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• How to create a datastore.Text object out of an array of dynamically created Strings?

  - by Adrogans

  I am creating a Google App Engine server for a project where I receive a large quantity of data via an HTTP POST request. The data is separated into lines, with 200 characters per line. The number of lines can go into the hundreds, so 10's of thousands of characters total. What I want to do is concatenate all of those lines into a single Text object, since Strings have a maximum length of 500 characters but the Text object can be as large as 1MB. Here is what I thought of so far: public void doPost(HttpServletRequest req, HttpServletResponse resp) { ... String[] audioSampleData = new String[numberOfLines]; for (int i = 0; i < numberOfLines; i++) { audioSampleData[i] = req.getReader().readLine(); } com.google.appengine.api.datastore.Text textAudioSampleData = new Text(audioSampleData[0] + audioSampleData[1] + ...); ... } But as you can see, I don't know how to do this without knowing the number of lines before-hand. Is there a way for me to iterate through the String indexes within the Text constructor? I can't seem to find anything on that. Of note is that the Text object can't be modified after being created, and it must have a String as parameter for the constructor. (Documentation here) Is there any way to this? I need all of the data in the String array in one Text object. Many Thanks!

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• Silverlight Tree View with Multiple Levels

  - by psheriff

  There are many examples of the Silverlight Tree View that you will find on the web, however, most of them only show you how to go to two levels. What if you have more than two levels? This is where understanding exactly how the Hierarchical Data Templates works is vital. In this blog post, I am going to break down how these templates work so you can really understand what is going on underneath the hood. To start, let’s look at the typical two-level Silverlight Tree View that has been hard coded with the values shown below: <sdk:TreeView>  <sdk:TreeViewItem Header="Managers">    <TextBlock Text="Michael" />    <TextBlock Text="Paul" />  </sdk:TreeViewItem>  <sdk:TreeViewItem Header="Supervisors">    <TextBlock Text="John" />    <TextBlock Text="Tim" />    <TextBlock Text="David" />  </sdk:TreeViewItem></sdk:TreeView> Figure 1 shows you how this tree view looks when you run the Silverlight application. Figure 1: A hard-coded, two level Tree View. Next, let’s create three classes to mimic the hard-coded Tree View shown above. First, you need an Employee class and an EmployeeType class. The Employee class simply has one property called Name. The constructor is created to accept a “name” argument that you can use to set the Name property when you create an Employee object. public class Employee{  public Employee(string name)  {    Name = name;  }   public string Name { get; set; }} Finally you create an EmployeeType class. This class has one property called EmpType and contains a generic List<> collection of Employee objects. The property that holds the collection is called Employees. public class EmployeeType{  public EmployeeType(string empType)  {    EmpType = empType;    Employees = new List<Employee>();  }   public string EmpType { get; set; }  public List<Employee> Employees { get; set; }} Finally we have a collection class called EmployeeTypes created using the generic List<> class. It is in the constructor for this class where you will build the collection of EmployeeTypes and fill it with Employee objects: public class EmployeeTypes : List<EmployeeType>{  public EmployeeTypes()  {    EmployeeType type;            type = new EmployeeType("Manager");    type.Employees.Add(new Employee("Michael"));    type.Employees.Add(new Employee("Paul"));    this.Add(type);     type = new EmployeeType("Project Managers");    type.Employees.Add(new Employee("Tim"));    type.Employees.Add(new Employee("John"));    type.Employees.Add(new Employee("David"));    this.Add(type);  }} You now have a data hierarchy in memory (Figure 2) which is what the Tree View control expects to receive as its data source. Figure 2: A hierachial data structure of Employee Types containing a collection of Employee objects. To connect up this hierarchy of data to your Tree View you create an instance of the EmployeeTypes class in XAML as shown in line 13 of Figure 3. The key assigned to this object is “empTypes”. This key is used as the source of data to the entire Tree View by setting the ItemsSource property as shown in Figure 3, Callout #1. Figure 3: You need to start from the bottom up when laying out your templates for a Tree View. The ItemsSource property of the Tree View control is used as the data source in the Hierarchical Data Template with the key of employeeTypeTemplate. In this case there is only one Hierarchical Data Template, so any data you wish to display within that template comes from the collection of Employee Types. The TextBlock control in line 20 uses the EmpType property of the EmployeeType class. You specify the name of the Hierarchical Data Template to use in the ItemTemplate property of the Tree View (Callout #2). For the second (and last) level of the Tree View control you use a normal <DataTemplate> with the name of employeeTemplate (line 14). The Hierarchical Data Template in lines 17-21 sets its ItemTemplate property to the key name of employeeTemplate (Line 19 connects to Line 14). The source of the data for the <DataTemplate> needs to be a property of the EmployeeTypes collection used in the Hierarchical Data Template. In this case that is the Employees property. In the Employees property there is a “Name” property of the Employee class that is used to display the employee name in the second level of the Tree View (Line 15). What is important here is that your lowest level in your Tree View is expressed in a <DataTemplate> and should be listed first in your Resources section. The next level up in your Tree View should be a <HierarchicalDataTemplate> which has its ItemTemplate property set to the key name of the <DataTemplate> and the ItemsSource property set to the data you wish to display in the <DataTemplate>. The Tree View control should have its ItemsSource property set to the data you wish to display in the <HierarchicalDataTemplate> and its ItemTemplate property set to the key name of the <HierarchicalDataTemplate> object. It is in this way that you get the Tree View to display all levels of your hierarchical data structure. Three Levels in a Tree View Now let’s expand upon this concept and use three levels in our Tree View (Figure 4). This Tree View shows that you now have EmployeeTypes at the top of the tree, followed by a small set of employees that themselves manage employees. This means that the EmployeeType class has a collection of Employee objects. Each Employee class has a collection of Employee objects as well. Figure 4: When using 3 levels in your TreeView you will have 2 Hierarchical Data Templates and 1 Data Template. The EmployeeType class has not changed at all from our previous example. However, the Employee class now has one additional property as shown below: public class Employee{  public Employee(string name)  {    Name = name;    ManagedEmployees = new List<Employee>();  }   public string Name { get; set; }  public List<Employee> ManagedEmployees { get; set; }} The next thing that changes in our code is the EmployeeTypes class. The constructor now needs additional code to create a list of managed employees. Below is the new code. public class EmployeeTypes : List<EmployeeType>{  public EmployeeTypes()  {    EmployeeType type;    Employee emp;    Employee managed;     type = new EmployeeType("Manager");    emp = new Employee("Michael");    managed = new Employee("John");    emp.ManagedEmployees.Add(managed);    managed = new Employee("Tim");    emp.ManagedEmployees.Add(managed);    type.Employees.Add(emp);     emp = new Employee("Paul");    managed = new Employee("Michael");    emp.ManagedEmployees.Add(managed);    managed = new Employee("Sara");    emp.ManagedEmployees.Add(managed);    type.Employees.Add(emp);    this.Add(type);     type = new EmployeeType("Project Managers");    type.Employees.Add(new Employee("Tim"));    type.Employees.Add(new Employee("John"));    type.Employees.Add(new Employee("David"));    this.Add(type);  }} Now that you have all of the data built in your classes, you are now ready to hook up this three-level structure to your Tree View. Figure 5 shows the complete XAML needed to hook up your three-level Tree View. You can see in the XAML that there are now two Hierarchical Data Templates and one Data Template. Again you list the Data Template first since that is the lowest level in your Tree View. The next Hierarchical Data Template listed is the next level up from the lowest level, and finally you have a Hierarchical Data Template for the first level in your tree. You need to work your way from the bottom up when creating your Tree View hierarchy. XAML is processed from the top down, so if you attempt to reference a XAML key name that is below where you are referencing it from, you will get a runtime error. Figure 5: For three levels in a Tree View you will need two Hierarchical Data Templates and one Data Template. Each Hierarchical Data Template uses the previous template as its ItemTemplate. The ItemsSource of each Hierarchical Data Template is used to feed the data to the previous template. This is probably the most confusing part about working with the Tree View control. You are expecting the content of the current Hierarchical Data Template to use the properties set in the ItemsSource property of that template. But you need to look to the template lower down in the XAML to see the source of the data as shown in Figure 6. Figure 6: The properties you use within the Content of a template come from the ItemsSource of the next template in the resources section. Summary Understanding how to put together your hierarchy in a Tree View is simple once you understand that you need to work from the bottom up. Start with the bottom node in your Tree View and determine what that will look like and where the data will come from. You then build the next Hierarchical Data Template to feed the data to the previous template you created. You keep doing this for each level in your Tree View until you get to the last level. The data for that last Hierarchical Data Template comes from the ItemsSource in the Tree View itself. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “Silverlight TreeView with Multiple Levels” from the drop down list.

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• MVVM in Task-It

  As I'm gearing up to write a post about dynamic XAP loading with MEF, I'd like to first talk a bit about MVVM, the Model-View-ViewModel pattern, as I will be leveraging this pattern in my future posts. Download Source Code Why MVVM? Your first question may be, "why do I need this pattern? I've been using a code-behind approach for years and it works fine." Well, you really don't have to make the switch to MVVM, but let me first explain some of the benefits I see for doing so. MVVM Benefits Testability - This is the one you'll probably hear the most about when it comes to MVVM. Moving most of the code from your code-behind to a separate view model class means you can now write unit tests against the view model without any knowledge of a view (UserControl). Multiple UIs - Let's just say that you've created a killer app, it's running in the browser, and maybe you've even made it run out-of-browser. Now what if your boss comes to you and says, "I heard about this new Windows Phone 7 device that is coming out later this year. Can you start porting the app to that device?". Well, now you have to create a new UI (UserControls, etc.) because you have a lot less screen real estate to work with. So what do you do, copy all of your existing UserControls, paste them, rename them, and then start changing the code? Hmm, that doesn't sound so good. But wait, if most of the code that makes your browser-based app tick lives in view model classes, now you can create new view (UserControls) for Windows Phone 7 that reference the same view model classes as your browser-based app. Page state - In Silverlight you're at some point going to be faced with the same issue you dealt with for years in ASP.NET, maintaining page state. Let's say a user hits your Products page, does some stuff (filters record, etc.), then leaves the page and comes back later. It would be best if the Products page was in the same state as when they left it right? Well, if you've thrown away your view (UserControl or Page) and moved off to another part of the UI, when you come back to Products you're probably going to re-instantiate your view...which will put it right back in the state it was when it started. Hmm, not good. Well, with a little help from MEF you can store the state in your view model class, MEF will keep that view model instance hanging around in memory, and then you simply rebind your view to the view model class. I made that sound easy, but it's actually a bit of work to properly store and restore the state. At least it can be done though, which will make your users a lot happier! I'll talk more about this in an upcoming blog post. No event handlers? Another nice thing about MVVM is that you can bind your UserControls to the view model, which may eliminate the need for event handlers in your code-behind. So instead of having a Click handler on a Button (or RadMenuItem), for example, you can now bind your control's Command property to a DelegateCommand in your view model (I'll talk more about Commands in an upcoming post). Instead of having a SelectionChanged event handler on your RadGridView you can now bind its SelectedItem property to a property in your view model, and each time the user clicks a row, the view model property's setter will be called. Now through the magic of binding we can eliminate the need for traditional code-behind based event handlers on our user interface controls, and the best thing is that the view model knows about everything that's going on...which means we can test things without a user interface. The brains of the operation So what we're seeing here is that the view is now just a dumb layer that binds to the view model, and that the view model is in control of just about everything, like what happens when a RadGridView row is selected, or when a RadComboBoxItem is selected, or when a RadMenuItem is clicked. It is also responsible for loading data when the page is hit, as well as kicking off data inserts, updates and deletions. Once again, all of this stuff can be tested without the need for a user interface. If the test works, then it'll work regardless of whether the user is hitting the browser-based version of your app, or the Windows Phone 7 version. Nice! The database Before running the code for this app you will need to create the database. First, create a database called MVVMProject in SQL Server, then run MVVMProject.sql in the MVVMProject/Database directory of your downloaded .zip file. This should give you a Task table with 3 records in it. When you fire up the solution you will also need to update the connection string in web.config to point to your database instead of IBM12\SQLSERVER2008. The code One note about this code is that it runs against the latest Silverlight 4 RC and WCF RIA Services code. Please see my first blog post about updating to the RC bits. Beta to RC - Part 1 At the top of this post is a link to a sample project that demonstrates a sample application with a Tasks page that uses the MVVM pattern. This is a simplified version of how I have implemented the Tasks page in the Task-It application. Youll notice that Tasks.xaml has very little code to it. Just a TextBlock that displays the page title and a ContentControl. <StackPanel>     <TextBlock Text="Tasks" Style="{StaticResource PageTitleStyle}"/>     <Rectangle Style="{StaticResource StandardSpacerStyle}"/>     <ContentControl x:Name="ContentControl1"/> </StackPanel> In List.xaml we have a RadGridView. Notice that the ItemsSource is bound to a property in the view model class call Tasks, SelectedItem is bound to a property in the view model called SelectedItem, and IsBusy is bound to a property in the view model called IsLoading. <Grid>     <telerikGridView:RadGridView ItemsSource="{Binding Tasks}" SelectedItem="{Binding SelectedItem, Mode=TwoWay}"                                  IsBusy="{Binding IsLoading}" AutoGenerateColumns="False" IsReadOnly="True" RowIndicatorVisibility="Collapsed"                IsFilteringAllowed="False" ShowGroupPanel="False">         <telerikGridView:RadGridView.Columns>             <telerikGridView:GridViewDataColumn Header="Name" DataMemberBinding="{Binding Name}" Width="3*"/>             <telerikGridView:GridViewDataColumn Header="Due" DataMemberBinding="{Binding DueDate}" DataFormatString="{}{0:d}" Width="*"/>         </telerikGridView:RadGridView.Columns>     </telerikGridView:RadGridView> </Grid> In Details.xaml we have a Save button that is bound to a property called SaveCommand in our view model. We also have a simple form (Im using a couple of controls here from Silverlight.FX for the form layout, FormPanel and Label simply because they make for a clean XAML layout). Notice that the FormPanel is also bound to the SelectedItem in the view model (the same one that the RadGridView is). The two form controls, the TextBox and RadDatePicker) are bound to the SelectedItem's Name and DueDate properties. These are properties of the Task object that WCF RIA Services creates. <StackPanel>     <Button Content="Save" Command="{Binding SaveCommand}" HorizontalAlignment="Left"/>     <Rectangle Style="{StaticResource StandardSpacerStyle}"/>     <fxui:FormPanel DataContext="{Binding SelectedItem}" Style="{StaticResource FormContainerStyle}">         <fxui:Label Text="Name:"/>         <TextBox Text="{Binding Name, Mode=TwoWay}"/>         <fxui:Label Text="Due:"/>         <telerikInput:RadDatePicker SelectedDate="{Binding DueDate, Mode=TwoWay}"/>     </fxui:FormPanel> </StackPanel> In the code-behind of the Tasks control, Tasks.xaml.cs, I created an instance of the view model class (TasksViewModel) in the constructor and set it as the DataContext for the control. The Tasks page will load one of two child UserControls depending on whether you are viewing the list of tasks (List.xaml) or the form for editing a task (Details.xaml). // Set the DataContext to an instance of the view model class var viewModel = new TasksViewModel(); DataContext = viewModel;   // Child user controls (inherit DataContext from this user control) List = new List(); // RadGridView Details = new Details(); // Form When the page first loads, the List is loaded into the ContentControl. // Show the RadGridView first ContentControl1.Content = List; In the code-behind we also listen for a couple of the view models events. The ItemSelected event will be fired when the user clicks on a record in the RadGridView in the List control. The SaveCompleted event will be fired when the user clicks Save in the Details control (the form). Here the view model is in control, and is letting the view know when something needs to change. // Listeners for the view model's events viewModel.ItemSelected += OnItemSelected; viewModel.SaveCompleted += OnSaveCompleted; The event handlers toggle the view between the RadGridView (List) and the form (Details). void OnItemSelected(object sender, RoutedEventArgs e) {     // Show the form     ContentControl1.Content = Details; }   void OnSaveCompleted(object sender, RoutedEventArgs e) {     // Show the RadGridView     ContentControl1.Content = List; } In TasksViewModel, we instantiate a DataContext object and a SaveCommand in the constructor. DataContext is a WCF RIA Services object that well use to retrieve the list of Tasks and to save any changes to a task. Ill talk more about this and Commands in future post, but for now think of the SaveCommand as an event handler that is called when the Save button in the form is clicked. DataContext = new DataContext(); SaveCommand = new DelegateCommand(OnSave); When the TasksViewModel constructor is called we also make a call to LoadTasks. This sets IsLoading to true (which causes the RadGridViews busy indicator to appear) and retrieves the records via WCF RIA Services.         public LoadOperation<Task> LoadTasks()         {             // Show the loading message             IsLoading = true;             // Get the data via WCF RIA Services. When the call has returned, called OnTasksLoaded.             return DataContext.Load(DataContext.GetTasksQuery(), OnTasksLoaded, false);         } When the data is returned, OnTasksLoaded is called. This sets IsLoading to false (which hides the RadGridViews busy indicator), and fires property changed notifications to the UI to let it know that the IsLoading and Tasks properties have changed. This property changed notification basically tells the UI to rebind. void OnTasksLoaded(LoadOperation<Task> lo) {     // Hide the loading message     IsLoading = false;       // Notify the UI that Tasks and IsLoading properties have changed     this.OnPropertyChanged(p => p.Tasks);     this.OnPropertyChanged(p => p.IsLoading); } Next lets look at the view models SelectedItem property. This is the one thats bound to both the RadGridView and the form. When the user clicks a record in the RadGridView its setter gets called (set a breakpoint and see what I mean). The other code in the setter lets the UI know that the SelectedItem has changed (so the form displays the correct data), and fires the event that notifies the UI that a selection has occurred (which tells the UI to switch from List to Details). public Task SelectedItem {     get { return _selectedItem; }     set     {         _selectedItem = value;           // Let the UI know that the SelectedItem has changed (forces it to re-bind)         this.OnPropertyChanged(p => p.SelectedItem);         // Notify the UI, so it can switch to the Details (form) page         NotifyItemSelected();     } } One last thing, saving the data. When the Save button in the form is clicked it fires the SaveCommand, which calls the OnSave method in the view model (once again, set a breakpoint to see it in action). public void OnSave() {     // Save the changes via WCF RIA Services. When the save is complete, call OnSaveCompleted.     DataContext.SubmitChanges(OnSaveCompleted, null); } In OnSave, we tell WCF RIA Services to submit any changes, which there will be if you changed either the Name or the Due Date in the form. When the save is completed, it calls OnSaveCompleted. This method fires a notification back to the UI that the save is completed, which causes the RadGridView (List) to show again. public virtual void OnSaveCompleted(SubmitOperation so) {     // Clear the item that is selected in the grid (in case we want to select it again)     SelectedItem = null;     // Notify the UI, so it can switch back to the List (RadGridView) page     NotifySaveCompleted(); } Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• A Communication System for XAML Applications

