Search Results

Search found 40226 results on 1610 pages for 'object relational model'.

Page 730/1610 | < Previous Page | 726 727 728 729 730 731 732 733 734 735 736 737  | Next Page >

  • NSCollectionView draws nothing

    - by PCWiz
    I'm trying to set up an NSCollectionView (I have done this successfully in the past, but for some reason it fails this time). I have a model class called "TestModel", and it has an NSString property that just returns a string (just for testing purposes right now). I then have an NSMutableArray property declaration in my main app delegate class, and to this array I add instances of the TestModel object. I then have an Array Controller that has its Content Array bound the app delegate's NSMutableArray. I can confirm that everything up to here is working fine; NSLogging: [[[arrayController arrangedObjects] objectAtIndex:0] teststring] worked fine. I then have all the appropriate bindings for the collection view set up, (itemPrototype and content), and for the Collection View Item (view). I then have a text field in the collection item view that is bound to Collection View Item.representedObject.teststring. However NOTHING displays in the collection view when I start the app, just a blank white screen. What am I missing? UPDATE: Here is the code I use (requested by wil shipley): // App delegate class @interface AppController : NSObject { NSMutableArray *objectArray; } @property (readwrite, retain) NSMutableArray *objectArray; @end @implementation AppController @synthesize objectArray; - (id)init { if (self = [super init]) { objectArray = [[NSMutableArray alloc] init]; } return self; } - (void)applicationDidFinishLaunching:(NSNotification *)aNotification { TestModel *test = [[[TestModel alloc] initWithString:@"somerandomstring"] autorelease]; if (test) [objectArray addObject:test]; } @end // The model class (TestModel) @interface TestModel : NSObject { NSString *teststring; } @property (readwrite, retain) NSString *teststring; - (id)initWithString:(NSString*)customString; @end @implementation TestModel @synthesize teststring; - (id)initWithString:(NSString*)customString { [self setTeststring:customString]; } - (void)dealloc { [teststring release]; } @end And then like I said the content array of the Array Controller is bound to this "objectArray", and the Content of the NSCollectionView is bound to Array Controller.arrangedObjects. I can verify that the Array Controller has the objects in it by NSLogging [arrayController arrangedObjects], and it returns the correct object. Its just that nothing displays in the NSCollectionView. UPDATE 2: If I log [collectionView content] I get nothing: 2009-10-21 08:02:42.385 CollViewTest[743:a0f] ( ) The problem is probably there. UPDATE 3: As requested here is the Xcode project: http://www.mediafire.com/?mjgdzgjjfzw Its a menubar app, so it has no window. When you build and run the app you'll see a menubar item that says "test", this opens the view that contains the NSCollectionView. Thanks

    Read the article

  • Adding image to RichTextBox programatically does not show in Xaml property

    - by rotary_engine
    Trying to add an image to a RichTextBox progamatically from a Stream. The image displays in the text box, however when reading the Xaml property there is no markup for the image. private void richTextBox3_Drop(object sender, DragEventArgs e) { if (e.Data.GetDataPresent(DataFormats.FileDrop)) { FileInfo[] files = (FileInfo[])e.Data.GetData(DataFormats.FileDrop); using (Stream s = files[0].OpenRead()) { InlineUIContainer container = new InlineUIContainer(); BitmapImage bmp = new BitmapImage(); bmp.SetSource(s); Image img = new Image(); img.SetValue(Image.SourceProperty, bmp); container.Child = img; richTextBox3.Selection.Insert(container); } } } private void Button_Click_1(object sender, RoutedEventArgs e) { // this doesn't have the markup from the inserted image System.Windows.MessageBox.Show(richTextBox3.Xaml); } What is the correct way to insert an image into the RichTextBox at runtime so that it can be persisted to a data store? In the Xaml property.

    Read the article

  • Why is my sound not working in Flash?

