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  • Is the ruby operator ||= intelligent?

    - by brad
    I have a question regarding the ||= statement in ruby and this is of particular interest to me as I'm using it to write to memcache. What I'm wondering is, does ||= check the receiver first to see if it's set before calling that setter, or is it literally an alias to x = x || y This wouldn't really matter in the case of a normal variable but using something like: CACHE[:some_key] ||= "Some String" could possibly do a memcache write which is more expensive than a simple variable set. I couldn't find anything about ||= in the ruby api oddly enough so I haven't been able to answer this myself. Of course I know that: CACHE[:some_key] = "Some String" if CACHE[:some_key].nil? would achieve this, I'm just looking for the most terse syntax.

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  • How to map a property for HQL usage only (in Hibernate)?

    - by ManBugra
    i have a table like this one: id | name | score mapped to a POJO via XML with Hibernate. The score column i only need in oder by - clauses in HQL. The value for the score column is calculated by an algorithm and updated every 24 hours via SQL batch process (JDBC). So i dont wanna pollute my POJO with properties i dont need at runtime. For a single column that may be not a problem, but i have several different score columns. Is there a way to map a property for HQL use only? For example like this: <property name="score" type="double" ignore="true"/> so that i still can do this: from Pojo p order by p.score but my POJO implementation can look like this: public class Pojo { private long id; private String name; // ... } No Setter for score provided or property added to implementation. using the latest Hibernate version for Java.

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  • Scala case class generated field value

    - by Petteri Hietavirta
    I have an existing Scala application and it uses case classes which are then persisted in MongoDB. I need to introduce a new field to a case class but the value of it is derived from existing field. For example, there is phone number and I want to add normalised phone number while keeping the original phone number. I'll update the existing records in MongoDB but I would need to add this normalisation feature to existing save and update code. So, is there any nice shortcut in Scala to add a "hook" to a certain field of a case class? For example, in Java one could modify setter of the phone number.

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  • C# DDD Populate Immutable Objects

    - by Russel
    Hi I have a immutable Customer class in my domain assembly. It contains the following GET properties : id, firstname and lastname. I have a CustomerRepository class in my persistence assembly. In turn, this CustomerRepository class should populate and return a Customer object using a remote web-serivce. My Customer class contains no setter properties and it contains a private constructor. The reason - I dont want the UI developer to get the wrong idea - He should not be able to create or change a Customer object. My question: How do I get my CustomerRepository to populate my Customer object. Reflection? Or should I sacrifice my design and enable a public constructor for constructing the customer object?

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  • Send copy of class to view class so it can render him? ( iPhone )

    - by Johannes Jensen
    I'm making a game for the iPhone, and I have a class called Robot. Then I have a class called View, which renders everything. I want to send a copy of my Robot, which I defined in my ViewController, and I send it to gameView (which is View *gameView), like this: robot = [Robot new]; [gameView setRobot: [robot copy]]; I tried to make a copy but that didn't work, I could also do it with a pointer to Robot (&robot) but sometimes it just crashes ? I tried this in my View.h @interface definition: @property (copy) Robot* robot; but I get the error /RobotsAdventure/Classes/View.h:24: error: setter '-robot' argument type does not match property type :/ Help? I'm pretty new at this, heh.

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  • WPF- Is there a way to stop TreeViewItems from becoming selected and activated when thier parent TreeViewItem is selected?

    - by Justin
    I have a control template for TreeViewItems and instead of showing the normal FocusVisualStyle I have a MultiTrigger set up like this: <MultiTrigger> <MultiTrigger.Conditions> <Condition Property="IsSelected" Value="true"/> <Condition Property="IsSelectionActive" Value="true"/> </MultiTrigger.Conditions> <Setter Property="FontWeight" Value="Bold"/> </MultiTrigger> However this also causes the FontWeight to change to bold when a TreeViewItem's parent item is selected. Is there any way I can stop that from happening?

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  • How do I define the default background color for window instances in a shared ResourceDictionary?

    - by Nicholas
    I can't seem to set a default background color for all of my windows in my application. Does anyone know how to do this? Currently I'm setting a theme in my App.xaml file like this. <Application> <Application.Resources> <ResourceDictionary Source="Themes/SomeTheme.xaml" /> This basically styles my entire application. Inside of SomeTheme.xaml I am trying to set a default color for all of my windows like this. <Style TargetType="{x:Type Window}"> <Setter Property="Background" Value="{DynamicResource MainColor}" /> </Style> This syntax works on a type of Button, but is completely ignored for Window. What am I doing wrong? Is there something special I have to do for a Window type.

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  • Set ListBoxItem.IsSelected when child TextBox is Focused

    - by jpsstavares
    Hi, I have a typical MVVM scenario: I have a ListBox that is binded to a List of StepsViewModels. I define a DataTemplate so that StepViewModels are rendered as StepViews. The StepView UserControl have a set of labels and TextBoxs. What I want to do is to select the ListBoxItem that is wrapping the StepView when a textBox is focused. I've tried to create a style for my TextBoxs with the following trigger: <Trigger Property="IsFocused" Value="true"> <Setter TargetName="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem}}}" Property="IsSelected" Value="True"/> </Trigger> But I get an error telling me that TextBoxs don't have an IsSelected property. I now that but the Target is a ListBoxItem. How can I make it work?

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  • What's the Difference Between These Two Ruby Class Initialaztion Definitions?

    - by michaelmichael
    I'm working through a book on Ruby, and the author used a slightly different form for writing a class initialization definition than he has in previous sections of the book. It looks like this: class Ticket attr_accessor :venue, :date def initialize(venue, date) self.venue = venue self.date = date end end In previous sections of the book, it would've been defined like this: class Ticket attr_accessor :venue, :date def initialize(venue, date) @venue = venue @date = date end end Is there any functional difference between using the setter method, as in the first example vs. using the instance variable in the second? They both seem to work. Even mixing them up seems to work: class Ticket attr_accessor :venue, :date def initialize(venue, date) @venue = venue self.date = date end end

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  • What's the Difference Between These Two Ruby Class Initialization Definitions?