  - by psheriff

  In any application, you want to keep the coupling between any two or more objects as loose as possible. Coupling happens when one class contains a property that is used in another class, or uses another class in one of its methods. If you have this situation, then this is called strong or tight coupling. One popular design pattern to help with keeping objects loosely coupled is called the Mediator design pattern. The basics of this pattern are very simple; avoid one object directly talking to another object, and instead use another class to mediate between the two. As with most of my blog posts, the purpose is to introduce you to a simple approach to using a message broker, not all of the fine details. IPDSAMessageBroker Interface As with most implementations of a design pattern, you typically start with an interface or an abstract base class. In this particular instance, an Interface will work just fine. The interface for our Message Broker class just contains a single method “SendMessage” and one event “MessageReceived”. public delegate void MessageReceivedEventHandler( object sender, PDSAMessageBrokerEventArgs e); public interface IPDSAMessageBroker{  void SendMessage(PDSAMessageBrokerMessage msg);   event MessageReceivedEventHandler MessageReceived;} PDSAMessageBrokerMessage Class As you can see in the interface, the SendMessage method requires a type of PDSAMessageBrokerMessage to be passed to it. This class simply has a MessageName which is a ‘string’ type and a MessageBody property which is of the type ‘object’ so you can pass whatever you want in the body. You might pass a string in the body, or a complete Customer object. The MessageName property will help the receiver of the message know what is in the MessageBody property. public class PDSAMessageBrokerMessage{  public PDSAMessageBrokerMessage()  {  }   public PDSAMessageBrokerMessage(string name, object body)  {    MessageName = name;    MessageBody = body;  }   public string MessageName { get; set; }   public object MessageBody { get; set; }} PDSAMessageBrokerEventArgs Class As our message broker class will be raising an event that others can respond to, it is a good idea to create your own event argument class. This class will inherit from the System.EventArgs class and add a couple of additional properties. The properties are the MessageName and Message. The MessageName property is simply a string value. The Message property is a type of a PDSAMessageBrokerMessage class. public class PDSAMessageBrokerEventArgs : EventArgs{  public PDSAMessageBrokerEventArgs()  {  }   public PDSAMessageBrokerEventArgs(string name,     PDSAMessageBrokerMessage msg)  {    MessageName = name;    Message = msg;  }   public string MessageName { get; set; }   public PDSAMessageBrokerMessage Message { get; set; }} PDSAMessageBroker Class Now that you have an interface class and a class to pass a message through an event, it is time to create your actual PDSAMessageBroker class. This class implements the SendMessage method and will also create the event handler for the delegate created in your Interface. public class PDSAMessageBroker : IPDSAMessageBroker{  public void SendMessage(PDSAMessageBrokerMessage msg)  {    PDSAMessageBrokerEventArgs args;     args = new PDSAMessageBrokerEventArgs(      msg.MessageName, msg);     RaiseMessageReceived(args);  }   public event MessageReceivedEventHandler MessageReceived;   protected void RaiseMessageReceived(    PDSAMessageBrokerEventArgs e)  {    if (null != MessageReceived)      MessageReceived(this, e);  }} The SendMessage method will take a PDSAMessageBrokerMessage object as an argument. It then creates an instance of a PDSAMessageBrokerEventArgs class, passing to the constructor two items: the MessageName from the PDSAMessageBrokerMessage object and also the object itself. It may seem a little redundant to pass in the message name when that same message name is part of the message, but it does make consuming the event and checking for the message name a little cleaner – as you will see in the next section. Create a Global Message Broker In your WPF application, create an instance of this message broker class in the App class located in the App.xaml file. Create a public property in the App class and create a new instance of that class in the OnStartUp event procedure as shown in the following code: public partial class App : Application{  public PDSAMessageBroker MessageBroker { get; set; }   protected override void OnStartup(StartupEventArgs e)  {    base.OnStartup(e);     MessageBroker = new PDSAMessageBroker();  }} Sending and Receiving Messages Let’s assume you have a user control that you load into a control on your main window and you want to send a message from that user control to the main window. You might have the main window display a message box, or put a string into a status bar as shown in Figure 1. Figure 1: The main window can receive and send messages The first thing you do in the main window is to hook up an event procedure to the MessageReceived event of the global message broker. This is done in the constructor of the main window: public MainWindow(){  InitializeComponent();   (Application.Current as App).MessageBroker.     MessageReceived += new MessageReceivedEventHandler(       MessageBroker_MessageReceived);} One piece of code you might not be familiar with is accessing a property defined in the App class of your XAML application. Within the App.Xaml file is a class named App that inherits from the Application object. You access the global instance of this App class by using Application.Current. You cast Application.Current to ‘App’ prior to accessing any of the public properties or methods you defined in the App class. Thus, the code (Application.Current as App).MessageBroker, allows you to get at the MessageBroker property defined in the App class. In the MessageReceived event procedure in the main window (shown below) you can now check to see if the MessageName property of the PDSAMessageBrokerEventArgs is equal to “StatusBar” and if it is, then display the message body into the status bar text block control. void MessageBroker_MessageReceived(object sender,   PDSAMessageBrokerEventArgs e){  switch (e.MessageName)  {    case "StatusBar":      tbStatus.Text = e.Message.MessageBody.ToString();      break;  }} In the Page 1 user control’s Loaded event procedure you will send the message “StatusBar” through the global message broker to any listener using the following code: private void UserControl_Loaded(object sender,  RoutedEventArgs e){  // Send Status Message  (Application.Current as App).MessageBroker.    SendMessage(new PDSAMessageBrokerMessage("StatusBar",      "This is Page 1"));} Since the main window is listening for the message ‘StatusBar’, it will display the value “This is Page 1” in the status bar at the bottom of the main window. Sending a Message to a User Control The previous example sent a message from the user control to the main window. You can also send messages from the main window to any listener as well. Remember that the global message broker is really just a broadcaster to anyone who has hooked into the MessageReceived event. In the constructor of the user control named ucPage1 you can hook into the global message broker’s MessageReceived event. You can then listen for any messages that are sent to this control by using a similar switch-case structure like that in the main window. public ucPage1(){  InitializeComponent();   // Hook to the Global Message Broker  (Application.Current as App).MessageBroker.    MessageReceived += new MessageReceivedEventHandler(      MessageBroker_MessageReceived);} void MessageBroker_MessageReceived(object sender,  PDSAMessageBrokerEventArgs e){  // Look for messages intended for Page 1  switch (e.MessageName)  {    case "ForPage1":      MessageBox.Show(e.Message.MessageBody.ToString());      break;  }} Once the ucPage1 user control has been loaded into the main window you can then send a message using the following code: private void btnSendToPage1_Click(object sender,  RoutedEventArgs e){  PDSAMessageBrokerMessage arg =     new PDSAMessageBrokerMessage();   arg.MessageName = "ForPage1";  arg.MessageBody = "Message For Page 1";   // Send a message to Page 1  (Application.Current as App).MessageBroker.SendMessage(arg);} Since the MessageName matches what is in the ucPage1 MessageReceived event procedure, ucPage1 can do anything in response to that event. It is important to note that when the message gets sent it is sent to all MessageReceived event procedures, not just the one that is looking for a message called “ForPage1”. If the user control ucPage1 is not loaded and this message is broadcast, but no other code is listening for it, then it is simply ignored. Remove Event Handler In each class where you add an event handler to the MessageReceived event you need to make sure to remove those event handlers when you are done. Failure to do so can cause a strong reference to the class and thus not allow that object to be garbage collected. In each of your user control’s make sure in the Unloaded event to remove the event handler. private void UserControl_Unloaded(object sender, RoutedEventArgs e){  if (_MessageBroker != null)    _MessageBroker.MessageReceived -=         _MessageBroker_MessageReceived;} Problems with Message Brokering As with most “global” classes or classes that hook up events to other classes, garbage collection is something you need to consider. Just the simple act of hooking up an event procedure to a global event handler creates a reference between your user control and the message broker in the App class. This means that even when your user control is removed from your UI, the class will still be in memory because of the reference to the message broker. This can cause messages to still being handled even though the UI is not being displayed. It is up to you to make sure you remove those event handlers as discussed in the previous section. If you don’t, then the garbage collector cannot release those objects. Instead of using events to send messages from one object to another you might consider registering your objects with a central message broker. This message broker now becomes a collection class into which you pass an object and what messages that object wishes to receive. You do end up with the same problem however. You have to un-register your objects; otherwise they still stay in memory. To alleviate this problem you can look into using the WeakReference class as a method to store your objects so they can be garbage collected if need be. Discussing Weak References is beyond the scope of this post, but you can look this up on the web. Summary In this blog post you learned how to create a simple message broker system that will allow you to send messages from one object to another without having to reference objects directly. This does reduce the coupling between objects in your application. You do need to remember to get rid of any event handlers prior to your objects going out of scope or you run the risk of having memory leaks and events being called even though you can no longer access the object that is responding to that event. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A Communication System for XAML Applications” from the drop down list.

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• Loosely coupled .NET Cache Provider using Dependency Injection

  - by Rhames

  I have recently been reading the excellent book “Dependency Injection in .NET”, written by Mark Seemann. I do not generally buy software development related books, as I never seem to have the time to read them, but I have found the time to read Mark’s book, and it was time well spent I think. Reading the ideas around Dependency Injection made me realise that the Cache Provider code I wrote about earlier (see http://geekswithblogs.net/Rhames/archive/2011/01/10/using-the-asp.net-cache-to-cache-data-in-a-model.aspx) could be refactored to use Dependency Injection, which should produce cleaner code. The goals are to: Separate the cache provider implementation (using the ASP.NET data cache) from the consumers (loose coupling). This will also mean that the dependency on System.Web for the cache provider does not ripple down into the layers where it is being consumed (such as the domain layer). Provide a decorator pattern to allow a consumer of the cache provider to be implemented separately from the base consumer (i.e. if we have a base repository, we can decorate this with a caching version). Although I used the term repository, in reality the cache consumer could be just about anything. Use constructor injection to provide the Dependency Injection, with a suitable DI container (I use Castle Windsor). The sample code for this post is available on github, https://github.com/RobinHames/CacheProvider.git ICacheProvider In the sample code, the key interface is ICacheProvider, which is in the domain layer. 1: using System; 2: using System.Collections.Generic; 3:   4: namespace CacheDiSample.Domain 5: { 6: public interface ICacheProvider<T> 7: { 8: T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 9: IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 10: } 11: }   This interface contains two methods to retrieve data from the cache, either as a single instance or as an IEnumerable. the second paramerter is of type Func<T>. This is the method used to retrieve data if nothing is found in the cache. The ASP.NET implementation of the ICacheProvider interface needs to live in a project that has a reference to system.web, typically this will be the root UI project, or it could be a separate project. The key thing is that the domain or data access layers do not need system.web references adding to them. In my sample MVC application, the CacheProvider is implemented in the UI project, in a folder called “CacheProviders”: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Caching; 6: using CacheDiSample.Domain; 7:   8: namespace CacheDiSample.CacheProvider 9: { 10: public class CacheProvider<T> : ICacheProvider<T> 11: { 12: public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 13: { 14: return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry); 15: } 16:   17: public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 18: { 19: return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry); 20: } 21:   22: #region Helper Methods 23:   24: private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 25: { 26: U value; 27: if (!TryGetValue<U>(key, out value)) 28: { 29: value = retrieveData(); 30: if (!absoluteExpiry.HasValue) 31: absoluteExpiry = Cache.NoAbsoluteExpiration; 32:   33: if (!relativeExpiry.HasValue) 34: relativeExpiry = Cache.NoSlidingExpiration; 35:   36: HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value); 37: } 38: return value; 39: } 40:   41: private bool TryGetValue<U>(string key, out U value) 42: { 43: object cachedValue = HttpContext.Current.Cache.Get(key); 44: if (cachedValue == null) 45: { 46: value = default(U); 47: return false; 48: } 49: else 50: { 51: try 52: { 53: value = (U)cachedValue; 54: return true; 55: } 56: catch 57: { 58: value = default(U); 59: return false; 60: } 61: } 62: } 63:   64: #endregion 65:   66: } 67: }   The FetchAndCache helper method checks if the specified cache key exists, if it does not, the Func<U> retrieveData method is called, and the results are added to the cache. Using Castle Windsor to register the cache provider In the MVC UI project (my application root), Castle Windsor is used to register the CacheProvider implementation, using a Windsor Installer: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain; 6: using CacheDiSample.CacheProvider; 7:   8: namespace CacheDiSample.WindsorInstallers 9: { 10: public class CacheInstaller : IWindsorInstaller 11: { 12: public void Install(IWindsorContainer container, IConfigurationStore store) 13: { 14: container.Register( 15: Component.For(typeof(ICacheProvider<>)) 16: .ImplementedBy(typeof(CacheProvider<>)) 17: .LifestyleTransient()); 18: } 19: } 20: }   Note that the cache provider is registered as a open generic type. Consuming a Repository I have an existing couple of repository interfaces defined in my domain layer: IRepository.cs 1: using System; 2: using System.Collections.Generic; 3:   4: using CacheDiSample.Domain.Model; 5:   6: namespace CacheDiSample.Domain.Repositories 7: { 8: public interface IRepository<T> 9: where T : EntityBase 10: { 11: T GetById(int id); 12: IList<T> GetAll(); 13: } 14: }   IBlogRepository.cs 1: using System; 2: using CacheDiSample.Domain.Model; 3:   4: namespace CacheDiSample.Domain.Repositories 5: { 6: public interface IBlogRepository : IRepository<Blog> 7: { 8: Blog GetByName(string name); 9: } 10: }   These two repositories are implemented in the DataAccess layer, using Entity Framework to retrieve data (this is not important though). One important point is that in the BaseRepository implementation of IRepository, the methods are virtual. This will allow the decorator to override them. The BlogRepository is registered in a RepositoriesInstaller, again in the MVC UI project. 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15: container.Register(Component.For<IBlogRepository>() 16: .ImplementedBy<BlogRepository>() 17: .LifestyleTransient() 18: .DependsOn(new 19: { 20: nameOrConnectionString = "BloggingContext" 21: })); 22: } 23: } 24: }   Now I can inject a dependency on the IBlogRepository into a consumer, such as a controller in my sample code: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Mvc; 6:   7: using CacheDiSample.Domain.Repositories; 8: using CacheDiSample.Domain.Model; 9:   10: namespace CacheDiSample.Controllers 11: { 12: public class HomeController : Controller 13: { 14: private readonly IBlogRepository blogRepository; 15:   16: public HomeController(IBlogRepository blogRepository) 17: { 18: if (blogRepository == null) 19: throw new ArgumentNullException("blogRepository"); 20:   21: this.blogRepository = blogRepository; 22: } 23:   24: public ActionResult Index() 25: { 26: ViewBag.Message = "Welcome to ASP.NET MVC!"; 27:   28: var blogs = blogRepository.GetAll(); 29:   30: return View(new Models.HomeModel { Blogs = blogs }); 31: } 32:   33: public ActionResult About() 34: { 35: return View(); 36: } 37: } 38: }   Consuming the Cache Provider via a Decorator I used a Decorator pattern to consume the cache provider, this means my repositories follow the open/closed principle, as they do not require any modifications to implement the caching. It also means that my controllers do not have any knowledge of the caching taking place, as the DI container will simply inject the decorator instead of the root implementation of the repository. The first step is to implement a BlogRepository decorator, with the caching logic in it. Note that this can reside in the domain layer, as it does not require any knowledge of the data access methods. BlogRepositoryWithCaching.cs 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5:   6: using CacheDiSample.Domain.Model; 7: using CacheDiSample.Domain; 8: using CacheDiSample.Domain.Repositories; 9:   10: namespace CacheDiSample.Domain.CacheDecorators 11: { 12: public class BlogRepositoryWithCaching : IBlogRepository 13: { 14: // The generic cache provider, injected by DI 15: private ICacheProvider<Blog> cacheProvider; 16: // The decorated blog repository, injected by DI 17: private IBlogRepository parentBlogRepository; 18:   19: public BlogRepositoryWithCaching(IBlogRepository parentBlogRepository, ICacheProvider<Blog> cacheProvider) 20: { 21: if (parentBlogRepository == null) 22: throw new ArgumentNullException("parentBlogRepository"); 23:   24: this.parentBlogRepository = parentBlogRepository; 25:   26: if (cacheProvider == null) 27: throw new ArgumentNullException("cacheProvider"); 28:   29: this.cacheProvider = cacheProvider; 30: } 31:   32: public Blog GetByName(string name) 33: { 34: string key = string.Format("CacheDiSample.DataAccess.GetByName.{0}", name); 35: // hard code 5 minute expiry! 36: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 37: return cacheProvider.Fetch(key, () => 38: { 39: return parentBlogRepository.GetByName(name); 40: }, 41: null, relativeCacheExpiry); 42: } 43:   44: public Blog GetById(int id) 45: { 46: string key = string.Format("CacheDiSample.DataAccess.GetById.{0}", id); 47:   48: // hard code 5 minute expiry! 49: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 50: return cacheProvider.Fetch(key, () => 51: { 52: return parentBlogRepository.GetById(id); 53: }, 54: null, relativeCacheExpiry); 55: } 56:   57: public IList<Blog> GetAll() 58: { 59: string key = string.Format("CacheDiSample.DataAccess.GetAll"); 60:   61: // hard code 5 minute expiry! 62: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 63: return cacheProvider.Fetch(key, () => 64: { 65: return parentBlogRepository.GetAll(); 66: }, 67: null, relativeCacheExpiry) 68: .ToList(); 69: } 70: } 71: }   The key things in this caching repository are: I inject into the repository the ICacheProvider<Blog> implementation, via the constructor. This will make the cache provider functionality available to the repository. I inject the parent IBlogRepository implementation (which has the actual data access code), via the constructor. This will allow the methods implemented in the parent to be called if nothing is found in the cache. I override each of the methods implemented in the repository, including those implemented in the generic BaseRepository. Each override of these methods follows the same pattern. It makes a call to the CacheProvider.Fetch method, and passes in the parentBlogRepository implementation of the method as the retrieval method, to be used if nothing is present in the cache. Configuring the Caching Repository in the DI Container The final piece of the jigsaw is to tell Castle Windsor to use the BlogRepositoryWithCaching implementation of IBlogRepository, but to inject the actual Data Access implementation into this decorator. This is easily achieved by modifying the RepositoriesInstaller to use Windsor’s implicit decorator wiring: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15:   16: // Use Castle Windsor implicit wiring for the block repository decorator 17: // Register the outermost decorator first 18: container.Register(Component.For<IBlogRepository>() 19: .ImplementedBy<BlogRepositoryWithCaching>() 20: .LifestyleTransient()); 21: // Next register the IBlogRepository inmplementation to inject into the outer decorator 22: container.Register(Component.For<IBlogRepository>() 23: .ImplementedBy<BlogRepository>() 24: .LifestyleTransient() 25: .DependsOn(new 26: { 27: nameOrConnectionString = "BloggingContext" 28: })); 29: } 30: } 31: }   This is all that is needed. Now if the consumer of the repository makes a call to the repositories method, it will be routed via the caching mechanism. You can test this by stepping through the code, and seeing that the DataAccess.BlogRepository code is only called if there is no data in the cache, or this has expired. The next step is to add the SQL Cache Dependency support into this pattern, this will be a future post.