    - by animuson
    This is what I have as far as code, it is in the first frame of the movie. nature = new Sound(this); nature.attachSound("sound_naturally"); nature.setVolume(50); nature.start(0,0); nature.onSoundComplete = function(){ nature.start(0,0); } trace(nature); The trace outputs '[object Object]' at runtime. I have the sound exporting to ActionScript with the link identifier 'sound_naturally', not exported to the first frame. I don't understand why it's not working. I did like the exact same thing like 3 hours ago and it worked fine, but I lost the file so I had to redo it and now it won't work at all. Using Flash 10 with ActionScript 2.0

    Read the article

  • Bind listbox in WPF with grouping

    - by Michael Stoll
    Hi, I've got a collection of ViewModels and want to bind a ListBox to them. Doing some investigation I found this. So my ViewModel look like this (Pseudo Code) interface IItemViewModel { string DisplayName { get; } } class AViewModel : IItemViewModel { string DisplayName { return "foo"; } } class BViewModel : IItemViewModel { string DisplayName { return "foo"; } } class ParentViewModel { IEnumerable<IItemViewModel> Items { get { return new IItemViewModel[] { new AItemViewModel(), new BItemViewModel() } } } } class GroupViewModel { static readonly GroupViewModel GroupA = new GroupViewModel(0); static readonly GroupViewModel GroupB = new GroupViewModel(1); int GroupIndex; GroupViewModel(int groupIndex) { this.GroupIndex = groupIndex; } string DisplayName { get { return "This is group " + GroupIndex.ToString(); } } } class ItemGroupTypeConverter : IValueConverter { object Convert(object value, Type targetType, object parameter, CultureInfo culture) { if (value is AItemViewModel) return GroupViewModel.GroupA; else return GroupViewModel.GroupB; } } And this XAML <UserControl.Resources> <vm:ItemsGroupTypeConverter x:Key="ItemsGroupTypeConverter "/> <CollectionViewSource x:Key="GroupedItems" Source="{Binding Items}"> <CollectionViewSource.GroupDescriptions> <PropertyGroupDescription Converter="{StaticResource ItemsGroupTypeConverter }"/> </CollectionViewSource.GroupDescriptions> </CollectionViewSource> </UserControl.Resources> <ListBox ItemsSource="{Binding Source={StaticResource GroupedItems}}"> <ListBox.GroupStyle> <GroupStyle> <GroupStyle.HeaderTemplate> <DataTemplate> <TextBlock Text="{Binding DisplayName}" FontWeight="bold" /> </DataTemplate> </GroupStyle.HeaderTemplate> </GroupStyle> </ListBox.GroupStyle> <ListBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding DisplayName}" /> </DataTemplate> </ListBox.ItemTemplate> </ListBox> This works somehow, exept of the fact that the binding of the HeaderTemplate does not work. Anyhow I'd prefer omitting the TypeConverter and the CollectionViewSource. Isn't there a way to use a property of the ViewModel for Grouping? I know that in this sample scenario it would be easy to replace the GroupViewModel with a string an have it working, but that's not an option. So how can I bind the HeaderTemplate to the GroupViewModel?

    Read the article

  • Use native HBitmap in C# while preserving alpha channel/transparency. Please check this code, it works on my computer...

