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• How can I model the data in a multi-language data editor in WPF with MVVM?

  - by Patrick Szalapski

  Are there any good practices to follow when designing a model/ViewModel to represent data in an app that will view/edit that data in multiple languages? Our top-level class--let's call it Course--contains several collection properties, say Books and TopicsCovered, which each might have a collection property among its data. For example, the data needs to represent course1.Books.First().Title in different languages, and course1.TopicsCovered.First().Name in different languages. We want a app that can edit any of the data for one given course in any of the available languages--as well as edit non-language-specific data, perhaps the Author of a Book (i.e. course1.Books.First().Author). We are having trouble figuring out how best to set up the model to enable binding in the XAML view. For example, do we replace (in the single-language model) each String with a collection of LanguageSpecificString instances? So to get the author in the current language: course1.Books.First().Author.Where(Function(a) a.Language = CurrentLanguage).SingleOrDefault If we do that, we cannot easily bind to any value in one given language, only to the collection of language values such as in an ItemsControl. <TextBox Text={Binding Author.???} /> <!-- no way to bind to the current language author --> Do we replace the top-level Course class with a collection of language-specific Courses? So to get the author in the current language: course1.GetLanguage(CurrentLanguage).Books.First.Author If we do that, we can only easily work with one language at a time; we might want a view to show one language and let the user edit the other. <TextBox Text={Binding Author} /> <!-- good --> <TextBlock Text={Binding ??? } /> <!-- no way to bind to the other language author --> Also, that has the disadvantage of not representing language-neutral data as such; every property (such as Author) would seem to be in multiple languages. Even non-string properties would be in multiple languages. Is there an option in between those two? Is there another way that we aren't thinking of? I realize this is somewhat vague, but it would seem to be a somewhat common problem to design for. Note: This is not a question about providing a multilingual UI, but rather about actually editing multi-language data in a flexible way.

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• C# Reading and Writing a Char[] to and from a Byte[]

  - by Simon G

  Hi, I have a byte array of around 10,000 bytes which is basically a blob from delphi that contains char, string, double and arrays of various types. This need to be read in and updated via C#. I've created a very basic reader that gets the byte array from the db and converts the bytes to the relevant object type when accessing the property which works fine. My problem is when I try to write to a specific char[] item, it doesn't seem to update the byte array. I've created the following extensions for reading and writing: public static class CharExtension { public static byte ToByte( this char c ) { return Convert.ToByte( c ); } public static byte ToByte( this char c, int position, byte[] blob ) { byte b = c.ToByte(); blob[position] = b; return b; } } public static class CharArrayExtension { public static byte[] ToByteArray( this char[] c ) { byte[] b = new byte[c.Length]; for ( int i = 1; i < c.Length; i++ ) { b[i] = c[i].ToByte(); } return b; } public static byte[] ToByteArray( this char[] c, int positon, int length, byte[] blob ) { byte[] b = c.ToByteArray(); Array.Copy( b, 0, blob, positon, length ); return b; } } public static class ByteExtension { public static char ToChar( this byte[] b, int position ) { return Convert.ToChar( b[position] ); } } public static class ByteArrayExtension { public static char[] ToCharArray( this byte[] b, int position, int length ) { char[] c = new char[length]; for ( int i = 0; i < length; i++ ) { c[i] = b.ToChar( position ); position += 1; } return c; } } to read and write chars and char arrays my code looks like: Byte[] _Blob; // set from a db field public char ubin { get { return _tariffBlob.ToChar( 14 ); } set { value.ToByte( 14, _Blob ); } } public char[] usercaplas { get { return _tariffBlob.ToCharArray( 2035, 10 ); } set { value.ToByteArray( 2035, 10, _Blob ); } } So to write to the objects I can do: ubin = 'C'; // this will update the byte[] usercaplas = new char[10] { 'A', 'B', etc. }; // this will update the byte[] usercaplas[3] = 'C'; // this does not update the byte[] I know the reason is that the setter property is not being called but I want to know is there a way around this using code similar to what I already have? I know a possible solution is to use a private variable called _usercaplas that I set and update as needed however as the byte array is nearly 10,000 bytes in length the class is already long and I would like a simpler approach as to reduce the overall code length and complexity. Thank

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• JavaScript: using constructor without operator 'new'

  - by GetFree

  Please help me to understand why the following code works: <script> var re = RegExp('\\ba\\b') ; alert(re.test('a')) ; alert(re.test('ab')) ; </script> In the first line there is no new operator. As far as I know, a contructor in JavaScript is a function that initialize objects created by the operator new and they are not meant to return anything.

