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  • sort django queryset by latest instance of a subset of related model

    - by rsp
    I have an Order model and order_event model. Each order_event has a foreignkey to order. so from an order instance i can get: myorder.order_event_set. I want to get a list of all orders but i want them to be sorted by the date of the last event. A statement like this works to sort by the latest event date: queryset = Order.objects.all().annotate(latest_event_date=Max('order_event__event_datetime')).order_by('latest_event_date') However, what I really need is a list of all orders sorted by latest date of A SUBSET OF EVENTS. For example my events are categorized into "scheduling", "processing", etc. So I should be able to get a list of all orders sorted by the latest scheduling event. This django doc (https://docs.djangoproject.com/en/dev/topics/db/aggregation/#filter-and-exclude) shows how I can get the latest schedule event using a filter but this excludes orders without a scheduling event. I thought I could combine the filtered queryset with a queryset that includes back those orders that are missing a scheduling event...but I'm not quite sure how to do this. I saw answers related to using python list but it would be much more useful to have a proper django queryset (ie for a view with pagination, etc.)

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  • CKEditor instance already exists

    - by jackboberg
    I am using jquery dialogs to present forms (fetched via AJAX). On some forms I am using a CKEditor for the textareas. The editor displays fine on the first load. When the user cancels the dialog, I am removing the contents so that they are loaded fresh on a later request. The issue is, once the dialog is reloaded, the CKEditor claims the editor already exists. uncaught exception: [CKEDITOR.editor] The instance "textarea_name" already exists. The API includes a method for destroying existing editors, and I have seen people claiming this is a solution: if (CKEDITOR.instances['textarea_name']) { CKEDITOR.instances['textarea_name'].destroy(); } CKEDITOR.replace('textarea_name'); This is not working for me, as I receive a new error instead: TypeError: Result of expression 'i.contentWindow' [null] is not an object. This error seems to occur on the "destroy()" rather than the "replace()". Has anyone experienced this and found a different solution? Is is possible to 're-render' the existing editor, rather than destroying and replacing it? UPDATED Here is another question dealing with the same problem, but he has provided a downloadable test case.

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  • -[CFString length]: message sent to deallocated instance 0x3881940 when i scroll to near the bottom

    - by James
    Hey guys, i've got a problem debugging an iphone app that i'm attempting to write and it's got me stumped, bear with me, i'm a n00b to programming and might get some of the terminology wrong but i'll try to explain it as best as i can. The app gets an XML doc from the a web site, parses it into an array, and then displays it in a table view, i have the parser in a separate file. The ViewDidLoad in RootViewController sends it a url, the parser goes to work and then returns an NSMutableArray. When i run the app it works fine with small XML files (5 entries or so, and 1-3 sections), but when i use a larger one(20+ rows, over 12 sections) i get the error "-[CFString length]: message sent to deallocated instance 0x3881940" when i scroll near the bottom of the tableview, just as the last section title is about to come onto the viewable area on the screen to be precise. if i return a static string instead of the object in my array in this method it doesn't crash, but i can use NSLog to call the array and it returns the title no problems. - (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)indexPath { return [[returnedEvents objectAtIndex:indexPath ] objectAtIndex:0]; } The returnedEvents array isn't released until -(void) dealloc {} I have read a few other posts on here, and a few guides on debugging and as of yet am unable to find anything that was able to help me, i'd be more than happy to post some code up here and any more information, i'm just not sure where to start... Thanks in advance for anyone willing to have a go at helping me out.

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  • Error Cannot create an Instance of "ObjectName" in Designer when using <UserControl.Resources>

    - by Mike Bynum
    Hi All, I'm tryihg to bind a combobox item source to a static resource. I'm oversimplfying my example so that it's easy to understand what i'm doing. So I have created a class public class A : ObservableCollection<string> { public A() { IKBDomainContext Context = new IKBDomainContext(); Context.Load(Context.GetIBOptionsQuery("2C6C1Q"), p => { foreach (var item in SkinContext.IKBOptions) { this.Add(item); } }, null); } } So the class has a constructor that populates itself using a domaincontext that gets data from a persisted database. I'm only doing reads on this list so dont have to worry about persisting back. in xaml i add a reference to the namespace of this class then I add it as a usercontrol.resources to the page control. <UserControl.Resources> <This:A x:Key="A"/> </UserControl.Resources> and then i use it this staticresource to bind it to my combobox items source.in reality i have to use a datatemplate to display this object properly but i wont add that here. <Combobox ItemsSource="{StaticResource A}"/> Now when I'm in the designer I get the error: Cannot Create an Instance of "A". If i compile and run the code, it runs just fine. This seems to only affect the editing of the xaml page. What am I doing wrong?