    - by David
    Let's say I get a HBITMAP object/handle from a native Windows function. I can convert it to a managed bitmap using Bitmap.FromHbitmap(nativeHBitmap), but if the native image has transparency information (alpha channel), it is lost by this conversion. There are a few questions on Stack Overflow regarding this issue. Using information from the first answer of this question (How to draw ARGB bitmap using GDI+?), I wrote a piece of code that I've tried and it works. It basically gets the native HBitmap width, height and the pointer to the location of the pixel data using GetObject and the BITMAP structure, and then calls the managed Bitmap constructor: Bitmap managedBitmap = new Bitmap(bitmapStruct.bmWidth, bitmapStruct.bmHeight, bitmapStruct.bmWidth * 4, PixelFormat.Format32bppArgb, bitmapStruct.bmBits); As I understand (please correct me if I'm wrong), this does not copy the actual pixel data from the native HBitmap to the managed bitmap, it simply points the managed bitmap to the pixel data from the native HBitmap. And I don't draw the bitmap here on another Graphics (DC) or on another bitmap, to avoid unnecessary memory copying, especially for large bitmaps. I can simply assign this bitmap to a PictureBox control or the the Form BackgroundImage property. And it works, the bitmap is displayed correctly, using transparency. When I no longer use the bitmap, I make sure the BackgroundImage property is no longer pointing to the bitmap, and I dispose both the managed bitmap and the native HBitmap. The Question: Can you tell me if this reasoning and code seems correct. I hope I will not get some unexpected behaviors or errors. And I hope I'm freeing all the memory and objects correctly. private void Example() { IntPtr nativeHBitmap = IntPtr.Zero; /* Get the native HBitmap object from a Windows function here */ // Create the BITMAP structure and get info from our nativeHBitmap NativeMethods.BITMAP bitmapStruct = new NativeMethods.BITMAP(); NativeMethods.GetObjectBitmap(nativeHBitmap, Marshal.SizeOf(bitmapStruct), ref bitmapStruct); // Create the managed bitmap using the pointer to the pixel data of the native HBitmap Bitmap managedBitmap = new Bitmap( bitmapStruct.bmWidth, bitmapStruct.bmHeight, bitmapStruct.bmWidth * 4, PixelFormat.Format32bppArgb, bitmapStruct.bmBits); // Show the bitmap this.BackgroundImage = managedBitmap; /* Run the program, use the image */ MessageBox.Show("running..."); // When the image is no longer needed, dispose both the managed Bitmap object and the native HBitmap this.BackgroundImage = null; managedBitmap.Dispose(); NativeMethods.DeleteObject(nativeHBitmap); } internal static class NativeMethods { [StructLayout(LayoutKind.Sequential)] public struct BITMAP { public int bmType; public int bmWidth; public int bmHeight; public int bmWidthBytes; public ushort bmPlanes; public ushort bmBitsPixel; public IntPtr bmBits; } [DllImport("gdi32", CharSet = CharSet.Auto, EntryPoint = "GetObject")] public static extern int GetObjectBitmap(IntPtr hObject, int nCount, ref BITMAP lpObject); [DllImport("gdi32.dll")] internal static extern bool DeleteObject(IntPtr hObject); }

    Read the article

  • Looking for a good example usage of get_or _create in Django views and raising a Form error

    - by Rik Wade
    I am looking for a good example of how to achieve the following: I would like to use get_or_create to check whether an object already exists in my database. If it does not, then it will be created. If it does exist, then I will not create the new object, but need to raise a form error to inform the user that they need to enter different data (for example, a different username). The view contains: p, created = Person.objects.get_or_create( email = registration_form.cleaned_data['email'], defaults = { 'creationDate': datetime.datetime.now(), 'dateOfBirth': datetime.date(1970,1,1) }) So 'p' will contain the existing Person if it exists, or the new Person if not. I would like to act on the boolean value in 'created' in order to skip over saving the Person and re-display the registration_form and raise an appropriate form validation error. The alternative I'm considering is doing a check in a custom Form validation method to see whether a Person exists with the data in the provided 'email' field, and just raising a validation error.

    Read the article

  • How to bind DataTable to Chart series?