    - by michaelmichael
    I'm working through a book on Ruby, and the author used a slightly different form for writing a class initialization definition than he has in previous sections of the book. It looks like this: class Ticket attr_accessor :venue, :date def initialize(venue, date) self.venue = venue self.date = date end end In previous sections of the book, it would've been defined like this: class Ticket attr_accessor :venue, :date def initialize(venue, date) @venue = venue @date = date end end Is there any functional difference between using the setter method, as in the first example, vs. using the instance variable as in the second? They both seem to work. Even mixing them up works: class Ticket attr_accessor :venue, :date def initialize(venue, date) @venue = venue self.date = date end end

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  • listbox isSelected databinding in DataTemplate

    - by Kinmarui
    I try to simply databind IsSelected property with IsSelected field in my class. But after I change the value in code its doesn't change the property, neither does clicking on ListBoxItem change the field value. XAML: <FlipView ItemsSource="{Binding Source={StaticResource itemsViewSource}}" ... > <FlipView.ItemTemplate> <DataTemplate> <UserControl Loaded="StartLayoutUpdates" Unloaded="StopLayoutUpdates"> <!-- other controls --> <ListBox Grid.Row="1" Grid.ColumnSpan="3" SelectionMode="Multiple" VerticalAlignment="Center" ItemsSource="{Binding Answers}"> <ListBox.Resources> <local:LogicToText x:Key="logToText" /> </ListBox.Resources> <!-- bind IsSelected only in one way from code to content --> <ItemsControl.ItemTemplate> <DataTemplate> <ListBoxItem IsSelected="{Binding IsSelected, Mode=TwoWay, Converter={StaticResource logToText}}" Content="{Binding IsSelected, Mode=TwoWay, Converter={StaticResource logToText}}"> </ListBoxItem> </DataTemplate> </ItemsControl.ItemTemplate> <!-- not working at all <ListBox.Resources> <Style TargetType="ListBoxItem"> <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}"/> <Setter Property="Content" Value="{Binding IsSelected, Mode=TwoWay}"/> </Style> </ListBox.Resources>--> </ListBox> </UserControl> </DataTemplate> </FlipView.ItemTemplate> </FlipView> Code: Answers private ObservableCollection<PrawoJazdyDataAnswer> _answers = new ObservableCollection<PrawoJazdyDataAnswer>(); public ObservableCollection<PrawoJazdyDataAnswer> Answers { get { return this._answers; } } Single item(Answer) public class PrawoJazdyDataAnswer : NPCHelper// PrawoJazdy.Common.BindableBase { public PrawoJazdyDataAnswer(String ans, bool ansb) { this._ans = ans; this._isSelected = ansb; } public override string ToString() { return _isSelected.ToString(); } //Only For debug purposes normally return _ans; private string _ans; public string Ans { get { return this._ans; } //set { this.SetProperty(ref this._ans, value); } } private bool _isSelected; public bool IsSelected { get { return this._isSelected; } set { _isSelected = value; FirePropertyChanged("IsSelected"); //this.SetProperty(ref this._isSelected, value); } } } FirePropertyChanged public class NPCHelper : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public void FirePropertyChanged(string prop) { if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(prop)); } } Converter(which sometimes seems to be needed and others not..., I tried ~10 approaches from different tutorials/examples) public class LogicToText : IValueConverter { /// <summary> /// /// </summary> public object Convert(object value, Type targetType, object parameter, string language) { //if (value == null || (bool)value == false) // return "False"; return value.ToString(); } /// <summary> /// /// </summary> public object ConvertBack(object value, Type targetType, object parameter, string language) { return value.ToString().Contains("True") ? true : false; } Thanks in advance, and sorry for my English(still learning). @edit Thanks for quick reply. For test purposes i created a button and text block: It's in other controls part (above list box, but in FlipView) <Button Click="spr" >Sprawdz</Button> <TextBlock Text="{Binding Answers[0].IsSelected, Mode=TwoWay}" > </TextBlock> Click method private void spr(object sender, RoutedEventArgs e) { var ans = ((PrawoJazdyDataQuestion)this.flipView.SelectedItem).Answers; foreach (var item in ans) item.IsSelected = item.IsSelected ? false : true; } As I wrote when i'm changing data from code side its change text, but not appearance of ListBoxItem, and if i just select it on ListBox its doesn't change the date i textblock neither in ListBox itself.

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  • how do you find the exact variable of a null pointer exception

    - by OVERTONE
    I've been at this one for a bit now. I've got a null pointer exception so im guessing somethings not been initialized. AdminMessages.inbox1.setText(messageRsetArray[0]); thats my code where its targetting. but i cant find what inside it hasnt been initiazed. AdminMessages is a class which contains a JTextField called inbox1, messageRsetArray is an array which has taken variables from an array. also inbox1 is static. i coulndt get the getters and setter to work. i know its bad practice though.

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  • WPF/XAML - compare the "SelectedIndex" of two comboboxes (DataTrigger?)

    - by Luaca
    hello, i've got two comboboxes with the same content. the user should not be allowed to choose the same item twice. therefore the comboboxes' contents (= selectedindex?) should never be equal. my first attempt was to comapare the selectedindex with a datatrigger to show/hide a button: <DataTrigger Binding="{Binding ElementName=comboBox1, Path=SelectedIndex}" Value="{Binding ElementName=comboBox2, Path=SelectedIndex}"> <Setter Property="Visibility" Value="Hidden" /> </DataTrigger> it seems that it is not possible to use Value={Binding}. is there any other way (if possible without using a converter)? thanks in advance!