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• Branding Support for TopComponents

  - by Geertjan

  In yesterday's blog entry, you saw how a menu item can be created, in this case with the label "Brand", especially for Java classes that extend TopComponent: And, as you can see here, it's not about the name of the class, i.e., not because the class above is named "BlaTopComponent" because below the "Brand" men item is also available for the class named "Bla": Both the files BlaTopComponent.java and Bla.java have the "Brand" menu item available, because both extend the "org.openide.windows.TopComponent"  class, as shown yesterday. Now we continue by creating a new JPanel, with checkboxes for each part of a TopComponent that we consider to be brandable. In my case, this is the end result, at deployment, when the Brand menu item is clicked for the Bla class: When the user (who, in this case, is a developer) clicks OK, a constructor is created and the related client properties are added, depending on which of the checkboxes are clicked: public Bla() {     putClientProperty(TopComponent.PROP_SLIDING_DISABLED, false);     putClientProperty(TopComponent.PROP_UNDOCKING_DISABLED, true);     putClientProperty(TopComponent.PROP_MAXIMIZATION_DISABLED, false);     putClientProperty(TopComponent.PROP_CLOSING_DISABLED, true);     putClientProperty(TopComponent.PROP_DRAGGING_DISABLED, false); } At this point, no check is done to see whether a constructor already exists, nor whether the client properties are already available. That's for an upcoming blog entry! Right now, the constructor is always created, regardless of whether it already exists, and the client properties are always added. The key to all this is the 'actionPeformed' of the TopComponent, which was left empty yesterday. We start by creating a JDialog from the JPanel and we retrieve the selected state of the checkboxes defined in the JPanel: @Override public void actionPerformed(ActionEvent ev) {     String msg = dobj.getName() + " Branding";     final BrandTopComponentPanel brandTopComponentPanel = new BrandTopComponentPanel();     dd = new DialogDescriptor(brandTopComponentPanel, msg, true, new ActionListener() {         @Override         public void actionPerformed(ActionEvent e) {             Object result = dd.getValue();             if (DialogDescriptor.OK_OPTION == result) {                 isClosing = brandTopComponentPanel.getClosingCheckBox().isSelected();                 isDragging = brandTopComponentPanel.getDraggingCheckBox().isSelected();                 isMaximization = brandTopComponentPanel.getMaximizationCheckBox().isSelected();                 isSliding = brandTopComponentPanel.getSlidingCheckBox().isSelected();                 isUndocking = brandTopComponentPanel.getUndockingCheckBox().isSelected();                 JavaSource javaSource = JavaSource.forFileObject(dobj.getPrimaryFile());                 try {                     javaSource.runUserActionTask(new ScanTask(javaSource), true);                 } catch (IOException ex) {                     Exceptions.printStackTrace(ex);                 }             }         }     });     DialogDisplayer.getDefault().createDialog(dd).setVisible(true); } Then we start a scan process, which introduces the branding. We're already doing a scan process for identifying whether a class is a TopComponent. So, let's combine those two scans, branching out based on which one we're doing: private class ScanTask implements Task<CompilationController> {     private BrandTopComponentAction action = null;     private JavaSource js = null;     private ScanTask(JavaSource js) {         this.js = js;     }     private ScanTask(BrandTopComponentAction action) {         this.action = action;     }     @Override     public void run(final CompilationController info) throws Exception {         info.toPhase(Phase.ELEMENTS_RESOLVED);         if (action != null) {             new EnableIfTopComponentScanner(info, action).scan(                     info.getCompilationUnit(), null);         } else {             introduceBranding();         }     }     private void introduceBranding() throws IOException {         CancellableTask task = new CancellableTask<WorkingCopy>() {             @Override             public void run(WorkingCopy workingCopy) throws IOException {                 workingCopy.toPhase(Phase.RESOLVED);                 CompilationUnitTree cut = workingCopy.getCompilationUnit();                 TreeMaker treeMaker = workingCopy.getTreeMaker();                 for (Tree typeDecl : cut.getTypeDecls()) {                     if (Tree.Kind.CLASS == typeDecl.getKind()) {                         ClassTree clazz = (ClassTree) typeDecl;                         ModifiersTree methodModifiers = treeMaker.Modifiers(Collections.<Modifier>singleton(Modifier.PUBLIC));                         MethodTree newMethod =                                 treeMaker.Method(methodModifiers,                                 "<init>",                                 treeMaker.PrimitiveType(TypeKind.VOID),                                 Collections.<TypeParameterTree>emptyList(),                                 Collections.EMPTY_LIST,                                 Collections.<ExpressionTree>emptyList(),                                 "{ putClientProperty(TopComponent.PROP_SLIDING_DISABLED, " + isSliding + ");\n"+                                 "  putClientProperty(TopComponent.PROP_UNDOCKING_DISABLED, " + isUndocking + ");\n"+                                 "  putClientProperty(TopComponent.PROP_MAXIMIZATION_DISABLED, " + isMaximization + ");\n"+                                 "  putClientProperty(TopComponent.PROP_CLOSING_DISABLED, " + isClosing + ");\n"+                                 "  putClientProperty(TopComponent.PROP_DRAGGING_DISABLED, " + isDragging + "); }\n",                                 null);                         ClassTree modifiedClazz = treeMaker.addClassMember(clazz, newMethod);                         workingCopy.rewrite(clazz, modifiedClazz);                     }                 }             }             @Override             public void cancel() {             }         };         ModificationResult result = js.runModificationTask(task);         result.commit();     } } private static class EnableIfTopComponentScanner extends TreePathScanner<Void, Void> {     private CompilationInfo info;     private final AbstractAction action;     public EnableIfTopComponentScanner(CompilationInfo info, AbstractAction action) {         this.info = info;         this.action = action;     }     @Override     public Void visitClass(ClassTree t, Void v) {         Element el = info.getTrees().getElement(getCurrentPath());         if (el != null) {             TypeElement te = (TypeElement) el;             if (te.getSuperclass().toString().equals("org.openide.windows.TopComponent")) {                 action.setEnabled(true);             } else {                 action.setEnabled(false);             }         }         return null;     } }

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• Informix "Database locale information mismatch"

  - by lmmortal

  I have informix 11.5 running in my Win-2003 box and few databases running in it. System databases have locale en_us.819 My custom databases have locale en_us.57372 (UTF8). There is also application deployed to JBoss 4.0.2 which has few datasources configured for those custom databases. <local-tx-datasource> <jndi-name>InformixDS</jndi-name> <connection-url>jdbc:informix-sqli://@database.server@:@database.port@/tcs_catalog:[email protected]@</connection-url> <driver-class>com.informix.jdbc.IfxDriver</driver-class> <user-name>@database.username@</user-name> <password>@database.password@</password> <new-connection-sql>set lock mode to wait 5</new-connection-sql> <check-valid-connection-sql>select '1' from dual</check-valid-connection-sql> <metadata> <type-mapping>InformixDB</type-mapping> </metadata> I'm logged in as Administrator and when I start JBoss the following error is shown Caused by: java.sql.SQLException: Database locale information mismatch. at com.informix.util.IfxErrMsg.getSQLException(IfxErrMsg.java:373) at com.informix.jdbc.IfxSqli.a(IfxSqli.java:3208) at com.informix.jdbc.IfxSqli.E(IfxSqli.java:3518) at com.informix.jdbc.IfxSqli.dispatchMsg(IfxSqli.java:2353) at com.informix.jdbc.IfxSqli.receiveMessage(IfxSqli.java:2269) at com.informix.jdbc.IfxSqli.executeOpenDatabase(IfxSqli.java:1786) at com.informix.jdbc.IfxSqliConnect.<init>(IfxSqliConnect.java:1327) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:501) at com.informix.jdbc.IfxDriver.connect(IfxDriver.java:254) at org.jboss.resource.adapter.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:151) ... 160 more Caused by: java.sql.SQLException at com.informix.util.IfxErrMsg.getSQLException(IfxErrMsg.java:373) at com.informix.jdbc.IfxSqli.E(IfxSqli.java:3523) ... 170 more DB_LOCALE and CLIENT_LOCALE are set to en_us.utf8 for Administrator. When I set in Server Studio DB_LOCALE and CLIENT_LOCALE to en_us.utf8 I can connect my databases. Where should I set DB_LOCALE and CLIENT_LOCALE to avoid this Database locale information mismatch error? Thanks.

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• WPF unity Activation error occured while trying to get instance of type