    - by user175908
    Hello, How to do bind data from DataTable to Chart series? I get null reference exception. I tried binding with square brackets and it did not worked either. So, how to do the binding? Thanks. P.S: I included DataGrid XAML and CS which works just fine. Converting data to List<KeyValuePair<string,int>> works good but it is kinda slow and is unnessesary trash in code. I use WPFToolkit (the latest version). XAML: <Window x:Class="BindingzTest.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="606" Width="988" xmlns:charting="clr-namespace:System.Windows.Controls.DataVisualization.Charting;assembly=System.Windows.Controls.DataVisualization.Toolkit"> <Grid Name="LayoutRoot"> <charting:Chart Title="Letters and Numbers" VerticalAlignment="Top" Height="400"> <charting:Chart.Series> <charting:ColumnSeries Name="myChartSeries" IndependentValueBinding="{Binding Letter}" DependentValueBinding="{Binding Number}" ItemsSource="{Binding}" /> </charting:Chart.Series> </charting:Chart> <DataGrid Name="myDataGrid" VerticalAlignment="Stretch" Margin="0,400,0,50" ItemsSource="{Binding}" AutoGenerateColumns="False"> <DataGrid.Columns> <DataGridTextColumn Header="Letter" Binding="{Binding Letter}"/> <DataGridTextColumn Header="Number" Binding="{Binding Number}"/> </DataGrid.Columns> </DataGrid> <Button Content="Generate" HorizontalAlignment="Left" Name="generateButton" Width="128" Click="GenerateButtonClicked" Height="52" VerticalAlignment="Bottom" /> </Grid> CS: public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } DataTable GenerateMyTable() { var myTable = new DataTable("MyTable"); myTable.Columns.Add("Letter"); myTable.Columns.Add("Number"); myTable.Rows.Add("A", 500); myTable.Rows.Add("B", 400); myTable.Rows.Add("C", 500); myTable.Rows.Add("D", 600); myTable.Rows.Add("E", 300); myTable.Rows.Add("F", 200); return myTable; } private void GenerateButtonClicked(object sender, RoutedEventArgs e) { var myGeneratedTable = GenerateMyTable(); myDataGrid.DataContext = myGeneratedTable; myChartSeries.DataContext = myGeneratedTable; // Calling this throws "Object reference not set to an instance of an object" exception } }

    Read the article

  • agility of asp.net MVC

    - by Hellnar
    Hello I am wondering how agile (fast to develop yet stable) asp.net MVC compared to frameworks using dynamic languages such as Django or Ruby on Rails. I will be happy if you share you experiance in the name of development speed (assuming each language/framework is known at a similar level) Things I love about Django Fast model design thanks to ORM Good template system Not too hard to deploy Easy to extend Lots of free apps to plugin and great documentation Thanks

    Read the article

  • Stop SWF file from repeating

    - by Samuel
    Hey people, I have converted a short clip to an .swf file, i want to implement it on my website: <object width="400" height="300"> <param name="movie" value="movie.swf"> <embed src="movie.swf" width="400" height="300"> </embed> </object> When i play it it autoplays (that's fine) but it also keeps repeating over and over, i'd like it to stop at the end and just display the end frame (as mentioned i converted a movie so i cant do it with actionscript in the .fla file). Thanks for any tips!

    Read the article

  • Silverlight 4 accessing WCF Data Services: BeginInvoke frustrations.

    - by Gatmando
    Hi, I'm attempting to follow a pattern for performing WCF data service queries using the Silverlight 4 beta. The following is my code: public CodeTables() { CodeCountries = new ObservableCollection<dsRealHomes.CodeCountries>(); dsRealHomes.RealHomesEntities myClient = null; myClient = staticGlobals.RealHomesContext(); object userState = null; myClient.BeginExecute<dsRealHomes.CodeCountries>(new Uri("CodeCountries"), (IAsyncResult asyncResult) => { Dispatcher.BeginInvoke( () => { var test = myClient.EndExecute<dsRealHomes.CodeCountries>asyncResult).ToList(); } ); }, userState); } This is derived from a number of examples I've come across for WCF data services with silverlight. Unfortunately no matter how I try to implement the code i end up with the following error on 'Dispatcher.BeginInvoke': 'An object reference is required for the non-static field, method, or property (System.Windows.Threading.Dispatcher.BeginInvoke(System.Action)' Thanks

    Read the article

  • ajax->form submit onchage event on selectTag keeping submit button on form without click

    - by prashant
    Hi, I am using cakephp 1.1. for my project.I used ajax-form for form creation.In one form, form submitted using onchange event of selectTag taking submit button and giving submit.click for that button.But it peroperly not redirect to view file gives error "cake/libs/model/datasources/dbo_source.php" and submit that form,but I am not getting to which view it is submitting(submittied form to itself).