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  • Scope of Connection Object for a Website using Connection Pooling (Local or Instance)

    - by Danny
    For a web application with connection polling enabled, is it better to work with a locally scoped connection object or instance scoped connection object. I know there is probably not a big performance improvement between the two (because of the pooling) but would you say that one follows a better pattern than the other. Thanks ;) public class MyServlet extends HttpServlet { DataSource ds; public void init() throws ServletException { ds = (DataSource) getServletContext().getAttribute("DBCPool"); } protected void doGet(HttpServletRequest arg0, HttpServletResponse arg1) throws ServletException, IOException { SomeWork("SELECT * FROM A"); SomeWork("SELECT * FROM B"); } void SomeWork(String sql) { Connection conn = null; try { conn = ds.getConnection(); // execute some sql ..... } finally { if(conn != null) { conn.close(); // return to pool } } } } Or public class MyServlet extends HttpServlet { DataSource ds; Connection conn;* public void init() throws ServletException { ds = (DataSource) getServletContext().getAttribute("DBCPool"); } protected void doGet(HttpServletRequest arg0, HttpServletResponse arg1) throws ServletException, IOException { try { conn = ds.getConnection(); SomeWork("SELECT * FROM A"); SomeWork("SELECT * FROM B"); } finally { if(conn != null) { conn.close(); // return to pool } } } void SomeWork(String sql) { // execute some sql ..... } }

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  • Embedding a File Explorer instance in a WinForms app form

    - by Unsliced
    My (C#, .NET 3.5) app generates files and, in addition to raising events that can be caught and reacted to, I want to display the target folder to the user in a form. The file-list is being shown within the same form as other information. I'm using an instance of the WebBrowser control (System.Windows.Forms.WebBrowser), then navigating to the folder. This shows some default view of the explorer window, with the file summary panel on the left and the files in the 'Tiles' (large icon and text) view. e.g. wb.Navigate(@"c:\path\to\folder\"); I'd like to suppress the panel and to view the file list in the Details view. The user can get to this via a right-click, context menu, but I'd like it to come up automatically. I'd rather not have to build my own TreeView, DataGridView or whatever; the WebBrowser control does all the updating and re-sorting and whatnot 'for free'. Does anybody have a better suggestion? A different control to use or some additional arguments to pass to the control? And if I could trap events (e.g. files being selected/renamed/double-clicked, etc.) then all the better!

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  • Cannot create instance of abstract class

    - by SmartestVEGA
    I am trying to compile the following code and i am getting the error: Cannot create instance of abstract class . Please help m_objExcel = new Excel.Application(); m_objBooks = (Excel.Workbooks)m_objExcel.Workbooks; m_objBook = (Excel._Workbook)(m_objBooks.Add(m_objOpt)); m_objSheets = (Excel.Sheets)m_objBook.Worksheets; m_objSheet = (Excel._Worksheet)(m_objSheets.get_Item(1)); // Create an array for the headers and add it to cells A1:C1. object[] objHeaders = {"Order ID", "Amount", "Tax"}; m_objRange = m_objSheet.get_Range("A1", "C1"); m_objRange.Value = objHeaders; m_objFont = m_objRange.Font; m_objFont.Bold=true; // Create an array with 3 columns and 100 rows and add it to // the worksheet starting at cell A2. object[,] objData = new Object[100,3]; Random rdm = new Random((int)DateTime.Now.Ticks); double nOrderAmt, nTax; for(int r=0;r<100;r++) { objData[r,0] = "ORD" + r.ToString("0000"); nOrderAmt = rdm.Next(1000); objData[r,1] = nOrderAmt.ToString("c"); nTax = nOrderAmt*0.07; objData[r,2] = nTax.ToString("c"); } m_objRange = m_objSheet.get_Range("A2", m_objOpt); m_objRange = m_objRange.get_Resize(100,3); m_objRange.Value = objData; // Save the Workbook and quit Excel. m_objBook.SaveAs(m_strSampleFolder + "Book2.xls", m_objOpt, m_objOpt, m_objOpt, m_objOpt, m_objOpt, Excel.XlSaveAsAccessMode.xlNoChange, m_objOpt, m_objOpt, m_objOpt, m_objOpt); m_objBook.Close(false, m_objOpt, m_objOpt); m_objExcel.Quit();