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  • NoSuchMethodException while using JAVA Reflection

    - by Appps
    Hi I'm trying to use reflection to invoke a method and update the setter value of that method. But I'm getting NoSuchMethodException while ivoking that method. com.test.Test.setAddress1(java.lang.Double) .But I've this method defined in my Class. Is the problem with my code. Can someone please help me? Thanks in advance. I've my code below. Class[] doubleArrayParamTypes = new Class[ 1 ]; doubleArrayParamTypes[ 0 ] = Double.class; Class class=Class.forName( "com.test.Test"); Object voObject = class.newInstance(); String data="TestData"; performMapping(class,"setAddress1",doubleArrayParamTypes ,voObject,data); /* Reflection to set the data */ private void performMapping(Class class,String methodName,Class[] clazz,Object voObject,Object data) { class.getMethod( "set" + methodName, clazz ).invoke( voObject, data ); }

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  • Does Core Data automatically validate new values when they are set?

    - by mystify
    In this question, someone asked how to write a validation method for Core Data. I did that, and it looks cool. But one thing doesn't happen: The validation. I can easily set any "bad" value and this method doesn't get called automatically. What's the concept behind this? Must I always first call the validation method before setting any value? So would I write setter methods which call the appropriate validation method first? And if yes, what's the point of following a strict convention in how to write the validation method signature? I guess there's also some automatic way of validation, then. How to activate this?

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  • WPF Button on or off coloured state

    - by wonea
    I'm trying to create a set of button which have an off or on state, much a checkbox without the check. Ideally I want the colour to change to represent the two different states off(red), green(on). I've tried setting a control template but this only changes the colour for a selection, then reverts back to it's original colour once the mouse leaves the button's vicinity. <ControlTemplate.Triggers> <Trigger Property="IsPressed" Value="True"> <Setter Property="Background" TargetName="Background" Value="Green"/> </Trigger> </ControlTemplate.Triggers>

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  • TDD, Unit Test and architectural changes

    - by Leandro
    I'm writing an RPC middleware in C++. I have a class named RPCClientProxy that contains a socket client inside: class RPCClientProxy { ... private: Socket* pSocket; ... } The constructor: RPCClientProxy::RPCClientProxy(host, port) { pSocket = new Socket(host, port); } As you can see, I don't need to tell the user that I have a socket inside. Although, to make unit tests for my proxies it would be necessary to create mocks for sockets and pass them to the proxies, and to do so I must use a setter or pass a factory to the sockets in the proxies's constructors. My question: According to TDD, is it acceptable to do it ONLY because the tests? As you can see, these changes would change the way the library is used by a programmer.

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  • Show/Hide GridView Header in ListView

    - by Chris
    I have a ListView in WPF, and I want to hide the headers for the ListView when the List the ItemsSource is bound to is null, and display the headers when the ItemsSource is not null and has at least 1 item in the collection. I have found the code online to hide the ListView headers like this: <Window.Resources> <Style x:Key="HideListViewHeaders" TargetType="{x:Type GridViewColumnHeader}"> <Setter Property="Visibility" Value="Collapsed" /> </Style> </Window.Resources> Thanks for any help!

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  • WPF: Set style on immediate children only

    - by ollifant
    In my application I have a tab control which has several tab items. The problem is that I want to apply a style to these tab items, but to no other (nested) tab items. I have tried setting the following style on the tab control, but this also effects all children: <Style x:Key="tabControlStyle" TargetType="{x:Type TabControl}"> <Setter Property="TabItem.Template" Value="{StaticResource tabItemTemplate}" /> </Style> By using the code above I get the following error: 'TabItem' ControlTemplate TargetType does not match templated type 'TabControl', as TabItem and TabControl have the same DependencyProperty "Template", and the code tries to set the TabItemTemplate as TabControl- Template. Can anybody help me?

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  • How to implement collection with covariance when delegating to another collection for storage?

    - by memelet
    I'm trying to implement a type of SortedMap with extended semantics. I'm trying to delegate to SortedMap as the storage but can't get around the variance constraints: class IntervalMap[A, +B](implicit val ordering: Ordering[A]) //extends ... { var underlying = SortedMap.empty[A, List[B]] } Here is the error I get. I understand why I get the error (I understand variance). What I don't get is how to implement this type of delegation. And yes, the covariance on B is required. error: covariant type B occurs in contravariant position in type scala.collection.immutable.SortedMap[A,List[B]] of parameter of setter underlying_=

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  • Why the data binding in this validation example works in WPF?

    - by MartyIX
    I'm wondering how exactly the XAML sample (MSDN sample) works: <Style x:Key="textBoxInError" TargetType="{x:Type TextBox}"> <Style.Triggers> <Trigger Property="Validation.HasError" Value="true"> <Setter Property="ToolTip" Value="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=(Validation.Errors)[0].ErrorContent}"/> </Trigger> </Style.Triggers> </Style> Questions: (Validation.Errors)[0].ErrorContent - Is this code somehow checked by WPF? Because Validation.Errors may be an empty collection and in ordinary C# code this code may throw an exception. If this data-binding returns null for valid input - the null value is then casted to empty string (in a text control for example)? The index 0 corresponds to the first error message. How can I return more error messages from Validate method? Thank you for responses!

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  • Why does FrameworkElement's FindResource() Method Accept an Object and not a String?

    - by ChrisNel52
    I understand that calling FindResource() on a FrameworkElement (e.g. a Window) can be used to find a resource in the FrameworkElement's ResourceDictionary. For example, I've used it many times to access a Style through code to add a new Setter to the Style dynamically. I always pass the x:Key value of the Style as a string into the FindResource() method. Like... Style style = w.FindResource("GridDescriptionColumn") as Style; My question is, I noticed that FindResource() accepts an argument of type object and not an argument of type string. I can't for the life of my think of a reason I would call FindResource() with an argument that is not a string. It makes me think that I may unaware of other ways to use FindResource(). Does anyone know why FindResource() accepts a parameter type of object and not string? If so, what would be an example of calling FindResource() with a parameter type other than a string? Thanks.