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• Hibernate mapping to object that already exists

  - by teehoo

  I have two classes, ServiceType and ServiceRequest. Every ServiceRequest must specify what kind of ServiceType it is. All ServiceType's are predefined in the database, and ServiceRequest is created at runtime by the client. Here are my .hbm files: <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceRequest" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="quantity"> <column name="quantity" not-null="true"/> </property> <many-to-one cascade="all" class="xxx.model.entity.ServiceType" column="service_type" name="serviceType" not-null="false" unique="false"/> </class> </hibernate-mapping> and <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceType" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="description"> <column name="description" not-null="false"/> </property> <property name="cost"> <column name="cost" not-null="true"/> </property> <property name="enabled"> <column name="enabled" not-null="true"/> </property> </class> </hibernate-mapping> When I run this, I get com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails I think my problem is that when I create a new ServiceRequest object, ServiceType is one of its properties, and therefore when I'm saving ServiceRequest to the database, Hibernate attempts to insert the ServiceType object once again, and finds that it is already exists. If this is the case, how do I make it so that Hibernate points to the exists ServiceType instead of trying to insert it again?

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• Order SimpleXMLElement by element

  - by ron

  Hi everyone I need to order a SimpleXMLElement by a node called padre like this. $xml = new SimpleXMLElement('sitemap.xml',null,true); sort($xml, "padre" ); foreach($xml as $url ) { echo "loc}' title='".rescue_name($url-loc)."'".rescue_name($url-loc)." {$url-padre}"; } I don't know why is not working please let me know what is my error. Thanks in advance

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• Design Technique: How to design a complex system for processing orders, products and units.

  - by Shyam

  Hi, Programming is fun: I learned that by trying out simple challenges, reading up some books and following some tutorials. I am able to grasp the concepts of writing with OO (I do so in Ruby), and write a bit of code myself. What bugs me though is that I feel re-inventing the wheel: I haven't followed an education or found a book (a free one that is) that explains me the why's instead of the how's, and I've learned from the A-team that it is the plan that makes it come together. So, armed with my nuby Ruby skills, I decided I wanted to program a virtual store. I figured out the following: My virtual Store will have: Products and Services Inventories Orders and Shipping Customers Now this isn't complex at all. With the help of some cool tools (CMapTools), I drew out some concepts, but quickly enough (thanks to my inferior experience in designing), my design started to bite me. My very first product-line were virtual "laptops". So, I created a class (Ruby): class Product attr_accessor :name, :price def initialize(name, price) @name = name @price = price end end which can be instantiated by doing (IRb) x = Product.new("Banana Pro", 250) Since I want my virtual customers to be able to purchase more than one product, or various types, I figured out I needed some kind of "Order" mechanism. class Order def initialize(order_no) @order_no = order_no @line_items = [] end def add_product(myproduct) @line_items << myproduct end def show_order() puts @order_no @line_items.each do |x| puts x.name.to_s + "\t" + x.price.to_s end end end that can be instantiated by doing (IRb) z = Order.new(1234) z.add_product(x) z.show_order Splendid, I have now a very simple ordering system that allows me to add products to an order. But, here comes my real question. What if I have three models of my product (economy, business, showoff)? Or have my products be composed out of separate units (bigger screen, nicer keyboard, different OS)? Surely I could make them three separate products, or add complexity to my product class, but I am looking for are best practices to design a flexible product object that can be used in the real world, to facilitate a complex system. My apologies if my grammar and my spelling are with error, as english is not my first language and I took the time to check as far I could understand and translate properly! Thank you for your answers, comments and feedback!