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  • CKEditor instance in a jQuery dialog

    - by Gazillion
    Hey, I am using jQuery to open a dialog window with a textarea transformed into an instance of CKEditor. I'm using the jQuery adapter provided by the CKEditor team but when the dialog window opens up I cannot interact with the editor (it's created but "null" is written in the content space and I can't click on anything or modify the content). This bug report seems to say that by using a patch provided the issue is fixed but it doesn't seem to be working for me... Here's my code (maybe I did something wrong programmatically): HTML: <div id="ad_div" title="Analyse documentaire"> <textarea id="ad_content" name="ad_content"></textarea> </div> My includes (Everything is included correctly but maybe it's an including order issue?): <script type="text/javascript" src="includes/ckeditor/ckeditor.js"></script> <link rel="stylesheet" type="text/css" href="includes/jquery/css/custom-theme/jquery-ui-1.7.2.custom.css" /> <script type="text/javascript" src="includes/jquery/js/jquery-1.3.2.min.js"></script> <script type="text/javascript" src="includes/jquery/js/jquery-ui-1.7.2.custom.min.js"></script> <script type="text/javascript" src="includes/jquery/plugins/dialog-patch.js"></script> <script type="text/javascript" src="includes/ckeditor/adapters/jquery.js"></script> Javascript: $('#ad_content').ckeditor(); /* snip */ $('#ad_div').dialog( { modal: true, resizable: false, draggable: false, position: ['center','center'], width: 600, height: 500, hide: 'slide', show: 'slide', closeOnEscape: true, autoOpen: false }); $('.analyse_cell').click(function(){ $('#ad_div').dialog('open'); });

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  • Problem with NSUserDefaults and deallocated Instance

    - by Peter A
    Hi, I'm having a problem with NSUserDefaults. I've followed the steps in the books as closely as I can for my app, but still get the same problem. I am getting a *** -[NSUserDefaults integerForKey:]: message sent to deallocated instance 0x3b375a0 error when I try and load in the settings. Here is the code that I have, it is in the App Delegate class. - (void)applicationDidFinishLaunching:(UIApplication *)application { recordingController = [[RecordingTableViewController alloc] initWithStyle:UITableViewStylePlain]; [recordingController retain]; // Add the tab bar controller's current view as a subview of the window [window addSubview:tabBarController.view]; [self loadSettings]; } -(void)loadSettings { NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults]; NSNumber loop = [defaults objectForKey:@"loop_preference"]; NSNumber play = [defaults objectForKey:@"play_me_preference"]; NSNumber volume = [defaults objectForKey:@"volume_preference"]; } As you can see I am not trying to do anything with the values yet, but I get the error on the line reading in the loop preference. I also get it if I try and read an NSString. Any suggestions would be greatly appreciated. Thanks Peter

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  • Remove CKEdit Instance

    - by Laramie
    I have an issue creating multiple instances of CKEdit with different toolbars wherein the second instance created is replacing the toolbar of the first. Unfortunately I can only reproduce it in a huge page containing update panels, which I suspect is the issue. That said, the issue at this point is I can't seem to destroy instances of CKEdit per the documentation. Consider the following: <input name="txt1" type="text" id="txt1" /><br /> <a href="javascript:void(0);" onclick="create()">Create</a><br /> <a href="javascript:void(0);" onclick="destroy()">Destroy</a> <script type= "text/javascript" > <!-- function create() { var hEd = CKEDITOR.instances['txt1']; if (hEd) { CKEDITOR.remove(hEd); } hEd = CKEDITOR.replace('txt1'); } function destroy(){ var hEd = CKEDITOR.instances['txt1']; if (hEd) { CKEDITOR.remove(hEd); } } --> </script> When destroy() runs, CKEDITOR.remove(hEd); is being called. Multiple clicks to create() produce multiple instances of CKEditor on screen, but their instances no longer appear in CKEDITOR.instances. Am I missing something?