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  • Spring security - Reach users ID without passing it through every controller

    - by nilsi
    I have a design issue that I don't know how to solve. I'm using Spring 3.2.4 and Spring security 3.1.4. I have a Account table in my database that looks like this: create table Account (id identity, username varchar unique, password varchar not null, firstName varchar not null, lastName varchar not null, university varchar not null, primary key (id)); Until recently my username was just only a username but I changed it to be the email address instead since many users want to login with that instead. I have a header that I include on all my pages which got a link to the users profile like this: <a href="/project/users/<%= request.getUserPrincipal().getName()%>" class="navbar-link"><strong><%= request.getUserPrincipal().getName()%></strong></a> The problem is that <%= request.getUserPrincipal().getName()%> returns the email now, I don't want to link the user's with thier emails. Instead I want to use the id every user have to link to the profile. How do I reach the users id's from every page? I have been thinking of two solutions but I'm not sure: Change the principal to contain the id as well, don't know how to do this and having problem finding good information on the topic. Add a model attribute to all my controllers that contain the whole user but this would be really ugly, like this. Account account = entityManager.find(Account.class, email); model.addAttribute("account", account); There are more way's as well and I have no clue which one is to prefer. I hope it's clear enough and thank you for any help on this. ====== Edit according to answer ======= I edited Account to implement UserDetails, it now looks like this (will fix the auto generated stuff later): @Entity @Table(name="Account") public class Account implements UserDetails { @Id private int id; private String username; private String password; private String firstName; private String lastName; @ManyToOne private University university; public Account() { } public Account(String username, String password, String firstName, String lastName, University university) { this.username = username; this.password = password; this.firstName = firstName; this.lastName = lastName; this.university = university; } public String getUsername() { return username; } public String getPassword() { return password; } public String getFirstName() { return firstName; } public String getLastName() { return lastName; } public void setUsername(String username) { this.username = username; } public void setPassword(String password) { this.password = password; } public void setFirstName(String firstName) { this.firstName = firstName; } public void setLastName(String lastName) { this.lastName = lastName; } public University getUniversity() { return university; } public void setUniversity(University university) { this.university = university; } public int getId() { return id; } public void setId(int id) { this.id = id; } @Override public Collection<? extends GrantedAuthority> getAuthorities() { // TODO Auto-generated method stub return null; } @Override public boolean isAccountNonExpired() { // TODO Auto-generated method stub return false; } @Override public boolean isAccountNonLocked() { // TODO Auto-generated method stub return false; } @Override public boolean isCredentialsNonExpired() { // TODO Auto-generated method stub return false; } @Override public boolean isEnabled() { // TODO Auto-generated method stub return true; } } I also added <%@ taglib prefix="sec" uri="http://www.springframework.org/security/tags" %> To my jsp files and trying to reach the id by <sec:authentication property="principal.id" /> This gives me the following org.springframework.beans.NotReadablePropertyException: Invalid property 'principal.id' of bean class [org.springframework.security.authentication.UsernamePasswordAuthenticationToken]: Bean property 'principal.id' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter? ====== Edit 2 according to answer ======= I based my application on spring social samples and I never had to change anything until now. This are the files I think are relevant, please tell me if theres something you need to see besides this. AccountRepository.java public interface AccountRepository { void createAccount(Account account) throws UsernameAlreadyInUseException; Account findAccountByUsername(String username); } JdbcAccountRepository.java @Repository public class JdbcAccountRepository implements AccountRepository { private final JdbcTemplate jdbcTemplate; private final PasswordEncoder passwordEncoder; @Inject public JdbcAccountRepository(JdbcTemplate jdbcTemplate, PasswordEncoder passwordEncoder) { this.jdbcTemplate = jdbcTemplate; this.passwordEncoder = passwordEncoder; } @Transactional public void createAccount(Account user) throws UsernameAlreadyInUseException { try { jdbcTemplate.update( "insert into Account (firstName, lastName, username, university, password) values (?, ?, ?, ?, ?)", user.getFirstName(), user.getLastName(), user.getUsername(), user.getUniversity(), passwordEncoder.encode(user.getPassword())); } catch (DuplicateKeyException e) { throw new UsernameAlreadyInUseException(user.getUsername()); } } public Account findAccountByUsername(String username) { return jdbcTemplate.queryForObject("select username, firstName, lastName, university from Account where username = ?", new RowMapper<Account>() { public Account mapRow(ResultSet rs, int rowNum) throws SQLException { return new Account(rs.getString("username"), null, rs.getString("firstName"), rs.getString("lastName"), new University("test")); } }, username); } } security.xml <?xml version="1.0" encoding="UTF-8"?> <beans:beans xmlns="http://www.springframework.org/schema/security" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans" xsi:schemaLocation="http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.1.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd"> <http pattern="/resources/**" security="none" /> <http pattern="/project/" security="none" /> <http use-expressions="true"> <!-- Authentication policy --> <form-login login-page="/signin" login-processing-url="/signin/authenticate" authentication-failure-url="/signin?error=bad_credentials" /> <logout logout-url="/signout" delete-cookies="JSESSIONID" /> <intercept-url pattern="/addcourse" access="isAuthenticated()" /> <intercept-url pattern="/courses/**/**/edit" access="isAuthenticated()" /> <intercept-url pattern="/users/**/edit" access="isAuthenticated()" /> </http> <authentication-manager alias="authenticationManager"> <authentication-provider> <password-encoder ref="passwordEncoder" /> <jdbc-user-service data-source-ref="dataSource" users-by-username-query="select username, password, true from Account where username = ?" authorities-by-username-query="select username, 'ROLE_USER' from Account where username = ?"/> </authentication-provider> <authentication-provider> <user-service> <user name="admin" password="admin" authorities="ROLE_USER, ROLE_ADMIN" /> </user-service> </authentication-provider> </authentication-manager> </beans:beans> And this is my try of implementing a UserDetailsService public class RepositoryUserDetailsService implements UserDetailsService { private final AccountRepository accountRepository; @Autowired public RepositoryUserDetailsService(AccountRepository repository) { this.accountRepository = repository; } @Override public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException { Account user = accountRepository.findAccountByUsername(username); if (user == null) { throw new UsernameNotFoundException("No user found with username: " + username); } return user; } } Still gives me the same error, do I need to add the UserDetailsService somewhere? This is starting to be something else compared to my initial question, I should maybe start another question. Sorry for my lack of experience in this. I have to read up.