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• Why doesn't Java support generic Throwables?

  - by polygenelubricants

  class Bouncy<T> extends Throwable { } // Error: the generic class Bouncy<T> may not subclass java.lang.Throwable Why doesn't Java support generic Throwables?

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• What's the point of this in objective-c

  - by Mk12

  SomeObject *temp = [[SomeObject alloc] init] self.theObject = temp; [temp release]; Why is it always done that way? Why not self.theObject = [[SomeObject alloc] init];

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• how to write a constructor...

  - by Nima

  is that correct to write a constructor like this? class A { A::A(const A& a) { .... } }; if yes, then is it correct to invoke it like this: A* other; ... A* instance = new A(*(other)); if not, what do you suggest? Thanks

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• How to check null objects in jQuery

  - by Prashant

  I am using jQuery, I want to check existence of an element in my page. I have done following code, but its not working? if ($("#btext" + i) != null){ //alert($("#btext" + i).text()); $("#btext" + i).text("Branch " + i); } Please tell me what will be the right code? Thanks

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• Why Java interfaces can't have constructors?

  - by AndrejaKo

  This question showed up on my mid-term exams and I've been searching for correct answer for some time. I know that Java interfaces can't be directly instantiated so they don't need constructors and that they can have only public static final attributes so they don't need constructors to set them up but that's not the expected answer.

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• Entity Framework 4 missing features?

  - by Roger Alsing

  I'm well aware that similair topics have been brought up before e.g. http://stackoverflow.com/questions/1639043/entity-framework-4-vs-nhibernate But instead of arguments like: NHibernate have been around longer and is more mature EF4 is drag n drop and not enterprisy EF4 and LinqToSql are ... I would like to see a more detailed list of features that you consider missing from EF4. Personally, I think the lack of enum support is the biggest drawback of EF4.

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• domain modeling naming problem

  - by cherouvim

  Hello There are some simple entities in an application (e.g containing only id and title) which rarely change and are being referenced by the more complex entities of the application. These are usually entities such as Country, City, Language etc. How are these called? I've used the following names for those in the past but I'm not sure which is the best way to call them: reference data lookup values dictionaries thanks

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• use inheritance to create a custom, type safe, null safe collection ?

  - by pointlesspolitics

  I am not clear with above statement. It would be great if anybody can explain how we can use inheritance to create a custom, type safe and null safe collection ? Thanks

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• Extended properties with Entity Framework or NHibernate

  - by Artem Tikhomirov

  Hello, everyone! Is there are an easy way to store some of entitie's properties in a column as a bulk, as XML or something? Querieng by those properties of course is not an option, but it still'd be valuble to be able to extend data model without database migration.

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• Do you think functional language is good for applications that have a lot of business rules but very

  - by StackUnderflow

  I am convinced that functional programming is an excellent choice when it comes to applications that require a lot of computation (data mining, AI, nlp etc). But is it wise to use functional programming for a typical enterprise application where there are a lot of business rules but not much in terms of computation? Please disregard the fact that there are very few people using functional programming and that it's kind of tough. Thanks

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• C++ keeping a list of objects and calling a contructor through another function

  - by Nona Urbiz

  why isnt my object being created? When I do it like so, I am told error C2065: 'AllReferrals' : undeclared identifier as well as error C2228: left of '.push_back' must have class/struct/union. If I put the list initialization before the class I get error C2065: 'AllReferrals' : undeclared identifier. Thanks! #include <iostream> #include <fstream> #include <regex> #include <string> #include <list> #include <map> using namespace std; using namespace tr1; class Referral { public: string url; map<string, int> keywords; static bool submit(string url, string keyword, int occurrences) { //if(lots of things i'll later add){ Referral(url, keyword, occurrences); return true; //} //else // return false; } private: list<string> urls; Referral(string url, string keyword, int occurrences) { url = url; keywords[keyword] = occurrences; AllReferrals.push_back(this); } }; static list<Referral> AllReferrals; int main() { Referral::submit("url", "keyword", 1); cout << AllReferrals.size(); cout << "\n why does that ^^ say 0 (help me make it say one)?"; cout << "\n and how can i AllReferrals.push_back(this) from my constructor?"; cout << " When I do it like so, I am told error C2065: 'AllReferrals' : undeclared identifier"; cout << " as well as error C2228: left of '.push_back' must have class/struct/union."; cout << " If I put the list initialization before the class I get error C2065: 'AllReferrals' : undeclared identifier."; cout << "\n\n\t Thanks!"; getchar(); }

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• Hibernate - EhCache - Which region to Cache associations/sets/collections ??