  - by Traci

  I am getting the following error when trying to Initialise the Module using Unity and Prism. The DLL is found by return new DirectoryModuleCatalog() { ModulePath = @".\Modules" }; The dll is found and the Name is Found #region Constructors public AdminModule( IUnityContainer container, IScreenFactoryRegistry screenFactoryRegistry, IEventAggregator eventAggregator, IBusyService busyService ) : base(container, screenFactoryRegistry) { this.EventAggregator = eventAggregator; this.BusyService = busyService; } #endregion #region Properties protected IEventAggregator EventAggregator { get; set; } protected IBusyService BusyService { get; set; } #endregion public override void Initialize() { base.Initialize(); } #region Register Screen Factories protected override void RegisterScreenFactories() { this.ScreenFactoryRegistry.Register(ScreenKeyType.ApplicationAdmin, typeof(AdminScreenFactory)); } #endregion #region Register Views and Various Services protected override void RegisterViewsAndServices() { //View Models this.Container.RegisterType<IAdminViewModel, AdminViewModel>(); } #endregion the code that produces the error is: namespace Microsoft.Practices.Composite.Modularity protected virtual IModule CreateModule(string typeName) { Type moduleType = Type.GetType(typeName); if (moduleType == null) { throw new ModuleInitializeException(string.Format(CultureInfo.CurrentCulture, Properties.Resources.FailedToGetType, typeName)); } return (IModule)this.serviceLocator.GetInstance(moduleType); <-- Error Here } Can Anyone Help Me Error Log Below: General Information Additional Info: ExceptionManager.MachineName: xxxxx ExceptionManager.TimeStamp: 22/02/2010 10:16:55 AM ExceptionManager.FullName: Microsoft.ApplicationBlocks.ExceptionManagement, Version=1.0.3591.32238, Culture=neutral, PublicKeyToken=null ExceptionManager.AppDomainName: Infinity.vshost.exe ExceptionManager.ThreadIdentity: ExceptionManager.WindowsIdentity: xxxxx 1) Exception Information Exception Type: Microsoft.Practices.Composite.Modularity.ModuleInitializeException ModuleName: AdminModule Message: An exception occurred while initializing module 'AdminModule'. - The exception message was: Activation error occured while trying to get instance of type AdminModule, key "" Check the InnerException property of the exception for more information. If the exception occurred while creating an object in a DI container, you can exception.GetRootException() to help locate the root cause of the problem. Data: System.Collections.ListDictionaryInternal TargetSite: Void HandleModuleInitializationError(Microsoft.Practices.Composite.Modularity.ModuleInfo, System.String, System.Exception) HelpLink: NULL Source: Microsoft.Practices.Composite StackTrace Information at Microsoft.Practices.Composite.Modularity.ModuleInitializer.HandleModuleInitializationError(ModuleInfo moduleInfo, String assemblyName, Exception exception) at Microsoft.Practices.Composite.Modularity.ModuleInitializer.Initialize(ModuleInfo moduleInfo) at Microsoft.Practices.Composite.Modularity.ModuleManager.InitializeModule(ModuleInfo moduleInfo) at Microsoft.Practices.Composite.Modularity.ModuleManager.LoadModulesThatAreReadyForLoad() at Microsoft.Practices.Composite.Modularity.ModuleManager.OnModuleTypeLoaded(ModuleInfo typeLoadedModuleInfo, Exception error) at Microsoft.Practices.Composite.Modularity.FileModuleTypeLoader.BeginLoadModuleType(ModuleInfo moduleInfo, ModuleTypeLoadedCallback callback) at Microsoft.Practices.Composite.Modularity.ModuleManager.BeginRetrievingModule(ModuleInfo moduleInfo) at Microsoft.Practices.Composite.Modularity.ModuleManager.LoadModuleTypes(IEnumerable`1 moduleInfos) at Microsoft.Practices.Composite.Modularity.ModuleManager.LoadModulesWhenAvailable() at Microsoft.Practices.Composite.Modularity.ModuleManager.Run() at Microsoft.Practices.Composite.UnityExtensions.UnityBootstrapper.InitializeModules() at Infinity.Bootstrapper.InitializeModules() in D:\Projects\dotNet\Infinity\source\Inifinty\Infinity\Application Modules\BootStrapper.cs:line 75 at Microsoft.Practices.Composite.UnityExtensions.UnityBootstrapper.Run(Boolean runWithDefaultConfiguration) at Microsoft.Practices.Composite.UnityExtensions.UnityBootstrapper.Run() at Infinity.App.Application_Startup(Object sender, StartupEventArgs e) in D:\Projects\dotNet\Infinity\source\Inifinty\Infinity\App.xaml.cs:line 37 at System.Windows.Application.OnStartup(StartupEventArgs e) at System.Windows.Application.<.ctorb__0(Object unused) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) 2) Exception Information Exception Type: Microsoft.Practices.ServiceLocation.ActivationException Message: Activation error occured while trying to get instance of type AdminModule, key "" Data: System.Collections.ListDictionaryInternal TargetSite: System.Object GetInstance(System.Type, System.String) HelpLink: NULL Source: Microsoft.Practices.ServiceLocation StackTrace Information at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance(Type serviceType, String key) at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance(Type serviceType) at Microsoft.Practices.Composite.Modularity.ModuleInitializer.CreateModule(String typeName) at Microsoft.Practices.Composite.Modularity.ModuleInitializer.Initialize(ModuleInfo moduleInfo) 3) Exception Information Exception Type: Microsoft.Practices.Unity.ResolutionFailedException TypeRequested: AdminModule NameRequested: NULL Message: Resolution of the dependency failed, type = "Infinity.Modules.Admin.AdminModule", name = "". Exception message is: The current build operation (build key Build Key[Infinity.Modules.Admin.AdminModule, null]) failed: The parameter screenFactoryRegistry could not be resolved when attempting to call constructor Infinity.Modules.Admin.AdminModule(Microsoft.Practices.Unity.IUnityContainer container, PhoenixIT.IScreenFactoryRegistry screenFactoryRegistry, Microsoft.Practices.Composite.Events.IEventAggregator eventAggregator, PhoenixIT.IBusyService busyService). (Strategy type BuildPlanStrategy, index 3) Data: System.Collections.ListDictionaryInternal TargetSite: System.Object DoBuildUp(System.Type, System.Object, System.String) HelpLink: NULL Source: Microsoft.Practices.Unity StackTrace Information at Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, Object existing, String name) at Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, String name) at Microsoft.Practices.Unity.UnityContainer.Resolve(Type t, String name) at Microsoft.Practices.Composite.UnityExtensions.UnityServiceLocatorAdapter.DoGetInstance(Type serviceType, String key) at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance(Type serviceType, String key) 4) Exception Information Exception Type: Microsoft.Practices.ObjectBuilder2.BuildFailedException ExecutingStrategyTypeName: BuildPlanStrategy ExecutingStrategyIndex: 3 BuildKey: Build Key[Infinity.Modules.Admin.AdminModule, null] Message: The current build operation (build key Build Key[Infinity.Modules.Admin.AdminModule, null]) failed: The parameter screenFactoryRegistry could not be resolved when attempting to call constructor Infinity.Modules.Admin.AdminModule(Microsoft.Practices.Unity.IUnityContainer container, PhoenixIT.IScreenFactoryRegistry screenFactoryRegistry, Microsoft.Practices.Composite.Events.IEventAggregator eventAggregator, PhoenixIT.IBusyService busyService). (Strategy type BuildPlanStrategy, index 3) Data: System.Collections.ListDictionaryInternal TargetSite: System.Object ExecuteBuildUp(Microsoft.Practices.ObjectBuilder2.IBuilderContext) HelpLink: NULL Source: Microsoft.Practices.ObjectBuilder2 StackTrace Information at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.Builder.BuildUp(IReadWriteLocator locator, ILifetimeContainer lifetime, IPolicyList policies, IStrategyChain strategies, Object buildKey, Object existing) at Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, Object existing, String name) 5) Exception Information Exception Type: System.InvalidOperationException Message: The parameter screenFactoryRegistry could not be resolved when attempting to call constructor Infinity.Modules.Admin.AdminModule(Microsoft.Practices.Unity.IUnityContainer container, PhoenixIT.IScreenFactoryRegistry screenFactoryRegistry, Microsoft.Practices.Composite.Events.IEventAggregator eventAggregator, PhoenixIT.IBusyService busyService). Data: System.Collections.ListDictionaryInternal TargetSite: Void ThrowForResolutionFailed(System.Exception, System.String, System.String, Microsoft.Practices.ObjectBuilder2.IBuilderContext) HelpLink: NULL Source: Microsoft.Practices.ObjectBuilder2 StackTrace Information at Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.ThrowForResolutionFailed(Exception inner, String parameterName, String constructorSignature, IBuilderContext context) at BuildUp_Infinity.Modules.Admin.AdminModule(IBuilderContext ) at Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) 6) Exception Information Exception Type: Microsoft.Practices.ObjectBuilder2.BuildFailedException ExecutingStrategyTypeName: BuildPlanStrategy ExecutingStrategyIndex: 3 BuildKey: Build Key[PhoenixIT.IScreenFactoryRegistry, null] Message: The current build operation (build key Build Key[PhoenixIT.IScreenFactoryRegistry, null]) failed: The current type, PhoenixIT.IScreenFactoryRegistry, is an interface and cannot be constructed. Are you missing a type mapping? (Strategy type BuildPlanStrategy, index 3) Data: System.Collections.ListDictionaryInternal TargetSite: System.Object ExecuteBuildUp(Microsoft.Practices.ObjectBuilder2.IBuilderContext) HelpLink: NULL Source: Microsoft.Practices.ObjectBuilder2 StackTrace Information at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) at Microsoft.Practices.Unity.ObjectBuilder.NamedTypeDependencyResolverPolicy.Resolve(IBuilderContext context) at BuildUp_Infinity.Modules.Admin.AdminModule(IBuilderContext ) 7) Exception Information Exception Type: System.InvalidOperationException Message: The current type, PhoenixIT.IScreenFactoryRegistry, is an interface and cannot be constructed. Are you missing a type mapping? Data: System.Collections.ListDictionaryInternal TargetSite: Void ThrowForAttemptingToConstructInterface(Microsoft.Practices.ObjectBuilder2.IBuilderContext) HelpLink: NULL Source: Microsoft.Practices.ObjectBuilder2 StackTrace Information at Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.ThrowForAttemptingToConstructInterface(IBuilderContext context) at BuildUp_PhoenixIT.IScreenFactoryRegistry(IBuilderContext ) at Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

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• NHibernate: Collection was modified; enumeration operation may not execute

  - by Daoming Yang

  Hi All, I'm currently struggling with this "Collection was modified; enumeration operation may not execute" issue. I have searched about this error message, and it's all related to the foreach statement. I do have the some foreach statements, but they are just simply representing the data. I did not using any remove or add inside the foreach statement. NOTE: The error randomly happens (about 4-5 times a day). The application is the MVC website. There are about 5 users operate this applications (about 150 orders a day). Could it be some another users modified the collection, and then occur this error? I have log4net setup and the settings can be found here Make sure that the controller has a parameterless public constructor I do have parameterless public constructor in AdminProductController Does anyone know why this happen and how to resolve this issue? A friend (Oskar) mentioned that "Theory: Maybe the problem is that your configuration and session factory is initialized on the first request after application restart. If a second request comes in before the first request is finished, maybe it will also try to initialize and then triggering this problem somehow." Many thanks. Daoming Here is the error message: System.InvalidOperationException Collection was modified; enumeration operation may not execute. System.InvalidOperationException: An error occurred when trying to create a controller of type 'WebController.Controllers.Admin.AdminProductController'. Make sure that the controller has a parameterless public constructor. --- System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. --- NHibernate.MappingException: Could not configure datastore from input stream DomainModel.Entities.Mappings.OrderProductVariant.hbm.xml --- System.InvalidOperationException: Collection was modified; enumeration operation may not execute. at System.Collections.ArrayList.ArrayListEnumeratorSimple.MoveNext() at System.Xml.Schema.XmlSchemaSet.AddSchemaToSet(XmlSchema schema) at System.Xml.Schema.XmlSchemaSet.Add(String targetNamespace, XmlSchema schema) at System.Xml.Schema.XmlSchemaSet.Add(XmlSchema schema) at NHibernate.Cfg.Configuration.LoadMappingDocument(XmlReader hbmReader, String name) at NHibernate.Cfg.Configuration.AddInputStream(Stream xmlInputStream, String name) --- End of inner exception stack trace --- at NHibernate.Cfg.Configuration.LogAndThrow(Exception exception) at NHibernate.Cfg.Configuration.AddInputStream(Stream xmlInputStream, String name) at NHibernate.Cfg.Configuration.AddResource(String path, Assembly assembly) at NHibernate.Cfg.Configuration.AddAssembly(Assembly assembly) at DomainModel.RepositoryBase..ctor() at WebController.Controllers._baseController..ctor() at WebController.Controllers.Admin.AdminProductController..ctor() at System.RuntimeType.CreateInstanceImpl(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean fillCache) --- End of inner exception stack trace --- at System.RuntimeType.CreateInstanceImpl(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean fillCache) at System.Activator.CreateInstance(Type type, Boolean nonPublic) at System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) --- End of inner exception stack trace --- at System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) at System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) at System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) UPDATE CODE: In my Global.asax.cs, I'm doing this: protected void Application_BeginRequest(object sender, EventArgs e) { ManagedWebSessionContext.Bind(HttpContext.Current, SessionManager.SessionFactory.OpenSession()); } protected void Application_EndRequest(object sender, EventArgs e) { ISession session = ManagedWebSessionContext.Unbind(HttpContext.Current, SessionManager.SessionFactory); if (session != null) { try { if (session.Transaction != null && session.Transaction.IsActive) { session.Transaction.Rollback(); } else { session.Flush(); } } finally { session.Close(); } } } In the SessionManager class, I'm doing: public class SessionManager { private readonly ISessionFactory sessionFactory; public static ISessionFactory SessionFactory { get { return Instance.sessionFactory; } } private ISessionFactory GetSessionFactory() { return sessionFactory; } public static SessionManager Instance { get { return NestedSessionManager.sessionManager; } } public static ISession OpenSession() { return Instance.GetSessionFactory().OpenSession(); } public static ISession CurrentSession { get { return Instance.GetSessionFactory().GetCurrentSession(); } } private SessionManager() { Configuration config = new Configuration().Configure(); config.AddAssembly(Assembly.GetExecutingAssembly()); sessionFactory = config.BuildSessionFactory(); } class NestedSessionManager { internal static readonly SessionManager sessionManager = new SessionManager(); } } In the Repository, I'm doing this: public IEnumerable<User> GetAll() { ICriteria criteria = SessionManager.CurrentSession.CreateCriteria(typeof(User)); return criteria.List<User>(); } In the Controller, I'm doing this: public class UserController : _baseController { IUserRoleRepository _userRoleRepository; internal static readonly ILogger log = LogManager.GetLogger(typeof(UserController)); public UserController() { _userRoleRepository = new UserRoleRepository(); } public ActionResult UserList() { var myList = _usersRepository.GetAll(); return View(myList); } }

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• Droid's mediaserver dies on camera.takePicture()

  - by SirBoss

  On Motorola Droid, Firmware 2.1-update1, Kernel 2.9.29-omap1, Build # ESE81 When attempting to take a picture, mediaserver dies with a segmentation fault. I've tried putting takePicture in a timer and running it a few seconds after camera initialization to check for race conditions, but no change. Just calling Camera.open() doesn't cause the crash. Also, calling Camera.open() causes what I think is the autofocus motor to make a sort of ticking sound. Code that breaks: import android.app.Activity; import android.os.Bundle; public final class ChopperMain extends Activity { public void onCreate(Bundle savedInstanceState) { try { Camera camera = Camera.open(); catch (Exception e) { e.printStackTrace(); } camera.takePicture( new Camera.ShutterCallback() { public void onShutter() { ; } }, new Camera.PictureCallback() { public void onPictureTaken(byte[] data, Camera camera) { ; } }, new Camera.PictureCallback() { public void onPictureTaken(byte[] data, Camera camera) { ; } }, new PictureCallback() { public void onPictureTaken(byte[] data, Camera camera) { System.out.println("Ta da."); } } }); } catch (Exception e) { e.printStackTrace(); } } } Debug Log: D/CameraHal(10158): CameraSettings constructor D/CameraHal(10158): CameraHal constructor D/CameraHal(10158): Model ID: Droid D/CameraHal(10158): Software ID 2.1-update1 D/dalvikvm( 988): GC freed 2 objects / 56 bytes in 215ms D/ViewFlipper( 1074): updateRunning() mVisible=false, mStarted=true, mUserPresent=false, mRunning=false I/HPAndroidHAL(10158): Version 2988. Build Time: Oct 26 2009:11:21:55. D/CameraHal(10158): 19 default parameters D/CameraHal(10158): Immediate Zoom/1:0. Current zoom level/1:0 D/CameraHal(10158): CameraHal constructor exited ok D/CameraService(10158): Client::Client X (pid 10400) D/CameraService(10158): CameraService::connect X D/CameraService(10158): takePicture (pid 10400) I/DEBUG (10159): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** I/DEBUG (10159): Build fingerprint: 'verizon/voles/sholes/sholes:2.1-update1/ESE81/29593:user/release-keys' I/DEBUG (10159): pid: 10158, tid: 10158 >>> /system/bin/mediaserver <<< I/DEBUG (10159): signal 11 (SIGSEGV), fault addr 00000008 I/DEBUG (10159): r0 00000000 r1 00000000 r2 a969030c r3 a9d1bfe0 I/DEBUG (10159): r4 00045eb0 r5 0000eb10 r6 000153a0 r7 a9c89fd2 I/DEBUG (10159): r8 00000000 r9 00000000 10 00000000 fp 00000000 I/DEBUG (10159): ip a969085c sp bec4fba0 lr a9689c65 pc a9d1bfde cpsr 60000030 I/DEBUG (10159): #00 pc 0001bfde /system/lib/libutils.so I/DEBUG (10159): #01 pc 00009c62 /system/lib/libcamera.so I/DEBUG (10159): #02 pc 00007b0c /system/lib/libcameraservice.so I/DEBUG (10159): #03 pc 00021f98 /system/lib/libui.so I/DEBUG (10159): #04 pc 00015514 /system/lib/libbinder.so I/DEBUG (10159): #05 pc 00018dd8 /system/lib/libbinder.so I/DEBUG (10159): #06 pc 00018fa6 /system/lib/libbinder.so I/DEBUG (10159): #07 pc 000087d2 /system/bin/mediaserver I/DEBUG (10159): #08 pc 0000c228 /system/lib/libc.so I/DEBUG (10159): I/DEBUG (10159): code around pc: I/DEBUG (10159): a9d1bfcc bd1061e3 f7f3b510 bd10e97e 4d17b570 I/DEBUG (10159): a9d1bfdc 6886a300 460418ed fff4f7ff d10a4286 I/DEBUG (10159): a9d1bfec 46234913 20054a13 f06f1869 18aa040a I/DEBUG (10159): I/DEBUG (10159): code around lr: I/DEBUG (10159): a9689c54 e0240412 0204f8d0 050cf104 edf0f7fd I/DEBUG (10159): a9689c64 f7fd4628 f8d4ecf2 b1533204 f852681a I/DEBUG (10159): a9689c74 18581c0c 7101f504 ed82f7fd f8c42000 I/DEBUG (10159): I/DEBUG (10159): stack: I/DEBUG (10159): bec4fb60 4000902c /dev/binder I/DEBUG (10159): bec4fb64 a9d19675 /system/lib/libutils.so I/DEBUG (10159): bec4fb68 00002bb4 I/DEBUG (10159): bec4fb6c a9d1b26f /system/lib/libutils.so I/DEBUG (10159): bec4fb70 bec4fbbc [stack] I/DEBUG (10159): bec4fb74 00095080 [heap] I/DEBUG (10159): bec4fb78 a9c8c028 /system/lib/libcameraservice.so I/DEBUG (10159): bec4fb7c a9c8c028 /system/lib/libcameraservice.so I/DEBUG (10159): bec4fb80 00015390 [heap] I/DEBUG (10159): bec4fb84 a9c89fd2 /system/lib/libcameraservice.so I/DEBUG (10159): bec4fb88 00045ebc [heap] I/DEBUG (10159): bec4fb8c afe0f110 /system/lib/libc.so I/DEBUG (10159): bec4fb90 00000000 I/DEBUG (10159): bec4fb94 afe0f028 /system/lib/libc.so I/DEBUG (10159): bec4fb98 df002777 I/DEBUG (10159): bec4fb9c e3a070ad I/DEBUG (10159): #00 bec4fba0 00045eb0 [heap] I/DEBUG (10159): bec4fba4 00045ebc [heap] I/DEBUG (10159): bec4fba8 000153a0 [heap] I/DEBUG (10159): bec4fbac a9689c65 /system/lib/libcamera.so I/DEBUG (10159): #01 bec4fbb0 a9c8c028 /system/lib/libcameraservice.so I/DEBUG (10159): bec4fbb4 00015390 [heap] I/DEBUG (10159): bec4fbb8 000153a0 [heap] I/DEBUG (10159): bec4fbbc a9c87b0f /system/lib/libcameraservice.so I/DEBUG (10159): debuggerd committing suicide to free the zombie! I/DEBUG (10426): debuggerd: Mar 22 2010 17:31:05 W/MediaPlayer( 1021): MediaPlayer server died! I/ServiceManager( 984): service 'media.audio_flinger' died I/ServiceManager( 984): service 'media.player' died I/ServiceManager( 984): service 'media.camera' died I/ServiceManager( 984): service 'media.audio_policy' died W/Camera (10400): Camera server died! W/Camera (10400): ICamera died E/Camera (10400): Error 100 I/System.out(10400): Camera error, code 100 W/AudioSystem( 1021): AudioFlinger server died! W/AudioSystem( 1021): AudioPolicyService server died! I/ (10425): ServiceManager: 0xad08 E/AudioPostProcessor(10425): E/AudioPostProcessor(10425): AudioMgr Error:Failed to open gains file /data/ap_gain.bin E/AudioPostProcessor(10425): E/AudioPostProcessor(10425): AudioMgr Error:Failed to read gains/coeffs from /data E/AudioPostProcessor(10425): Audio coeffs init success. I/CameraService(10425): CameraService started: pid=10425 D/Audio_Unsolicited(10425): in readyToRun D/Audio_Unsolicited(10425): Create socket successful 10 I/AudioFlinger(10425): AudioFlinger's thread 0x11c30 ready to run E/AudioService( 1021): Media server died. E/AudioService( 1021): Media server started. W/AudioPolicyManager(10425): setPhoneState() setting same state 0