    Read the article

  • Ruby Rss parser and event trigger

    - by fenec
    I'm using RSS library so i can parse Atom and RSS in Ruby and Rails and store it in a model. I've looked at the standard RSS library, but is there one library that will auto-detect that there is a new rss feed so i can update my database ? what are the best practice to trigger an instruction in order to store the new rss feed ? should i use threads to handle that problem ?is it going to be slow? thank you for your help

    Read the article

  • Django - Specifying default attr for Custom widget

    - by Pierre de LESPINAY
    I have created this widget class DateTimeWidget(forms.TextInput): attr = {'class': 'datetimepicker'} class Media: js = ('js/jquery-ui-timepicker-addon.js',) Then I use it on my form class SessionForm(forms.ModelForm): class Meta: model = Session def __init__(self, *args, **kwargs): super(SessionForm, self).__init__(*args, **kwargs) self.fields['start_time'].widget = DateTimeWidget() self.fields['end_time'].widget = DateTimeWidget() No css class is applied to my fields (I'm expecting datetimepicker applied to both start_time & end_time). I imagine I have put attr at a wrong location. Where am I supposed to specify it ?

    Read the article

  • Django Admin Actions missing

    - by Andrew C
    One of my Django sites is missing the Django Admin Action bar shown here: http://docs.djangoproject.com/en/dev/ref/contrib/admin/actions/#ref-contrib-admin-actions There is no checkbox next to each row and no Action select box near the top of the page. This is happening on every model. I have several sites running Django 1.1, and they all show the Admin Actions, so it feels like a local configuration issue. Anyone seen this before?

    Read the article

  • Can't transfer list<T> to web service?

    - by iTayb
    I have the same classes on my server and on my web service. I have the following WebMethod: [WebMethod] public int CreateOrder(List<Purchase> p, string username) { o.Add(new Order(p,username)); return o.Count; } However the following code, run at server: protected void CartRepeater_ItemCommand(object source, RepeaterCommandEventArgs e) { List<Purchase> l = ((List<Purchase>)Session["Cart"]); if (e.CommandName == "Order") { localhost.ValidateService WS = new localhost.ValidateService(); WS.CreateOrder(l, Session["username"].ToString()); } } gives the following error: Argument '1': cannot convert from 'System.Collections.Generic.List<Purchase>' to 'localhost.Purchase[]'. How can I transfer the list<Purchase> object to the web service? Thank you very much.

    Read the article

  • MouseLeave event in Silverlight 3 PopUp control

    - by AKa
    I want use PopUp (System.Windows.Controls.Primitives.PopUp) control to show some context menu. After mouse leaves, should automatically close. But eventhandler for MouseLeave is never executed. Why? SAMPLE: void DocumentLibrary_Loaded(object sender, RoutedEventArgs e) { DocumentLibraryDialog documentLibraryDialog = new DocumentLibraryDialog(); _popUpDocumentLibraryDialog = new Popup(); _popUpDocumentLibraryDialog.Width = 70; _popUpDocumentLibraryDialog.Height = 20; _popUpDocumentLibraryDialog.MouseLeave += new MouseEventHandler(_popUpDocumentLibraryDialog_MouseLeave); _popUpDocumentLibraryDialog.Child = documentLibraryDialog; } void _popUpDocumentLibraryDialog_MouseLeave(object sender, MouseEventArgs e) { Popup currentPopUp = (Popup)sender; if (currentPopUp.IsOpen) (currentPopUp.IsOpen) = false; } Regards Anton Kalcik

    Read the article

  • Generic collection as a Java method argument

    - by Guido
    Is there any way to make this work in Java? public static void change(List<? extends Object> list, int position1, int position2) { Object obj = list.get(position1); list.set(position1, list.get(position2)); list.set(position2, obj); } The only way I've successfully avoided warnings and errors is this: public static <T> T change(List<T> list, int position1, int position2) { T obj = list.get(position1); list.set(position1, list.get(position2)); list.set(position2, obj); return obj; } but I don't like to be forced to return a value.