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  • VB.NET - Object reference not set to an instance of an object

    - by Daniel
    I need some help with my program. I get this error when I run my VB.NET program with a custom DayView control. ***** Exception Text ******* System.NullReferenceException: Object reference not set to an instance of an object. at SeaCow.Main.DayView1_ResolveAppointments(Object sender, ResolveAppointmentsEventArgs args) in C:\Users\Daniel\My Programs\Visual Basic\SeaCow\SeaCow\SeaCow\Main.vb:line 120 at Calendar.DayView.OnResolveAppointments(ResolveAppointmentsEventArgs args) at Calendar.DayView.OnPaint(PaintEventArgs e) at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer) at System.Windows.Forms.Control.WmPaint(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) According to the error code, the 'for each' loop below is causing the NullReferenceException error. At default, the 'appointments' list is assigned to nothing and I can't find where the ResolveAppointments function is being called at. Private Sub DayView1_ResolveAppointments(ByVal sender As Object, ByVal args As Calendar.ResolveAppointmentsEventArgs) Handles DayView1.ResolveAppointments Dim m_Apps As New List(Of Calendar.Appointment) For Each m_App As Calendar.Appointment In appointments If (m_App.StartDate >= args.StartDate) AndAlso (m_App.StartDate <= args.EndDate) Then m_Apps.Add(m_App) End If Next args.Appointments = m_Apps End Sub Anyone have any suggestions?

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  • -[NSCFData writeStreamHandleEvent:]: unrecognized selector sent to instance in a stream callback

    - by user295491
    Hi everyone, I am working with streams and sockets in iPhone SDK 3.1.3 the issue is when the program accept a callback and I want to handle this writestream callback the following error is triggered " Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: ' -[NSCFData writeStreamHandleEvent:]: unrecognized selector sent to instance 0x17bc70'" But I don't know how to solve it because everything seems fine. Even when I run the debugger there is no error the program works. Any hint here will help! The code of the callback is: void myWriteStreamCallBack (CFWriteStreamRef stream, CFStreamEventType eventType, void *info){ NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; Connection *handlerEv = [(Connection *)info retain] autorelease]; [handlerEv writeStreamHandleEvent:eventType]; [pool release]; } The code of the writeStreamHandleEvent: - (void)writeStreamHandleEvent:(CFStreamEventType) eventType{ switch(eventType) { case kCFStreamEventOpenCompleted: writeStreamOpen = YES; break; case kCFStreamEventCanAcceptBytes: NSLog(@"Writing in the stream"); [self writeOutgoingBufferToStream]; break; case kCFStreamEventErrorOccurred: error = CFWriteStreamGetError(writeStream); fprintf(stderr, "CFReadStreamGetError returned (%ld, %ld)\n", error.domain, error.error); CFWriteStreamUnscheduleFromRunLoop(writeStream, CFRunLoopGetCurrent(),kCFRunLoopCommonModes); CFWriteStreamClose(writeStream); CFRelease(writeStream); break; case kCFStreamEventEndEncountered: CFWriteStreamUnscheduleFromRunLoop(writeStream, CFRunLoopGetCurrent(),kCFRunLoopCommonModes); CFWriteStreamClose(writeStream); CFRelease(writeStream); break; } } The code of the stream configuration: CFSocketContext ctx = {0, self, nil, nil, nil}; CFWriteStreamSetClient (writeStream,registeredEvents, (CFWriteStreamClientCallBack)&myWriteStreamCallBack,(CFStreamClientContext *)(&ctx) ); CFWriteStreamScheduleWithRunLoop (writeStream, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode); You can see that there is nothing strange!, well at least I don't see it. Thank you in advance.

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  • [CFArray release]: message sent to deallocated instance

    - by arielcamus
    Hi, I'm using the following method in my code: - (NSMutableArray *) newOrderedArray:(NSMutableArray *)array ByKey:(NSString *)key ascending:(BOOL)ascending { NSSortDescriptor *idDescriptor = [[NSSortDescriptor alloc] initWithKey:key ascending:ascending]; NSArray *sortDescriptors = [NSArray arrayWithObject:idDescriptor]; NSArray *orderArray = [array sortedArrayUsingDescriptors:sortDescriptors]; [idDescriptor release]; NSMutableArray *result = [NSMutableArray arrayWithArray:orderArray]; return result; } Is this a well-coded convenience method? As I think, it returns an autoreleased NSMutableArray. This method is called by another one: - (id) otherMethod { NSMutableArray *otherResult = [[[NSMutableArray alloc] initWithCapacity:[otherArray count]] autorelease]; // I add some stuff to otherResult and then... NSMutableArray *result = [dbUtils newOrderedArray:otherResult ByKey:@"objectId" ascending:NO]; return result; } This method (otherMethod) is called in some view controller where I want to store returned array and release it when deallocating the view controller. However, when [result retain] is called in this view controller (because I need it to be available and I can't allow it to be deallocated) I receive the following error: [CFArray release]: message sent to deallocated instance I've tried to log [result retainCount] just before calling retain and it print "1". I don't understand why an error is thrown when calling retain. Thank you, A