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• Loading FireMonkey style resourses with RTTI

  - by HeMet

  I am trying to write class that inherits from FMX TStyledControl. When style is updated it loads style resource objects to cache. I created project group for package with custom controls and test FMX HD project as it describes in Delphi help. After installing package and placing TsgSlideHost on the test form I run test app. It’s work well, but when I close it and try to rebuild package RAD Studio says “Error in rtl160.bpl” or “invalid pointer operation”. It seems what problem in LoadToCacheIfNeeded procedure from TsgStyledControl, but I’m not understand why. Is there any restriction on using RTTI with FMX styles or anything? TsgStyledControl sources: unit SlideGUI.TsgStyledControl; interface uses System.SysUtils, System.Classes, System.Types, FMX.Types, FMX.Layouts, FMX.Objects, FMX.Effects, System.UITypes, FMX.Ani, System.Rtti, System.TypInfo; type TCachedAttribute = class(TCustomAttribute) private fStyleName: string; public constructor Create(const aStyleName: string); property StyleName: string read fStyleName; end; TsgStyledControl = class(TStyledControl) private procedure CacheStyleObjects; procedure LoadToCacheIfNeeded(aField: TRttiField); protected function FindStyleResourceAs<T: class>(const AStyleLookup: string): T; function GetStyleName: string; virtual; abstract; function GetStyleObject: TControl; override; public procedure ApplyStyle; override; published { Published declarations } end; implementation { TsgStyledControl } procedure TsgStyledControl.ApplyStyle; begin inherited; CacheStyleObjects; end; procedure TsgStyledControl.CacheStyleObjects; var ctx: TRttiContext; typ: TRttiType; fld: TRttiField; begin ctx := TRttiContext.Create; try typ := ctx.GetType(Self.ClassType); for fld in typ.GetFields do LoadFromCacheIfNeeded(fld); finally ctx.Free end; end; function TsgStyledControl.FindStyleResourceAs<T>(const AStyleLookup: string): T; var fmxObj: TFmxObject; begin fmxObj := FindStyleResource(AStyleLookup); if Assigned(fmxObj) and (fmxObj is T) then Result := fmxObj as T else Result := nil; end; function TsgStyledControl.GetStyleObject: TControl; var S: TResourceStream; begin if (FStyleLookup = '') then begin if FindRCData(HInstance, GetStyleName) then begin S := TResourceStream.Create(HInstance, GetStyleName, RT_RCDATA); try Result := TControl(CreateObjectFromStream(nil, S)); Exit; finally S.Free; end; end; end; Result := inherited GetStyleObject; end; procedure TsgStyledControl.LoadToCacheIfNeeded(aField: TRttiField); var attr: TCustomAttribute; styleName: string; styleObj: TFmxObject; val: TValue; begin for attr in aField.GetAttributes do begin if attr is TCachedAttribute then begin styleName := TCachedAttribute(attr).StyleName; if styleName <> '' then begin styleObj := FindStyleResource(styleName); val := TValue.From<TFmxObject>(styleObj); aField.SetValue(Self, val); end; end; end; end; { TCachedAttribute } constructor TCachedAttribute.Create(const aStyleName: string); begin fStyleName := aStyleName; end; end. Using of TsgStyledControl: type TsgSlideHost = class(TsgStyledControl) private [TCached('SlideHost')] fSlideHost: TLayout; [TCached('SideMenu')] fSideMenuLyt: TLayout; [TCached('SlideContainer')] fSlideContainer: TLayout; fSideMenu: IsgSideMenu; procedure ReapplyProps; procedure SetSideMenu(const Value: IsgSideMenu); protected function GetStyleName: string; override; function GetStyleObject: TControl; override; procedure UpdateSideMenuLyt; public constructor Create(AOwner: TComponent); override; procedure ApplyStyle; override; published property SideMenu: IsgSideMenu read fSideMenu write SetSideMenu; end;

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• android.view.InflateException: Binary XML file line #11

  - by kostas

  i have a listview with some items.when the user touch the first list item it starts a dialog activity with a photo and some text below.that happens for every list item.but unfortunately i m getting this android.view.InflateException: Binary XML file line #11 force down error..this is a part of my manifest: <activity android:name=".kalamaki" android:label="Beaches in Chania" android:screenOrientation="portrait" android:configChanges="orientation|keyboardHidden" android:theme="@android:style/Theme.Dialog" /> this is my .xml file: <?xml version="1.0" encoding="utf-8"?> <ScrollView xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="#cfcfcc" > <LinearLayout android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <ImageView android:layout_marginTop="5px" android:id="@+id/image" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@+id/image" /> <TextView android:layout_marginTop="5px" android:id="@+id/text" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@+id/text" android:textColor="#262626" /> </LinearLayout> </ScrollView> and this is my logcat error: 04-30 19:08:34.433: ERROR/AndroidRuntime(405): Uncaught handler: thread main exiting due to uncaught exception 04-30 19:08:34.463: ERROR/AndroidRuntime(405): java.lang.RuntimeException: Unable to start activity ComponentInfo{kostas.menu.chania/kostas.menu.chania.sfinari}: android.view.InflateException: Binary XML file line #11: Error inflating class <unknown> 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2454) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2470) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.app.ActivityThread.access$2200(ActivityThread.java:119) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.os.Handler.dispatchMessage(Handler.java:99) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.os.Looper.loop(Looper.java:123) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.app.ActivityThread.main(ActivityThread.java:4310) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at java.lang.reflect.Method.invokeNative(Native Method) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at java.lang.reflect.Method.invoke(Method.java:521) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at dalvik.system.NativeStart.main(Native Method) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): Caused by: android.view.InflateException: Binary XML file line #11: Error inflating class <unknown> 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.view.LayoutInflater.createView(LayoutInflater.java:513) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:563) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.view.LayoutInflater.rInflate(LayoutInflater.java:618) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.view.LayoutInflater.rInflate(LayoutInflater.java:621) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.view.LayoutInflater.inflate(LayoutInflater.java:407) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.view.LayoutInflater.inflate(LayoutInflater.java:320) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.view.LayoutInflater.inflate(LayoutInflater.java:276) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:198) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.app.Activity.setContentView(Activity.java:1622) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at kostas.menu.chania.sfinari.onCreate(sfinari.java:15) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2417) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): ... 11 more 04-30 19:08:34.463: ERROR/AndroidRuntime(405): Caused by: java.lang.reflect.InvocationTargetException 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.widget.ImageView.<init>(ImageView.java:105) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at java.lang.reflect.Constructor.constructNative(Native Method) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at java.lang.reflect.Constructor.newInstance(Constructor.java:446) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.view.LayoutInflater.createView(LayoutInflater.java:500) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): ... 23 more 04-30 19:08:34.463: ERROR/AndroidRuntime(405): Caused by: android.content.res.Resources$NotFoundException: File res/drawable-mdpi/scrollbar_handle_vertical.9.png from drawable resource ID #0x7f050000 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.content.res.Resources.loadDrawable(Resources.java:1710) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.content.res.TypedArray.getDrawable(TypedArray.java:548) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.widget.ImageView.<init>(ImageView.java:115) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): ... 27 more 04-30 19:08:34.463: ERROR/AndroidRuntime(405): Caused by: java.io.FileNotFoundException: res/drawable-mdpi/scrollbar_handle_vertical.9.png 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.content.res.AssetManager.openNonAssetNative(Native Method) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.content.res.AssetManager.openNonAsset(AssetManager.java:391) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): at android.content.res.Resources.loadDrawable(Resources.java:1702) 04-30 19:08:34.463: ERROR/AndroidRuntime(405): ... 29 more

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• Making swap faster, easier to use and exception-safe

  - by FredOverflow

  I could not sleep last night and started thinking about std::swap. Here is the familiar C++98 version: template <typename T> void swap(T& a, T& b) { T c(a); a = b; b = c; } If a user-defined class Foo uses external ressources, this is inefficient. The common idiom is to provide a method void Foo::swap(Foo& other) and a specialization of std::swap<Foo>. Note that this does not work with class templates since you cannot partially specialize a function template, and overloading names in the std namespace is illegal. The solution is to write a template function in one's own namespace and rely on argument dependent lookup to find it. This depends critically on the client to follow the "using std::swap idiom" instead of calling std::swap directly. Very brittle. In C++0x, if Foo has a user-defined move constructor and a move assignment operator, providing a custom swap method and a std::swap<Foo> specialization has little to no performance benefit, because the C++0x version of std::swap uses efficient moves instead of copies: #include <utility> template <typename T> void swap(T& a, T& b) { T c(std::move(a)); a = std::move(b); b = std::move(c); } Not having to fiddle with swap anymore already takes a lot of burden away from the programmer. Current compilers do not generate move constructors and move assignment operators automatically yet, but as far as I know, this will change. The only problem left then is exception-safety, because in general, move operations are allowed to throw, and this opens up a whole can of worms. The question "What exactly is the state of a moved-from object?" complicates things further. Then I was thinking, what exactly are the semantics of std::swap in C++0x if everything goes fine? What is the state of the objects before and after the swap? Typically, swapping via move operations does not touch external resources, only the "flat" object representations themselves. So why not simply write a swap template that does exactly that: swap the object representations? #include <cstring> template <typename T> void swap(T& a, T& b) { unsigned char c[sizeof(T)]; memcpy( c, &a, sizeof(T)); memcpy(&a, &b, sizeof(T)); memcpy(&b, c, sizeof(T)); } This is as efficient as it gets: it simply blasts through raw memory. It does not require any intervention from the user: no special swap methods or move operations have to be defined. This means that it even works in C++98 (which does not have rvalue references, mind you). But even more importantly, we can now forget about the exception-safety issues, because memcpy never throws. I can see two potential problems with this approach: First, not all objects are meant to be swapped. If a class designer hides the copy constructor or the copy assignment operator, trying to swap objects of the class should fail at compile-time. We can simply introduce some dead code that checks whether copying and assignment are legal on the type: template <typename T> void swap(T& a, T& b) { if (false) // dead code, never executed { T c(a); // copy-constructible? a = b; // assignable? } unsigned char c[sizeof(T)]; std::memcpy( c, &a, sizeof(T)); std::memcpy(&a, &b, sizeof(T)); std::memcpy(&b, c, sizeof(T)); } Any decent compiler can trivially get rid of the dead code. (There are probably better ways to check the "swap conformance", but that is not the point. What matters is that it's possible). Second, some types might perform "unusual" actions in the copy constructor and copy assignment operator. For example, they might notify observers of their change. I deem this a minor issue, because such kinds of objects probably should not have provided copy operations in the first place. Please let me know what you think of this approach to swapping. Would it work in practice? Would you use it? Can you identify library types where this would break? Do you see additional problems? Discuss!

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• Why can't my main class see the array in my calender class

  - by Rocky Celltick Eadie

  This is a homework problem. I'm already 5 days late and can't figure out what I'm doing wrong.. this is my 1st semester in Java and my first post on this site Here is the assignment.. Create a class called Calendar. The class should contain a variable called events that is a String array. The array should be created to hold 5 elements. Use a constant value to specify the array size. Do not hard code the array size. Initialize the array in the class constructor so that each element contains the string “ – No event planned – “. The class should contain a method called CreateEvent. This method should accept a String argument that contains a one-word user event and an integer argument that represents the day of the week. Monday should be represented by the number 1 and Friday should be represented by the number 5. Populate the events array with the event info passed into the method. Although the user will input one-word events, each event string should prepend the following string to each event: event_dayAppoinment: (where event_day is the day of the week) For example, if the user enters 1 and “doctor” , the first array element should read: Monday Appointment: doctor If the user enters 2 and “PTA” , the second array element should read: Tuesday Appointment: PTA Write a driver program (in a separate class) that creates and calls your Calendar class. Then use a loop to gather user input. Ask for the day (as an integer) and then ask for the event (as a one word string). Pass the integer and string to the Calendar object’s CreateEvent method. The user should be able enter 0 – 5 events. If the user enters -1, the loop should exit and your application should print out all the events in a tabular format. Your program should not allow the user to enter invalid values for the day of the week. Any input other than 1 – 5 or -1 for the day of the week would be considered invalid. Notes: When obtaining an integer from the user, you will need to use the nextInt() method on your Scanner object. When obtaining a string from a user, you will need to use the next() method on your Scanner object. Here is my code so far.. //DRIVER CLASS /** * * @author Rocky */ //imports scanner import java.util.Scanner; //begin class driver public class driver { /** * @paramargs the command line arguments */ //begin main method public static void main(String[] args) { //initiates scanner Scanner userInput = new Scanner (System.in); //declare variables int dayOfWeek; String userEvent; //creates object for calender class calendercalenderObject = new calender(); //user prompt System.out.println("Enter day of week for your event in the following format:"); System.out.println("Enter 1 for Monday"); System.out.println("Enter 2 for Tuesday"); System.out.println("Enter 3 for Wednsday"); System.out.println("Enter 4 for Thursday"); System.out.println("Enter 5 for Friday"); System.out.println("Enter -1 to quit"); //collect user input dayOfWeek = userInput.nextInt(); //user prompt System.out.println("Please type in the name of your event"); //collect user input userEvent = userInput.next(); //begin while loop while (dayOfWeek != -1) { //test for valid day of week if ((dayOfWeek>=1) && (dayOfWeek<=5)){ //calls createEvent method in calender class and passes 2 variables calenderObject.createEvent(userEvent,dayOfWeek); } else { //error message System.out.println("You have entered an invalid number"); //user prompts System.out.println("Press -1 to quit or enter another day"); System.out.println("Enter 1 for Monday"); System.out.println("Enter 2 for Tuesday"); System.out.println("Enter 3 for Wednsday"); System.out.println("Enter 4 for Thursday"); System.out.println("Enter 5 for Friday"); System.out.println("Enter -1 to quit"); //collect user input dayOfWeek = userInput.nextInt(); //end data validity test } //end while loop } //prints array to screen int i=0; for (i=0;i<events.length;i++){ System.out.println(events[i]); } //end main method } } /** * * @author Rocky */ //imports scanner import java.util.Scanner; //begin calender class public class calender { //creates events array String[] events = new String[5]; //begin calender class constructor public calender() { //Initializes array String[] events = {"-No event planned-","-No event planned-","-No event planned-","-No event planned-","-No event planned-"}; //end calender class constructor } //begin createEvent method public String[] createEvent (String userEvent, int dayOfWeek){ //Start switch test switch (dayOfWeek){ case 1: events[0] = ("Monday Appoinment:") + userEvent; break; case 2: events[1] = ("Tuesday Appoinment:") + userEvent; break; case 3: events[2] = ("WednsdayAppoinment:") + userEvent; break; case 4: events[3] = ("Thursday Appoinment:") + userEvent; break; case 5: events[4] = ("Friday Appoinment:") + userEvent; break; default: break; //End switch test } //returns events array return events; //end create event method } //end calender class }