  - by lifeisnotfair

  Hi all, I am a newcomer to hibernate. It would be great if someone could comment over the following query that i have: Say i have a parent class and each parent has multiple children. So the mapping file of parent class would be something like: parent.hbm.xml <hibernate-mapping > <class name="org.demo.parent" table="parent" lazy="true"> <cache usage="read-write" region="org.demo.parent"/> <id name="id" column="id" type="integer" length="10"> <generator class="native"> </generator> </id> <property name="name" column="name" type="string" length="50"/> <set name="children" lazy="true"> <cache usage="read-write" region="org.demo.parent.children" /> <key column="parent_id"/> <one-to-many class="org.demo.children"/> </set> </class> </hibernate-mapping> children.hbm.xml <hibernate-mapping > <class name="org.demo.children" table="children" lazy="true"> <cache usage="read-write" region="org.demo.children"/> <id name="id" column="id" type="integer" length="10"> <generator class="native"> </generator> </id> <property name="name" column="name" type="string" length="50"/> <many-to-one name="parent_id" column="parent_id" type="integer" length="10" not-null="true"/> </class> </hibernate-mapping> So for the set children, should we specify the region org.demo.parent.children where it should cache the association or should we use the cache region of org.demo.children where the children would be getting cached. I am using EHCache as the 2nd level cache provider. I tried to search for the answer to this question but couldnt find any answer in this direction. It makes more sense to use org.demo.children but I dont know in which scenarios one should use a separate cache region for associations/sets/collections as in the above case. Kindly provide your inputs also let me know if I am not clear in my question. Thanks all.

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• Creating relationship between two model instances

  - by Lowgain

  This is probably pretty simple, but here: Say I've got two models, Thing and Tag class Thing < ActiveRecord::Base has_and_belongs_to_many :tags end class Tag < ActiveRecord::Base has_and_belongs_to_many :things end And I have an instance of each. I want to link them. Can I do something like: @thing = Thing.find(1) @tag = Tag.find(1) @thing.tags.add(@tag) If not, what is the best way to do this? Thanks!

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• when to make a method static

  - by Don

  Hi, I'd like to know how people decide whether to define a method as static. I'm aware that a method can only be defined as static if it doesn't require access to instance fields. So lets say we have a method that does not access instance fields, do you always define such a method as static, or only if you need to call it statically (without a reference to an instance). Perhaps another way of asking the same question, is whether you use static or non-static as the default? Thanks, Don

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• Returning different data types C#