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  • Unrecognised selector sent to instance uitableview

    - by ct2k7
    I'm getting error: Unrecognised selector sent to instance, upon inspection, I see there is an issue in this section of code, and more specifically: [self.tableView insertSubview:ovController.view aboveSubview:self.parentViewController.view]; - (void) searchBarTextDidBeginEditing:(UISearchBar *)theSearchBar { if(searching) return; //Add the overlay view. ovController = [[OverlayViewController alloc] initWithNibName:@"OverlayView" bundle:[NSBundle mainBundle]]; CGFloat yaxis = self.navigationController.navigationBar.frame.size.height; CGFloat width = self.view.frame.size.width; CGFloat height = self.view.frame.size.height; //Parameters x = origion on x-axis, y = origon on y-axis. CGRect frame = CGRectMake(0, yaxis, width, height); ovController.view.frame = frame; ovController.view.backgroundColor = [UIColor grayColor]; ovController.view.alpha = 0.5; ovController.rvController = self; [self.tableView insertSubview:ovController.view aboveSubview:self.parentViewController.view]; searching = YES; letUserSelectRow = NO; //self.tableView.scrollEnabled = NO; } Looks like there's an issue with tableview?

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  • Are MEF's ComposableParts contracts instance-based?

    - by Dave
    I didn't really know how to phrase the title of my questions, so my apologies in advance. I read through parts of the MEF documentation to try to find the answer to my question, but couldn't find it. I'm using ImportMany to allow MEF to create multiple instances of a specific plugin. That plugin Imports several parts, and within calls to a specific instance, it wants these Imports to be singletons. However, what I don't want is for all instances of this plugin to use the same singleton. For example, let's say my application ImportManys Blender appliances. Every time I ask for one, I want a different Blender. However, each Blender Imports a ControlPanel. I want each Blender to have its own ControlPanel. To make things a little more interesting, each Blender can load BlendPrograms, which are also contained within their own assemblies, and MEF takes care of this loading. A BlendProgram might need to access the ControlPanel to get the speed, but I want to ensure that it is accessing the correct ControlPanel (i.e. the one that is associated with the Blender that is associated with the program!) This diagram might clear things up a little bit: As the note shows, I believe that the confusion could come from an inherently-poor design. The BlendProgram shouldn't touch the ControlPanel directly, and instead perhaps the BlendProgram should get the speed via the Blender, which will then delegate the request to its ControlPanel. If this is the case, then I assume the BlendProgram needs to have a reference to a specific Blender. In order to do this, is the right way to leverage MEF and use an ImportingConstructor for BlendProgram, i.e. [ImportingConstructor] public class BlendProgram : IBlendProgram { public BlendProgram( Blender blender) {} } And if this is the case, how do I know that MEF will use the intended Blender plugin?

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  • Regular expressions - finding and comparing the first instance of a word

    - by Dan
    Hi there, I am currently trying to write a regular expression to pull links out of a page I have. The problem is the links need to be pulled out only if the links have 'stock' for example. This is an outline of what I have code wise: <td class="prd-details"> <a href="somepage"> ... <span class="collect unavailable"> </td> <td class="prd-details"> <a href="somepage"> ... <span class="collect available"> </td> What I would like to do is pull out the links only if 'collect available' is in the tag. I have tried to do this with the regular expression: (?s)prd-details[^=]+="([^"]+)" .+?collect{1}[^\s]+ available However on running it, it will find the first 'prd-details' class and keep going until it finds 'collect available', thereby taking the incorrect results. I thought by specifying the {1} after the word collect it would only use the first instance of the word it finds, but apparently I'm wrong. I've been trying to use different things such as positive and negative lookaheads but I cant seem to get anything to work. Might anyone be able to help me with this issue? Thanks, Dan

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  • jQuery Cycle : Multiple Instances, detect end of each instance