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  • selectOneMenu - java.lang.NullPointerException when adding record to the database (JSF2 and JPA2-OpenJPA)

    - by rogie
    Good day to all; I'm developing a program using JSF2 and JPA2 (OpenJPA). Im also using IBM Rapid App Dev't v8 with WebSphere App Server v8 test server. I have two simple entities, Employee and Department. Each Department has many Employees and each Employee belongs to a Department (using deptno and workdept). My problem occurs when i tried to add a new employee and selecting a department from a combo box (using selectOneMenu - populated from Department table): when i run the program, the following error messages appeared: An Error Occurred: java.lang.NullPointerException Caused by: java.lang.NullPointerException - java.lang.NullPointerException I also tried to make another program using Deptno and Workdept as String instead of integer, still doesn't work. Pls help. Im also a newbie. Tnx and God bless. Below are my codes, configurations and setup. Just tell me if there are some codes that I forgot to include. Im also using Derby v10.5 as my database: CREATE SCHEMA RTS; CREATE TABLE RTS.DEPARTMENT (DEPTNO INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1), DEPTNAME VARCHAR(30)); ALTER TABLE RTS.DEPARTMENT ADD CONSTRAINT PK_DEPARTMNET PRIMARY KEY (DEPTNO); CREATE TABLE RTS.EMPLOYEE (EMPNO INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1), NAME VARCHAR(50), WORKDEPT INTEGER); ALTER TABLE RTS.EMPLOYEE ADD CONSTRAINT PK_EMPLOYEE PRIMARY KEY (EMPNO); Employee and Department Entities package rts.entities; import java.io.Serializable; import javax.persistence.*; @Entity public class Employee implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int empno; private String name; //bi-directional many-to-one association to Department @ManyToOne @JoinColumn(name="WORKDEPT") private Department department; ....... getter and setter methods package rts.entities; import java.io.Serializable; import javax.persistence.*; import java.util.List; @Entity public class Department implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int deptno; private String deptname; //bi-directional many-to-one association to Employee @OneToMany(mappedBy="department") private List<Employee> employees; ....... getter and setter methods JSF 2 snipet using combo box (populated from Department table) <tr> <td align="left">Department</td> <td style="width: 5px">&#160;</td> <td><h:selectOneMenu styleClass="selectOneMenu" id="department1" value="#{pc_EmployeeAdd.employee.department}"> <f:selectItems value="#{DepartmentManager.departmentSelectList}" id="selectItems1"></f:selectItems> </h:selectOneMenu></td> </tr> package rts.entities.controller; import com.ibm.jpa.web.JPAManager; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import com.ibm.jpa.web.NamedQueryTarget; import com.ibm.jpa.web.Action; import javax.persistence.PersistenceUnit; import javax.annotation.Resource; import javax.transaction.UserTransaction; import rts.entities.Department; import java.util.List; import javax.persistence.Query; import java.util.ArrayList; import java.text.MessageFormat; import javax.faces.model.SelectItem; @SuppressWarnings("unchecked") @JPAManager(targetEntity = rts.entities.Department.class) public class DepartmentManager { ....... public List<SelectItem> getDepartmentSelectList() { List<Department> departmentList = getDepartment(); List<SelectItem> selectList = new ArrayList<SelectItem>(); MessageFormat mf = new MessageFormat("{0}"); for (Department department : departmentList) { selectList.add(new SelectItem(department, mf.format( new Object[] { department.getDeptname() }, new StringBuffer(), null).toString())); } return selectList; } Converter: package rts.entities.converter; import javax.faces.component.UIComponent; import javax.faces.context.FacesContext; import javax.faces.convert.Converter; import rts.entities.Department; import rts.entities.controller.DepartmentManager; import com.ibm.jpa.web.TypeCoercionUtility; public class DepartmentConverter implements Converter { public Object getAsObject(FacesContext facesContext, UIComponent arg1, String entityId) { DepartmentManager departmentManager = (DepartmentManager) facesContext .getApplication().createValueBinding("#{DepartmentManager}") .getValue(facesContext); int deptno = (Integer) TypeCoercionUtility.coerceType("int", entityId); Department result = departmentManager.findDepartmentByDeptno(deptno); return result; } public String getAsString(FacesContext arg0, UIComponent arg1, Object object) { if (object instanceof Department) { return "" + ((Department) object).getDeptno(); } else { throw new IllegalArgumentException("Invalid object type:" + object.getClass().getName()); } } } Method for Add button: public String createEmployeeAction() { EmployeeManager employeeManager = (EmployeeManager) getManagedBean("EmployeeManager"); try { employeeManager.createEmployee(employee); } catch (Exception e) { logException(e); } return ""; } faces-conf.xml <converter> <converter-for-class>rts.entities.Department</converter-for-class> <converter-class>rts.entities.converter.DepartmentConverter</converter-class> </converter> Stack trace javax.faces.FacesException: java.lang.NullPointerException at org.apache.myfaces.shared_impl.context.ExceptionHandlerImpl.wrap(ExceptionHandlerImpl.java:241) at org.apache.myfaces.shared_impl.context.ExceptionHandlerImpl.handle(ExceptionHandlerImpl.java:156) at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:258) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:191) at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1147) at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:722) at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:449) at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:178) at com.ibm.ws.webcontainer.filter.WebAppFilterManager.invokeFilters(WebAppFilterManager.java:1020) at com.ibm.ws.webcontainer.servlet.CacheServletWrapper.handleRequest(CacheServletWrapper.java:87) at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:886) at com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1655) at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:195) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:452) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:511) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:305) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:276) at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.sendToDiscriminators(NewConnectionInitialReadCallback.java:214) at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.complete(NewConnectionInitialReadCallback.java:113) at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165) at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217) at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161) at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138) at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204) at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:775) at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:905) at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1650) Caused by: java.lang.NullPointerException at rts.entities.converter.DepartmentConverter.getAsString(DepartmentConverter.java:29) at org.apache.myfaces.shared_impl.renderkit.RendererUtils.getConvertedStringValue(RendererUtils.java:656) at org.apache.myfaces.shared_impl.renderkit.html.HtmlRendererUtils.getSubmittedOrSelectedValuesAsSet(HtmlRendererUtils.java:444) at org.apache.myfaces.shared_impl.renderkit.html.HtmlRendererUtils.internalRenderSelect(HtmlRendererUtils.java:421) at org.apache.myfaces.shared_impl.renderkit.html.HtmlRendererUtils.renderMenu(HtmlRendererUtils.java:359) at org.apache.myfaces.shared_impl.renderkit.html.HtmlMenuRendererBase.encodeEnd(HtmlMenuRendererBase.java:76) at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:519) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:626) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:622) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:622) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:622) at org.apache.myfaces.view.facelets.FaceletViewDeclarationLanguage.renderView(FaceletViewDeclarationLanguage.java:1320) at org.apache.myfaces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:263) at org.apache.myfaces.lifecycle.RenderResponseExecutor.execute(RenderResponseExecutor.java:85) at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:239) ... 24 more