    Read the article

  • EF4 cross database relationships

    - by Daniel
    Hello all, I was wondering if EF4 support cross-databse relationships? For instance: db1 Author Id Name db2 Posts Id Content db1.Author.Id What ideally I need to do to get this relation in my ef4 model? Do you guys have any idea? Thanks

    Read the article

  • WinForms Form won't close on pressing X or Close() in C#

    - by MadBoy
    I'm having a bit weird problem with WinForm which seems to refuse to close for some weird reason. I've got very simple gui which sometimes doesn't react for me pressing X or when i use events on buttons it even reaches Close() and does nothing.. private void buttonZapisz_Click(object sender, EventArgs e) { string plik = textBoxDokumentDoZaladowania.Text; if (File.Exists(plik)) { string extension = Path.GetExtension(plik); string nazwaPliku = Path.GetFileName(plik); SqlMethods.databaseFilePut(plik, comboBoxTypDokumentu.Text, textBoxKomentarz.Text, sKlienciID, sPortfelID, extension, nazwaPliku); Close(); } } There are no events assigned to FormClosed or FormClosing. So how can I find out what's wrong. Sometimes X will work after the GUI is loaded but after i press Button to save some stuff to database it reaches Close() in that button event and it still is visible and does nothing. Can't use X, nor ALT+F4. I can go around GUI and choose other values for ComboBox without problem. I call GUI like this: private void contextMenuDokumentyDodaj_Click(object sender, EventArgs e) { var lv = (ListView) contextMenuDokumenty.SourceControl; string varPortfelID = Locale.ustalDaneListViewKolumny(listViewNumeryUmow, 0); string varKlienciID = Locale.ustalDaneListViewKolumny(listViewKlienci, 0); if (lv == listViewDokumentyPerKlient) { if (varKlienciID != "") { var dokumenty = new DocumentsGui(varKlienciID); dokumenty.Show(); dokumenty.FormClosed += varDocumentsGuiKlienci_FormClosed; } } else if (lv == listViewDokumentyPerPortfel) { if (varPortfelID != "" && varKlienciID != "") { var dokumenty = new DocumentsGui(varKlienciID, varPortfelID); dokumenty.Show(); dokumenty.FormClosed += varDocumentsGuiPortfele_FormClosed; } } } While I can't close GUI i can work on the main gui without problem too. I can open up same GUI and after opening new GUI i can quickly close it. GUI is very simple with few ComboBoxes,TextBoxes and one EditButton from Devexpress. Edit: varDocumentsGuiPortfele_FormClosed code allows me to refresh GUI (reload ListView's depending on where the user is on now). private void varDocumentsGuiPortfele_FormClosed(object sender, FormClosedEventArgs e) { TabControl varTabControl = tabControlKlientPortfele; if (varTabControl.TabPages.IndexOf(tabPageDokumentyPerKlient) == varTabControl.SelectedIndex) { loadTabControlKlientPortfeleBezZmianyUmowy(); } }

    Read the article

  • HTML Encoding Blocks - Invalid expression term ':'

    - by Jamie Dixon
    Hey everyone, I'm developing a new ASP.NET MVC 2.0 application and wanting to use the new ASP.NET 4 encoding blocks. My View code contains <%: Model.ActivityName %> however Visual Studio is reporting: Unexpected toke at the position of the : (colon). When I run the application I get the following compilation error: Compiler Error Message: CS1525: Invalid expression term ':' What am i missing? Cheers for any help/advice.

    Read the article

  • Error loading contents from a XML file into a dropdownlist

    - by Chaitanya
    private void BindCountry() { XmlDocument doc = new XmlDocument(); doc.Load(Server.MapPath("countries.xml")); foreach (XmlNode node in doc.SelectNodes("//country")) { usrlocationddl.Items.Add(new ListItem(node.InnerText, node.Attributes["codes"].InnerText)); //ddlCountry.Items.Add(new ListItem(node.InnerText, node.Attributes["code"].InnerText)); } } The above code am using for loading countries List from an xml file into a dropdown list. But while doing so am encountering a Null Reference error. Object reference not set to an instance of an object. Where in the code should I be changing, so that I can escape the error.

    Read the article

  • Display vimeo in fancybox , trouble in IE

    - by Alexander Corotchi
    Hi all, i have a problem with VIMEO video . I want to display it in fancybox : this is HTML : <a href="#content" class="zoom">test</a> <div id="content" style="display:none;"> <object width="504" height="280" data="http://vimeo.com/moogaloop.swf" type="application/x-shockwave-flash"> <param value="always" name="allowscriptaccess"><param value="true" name="allowfullscreen"> <param value="http://vimeo.com/moogaloop.swf" name="movie"> <param value="clip_id=6999704&amp;server=vimeo.com&amp;fullscreen=1&amp;show_title=1&amp;show_byline=1&amp;show_portrait=1&amp;color=00ADEF" name="flashvars"> </object> </div> and js: $(document).ready(function() { $("a.zoom").fancybox(); }); Can somebody help me with this , maybe somebody knows hot to fix it .. Thanks !!