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• Get the property, as a string, from an Expression<Func<TModel,TProperty>>

  - by Jaxidian

  I use some strongly-typed expressions that get serialized to allow my UI code to have strongly-typed sorting and searching expressions. These are of type Expression<Func<TModel,TProperty>> and are used as such: SortOption.Field = (p => p.FirstName);. I've gotten this working perfectly for this simple case. The code that I'm using for parsing the "FirstName" property out of there is actually reusing some existing functionality in a third-party product that we use and it works great, until we start working with deeply-nested properties(SortOption.Field = (p => p.Address.State.Abbreviation);). This code has some very different assumptions in the need to support deeply-nested properties. As for what this code does, I don't really understand it and rather than changing that code, I figured I should just write from scratch this functionality. However, I don't know of a good way to do this. I suspect we can do something better than doing a ToString() and performing string parsing. So what's a good way to do this to handle the trivial and deeply-nested cases? Requirements: Given the expression p => p.FirstName I need a string of "FirstName". Given the expression p => p.Address.State.Abbreviation I need a string of "Address.State.Abbreviation" While it's not important for an answer to my question, I suspect my serialization/deserialization code could be useful to somebody else who finds this question in the future, so it is below. Again, this code is not important to the question - I just thought it might help somebody. Note that DynamicExpression.ParseLambda comes from the Dynamic LINQ stuff and Property.PropertyToString() is what this question is about. /// <summary> /// This defines a framework to pass, across serialized tiers, sorting logic to be performed. /// </summary> /// <typeparam name="TModel">This is the object type that you are filtering.</typeparam> /// <typeparam name="TProperty">This is the property on the object that you are filtering.</typeparam> [Serializable] public class SortOption<TModel, TProperty> : ISerializable where TModel : class { /// <summary> /// Convenience constructor. /// </summary> /// <param name="property">The property to sort.</param> /// <param name="isAscending">Indicates if the sorting should be ascending or descending</param> /// <param name="priority">Indicates the sorting priority where 0 is a higher priority than 10.</param> public SortOption(Expression<Func<TModel, TProperty>> property, bool isAscending = true, int priority = 0) { Property = property; IsAscending = isAscending; Priority = priority; } /// <summary> /// Default Constructor. /// </summary> public SortOption() : this(null) { } /// <summary> /// This is the field on the object to filter. /// </summary> public Expression<Func<TModel, TProperty>> Property { get; set; } /// <summary> /// This indicates if the sorting should be ascending or descending. /// </summary> public bool IsAscending { get; set; } /// <summary> /// This indicates the sorting priority where 0 is a higher priority than 10. /// </summary> public int Priority { get; set; } #region Implementation of ISerializable /// <summary> /// This is the constructor called when deserializing a SortOption. /// </summary> protected SortOption(SerializationInfo info, StreamingContext context) { IsAscending = info.GetBoolean("IsAscending"); Priority = info.GetInt32("Priority"); // We just persisted this by the PropertyName. So let's rebuild the Lambda Expression from that. Property = DynamicExpression.ParseLambda<TModel, TProperty>(info.GetString("Property"), default(TModel), default(TProperty)); } /// <summary> /// Populates a <see cref="T:System.Runtime.Serialization.SerializationInfo"/> with the data needed to serialize the target object. /// </summary> /// <param name="info">The <see cref="T:System.Runtime.Serialization.SerializationInfo"/> to populate with data. </param> /// <param name="context">The destination (see <see cref="T:System.Runtime.Serialization.StreamingContext"/>) for this serialization. </param> public void GetObjectData(SerializationInfo info, StreamingContext context) { // Just stick the property name in there. We'll rebuild the expression based on that on the other end. info.AddValue("Property", Property.PropertyToString()); info.AddValue("IsAscending", IsAscending); info.AddValue("Priority", Priority); } #endregion }

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• Compile error with initializer_list when trying to use it to initialize member value of class

  - by ilektron

  I am trying to make a class initializable from an initialization_list in a class constructor's constructor's initialization list. It works for a std::map, but not for my custom class. I don't see any difference other than templates are used in std::map. #include <iostream> #include <initializer_list> #include <string> #include <sstream> #include <map> using std::string; class text_thing { private: string m_text; public: text_thing() { } text_thing(text_thing& other); text_thing(std::initializer_list< std::pair<const string, const string> >& il); text_thing& operator=(std::initializer_list< std::pair<const string, const string> >& il); operator string() { return m_text; } }; class static_base { private: std::map<string, string> m_test_map; text_thing m_thing; static_base(); public: static static_base& getInstance() { static static_base instance; return instance; } string getText() { return (string)m_thing; } }; typedef std::pair<const string, const string> spair; text_thing::text_thing(text_thing& other) { m_text = other.m_text; } text_thing::text_thing(std::initializer_list< std::pair<const string, const string> >& il) { std::stringstream text_gen; for (auto& apair : il) { text_gen << "{" << apair.first << ", " << apair.second << "}" << std::endl; } } text_thing& text_thing::operator=(std::initializer_list< std::pair<const string, const string> >& il) { std::stringstream text_gen; for (auto& apair : il) { text_gen << "{" << apair.first << ", " << apair.second << "}" << std::endl; } return *this; } static_base::static_base() : m_test_map{{"test", "1"}, {"test2", "2"}}, // Compiler fine with this m_thing{{"test", "1"}, {"test2", "2"}} // Compiler doesn't like this { } int main() { std::cout << "Starting the program" << std::endl; std::cout << "The text thing: " << std::endl << static_base::getInstance().getText(); } I get this compiler output g++ -O0 -g3 -Wall -c -fmessage-length=0 -std=c++11 -MMD -MP -MF"static_base.d" -MT"static_base.d" -o "static_base.o" "../static_base.cpp" Finished building: ../static_base.cpp Building file: ../test.cpp Invoking: GCC C++ Compiler g++ -O0 -g3 -Wall -c -fmessage-length=0 -std=c++11 -MMD -MP -MF"test.d" -MT"test.d" -o "test.o" "../test.cpp" ../test.cpp: In constructor ‘static_base::static_base()’: ../test.cpp:94:40: error: no matching function for call to ‘text_thing::text_thing(<brace-enclosed initializer list>)’ m_thing{{"test", "1"}, {"test2", "2"}} ^ ../test.cpp:94:40: note: candidates are: ../test.cpp:72:1: note: text_thing::text_thing(std::initializer_list<std::pair<const std::basic_string<char>, const std::basic_string<char> > >&) text_thing::text_thing(std::initializer_list< std::pair<const string, const string> >& il) ^ ../test.cpp:72:1: note: candidate expects 1 argument, 2 provided ../test.cpp:67:1: note: text_thing::text_thing(text_thing&) text_thing::text_thing(text_thing& other) ^ ../test.cpp:67:1: note: candidate expects 1 argument, 2 provided ../test.cpp:23:2: note: text_thing::text_thing() text_thing() ^ ../test.cpp:23:2: note: candidate expects 0 arguments, 2 provided make: *** [test.o] Error 1 Output of gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.1-2ubuntu1~13.04' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.8.1 (Ubuntu 4.8.1-2ubuntu1~13.04) It compiles fine with the std::map constructed this way, and if I modify the static_base to return the strings from the maps, all is fine and dandy. Please help me understand what is going on here.

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• Creating a new plugin for mpld3

  - by sjp14051

  Toward learning how to create a new mpld3 plugin, I took an existing example, LinkedDataPlugin (http://mpld3.github.io/examples/heart_path.html), and modified it slightly by deleting references to lines object. That is, I created the following: class DragPlugin(plugins.PluginBase): JAVASCRIPT = r""" mpld3.register_plugin("drag", DragPlugin); DragPlugin.prototype = Object.create(mpld3.Plugin.prototype); DragPlugin.prototype.constructor = DragPlugin; DragPlugin.prototype.requiredProps = ["idpts", "idpatch"]; DragPlugin.prototype.defaultProps = {} function DragPlugin(fig, props){ mpld3.Plugin.call(this, fig, props); }; DragPlugin.prototype.draw = function(){ var patchobj = mpld3.get_element(this.props.idpatch, this.fig); var ptsobj = mpld3.get_element(this.props.idpts, this.fig); var drag = d3.behavior.drag() .origin(function(d) { return {x:ptsobj.ax.x(d[0]), y:ptsobj.ax.y(d[1])}; }) .on("dragstart", dragstarted) .on("drag", dragged) .on("dragend", dragended); patchobj.path.attr("d", patchobj.datafunc(ptsobj.offsets, patchobj.pathcodes)); patchobj.data = ptsobj.offsets; ptsobj.elements() .data(ptsobj.offsets) .style("cursor", "default") .call(drag); function dragstarted(d) { d3.event.sourceEvent.stopPropagation(); d3.select(this).classed("dragging", true); } function dragged(d, i) { d[0] = ptsobj.ax.x.invert(d3.event.x); d[1] = ptsobj.ax.y.invert(d3.event.y); d3.select(this) .attr("transform", "translate(" + [d3.event.x,d3.event.y] + ")"); patchobj.path.attr("d", patchobj.datafunc(ptsobj.offsets, patchobj.pathcodes)); } function dragended(d, i) { d3.select(this).classed("dragging", false); } } mpld3.register_plugin("drag", DragPlugin); """ def __init__(self, points, patch): print "Points ID : ", utils.get_id(points) self.dict_ = {"type": "drag", "idpts": utils.get_id(points), "idpatch": utils.get_id(patch)} However, when I try to link the plugin to a figure, as in plugins.connect(fig, DragPlugin(points[0], patch)) I get an error, 'module' is not callable, pointing to this line. What does this mean and why doesn't it work? Thanks. I'm adding additional code to show that linking more than one Plugin might be problematic. But this may be entirely due to some silly mistake on my part, or there is a way around it. The following code based on LinkedViewPlugin generates three panels, in which the top and the bottom panel are supposed to be identical. Mouseover in the middle panel was expected to control the display in the top and bottom panels, but updates occur in the bottom panel only. It would be nice to be able to figure out how to reflect the changes in multiple panels. Thanks. import matplotlib import matplotlib.pyplot as plt import numpy as np import mpld3 from mpld3 import plugins, utils class LinkedView(plugins.PluginBase): """A simple plugin showing how multiple axes can be linked""" JAVASCRIPT = """ mpld3.register_plugin("linkedview", LinkedViewPlugin); LinkedViewPlugin.prototype = Object.create(mpld3.Plugin.prototype); LinkedViewPlugin.prototype.constructor = LinkedViewPlugin; LinkedViewPlugin.prototype.requiredProps = ["idpts", "idline", "data"]; LinkedViewPlugin.prototype.defaultProps = {} function LinkedViewPlugin(fig, props){ mpld3.Plugin.call(this, fig, props); }; LinkedViewPlugin.prototype.draw = function(){ var pts = mpld3.get_element(this.props.idpts); var line = mpld3.get_element(this.props.idline); var data = this.props.data; function mouseover(d, i){ line.data = data[i]; line.elements().transition() .attr("d", line.datafunc(line.data)) .style("stroke", this.style.fill); } pts.elements().on("mouseover", mouseover); }; """ def __init__(self, points, line, linedata): if isinstance(points, matplotlib.lines.Line2D): suffix = "pts" else: suffix = None self.dict_ = {"type": "linkedview", "idpts": utils.get_id(points, suffix), "idline": utils.get_id(line), "data": linedata} class LinkedView2(plugins.PluginBase): """A simple plugin showing how multiple axes can be linked""" JAVASCRIPT = """ mpld3.register_plugin("linkedview", LinkedViewPlugin2); LinkedViewPlugin2.prototype = Object.create(mpld3.Plugin.prototype); LinkedViewPlugin2.prototype.constructor = LinkedViewPlugin2; LinkedViewPlugin2.prototype.requiredProps = ["idpts", "idline", "data"]; LinkedViewPlugin2.prototype.defaultProps = {} function LinkedViewPlugin2(fig, props){ mpld3.Plugin.call(this, fig, props); }; LinkedViewPlugin2.prototype.draw = function(){ var pts = mpld3.get_element(this.props.idpts); var line = mpld3.get_element(this.props.idline); var data = this.props.data; function mouseover(d, i){ line.data = data[i]; line.elements().transition() .attr("d", line.datafunc(line.data)) .style("stroke", this.style.fill); } pts.elements().on("mouseover", mouseover); }; """ def __init__(self, points, line, linedata): if isinstance(points, matplotlib.lines.Line2D): suffix = "pts" else: suffix = None self.dict_ = {"type": "linkedview", "idpts": utils.get_id(points, suffix), "idline": utils.get_id(line), "data": linedata} fig, ax = plt.subplots(3) # scatter periods and amplitudes np.random.seed(0) P = 0.2 + np.random.random(size=20) A = np.random.random(size=20) x = np.linspace(0, 10, 100) data = np.array([[x, Ai * np.sin(x / Pi)] for (Ai, Pi) in zip(A, P)]) points = ax[1].scatter(P, A, c=P + A, s=200, alpha=0.5) ax[1].set_xlabel('Period') ax[1].set_ylabel('Amplitude') # create the line object lines = ax[0].plot(x, 0 * x, '-w', lw=3, alpha=0.5) ax[0].set_ylim(-1, 1) ax[0].set_title("Hover over points to see lines") linedata = data.transpose(0, 2, 1).tolist() plugins.connect(fig, LinkedView(points, lines[0], linedata)) # second set of lines exactly the same but in a different panel lines2 = ax[2].plot(x, 0 * x, '-w', lw=3, alpha=0.5) ax[2].set_ylim(-1, 1) ax[2].set_title("Hover over points to see lines #2") plugins.connect(fig, LinkedView2(points, lines2[0], linedata)) mpld3.show()

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• I'm new to C++. Please Help me with the Linked List (What functions to add)?