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  • Creating a dynamic, extensible C# Expando Object

    - by Rick Strahl
    I love dynamic functionality in a strongly typed language because it offers us the best of both worlds. In C# (or any of the main .NET languages) we now have the dynamic type that provides a host of dynamic features for the static C# language. One place where I've found dynamic to be incredibly useful is in building extensible types or types that expose traditionally non-object data (like dictionaries) in easier to use and more readable syntax. I wrote about a couple of these for accessing old school ADO.NET DataRows and DataReaders more easily for example. These classes are dynamic wrappers that provide easier syntax and auto-type conversions which greatly simplifies code clutter and increases clarity in existing code. ExpandoObject in .NET 4.0 Another great use case for dynamic objects is the ability to create extensible objects - objects that start out with a set of static members and then can add additional properties and even methods dynamically. The .NET 4.0 framework actually includes an ExpandoObject class which provides a very dynamic object that allows you to add properties and methods on the fly and then access them again. For example with ExpandoObject you can do stuff like this:dynamic expand = new ExpandoObject(); expand.Name = "Rick"; expand.HelloWorld = (Func<string, string>) ((string name) => { return "Hello " + name; }); Console.WriteLine(expand.Name); Console.WriteLine(expand.HelloWorld("Dufus")); Internally ExpandoObject uses a Dictionary like structure and interface to store properties and methods and then allows you to add and access properties and methods easily. As cool as ExpandoObject is it has a few shortcomings too: It's a sealed type so you can't use it as a base class It only works off 'properties' in the internal Dictionary - you can't expose existing type data It doesn't serialize to XML or with DataContractSerializer/DataContractJsonSerializer Expando - A truly extensible Object ExpandoObject is nice if you just need a dynamic container for a dictionary like structure. However, if you want to build an extensible object that starts out with a set of strongly typed properties and then allows you to extend it, ExpandoObject does not work because it's a sealed class that can't be inherited. I started thinking about this very scenario for one of my applications I'm building for a customer. In this system we are connecting to various different user stores. Each user store has the same basic requirements for username, password, name etc. But then each store also has a number of extended properties that is available to each application. In the real world scenario the data is loaded from the database in a data reader and the known properties are assigned from the known fields in the database. All unknown fields are then 'added' to the expando object dynamically. In the past I've done this very thing with a separate property - Properties - just like I do for this class. But the property and dictionary syntax is not ideal and tedious to work with. I started thinking about how to represent these extra property structures. One way certainly would be to add a Dictionary, or an ExpandoObject to hold all those extra properties. But wouldn't it be nice if the application could actually extend an existing object that looks something like this as you can with the Expando object:public class User : Westwind.Utilities.Dynamic.Expando { public string Email { get; set; } public string Password { get; set; } public string Name { get; set; } public bool Active { get; set; } public DateTime? ExpiresOn { get; set; } } and then simply start extending the properties of this object dynamically? Using the Expando object I describe later you can now do the following:[TestMethod] public void UserExampleTest() { var user = new User(); // Set strongly typed properties user.Email = "[email protected]"; user.Password = "nonya123"; user.Name = "Rickochet"; user.Active = true; // Now add dynamic properties dynamic duser = user; duser.Entered = DateTime.Now; duser.Accesses = 1; // you can also add dynamic props via indexer user["NickName"] = "AntiSocialX"; duser["WebSite"] = "http://www.west-wind.com/weblog"; // Access strong type through dynamic ref Assert.AreEqual(user.Name,duser.Name); // Access strong type through indexer Assert.AreEqual(user.Password,user["Password"]); // access dyanmically added value through indexer Assert.AreEqual(duser.Entered,user["Entered"]); // access index added value through dynamic Assert.AreEqual(user["NickName"],duser.NickName); // loop through all properties dynamic AND strong type properties (true) foreach (var prop in user.GetProperties(true)) { object val = prop.Value; if (val == null) val = "null"; Console.WriteLine(prop.Key + ": " + val.ToString()); } } As you can see this code somewhat blurs the line between a static and dynamic type. You start with a strongly typed object that has a fixed set of properties. You can then cast the object to dynamic (as I discussed in my last post) and add additional properties to the object. You can also use an indexer to add dynamic properties to the object. To access the strongly typed properties you can use either the strongly typed instance, the indexer or the dynamic cast of the object. Personally I think it's kinda cool to have an easy way to access strongly typed properties by string which can make some data scenarios much easier. To access the 'dynamically added' properties you can use either the indexer on the strongly typed object, or property syntax on the dynamic cast. Using the dynamic type allows all three modes to work on both strongly typed and dynamic properties. Finally you can iterate over all properties, both dynamic and strongly typed if you chose. Lots of flexibility. Note also that by default the Expando object works against the (this) instance meaning it extends the current object. You can also pass in a separate instance to the constructor in which case that object will be used to iterate over to find properties rather than this. Using this approach provides some really interesting functionality when use the dynamic type. To use this we have to add an explicit constructor to the Expando subclass:public class User : Westwind.Utilities.Dynamic.Expando { public string Email { get; set; } public string Password { get; set; } public string Name { get; set; } public bool Active { get; set; } public DateTime? ExpiresOn { get; set; } public User() : base() { } // only required if you want to mix in seperate instance public User(object instance) : base(instance) { } } to allow the instance to be passed. When you do you can now do:[TestMethod] public void ExpandoMixinTest() { // have Expando work on Addresses var user = new User( new Address() ); // cast to dynamicAccessToPropertyTest dynamic duser = user; // Set strongly typed properties duser.Email = "[email protected]"; user.Password = "nonya123"; // Set properties on address object duser.Address = "32 Kaiea"; //duser.Phone = "808-123-2131"; // set dynamic properties duser.NonExistantProperty = "This works too"; // shows default value Address.Phone value Console.WriteLine(duser.Phone); } Using the dynamic cast in this case allows you to access *three* different 'objects': The strong type properties, the dynamically added properties in the dictionary and the properties of the instance passed in! Effectively this gives you a way to simulate multiple inheritance (which is scary - so be very careful with this, but you can do it). How Expando works Behind the scenes Expando is a DynamicObject subclass as I discussed in my last post. By implementing a few of DynamicObject's methods you can basically create a type that can trap 'property missing' and 'method missing' operations. When you access a non-existant property a known method is fired that our code can intercept and provide a value for. Internally Expando uses a custom dictionary implementation to hold the dynamic properties you might add to your expandable object. Let's look at code first. The code for the Expando type is straight forward and given what it provides relatively short. Here it is.using System; using System.Collections.Generic; using System.Linq; using System.Dynamic; using System.Reflection; namespace Westwind.Utilities.Dynamic { /// <summary> /// Class that provides extensible properties and methods. This /// dynamic object stores 'extra' properties in a dictionary or /// checks the actual properties of the instance. /// /// This means you can subclass this expando and retrieve either /// native properties or properties from values in the dictionary. /// /// This type allows you three ways to access its properties: /// /// Directly: any explicitly declared properties are accessible /// Dynamic: dynamic cast allows access to dictionary and native properties/methods /// Dictionary: Any of the extended properties are accessible via IDictionary interface /// </summary> [Serializable] public class Expando : DynamicObject, IDynamicMetaObjectProvider { /// <summary> /// Instance of object passed in /// </summary> object Instance; /// <summary> /// Cached type of the instance /// </summary> Type InstanceType; PropertyInfo[] InstancePropertyInfo { get { if (_InstancePropertyInfo == null && Instance != null) _InstancePropertyInfo = Instance.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly); return _InstancePropertyInfo; } } PropertyInfo[] _InstancePropertyInfo; /// <summary> /// String Dictionary that contains the extra dynamic values /// stored on this object/instance /// </summary> /// <remarks>Using PropertyBag to support XML Serialization of the dictionary</remarks> public PropertyBag Properties = new PropertyBag(); //public Dictionary<string,object> Properties = new Dictionary<string, object>(); /// <summary> /// This constructor just works off the internal dictionary and any /// public properties of this object. /// /// Note you can subclass Expando. /// </summary> public Expando() { Initialize(this); } /// <summary> /// Allows passing in an existing instance variable to 'extend'. /// </summary> /// <remarks> /// You can pass in null here if you don't want to /// check native properties and only check the Dictionary! /// </remarks> /// <param name="instance"></param> public Expando(object instance) { Initialize(instance); } protected virtual void Initialize(object instance) { Instance = instance; if (instance != null) InstanceType = instance.GetType(); } /// <summary> /// Try to retrieve a member by name first from instance properties /// followed by the collection entries. /// </summary> /// <param name="binder"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; // first check the Properties collection for member if (Properties.Keys.Contains(binder.Name)) { result = Properties[binder.Name]; return true; } // Next check for Public properties via Reflection if (Instance != null) { try { return GetProperty(Instance, binder.Name, out result); } catch { } } // failed to retrieve a property result = null; return false; } /// <summary> /// Property setter implementation tries to retrieve value from instance /// first then into this object /// </summary> /// <param name="binder"></param> /// <param name="value"></param> /// <returns></returns> public override bool TrySetMember(SetMemberBinder binder, object value) { // first check to see if there's a native property to set if (Instance != null) { try { bool result = SetProperty(Instance, binder.Name, value); if (result) return true; } catch { } } // no match - set or add to dictionary Properties[binder.Name] = value; return true; } /// <summary> /// Dynamic invocation method. Currently allows only for Reflection based /// operation (no ability to add methods dynamically). /// </summary> /// <param name="binder"></param> /// <param name="args"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { if (Instance != null) { try { // check instance passed in for methods to invoke if (InvokeMethod(Instance, binder.Name, args, out result)) return true; } catch { } } result = null; return false; } /// <summary> /// Reflection Helper method to retrieve a property /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="result"></param> /// <returns></returns> protected bool GetProperty(object instance, string name, out object result) { if (instance == null) instance = this; var miArray = InstanceType.GetMember(name, BindingFlags.Public | BindingFlags.GetProperty | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0]; if (mi.MemberType == MemberTypes.Property) { result = ((PropertyInfo)mi).GetValue(instance,null); return true; } } result = null; return false; } /// <summary> /// Reflection helper method to set a property value /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="value"></param> /// <returns></returns> protected bool SetProperty(object instance, string name, object value) { if (instance == null) instance = this; var miArray = InstanceType.GetMember(name, BindingFlags.Public | BindingFlags.SetProperty | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0]; if (mi.MemberType == MemberTypes.Property) { ((PropertyInfo)mi).SetValue(Instance, value, null); return true; } } return false; } /// <summary> /// Reflection helper method to invoke a method /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="args"></param> /// <param name="result"></param> /// <returns></returns> protected bool InvokeMethod(object instance, string name, object[] args, out object result) { if (instance == null) instance = this; // Look at the instanceType var miArray = InstanceType.GetMember(name, BindingFlags.InvokeMethod | BindingFlags.Public | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0] as MethodInfo; result = mi.Invoke(Instance, args); return true; } result = null; return false; } /// <summary> /// Convenience method that provides a string Indexer /// to the Properties collection AND the strongly typed /// properties of the object by name. /// /// // dynamic /// exp["Address"] = "112 nowhere lane"; /// // strong /// var name = exp["StronglyTypedProperty"] as string; /// </summary> /// <remarks> /// The getter checks the Properties dictionary first /// then looks in PropertyInfo for properties. /// The setter checks the instance properties before /// checking the Properties dictionary. /// </remarks> /// <param name="key"></param> /// /// <returns></returns> public object this[string key] { get { try { // try to get from properties collection first return Properties[key]; } catch (KeyNotFoundException ex) { // try reflection on instanceType object result = null; if (GetProperty(Instance, key, out result)) return result; // nope doesn't exist throw; } } set { if (Properties.ContainsKey(key)) { Properties[key] = value; return; } // check instance for existance of type first var miArray = InstanceType.GetMember(key, BindingFlags.Public | BindingFlags.GetProperty); if (miArray != null && miArray.Length > 0) SetProperty(Instance, key, value); else Properties[key] = value; } } /// <summary> /// Returns and the properties of /// </summary> /// <param name="includeProperties"></param> /// <returns></returns> public IEnumerable<KeyValuePair<string,object>> GetProperties(bool includeInstanceProperties = false) { if (includeInstanceProperties && Instance != null) { foreach (var prop in this.InstancePropertyInfo) yield return new KeyValuePair<string, object>(prop.Name, prop.GetValue(Instance, null)); } foreach (var key in this.Properties.Keys) yield return new KeyValuePair<string, object>(key, this.Properties[key]); } /// <summary> /// Checks whether a property exists in the Property collection /// or as a property on the instance /// </summary> /// <param name="item"></param> /// <returns></returns> public bool Contains(KeyValuePair<string, object> item, bool includeInstanceProperties = false) { bool res = Properties.ContainsKey(item.Key); if (res) return true; if (includeInstanceProperties && Instance != null) { foreach (var prop in this.InstancePropertyInfo) { if (prop.Name == item.Key) return true; } } return false; } } } Although the Expando class supports an indexer, it doesn't actually implement IDictionary or even IEnumerable. It only provides the indexer and Contains() and GetProperties() methods, that work against the Properties dictionary AND the internal instance. The reason for not implementing IDictionary is that a) it doesn't add much value since you can access the Properties dictionary directly and that b) I wanted to keep the interface to class very lean so that it can serve as an entity type if desired. Implementing these IDictionary (or even IEnumerable) causes LINQ extension methods to pop up on the type which obscures the property interface and would only confuse the purpose of the type. IDictionary and IEnumerable are also problematic for XML and JSON Serialization - the XML Serializer doesn't serialize IDictionary<string,object>, nor does the DataContractSerializer. The JavaScriptSerializer does serialize, but it treats the entire object like a dictionary and doesn't serialize the strongly typed properties of the type, only the dictionary values which is also not desirable. Hence the decision to stick with only implementing the indexer to support the user["CustomProperty"] functionality and leaving iteration functions to the publicly exposed Properties dictionary. Note that the Dictionary used here is a custom PropertyBag class I created to allow for serialization to work. One important aspect for my apps is that whatever custom properties get added they have to be accessible to AJAX clients since the particular app I'm working on is a SIngle Page Web app where most of the Web access is through JSON AJAX calls. PropertyBag can serialize to XML and one way serialize to JSON using the JavaScript serializer (not the DCS serializers though). The key components that make Expando work in this code are the Properties Dictionary and the TryGetMember() and TrySetMember() methods. The Properties collection is public so if you choose you can explicitly access the collection to get better performance or to manipulate the members in internal code (like loading up dynamic values form a database). Notice that TryGetMember() and TrySetMember() both work against the dictionary AND the internal instance to retrieve and set properties. This means that user["Name"] works against native properties of the object as does user["Name"] = "RogaDugDog". What's your Use Case? This is still an early prototype but I've plugged it into one of my customer's applications and so far it's working very well. The key features for me were the ability to easily extend the type with values coming from a database and exposing those values in a nice and easy to use manner. I'm also finding that using this type of object for ViewModels works very well to add custom properties to view models. I suspect there will be lots of uses for this - I've been using the extra dictionary approach to extensibility for years - using a dynamic type to make the syntax cleaner is just a bonus here. What can you think of to use this for? Resources Source Code and Tests (GitHub) Also integrated in Westwind.Utilities of the West Wind Web Toolkit West Wind Utilities NuGet© Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp  .NET  Dynamic Types   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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