    Read the article

  • Erasing and modifying elements in Boost MultiIndex Container

    - by Sarah
    I'm trying to use a Boost MultiIndex container in my simulation. My knowledge of C++ syntax is very weak, and I'm concerned I'm not properly removing an element from the container or deleting it from memory. I also need to modify elements, and I was hoping to confirm the syntax and basic philosophy here too. // main.cpp ... #include <boost/multi_index_container.hpp> #include <boost/multi_index/hashed_index.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/mem_fun.hpp> #include <boost/tokenizer.hpp> #include <boost/shared_ptr.hpp> ... #include "Host.h" // class Host, all members private, using get fxns to access using boost::multi_index_container; using namespace boost::multi_index; typedef multi_index_container< boost::shared_ptr< Host >, indexed_by< hashed_unique< const_mem_fun<Host,int,&Host::getID> > // ordered_non_unique< BOOST_MULTI_INDEX_MEM_FUN(Host,int,&Host::getAge) > > // end indexed_by > HostContainer; typedef HostContainer::nth_index<0>::type HostsByID; int main() { ... HostContainer allHosts; Host * newHostPtr; newHostPtr = new Host( t, DOB, idCtr, 0, currentEvents ); allHosts.insert( boost::shared_ptr<Host>(newHostPtr) ); // allHosts gets filled up int randomHostID = 4; int newAge = 50; modifyHost( randomHostID, allHosts, newAge ); killHost( randomHostID, allHosts ); } void killHost( int id, HostContainer & hmap ){ HostsByID::iterator it = hmap.find( id ); cout << "Found host id " << (*it)->getID() << "Attempting to kill. hmap.size() before is " << hmap.size() << " and "; hmap.erase( it ); // Is this really erasing (freeing from mem) the underlying Host object? cout << hmap.size() << " after." << endl; } void modifyHost( int id, HostContainer & hmap, int newAge ){ HostsByID::iterator it = hmap.find( id ); (*it) -> setAge( newAge ); // Not actually the "modify" function for MultiIndex... } My questions are In the MultiIndex container allHosts of shared_ptrs to Host objects, is calling allHosts.erase( it ) on an iterator to the object's shared_ptr enough to delete the object permanently and free it from memory? It appears to be removing the shared_ptr from the container. The allhosts container currently has one functioning index that relies on the host's ID. If I introduce an ordered second index that calls on a member function (Host::getAge()), where the age changes over the course of the simulation, is the index always going to be updated when I refer to it? What is the difference between using the MultiIndex's modify to modify the age of the underlying object versus the approach I show above? I'm vaguely confused about what is assumed/required to be constant in MultiIndex. Thanks in advance. Update Here's my attempt to get the modify syntax working, based on what I see in a related Boost example. struct update_age { update_age():(){} // have no idea what this really does... elicits error void operator() (boost::shared_ptr<Host> ptr) { ptr->incrementAge(); // incrementAge() is a member function of class Host } }; and then in modifyHost, I'd have hmap.modify(it,update_age). Even if by some miracle this turns out to be right, I'd love some kind of explanation of what's going on.

    Read the article

  • Why does python use 'magic methods'?

    - by Greg Beech
    I've been playing around with Python recently, and one thing I'm finding a bit odd is the extensive use of 'magic methods', e.g. to make its length available an object implements a method def __len__(self) and then it is called when you write len(obj). I was just wondering why objects don't simply define a len(self) method and have it called directly as a member of the object, e.g. obj.len()? I'm sure there must be good reasons for Python doing it the way it does, but as a newbie I haven't worked out what they are yet.

    Read the article

< Previous Page | 726 727 728 729 730 731 732 733 734 735 736 737  | Next Page >