  - by Igal

  DEAR All; Hi, I'm just beginner to C++; Please help me to understand: What functions should be in the Linked list class ? I think there should be overloaded operators << and ; Please help me to improve the code (style, errors, etc,) Thanks for advance. Igal. Please review the small code for the integer List (enclosed MyNODE.h and ListDriver1.cpp); MyNODE.h // This is my first attempt to write linked list. Igal Spector, June 2010. #include <iostream.h> #include <assert.h> //Forward Declaration of the classes: class ListNode; class TheLinkedlist; // Definition of the node (WITH IMPLEMENTATION !!!, without test drive): class ListNode{ friend class TheLinkedlist; public: // constructor: ListNode(const int& value, ListNode *next= 0); // note: no destructor, as this handled by TheLinkedList class. // accessor: return data in the node. // int Show() const {return theData;} private: int theData; //the Data ListNode* theNext; //points to the next node in the list. }; //Implementations: //constructor: inline ListNode::ListNode(const int &value,ListNode *next) :theData(value),theNext(next){} //end of ListNode class, now for the LL class: class TheLinkedlist { public: //constructors: TheLinkedlist(); virtual ~TheLinkedlist(); // Accessors: void InsertAtFront(const &); void AppendAtBack(const &); // void InOrderInsert(const &); bool IsEmpty()const;//predicate function void Print() const; private: ListNode * Head; //pointer to first node ListNode * Tail; //pointer to last node. }; //Implementation: //Default constructor inline TheLinkedlist::TheLinkedlist():Head(0),Tail(0) {} //Destructor inline TheLinkedlist::~TheLinkedlist(){ if(!IsEmpty()){ //list is not empty cout<<"\n\tDestroying Nodes"<<endl; ListNode *currentPointer=Head, *tempPtr; while(currentPointer != 0){ //Delete remaining Nodes. tempPtr=currentPointer; cout<<"The node: "<<tempPtr->theData <<" is Destroyed."<<endl<<endl; currentPointer=currentPointer->theNext; delete tempPtr; } Head=Tail = 0; //don't forget this, as it may be checked one day. } } //Insert the Node to the beginning of the list: void TheLinkedlist::InsertAtFront(const int& value){ ListNode *newPtr = new ListNode(value,Head); assert(newPtr!=0); if(IsEmpty()) //list is empty Head = Tail = newPtr; else { //list is NOT empty newPtr->theNext = Head; Head = newPtr; } } //Insert the Node to the beginning of the list: void TheLinkedlist::AppendAtBack(const int& value){ ListNode *newPtr = new ListNode(value, NULL); assert(newPtr!=0); if(IsEmpty()) //list is empty Head = Tail = newPtr; else { //list is NOT empty Tail->theNext = newPtr; Tail = newPtr; } } //is the list empty? inline bool TheLinkedlist::IsEmpty() const { return (Head == 0); } // Display the contents of the list void TheLinkedlist::Print()const{ if ( IsEmpty() ){ cout << "\n\t The list is empty!!"<<endl; return; } ListNode *tempPTR = Head; cout<<"\n\t The List is: "; while ( tempPTR != 0 ){ cout<< tempPTR->theData <<" "; tempPTR = tempPTR->theNext; } cout<<endl<<endl; } ////////////////////////////////////// The test Driver: //Driver test for integer Linked List. #include <iostream.h> #include "MyNODE.h" // main Driver int main(){ cout<< "\n\t This is the test for integer LinkedList."<<endl; const int arraySize=11, ARRAY[arraySize]={44,77,88,99,11,2,22,204,50,58,12}; cout << "\n\tThe array is: "; //print the numbers. for (int i=0;i<arraySize; i++) cout<<ARRAY[i]<<", "; TheLinkedlist list; //declare the list for(int index=0;index<arraySize;index++) list.AppendAtBack( ARRAY[index] );//create the list cout<<endl<<endl; list.Print(); //print the list return 0; //end of the program. }

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• Android Out of memory regarding png image

  - by turtleboy

  I have a jpg image in my app that shows correctly. In my listview i'd like to make the image more transparent so it is easier to see the text. I changed the image to a png format and altered it's opacity in GIMP. Now that the new image is in the app drawable folder. Im getting the following error. why? 09-28 09:24:07.560: I/global(20140): call socket shutdown, tmpsocket=Socket[address=/178.250.50.40,port=80,localPort=35172] 09-28 09:24:07.570: I/global(20140): call socket shutdown, tmpsocket=Socket[address=/212.169.27.217,port=84,localPort=55656] 09-28 09:24:07.690: D/dalvikvm(20140): GC_FOR_ALLOC freed 113K, 4% free 38592K/39907K, paused 32ms 09-28 09:24:07.690: I/dalvikvm-heap(20140): Forcing collection of SoftReferences for 28072816-byte allocation 09-28 09:24:07.740: D/dalvikvm(20140): GC_BEFORE_OOM freed 9K, 4% free 38582K/39907K, paused 43ms 09-28 09:24:07.740: E/dalvikvm-heap(20140): Out of memory on a 28072816-byte allocation. 09-28 09:24:07.740: I/dalvikvm(20140): "main" prio=5 tid=1 RUNNABLE 09-28 09:24:07.740: I/dalvikvm(20140): | group="main" sCount=0 dsCount=0 obj=0x40a57490 self=0x1b6e9a8 09-28 09:24:07.740: I/dalvikvm(20140): | sysTid=20140 nice=0 sched=0/0 cgrp=default handle=1074361640 09-28 09:24:07.740: I/dalvikvm(20140): | schedstat=( 2289118000 760844000 2121 ) utm=195 stm=33 core=1 09-28 09:24:07.740: I/dalvikvm(20140): at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method) 09-28 09:24:07.740: I/dalvikvm(20140): at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:486) 09-28 09:24:07.740: I/dalvikvm(20140): at android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:773) 09-28 09:24:07.740: I/dalvikvm(20140): at android.content.res.Resources.loadDrawable(Resources.java:2042) 09-28 09:24:07.740: I/dalvikvm(20140): at android.content.res.TypedArray.getDrawable(TypedArray.java:601) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.View.<init>(View.java:2812) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.ViewGroup.<init>(ViewGroup.java:410) 09-28 09:24:07.740: I/dalvikvm(20140): at android.widget.LinearLayout.<init>(LinearLayout.java:174) 09-28 09:24:07.740: I/dalvikvm(20140): at android.widget.LinearLayout.<init>(LinearLayout.java:170) 09-28 09:24:07.740: I/dalvikvm(20140): at java.lang.reflect.Constructor.constructNative(Native Method) 09-28 09:24:07.740: I/dalvikvm(20140): at java.lang.reflect.Constructor.newInstance(Constructor.java:417) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.createView(LayoutInflater.java:586) 09-28 09:24:07.740: I/dalvikvm(20140): at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.onCreateView(LayoutInflater.java:653) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:678) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.inflate(LayoutInflater.java:466) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.inflate(LayoutInflater.java:396) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.inflate(LayoutInflater.java:352) 09-28 09:24:07.740: I/dalvikvm(20140): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:278) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.Activity.setContentView(Activity.java:1897) 09-28 09:24:07.740: I/dalvikvm(20140): at com.carefreegroup.ShowMoreDetails.onCreate(ShowMoreDetails.java:26) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.Activity.performCreate(Activity.java:4543) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1071) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2181) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2260) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread.access$600(ActivityThread.java:139) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1277) 09-28 09:24:07.740: I/dalvikvm(20140): at android.os.Handler.dispatchMessage(Handler.java:99) 09-28 09:24:07.740: I/dalvikvm(20140): at android.os.Looper.loop(Looper.java:156) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread.main(ActivityThread.java:5045) 09-28 09:24:07.740: I/dalvikvm(20140): at java.lang.reflect.Method.invokeNative(Native Method) 09-28 09:24:07.740: I/dalvikvm(20140): at java.lang.reflect.Method.invoke(Method.java:511) 09-28 09:24:07.740: I/dalvikvm(20140): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 09-28 09:24:07.740: I/dalvikvm(20140): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 09-28 09:24:07.740: I/dalvikvm(20140): at dalvik.system.NativeStart.main(Native Method) 09-28 09:24:07.740: E/dalvikvm(20140): Out of memory: Heap Size=46115KB, Allocated=38582KB, Limit=65536KB 09-28 09:24:07.740: E/dalvikvm(20140): Extra info: Footprint=39907KB, Allowed Footprint=46115KB, Trimmed=892KB 09-28 09:24:07.740: E/Bitmap_JNI(20140): Create Bitmap Failed. 09-28 09:24:07.740: A/libc(20140): Fatal signal 11 (SIGSEGV) at 0x00000004 (code=1) 09-28 09:24:09.750: I/dalvikvm(20367): Turning on JNI app bug workarounds for target SDK version 10... 09-28 09:24:09.940: D/dalvikvm(20367): GC_CONCURRENT freed 864K, 21% free 3797K/4771K, paused 2ms+2ms thanks. [update] @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.showmoredetailslayout); actualCallTime = (TextView)findViewById(R.id.actualcalltime); doubleUp = (TextView)findViewById(R.id.doubleupcallid); needName = (TextView)findViewById(R.id.needname); needNameLabel = (TextView)findViewById(R.id.neednamelabel); getRotaDetails = (Button)findViewById(R.id.buttongetrotadetails); intent = this.getIntent(); String actualTimeIn = intent.getStringExtra("actTimeIn"); String actualTimeOut = intent.getStringExtra("actTimeOut"); String doubleUpValue = intent.getStringExtra("doubleUpValue"); String needNameWithCommas = intent.getStringExtra("needNameWithCommas"); callID = intent.getStringExtra("callID"); String[] needs = needNameWithCommas.split(","); actualCallTime.setText("This call was completed at " + actualTimeIn + " -" + actualTimeOut); if( ! doubleUpValue.equalsIgnoreCase("") || doubleUpValue.equalsIgnoreCase("]")){ doubleUp.setText("This call was not a double up "); }else{ doubleUp.setText("This call was a double up " + doubleUpValue); } needNameLabel.setText("Purpose of Call: "); for (int i = 0; i < needs.length; i++){ needName.append( needs[i] + "\n"); } getRotaDetails.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(ShowMoreDetails.this, GetRotaDetails.class); intent.putExtra("callIDExtra", callID); startActivity(intent); } }); } }

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• Assigning two strings together getting Access Read Violation

  - by Jay Bell

  I am trying to pass a string to a class mutator and set the private member to that string here is the code that is sending the string void parseTradePairs(Exchange::Currency *curr, std::string *response, int begin, int exit) { int start; int end; string temp; string dataResponse; CURL *tempCurl; initializeCurl(tempCurl); int location = response->find("marketid", begin); if(location <= exit) { start = location + 11; begin = response->find("label", start); end = begin - start - 3; findStrings(start, end, temp, response); getMarketInfo(tempCurl, temp, dataResponse); curr->_coin->setExch(temp); // here is the line of code that is sending the string dataResponse >> *(curr->_coin); curr->_next = new Exchange::Currency(curr, curr->_position + 1); parseTradePairs(curr->_next, response, begin, exit); } } and here is the mutator within the coin class that is receiving the string and assigning it to _exch void Coin::setExch(string exch) { _exch = exch; } I have stepped through it and made sure that exch has the string in it. "105" but soon as it hits _exch = exch; I get the reading violation. I tried passing as pointer as well. I do not believe it should go out of scope. and the string variable in the class is initialized to zero in the default constructor but again that should matter unless I am trying to read from it instead of writing to it. /* defualt constructor */ Coin::Coin() { _id = ""; _label = ""; _code= ""; _name = ""; _marketCoin = ""; _volume = 0; _last = 0; _exch = ""; } Exchange::Exchange(std::string str) { _exch = str; _currencies = new Currency; std::string pair; std::string response; CURL *curl; initializeCurl(curl); getTradePairs(curl, response); int exit = response.find_last_of("marketid"); parseTradePairs(_currencies, &response, 0, exit); } int main(void) { CURL *curl; string str; string id; Coin coin1; initializeCurl(curl); Exchange ex("cryptsy"); curl_easy_cleanup(curl); system("pause"); return 0; } class Exchange { public: typedef struct Currency { Currency(Coin *coin, Currency *next, Currency *prev, int position) : _coin(coin), _next(next), _prev(prev), _position(position) {} Currency(Currency *prev, int position) : _prev(prev), _position(position), _next(NULL), _coin(&Coin()){} Currency() : _next(NULL), _prev(NULL), _position(0) {} Coin *_coin; Currency *_next; Currency *_prev; int _position; }; /* constructor and destructor */ Exchange(); Exchange(std::string str); ~Exchange(); /* Assignment operator */ Exchange& operator =(const Exchange& copyExchange); /* Parse Cryptsy Pairs */ friend void parseTradePairs(Currency *curr, std::string *response, int begin, int exit); private: std::string _exch; Currency *_currencies; }; here is what i changed it to to fix it. typedef struct Currency { Currency(Coin *coin, Currency *next, Currency *prev, int position) : _coin(coin), _next(next), _prev(prev), _position(position) {} Currency(Currency *prev, int position) : _prev(prev), _position(position), _next(NULL), _coin(&Coin()){} Currency() { _next = NULL; _prev = NULL; _position = 0; _coin = new Coin(); } Coin *_coin; Currency *_next; Currency *_prev; int _position; };

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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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• Creating Custom Ajax Control Toolkit Controls