  - by user1810659

  i have create a class library (DLL) with many different methods. and the return different types of data(string string[] double double[]). Therefore i have created one class i called CustomDataType for all the methods containing different data types so each method in the Library can return object of the custom class and this way be able to return multiple data types I have done it like this: public class CustomDataType { public double Value; public string Timestamp; public string Description; public string Unit; // special for GetparamterInfo public string OpcItemUrl; public string Source; public double Gain; public double Offset; public string ParameterName; public int ParameterID; public double[] arrayOfValue; public string[] arrayOfTimestamp; // public string[] arrayOfParameterName; public string[] arrayOfUnit; public string[] arrayOfDescription; public int[] arrayOfParameterID; public string[] arrayOfItemUrl; public string[] arrayOfSource; public string[] arrayOfModBusRegister; public string[] arrayOfGain; public string[] arrayOfOffset; } The Library contains methods like these: public CustomDataType GetDeviceParameters(string deviceName) { ...................... code getDeviceParametersObj.arrayOfParameterName; return getDeviceParametersObj; } public CustomDataType GetMaxMin(string parameterName, string period, string maxMin) { .....................................code getMaxMingObj.Value = (double)reader["MaxMinValue"]; getMaxMingObj.Timestamp = reader["MeasurementDateTime"].ToString(); getMaxMingObj.Unit = reader["Unit"].ToString(); getMaxMingObj.Description = reader["Description"].ToString(); return getMaxMingObj; } public CustomDataType GetSelectedMaxMinData(string[] parameterName, string period, string mode) {................................code selectedMaxMinObj.arrayOfValue = MaxMinvalueList.ToArray(); selectedMaxMinObj.arrayOfTimestamp = MaxMintimeStampList.ToArray(); selectedMaxMinObj.arrayOfDescription = MaxMindescriptionList.ToArray(); selectedMaxMinObj.arrayOfUnit = MaxMinunitList.ToArray(); return selectedMaxMinObj; } As illustrated thi different methods returns different data types,and it works fine for me but when i import the DLL and want to use the methods Visual studio shwos all the data types in the CustomDataType class as suggestion for all the methods even though the return different data.This is illusrtated in the picture below. As we can see from the picture with the suggestion of all the different return data the user can get confused and choose wrong return data for some of the methods. So my question is how can i improve this. so Visual studio suggest just the belonging return data type for each method.

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• Objects with the same set of attributes and methods belongs to the same class?

  - by TiuTalk

  Objects with the same set of attributes and methods belongs to the same class? Can't I declare two identical classes with the same methods and attributes, instanciate them and have "objects with the same set of attributes and methods that belongs to different class"? This question is not about good practices... It's about the logical value (true or false) of the question on the title.

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• Encapsulating a Windows.Forms.Button

  - by devoured elysium

  I want to define a special kind of button that only allows two possible labels: "ON" and "OFF". I decided to inherit from a Windows.Forms.Button to implement this but now I don't know I how should enforce this rule. Should I just override the Text property like this? public override string Text { set { throw new InvalidOperationException("Invalid operation on StartStopButton!"); } } The problem I see with this is that I am breaking the contract that all buttons should have. If any code tries something like foreach (Button button in myForm) { button.Text = "123"; } they will get an Exception if I have any of my special buttons on the form, which is something that isn't expectable. First, because people think of properties just as "public" variables, not methods, second, because they are used to using and setting whatever they want to buttons without having to worry with Exceptions. Should I instead just make the set property do nothing? That could also lead to awkward results: myButton.Text = "abc"; MessageBox.Show(abc); //not "abc"! The general idea from the OO world is to in this kind of cases use Composition instead of inheritance. public class MySpecialButton : <Some class from System.Windows.Forms that already knows how to draw itself on forms> private Button button = new Button(); //I'd just draw this button on this class //and I'd then only show the fields I consider //relevant to the outside world. ... } But to make the Button "live" on a form it must inherit from some special class. I've looked on Control, but it seems to already have the Text property defined. I guess the ideal situation would be to inherit from some kind of class that wouldn't even have the Text property defined, but that'd have position, size, etc properties available. Upper in the hierarchy, after Control, we have Component, but that looks like a really raw class. Any clue about how to achieve this? I know this was a long post :( Thanks

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• One UI for two business objects

  - by JC

  I have an order edit and quote edit screen that are very similar. I want to try to avoid code like this: if (order is Order) SetupScreenForOrder(); if (order is Quote) SetupScreenForQuote(); But maintaining two screens is not good either. If I create some common interface between a Quote and Order then how do you deal with fields like OrderNumber or QuoteDate? What's the best way to handle this?

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• Why are interfaces unusable in PHP?

  - by streetparade

  I mean an interface definition without defining the return type makes it unusable? This makes more Clear Interface run { public function getInteger(); } class MyString implements run { public function myNumber() { } public function getInteger() { return "Not a number"; } } In Java every Interface has a return type like Integer,String,Void I know that PHP is unfortunately a loosly typed Language but isnt there a Solution for that Problem? Is it Possible to defining a Interface with a Return type like Integer?

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