structs have no inheritance capabilites. Another Edit: I understand the technical differences, I just don't have a good feel for WHEN to use a struct.

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  • Fluent NHibernate ExportSchema without connexion string

    - by Vince
    Hi all, I want to propose to user a way to generate database table script creation. To do this for now i use NHibernate ExportSchema bases on a NHibernate configuration generated with Fluent NHibernate this way (during my ISessionFactory creation method): FluentConfiguration configuration = Fluently.Configure(); ... Mapping conf ... configuration.Database(fluentDatabaseProvider); this.nhibernateConfiguration = configuration.BuildConfiguration(); returnSF = configuration.BuildSessionFactory(); ... Later new SchemaExport(this.nhibernateConfiguration) .SetOutputFile(filePath) .Execute(false, false, false); fluentDatabaseProvider is a FluentNHibernate IPersistenceConfigurer which is needed to get proper sql dialect for database creation. When factory is created with an existing database, everything works fine. But what i want to do is to create an NHibernate Configuration object on a selected database engine without a real database behind the scene... And i don't manage to do this. If anybody has some idea.

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  • Is there a design pattern to cut down on code duplication when subclassing Activities in Android?

    - by Daniel Lew
    I've got a common task that I do with some Activities - downloading data then displaying it. I've got the downloading part down pat; it is, of course, a little tricky due to the possibility of the user changing the orientation or cancelling the Activity before the download is complete, but the code is there. There is enough code handling these cases such that I don't want to have to copy/paste it to each Activity I have, so I thought to create an abstract subclass Activity itself such that it handles a single background download which then launches a method which fills the page with data. This all works. The issue is that, due to single inheritance, I am forced to recreate the exact same class for any other type of Activity - for example, I use Activity, ListActivity and MapActivity. To use the same technique for all three requires three duplicate classes, except each extends a different Activity. Is there a design pattern that can cut down on the code duplication? As it stands, I have saved much duplication already, but it pains me to see the exact same code in three classes just so that they each subclass a different type of Activity.

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  • How to amend return value design in OO manner?

    - by FrontierPsycho
    Hello. I am no newb on OO programming, but I am faced with a puzzling situation. I have been given a program to work on and extend, but the previous developers didn't seem that comfortable with OO, it seems they either had a C background or an unclear understanding of OO. Now, I don't suggest I am a better developer, I just think that I can spot some common OO errors. The difficult task is how to amend them. In my case, I see a lot of this: if (ret == 1) { out.print("yadda yadda"); } else if (ret == 2) { out.print("yadda yadda"); } else if (ret == 3) { out.print("yadda yadda"); } else if (ret == 0) { out.print("yadda yadda"); } else if (ret == 5) { out.print("yadda yadda"); } else if (ret == 6) { out.print("yadda yadda"); } else if (ret == 7) { out.print("yadda yadda"); } ret is a value returned by a function, in which all Exceptions are swallowed, and in the catch blocks, the above values are returned explicitly. Oftentimes, the Exceptions are simply swallowed, with empty catch blocks. It's obvious that swalllowing exceptions is wrong OO design. My question concerns the use of return values. I believe that too is wrong, however I think that using Exceptions for control flow is equally wrong, and I can't think of anything to replace the above in a correct, OO manner. Your input, please?

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  • Pattern for iPhone background loading during init?

    - by Rob S.
    Hi everyone, I'm currently kicking off a background thread to do some REST queries in my app delegate's didFinishLaunchingWithOptions. This thread creates some objects and populates the model as the rest of the app continues to load (because I don't block, and didFinishLaunchingWithOptions returns YES). I also put up a loading UIViewController 'on top' of the main view that I tear down after the background initialization is complete. My problem is that I need to notify the first view (call it the Home view) that the model is ready, and that it should populate itself. The trick is that the background download could have finished before Home.viewDidAppear is called, or any of the other Home.initX methods. I'm having difficulty synchronizing all of this and I've thought about it long enough that it feels like I'm barking up the wrong tree. Are there any patterns here for this sort of thing? I'm sure other apps start by performing lengthy operations with loading screens :) Thanks!

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  • How to determine if object in another AppDomain has gone

    - by Dmitry Lobanov
    I instantiate an object of some class in other ApDomain using CreateInstanceAndUnwrap(). I can determine if this object resides in other domain by using RemotingServices.IsTransparentProxy(). But can I determine if the real remote object has gone away (e.g. was garbage collected) without probing a call on proxy and catching RemotingException? Is it possible?

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  • How to call virtual function of an object in C++

    - by SoonDead
    I'm struggling with calling a virtual function in C++. I'm not experienced in C++, I mainly use C# and Java so I might have some delusions, but bear with me. I have to write a program where I have to avoid dynamic memory allocation if possible. I have made a class called List: template <class T> class List { public: T items[maxListLength]; int length; List() { length = 0; } T get(int i) const { if (i >= 0 && i < length) { return items[i]; } else { throw "Out of range!"; } }; // set the value of an already existing element void set(int i, T p) { if (i >= 0 && i < length) { items[i] = p; } else { throw "Out of range!"; } } // returns the index of the element int add(T p) { if (length >= maxListLength) { throw "Too many points!"; } items[length] = p; return length++; } // removes and returns the last element; T pop() { if (length > 0) { return items[--length]; } else { throw "There is no element to remove!"; } } }; It just makes an array of the given type, and manages the length of it. There is no need for dynamic memory allocation, I can just write: List<Object> objects; MyObject obj; objects.add(obj); MyObject inherits form Object. Object has a virtual function which is supposed to be overridden in MyObject: struct Object { virtual float method(const Input& input) { return 0.0f; } }; struct MyObject: public Object { virtual float method(const Input& input) { return 1.0f; } }; I get the elements as: objects.get(0).method(asdf); The problem is that even though the first element is a MyObject, the Object's method function is called. I'm guessing there is something wrong with storing the object in an array of Objects without dynamically allocating memory for the MyObject, but I'm not sure. Is there a way to call MyObject's method function? How? It's supposed to be a heterogeneous collection btw, so that's why the inheritance is there in the first place. If there is no way to call the MyObject's method function, then how should I make my list in the first place?

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  • Existing SQL database android help

    - by basketball4567
    Hey guys, I am new to android programming and i am trying to make an app that will interface with a website i have. It is a movie website with all of its information stored in SQL database. I know how to write the requests and queries in .asp but dont know how to get information from the database in my app. I want the user to be able to enter a movie title, and through a couple of stored procedures that are in my SQL database, return the info on that movie(actor, budget, genre....). I would like to have little info stored on the device, have all of the queries being sent to my SQL server and just have the info being returned. So my question boils down to, how do i link my existing SQL database with an android app. Any help would be great. Thanks Basketball4567

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