  - by Stephen Walther

  The goal of this blog entry is to explain how you can extend the Ajax Control Toolkit with custom Ajax Control Toolkit controls. I describe how you can create the two halves of an Ajax Control Toolkit control: the server-side control extender and the client-side control behavior. Finally, I explain how you can use the new Ajax Control Toolkit control in a Web Forms page. At the end of this blog entry, there is a link to download a Visual Studio 2010 solution which contains the code for two Ajax Control Toolkit controls: SampleExtender and PopupHelpExtender. The SampleExtender contains the minimum skeleton for creating a new Ajax Control Toolkit control. You can use the SampleExtender as a starting point for your custom Ajax Control Toolkit controls. The PopupHelpExtender control is a super simple custom Ajax Control Toolkit control. This control extender displays a help message when you start typing into a TextBox control. The animated GIF below demonstrates what happens when you click into a TextBox which has been extended with the PopupHelp extender. Here’s a sample of a Web Forms page which uses the control: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowPopupHelp.aspx.cs" Inherits="MyACTControls.Web.Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html > <head runat="server"> <title>Show Popup Help</title> </head> <body> <form id="form1" runat="server"> <div> <act:ToolkitScriptManager ID="tsm" runat="server" /> <%-- Social Security Number --%> <asp:Label ID="lblSSN" Text="SSN:" AssociatedControlID="txtSSN" runat="server" /> <asp:TextBox ID="txtSSN" runat="server" /> <act:PopupHelpExtender id="ph1" TargetControlID="txtSSN" HelpText="Please enter your social security number." runat="server" /> <%-- Social Security Number --%> <asp:Label ID="lblPhone" Text="Phone Number:" AssociatedControlID="txtPhone" runat="server" /> <asp:TextBox ID="txtPhone" runat="server" /> <act:PopupHelpExtender id="ph2" TargetControlID="txtPhone" HelpText="Please enter your phone number." runat="server" /> </div> </form> </body> </html> In the page above, the PopupHelp extender is used to extend the functionality of the two TextBox controls. When focus is given to a TextBox control, the popup help message is displayed. An Ajax Control Toolkit control extender consists of two parts: a server-side control extender and a client-side behavior. For example, the PopupHelp extender consists of a server-side PopupHelpExtender control (PopupHelpExtender.cs) and a client-side PopupHelp behavior JavaScript script (PopupHelpBehavior.js). Over the course of this blog entry, I describe how you can create both the server-side extender and the client-side behavior. Writing the Server-Side Code Creating a Control Extender You create a control extender by creating a class that inherits from the abstract ExtenderControlBase class. For example, the PopupHelpExtender control is declared like this: public class PopupHelpExtender: ExtenderControlBase { } The ExtenderControlBase class is part of the Ajax Control Toolkit. This base class contains all of the common server properties and methods of every Ajax Control Toolkit extender control. The ExtenderControlBase class inherits from the ExtenderControl class. The ExtenderControl class is a standard class in the ASP.NET framework located in the System.Web.UI namespace. This class is responsible for generating a client-side behavior. The class generates a call to the Microsoft Ajax Library $create() method which looks like this: <script type="text/javascript"> $create(MyACTControls.PopupHelpBehavior, {"HelpText":"Please enter your social security number.","id":"ph1"}, null, null, $get("txtSSN")); }); </script> The JavaScript $create() method is part of the Microsoft Ajax Library. The reference for this method can be found here: http://msdn.microsoft.com/en-us/library/bb397487.aspx This method accepts the following parameters: type – The type of client behavior to create. The $create() method above creates a client PopupHelpBehavior. Properties – Enables you to pass initial values for the properties of the client behavior. For example, the initial value of the HelpText property. This is how server property values are passed to the client. Events – Enables you to pass client-side event handlers to the client behavior. References – Enables you to pass references to other client components. Element – The DOM element associated with the client behavior. This will be the DOM element associated with the control being extended such as the txtSSN TextBox. The $create() method is generated for you automatically. You just need to focus on writing the server-side control extender class. Specifying the Target Control All Ajax Control Toolkit extenders inherit a TargetControlID property from the ExtenderControlBase class. This property, the TargetControlID property, points at the control that the extender control extends. For example, the Ajax Control Toolkit TextBoxWatermark control extends a TextBox, the ConfirmButton control extends a Button, and the Calendar control extends a TextBox. You must indicate the type of control which your extender is extending. You indicate the type of control by adding a [TargetControlType] attribute to your control. For example, the PopupHelp extender is declared like this: [TargetControlType(typeof(TextBox))] public class PopupHelpExtender: ExtenderControlBase { } The PopupHelp extender can be used to extend a TextBox control. If you try to use the PopupHelp extender with another type of control then an exception is thrown. If you want to create an extender control which can be used with any type of ASP.NET control (Button, DataView, TextBox or whatever) then use the following attribute: [TargetControlType(typeof(Control))] Decorating Properties with Attributes If you decorate a server-side property with the [ExtenderControlProperty] attribute then the value of the property gets passed to the control’s client-side behavior. The value of the property gets passed to the client through the $create() method discussed above. The PopupHelp control contains the following HelpText property: [ExtenderControlProperty] [RequiredProperty] public string HelpText { get { return GetPropertyValue("HelpText", "Help Text"); } set { SetPropertyValue("HelpText", value); } } The HelpText property determines the help text which pops up when you start typing into a TextBox control. Because the HelpText property is decorated with the [ExtenderControlProperty] attribute, any value assigned to this property on the server is passed to the client automatically. For example, if you declare the PopupHelp extender in a Web Form page like this: <asp:TextBox ID="txtSSN" runat="server" /> <act:PopupHelpExtender id="ph1" TargetControlID="txtSSN" HelpText="Please enter your social security number." runat="server" />   Then the PopupHelpExtender renders the call to the the following Microsoft Ajax Library $create() method: $create(MyACTControls.PopupHelpBehavior, {"HelpText":"Please enter your social security number.","id":"ph1"}, null, null, $get("txtSSN")); You can see this call to the JavaScript $create() method by selecting View Source in your browser. This call to the $create() method calls a method named set_HelpText() automatically and passes the value “Please enter your social security number”. There are several attributes which you can use to decorate server-side properties including: ExtenderControlProperty – When a property is marked with this attribute, the value of the property is passed to the client automatically. ExtenderControlEvent – When a property is marked with this attribute, the property represents a client event handler. Required – When a value is not assigned to this property on the server, an error is displayed. DefaultValue – The default value of the property passed to the client. ClientPropertyName – The name of the corresponding property in the JavaScript behavior. For example, the server-side property is named ID (uppercase) and the client-side property is named id (lower-case). IDReferenceProperty – Applied to properties which refer to the IDs of other controls. URLProperty – Calls ResolveClientURL() to convert from a server-side URL to a URL which can be used on the client. ElementReference – Returns a reference to a DOM element by performing a client $get(). The WebResource, ClientResource, and the RequiredScript Attributes The PopupHelp extender uses three embedded resources named PopupHelpBehavior.js, PopupHelpBehavior.debug.js, and PopupHelpBehavior.css. The first two files are JavaScript files and the final file is a Cascading Style sheet file. These files are compiled as embedded resources. You don’t need to mark them as embedded resources in your Visual Studio solution because they get added to the assembly when the assembly is compiled by a build task. You can see that these files get embedded into the MyACTControls assembly by using Red Gate’s .NET Reflector tool: In order to use these files with the PopupHelp extender, you need to work with both the WebResource and the ClientScriptResource attributes. The PopupHelp extender includes the following three WebResource attributes. [assembly: WebResource("PopupHelp.PopupHelpBehavior.js", "text/javascript")] [assembly: WebResource("PopupHelp.PopupHelpBehavior.debug.js", "text/javascript")] [assembly: WebResource("PopupHelp.PopupHelpBehavior.css", "text/css", PerformSubstitution = true)] These WebResource attributes expose the embedded resource from the assembly so that they can be accessed by using the ScriptResource.axd or WebResource.axd handlers. The first parameter passed to the WebResource attribute is the name of the embedded resource and the second parameter is the content type of the embedded resource. The PopupHelp extender also includes the following ClientScriptResource and ClientCssResource attributes: [ClientScriptResource("MyACTControls.PopupHelpBehavior", "PopupHelp.PopupHelpBehavior.js")] [ClientCssResource("PopupHelp.PopupHelpBehavior.css")] Including these attributes causes the PopupHelp extender to request these resources when you add the PopupHelp extender to a page. If you open View Source in a browser which uses the PopupHelp extender then you will see the following link for the Cascading Style Sheet file: <link href="/WebResource.axd?d=0uONMsWXUuEDG-pbJHAC1kuKiIMteQFkYLmZdkgv7X54TObqYoqVzU4mxvaa4zpn5H9ch0RDwRYKwtO8zM5mKgO6C4WbrbkWWidKR07LD1d4n4i_uNB1mHEvXdZu2Ae5mDdVNDV53znnBojzCzwvSw2&amp;t=634417392021676003" type="text/css" rel="stylesheet" /> You also will see the following script include for the JavaScript file: <script src="/ScriptResource.axd?d=pIS7xcGaqvNLFBvExMBQSp_0xR3mpDfS0QVmmyu1aqDUjF06TrW1jVDyXNDMtBHxpRggLYDvgFTWOsrszflZEDqAcQCg-hDXjun7ON0Ol7EXPQIdOe1GLMceIDv3OeX658-tTq2LGdwXhC1-dE7_6g2&amp;t=ffffffff88a33b59" type="text/javascript"></script> The JavaScrpt file returned by this request to ScriptResource.axd contains the combined scripts for any and all Ajax Control Toolkit controls in a page. By default, the Ajax Control Toolkit combines all of the JavaScript files required by a page into a single JavaScript file. Combining files in this way really speeds up how quickly all of the JavaScript files get delivered from the web server to the browser. So, by default, there will be only one ScriptResource.axd include for all of the JavaScript files required by a page. If you want to disable Script Combining, and create separate links, then disable Script Combining like this: <act:ToolkitScriptManager ID="tsm" runat="server" CombineScripts="false" /> There is one more important attribute used by Ajax Control Toolkit extenders. The PopupHelp behavior uses the following two RequirdScript attributes to load the JavaScript files which are required by the PopupHelp behavior: [RequiredScript(typeof(CommonToolkitScripts), 0)] [RequiredScript(typeof(PopupExtender), 1)] The first parameter of the RequiredScript attribute represents either the string name of a JavaScript file or the type of an Ajax Control Toolkit control. The second parameter represents the order in which the JavaScript files are loaded (This second parameter is needed because .NET attributes are intrinsically unordered). In this case, the RequiredScript attribute will load the JavaScript files associated with the CommonToolkitScripts type and the JavaScript files associated with the PopupExtender in that order. The PopupHelp behavior depends on these JavaScript files. Writing the Client-Side Code The PopupHelp extender uses a client-side behavior written with the Microsoft Ajax Library. Here is the complete code for the client-side behavior: (function () { // The unique name of the script registered with the // client script loader var scriptName = "PopupHelpBehavior"; function execute() { Type.registerNamespace('MyACTControls'); MyACTControls.PopupHelpBehavior = function (element) { /// <summary> /// A behavior which displays popup help for a textbox /// </summmary> /// <param name="element" type="Sys.UI.DomElement">The element to attach to</param> MyACTControls.PopupHelpBehavior.initializeBase(this, [element]); this._textbox = Sys.Extended.UI.TextBoxWrapper.get_Wrapper(element); this._cssClass = "ajax__popupHelp"; this._popupBehavior = null; this._popupPosition = Sys.Extended.UI.PositioningMode.BottomLeft; this._popupDiv = null; this._helpText = "Help Text"; this._element$delegates = { focus: Function.createDelegate(this, this._element_onfocus), blur: Function.createDelegate(this, this._element_onblur) }; } MyACTControls.PopupHelpBehavior.prototype = { initialize: function () { MyACTControls.PopupHelpBehavior.callBaseMethod(this, 'initialize'); // Add event handlers for focus and blur var element = this.get_element(); $addHandlers(element, this._element$delegates); }, _ensurePopup: function () { if (!this._popupDiv) { var element = this.get_element(); var id = this.get_id(); this._popupDiv = $common.createElementFromTemplate({ nodeName: "div", properties: { id: id + "_popupDiv" }, cssClasses: ["ajax__popupHelp"] }, element.parentNode); this._popupBehavior = new $create(Sys.Extended.UI.PopupBehavior, { parentElement: element }, {}, {}, this._popupDiv); this._popupBehavior.set_positioningMode(this._popupPosition); } }, get_HelpText: function () { return this._helpText; }, set_HelpText: function (value) { if (this._HelpText != value) { this._helpText = value; this._ensurePopup(); this._popupDiv.innerHTML = value; this.raisePropertyChanged("Text") } }, _element_onfocus: function (e) { this.show(); }, _element_onblur: function (e) { this.hide(); }, show: function () { this._popupBehavior.show(); }, hide: function () { if (this._popupBehavior) { this._popupBehavior.hide(); } }, dispose: function() { var element = this.get_element(); $clearHandlers(element); if (this._popupBehavior) { this._popupBehavior.dispose(); this._popupBehavior = null; } } }; MyACTControls.PopupHelpBehavior.registerClass('MyACTControls.PopupHelpBehavior', Sys.Extended.UI.BehaviorBase); Sys.registerComponent(MyACTControls.PopupHelpBehavior, { name: "popupHelp" }); } // execute if (window.Sys && Sys.loader) { Sys.loader.registerScript(scriptName, ["ExtendedBase", "ExtendedCommon"], execute); } else { execute(); } })();   In the following sections, we’ll discuss how this client-side behavior works. Wrapping the Behavior for the Script Loader The behavior is wrapped with the following script: (function () { // The unique name of the script registered with the // client script loader var scriptName = "PopupHelpBehavior"; function execute() { // Behavior Content } // execute if (window.Sys && Sys.loader) { Sys.loader.registerScript(scriptName, ["ExtendedBase", "ExtendedCommon"], execute); } else { execute(); } })(); This code is required by the Microsoft Ajax Library Script Loader. You need this code if you plan to use a behavior directly from client-side code and you want to use the Script Loader. If you plan to only use your code in the context of the Ajax Control Toolkit then you can leave out this code. Registering a JavaScript Namespace The PopupHelp behavior is declared within a namespace named MyACTControls. In the code above, this namespace is created with the following registerNamespace() method: Type.registerNamespace('MyACTControls'); JavaScript does not have any built-in way of creating namespaces to prevent naming conflicts. The Microsoft Ajax Library extends JavaScript with support for namespaces. You can learn more about the registerNamespace() method here: http://msdn.microsoft.com/en-us/library/bb397723.aspx Creating the Behavior The actual Popup behavior is created with the following code. MyACTControls.PopupHelpBehavior = function (element) { /// <summary> /// A behavior which displays popup help for a textbox /// </summmary> /// <param name="element" type="Sys.UI.DomElement">The element to attach to</param> MyACTControls.PopupHelpBehavior.initializeBase(this, [element]); this._textbox = Sys.Extended.UI.TextBoxWrapper.get_Wrapper(element); this._cssClass = "ajax__popupHelp"; this._popupBehavior = null; this._popupPosition = Sys.Extended.UI.PositioningMode.BottomLeft; this._popupDiv = null; this._helpText = "Help Text"; this._element$delegates = { focus: Function.createDelegate(this, this._element_onfocus), blur: Function.createDelegate(this, this._element_onblur) }; } MyACTControls.PopupHelpBehavior.prototype = { initialize: function () { MyACTControls.PopupHelpBehavior.callBaseMethod(this, 'initialize'); // Add event handlers for focus and blur var element = this.get_element(); $addHandlers(element, this._element$delegates); }, _ensurePopup: function () { if (!this._popupDiv) { var element = this.get_element(); var id = this.get_id(); this._popupDiv = $common.createElementFromTemplate({ nodeName: "div", properties: { id: id + "_popupDiv" }, cssClasses: ["ajax__popupHelp"] }, element.parentNode); this._popupBehavior = new $create(Sys.Extended.UI.PopupBehavior, { parentElement: element }, {}, {}, this._popupDiv); this._popupBehavior.set_positioningMode(this._popupPosition); } }, get_HelpText: function () { return this._helpText; }, set_HelpText: function (value) { if (this._HelpText != value) { this._helpText = value; this._ensurePopup(); this._popupDiv.innerHTML = value; this.raisePropertyChanged("Text") } }, _element_onfocus: function (e) { this.show(); }, _element_onblur: function (e) { this.hide(); }, show: function () { this._popupBehavior.show(); }, hide: function () { if (this._popupBehavior) { this._popupBehavior.hide(); } }, dispose: function() { var element = this.get_element(); $clearHandlers(element); if (this._popupBehavior) { this._popupBehavior.dispose(); this._popupBehavior = null; } } }; The code above has two parts. The first part of the code is used to define the constructor function for the PopupHelp behavior. This is a factory method which returns an instance of a PopupHelp behavior: MyACTControls.PopupHelpBehavior = function (element) { } The second part of the code modified the prototype for the PopupHelp behavior: MyACTControls.PopupHelpBehavior.prototype = { } Any code which is particular to a single instance of the PopupHelp behavior should be placed in the constructor function. For example, the default value of the _helpText field is assigned in the constructor function: this._helpText = "Help Text"; Any code which is shared among all instances of the PopupHelp behavior should be added to the PopupHelp behavior’s prototype. For example, the public HelpText property is added to the prototype: get_HelpText: function () { return this._helpText; }, set_HelpText: function (value) { if (this._HelpText != value) { this._helpText = value; this._ensurePopup(); this._popupDiv.innerHTML = value; this.raisePropertyChanged("Text") } }, Registering a JavaScript Class After you create the PopupHelp behavior, you must register the behavior as a class by using the Microsoft Ajax registerClass() method like this: MyACTControls.PopupHelpBehavior.registerClass('MyACTControls.PopupHelpBehavior', Sys.Extended.UI.BehaviorBase); This call to registerClass() registers PopupHelp behavior as a class which derives from the base Sys.Extended.UI.BehaviorBase class. Like the ExtenderControlBase class on the server side, the BehaviorBase class on the client side contains method used by every behavior. The documentation for the BehaviorBase class can be found here: http://msdn.microsoft.com/en-us/library/bb311020.aspx The most important methods and properties of the BehaviorBase class are the following: dispose() – Use this method to clean up all resources used by your behavior. In the case of the PopupHelp behavior, the dispose() method is used to remote the event handlers created by the behavior and disposed the Popup behavior. get_element() -- Use this property to get the DOM element associated with the behavior. In other words, the DOM element which the behavior extends. get_id() – Use this property to the ID of the current behavior. initialize() – Use this method to initialize the behavior. This method is called after all of the properties are set by the $create() method. Creating Debug and Release Scripts You might have noticed that the PopupHelp behavior uses two scripts named PopupHelpBehavior.js and PopupHelpBehavior.debug.js. However, you never create these two scripts. Instead, you only create a single script named PopupHelpBehavior.pre.js. The pre in PopupHelpBehavior.pre.js stands for preprocessor. When you build the Ajax Control Toolkit (or the sample Visual Studio Solution at the end of this blog entry), a build task named JSBuild generates the PopupHelpBehavior.js release script and PopupHelpBehavior.debug.js debug script automatically. The JSBuild preprocessor supports the following directives: #IF #ELSE #ENDIF #INCLUDE #LOCALIZE #DEFINE #UNDEFINE The preprocessor directives are used to mark code which should only appear in the debug version of the script. The directives are used extensively in the Microsoft Ajax Library. For example, the Microsoft Ajax Library Array.contains() method is created like this: $type.contains = function Array$contains(array, item) { //#if DEBUG var e = Function._validateParams(arguments, [ {name: "array", type: Array, elementMayBeNull: true}, {name: "item", mayBeNull: true} ]); if (e) throw e; //#endif return (indexOf(array, item) >= 0); } Notice that you add each of the preprocessor directives inside a JavaScript comment. The comment prevents Visual Studio from getting confused with its Intellisense. The release version, but not the debug version, of the PopupHelpBehavior script is also minified automatically by the Microsoft Ajax Minifier. The minifier is invoked by a build step in the project file. Conclusion The goal of this blog entry was to explain how you can create custom AJAX Control Toolkit controls. In the first part of this blog entry, you learned how to create the server-side portion of an Ajax Control Toolkit control. You learned how to derive a new control from the ExtenderControlBase class and decorate its properties with the necessary attributes. Next, in the second part of this blog entry, you learned how to create the client-side portion of an Ajax Control Toolkit control by creating a client-side behavior with JavaScript. You learned how to use the methods of the Microsoft Ajax Library to extend your client behavior from the BehaviorBase class. Download the Custom ACT Starter Solution

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• Mouse input not updating in custom XNA/Winforms panel

  - by ChocoMan

  I have a custom Panel residing within my WinForm. the custom Panel holds the XNA rendering. So far, I've rendered an 3D test model. What I'm doing now is trying to handle the input.Using a camera from another working game, keyboard input works fine moving the camera in all 6 directions. But when it comes to handling the mouse to yaw and pitch the camera, nothing happens. I've searched about to see if anyone has come across this problem, but found no testable solutions to my problem. Does anyone understand as to what may be causing the Mouse not to be called when moved? Within MainForm constructor: public MainForm() { InitializeComponent(); Mouse.WindowHandle = panel3D.Handle; } Panel3D.cs Custom XNA Panel class FreeCamera.cs FreeCamera class

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• RSS feeds in Orchard

  When we added RSS to Orchard, we wanted to make it easy for any module to expose any contents as a feed. We also wanted the rendering of the feed to be handled by Orchard in order to minimize the amount of work from the module developer. A typical example of such feed exposition is of course blog feeds. We have an IFeedManager interface for which you can get the built-in implementation through dependency injection. Look at the BlogController constructor for an example: public BlogController(...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Best methods for Lazy Initialization with properties

  - by Stuart Pegg

  I'm currently altering a widely used class to move as much of the expensive initialization from the class constructor into Lazy Initialized properties. Below is an example (in c#): Before: public class ClassA { public readonly ClassB B; public void ClassA() { B = new ClassB(); } } After: public class ClassA { private ClassB _b; public ClassB B { get { if (_b == null) { _b = new ClassB(); } return _b; } } } There are a fair few more of these properties in the class I'm altering, and some are not used in certain contexts (hence the Laziness), but if they are used they're likely to be called repeatedly. Unfortunately, the properties are often also used inside the class. This means there is a potential for the private variable (_b) to be used directly by a method without it being initialized. Is there a way to make only the public property (B) available inside the class, or even an alternative method with the same initialized-when-needed?

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