    - by guylabbe.ca
    I am using multiple instances of Cycle for a portfolio; Only one is shown and the others are hidden. Each Cycle is a project with multiple images. The only thing I can't figure out is how to detect the end of the « current » Cycle instance. with after: function, it is triggered for all instances at once, impossible to get « local » events. Here is my code : $('.sldr_closeup').each(function() { var currId = $(this).attr('id'); window['num_'+currId] = 0; $(this).cycle({ timeout:0, speed:500, fx:'fade', next:'.nextimages', prev:'.previmages', fit:1, nowrap:1, autstop:0, after : function(c,n,o,f) { var currId = $(this).parent('div').attr('id'); (f) ? window['num_'+currId] ++ : window['num_'+currId] --; if ((o.slideCount == window['num_'+currId] )) { alert(currId); $('.nextimages').stop().fadeTo(400,0,function(){ if(currId != $('.projectList .projet').last().find('a').attr('rel')) $('.nextproject').stop().fadeTo(400,1); $(this).hide(); }); } } }).cycle('pause'); });

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  • PHP/MySQL - Working with two databases, one shared and one local to an instance of application

    - by Extrakun
    The situation: Using a off-the-shelf PHP application, I have to add in a new module for extra functionality. Today, it is made known that eventually four different instances of the application are to be deployed, but the data from the new functionality is to be shared among those 4 instances. Each instance should still have their own database for users, content and etc. So the data for the new functionality goes into a 'shared' database. The data for the application (user login, content, uploads) go into a 'local' database To make things more complex, the new module I am writing will fetch data from the local DB and the shared DB at the same time. A re-write of the base application will take too long. I only have control over the new module which I am writing. The ideal solution: Is there a way to encapsulate 2 databases into one name using MySQL? I do not wish to switch DB connections or specifically name the DB to query from inside my SQL statements. The application uses a DB wrapper, so I am able to change it somehow so I can invisibly attempt to read/write to two different DB. What is the best way to handle this problem?

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  • Create an instance of an exported C++ class from Delphi

    - by Alan G.
    I followed an excellent article by Rudy Velthuis about using C++ classes in DLL's. Everything was golden, except that I need access to some classes that do not have corresponding factories in the C++ DLL. How can I construct an instance of a class in the DLL? The classes in question are defined as class __declspec(dllexport) exampleClass { public: void foo(); }; Now without a factory, I have no clear way of instantiating the class, but I know it can be done, as I have seen SWIG scripts (.i files) that make these classes available to Python. If Python&SWIG can do it, then I presume/hope there is some way to make it happen in Delphi too. Now I don't know much about SWIG, but it seems like it generates some sort of map for C++ mangled names? Is that anywhere near right? Looking at the exports from the DLL, I suppose I could access functions & constructor/destructor by index or the mangled name directly, but that would be nasty; and would it even work? Even if I can call the constructor, how can I do the equivalent of "new CClass();" in Delphi?

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  • Choosing between instance methods and separate functions?

    - by StackedCrooked
    Adding functionality to a class can be done by adding a method or by defining a function that takes an object as its first parameter. Most programmers that I know would choose for the solution of adding a instance method. However, I sometimes prefer to create a separate function. For example, in the example code below Area and Diagonal are defined as separate functions instead of methods. I find it better this way because I think these functions provide enhancements rather than core functionality. Is this considered a good/bad practice? If the answer is "it depends", then what are the rules for deciding between adding method or defining a separate function? class Rect { public: Rect(int x, int y, int w, int h) : mX(x), mY(y), mWidth(w), mHeight(h) { } int x() const { return mX; } int y() const { return mY; } int width() const { return mWidth; } int height() const { return mHeight; } private: int mX, mY, mWidth, mHeight; }; int Area(const Rect & inRect) { return inRect.width() * inRect.height(); } float Diagonal(const Rect & inRect) { return std::sqrt(std::pow(static_cast<float>(inRect.width()), 2) + std::pow(static_cast<float>(inRect.height()), 2)); }

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  • Object reference not set to an instance of an object

    - by MBTHQ
    Can anyone help with the following code? I'm trying to get data from the database colum to the datagridview... I'm getting error over here "Dim sql_1 As String = "SELECT * FROM item where item_id = '" + DataGridView_stockout.CurrentCell.Value.ToString() + "'"" Private Sub DataGridView_stockout_CellMouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellMouseEventArgs) Handles DataGridView_stockout.CellMouseClick Dim i As Integer = Stock_checkDataSet1.Tables(0).Rows.Count > 0 Dim thiscur_stok As New System.Data.SqlClient.SqlConnection("Data Source=MBTHQ\SQLEXPRESS;Initial Catalog=stock_check;Integrated Security=True") ' Sql Query Dim sql_1 As String = "SELECT * FROM item where item_id = '" + DataGridView_stockout.CurrentCell.Value.ToString() + "'" ' Create Data Adapter Dim da_1 As New SqlDataAdapter(sql_1, thiscur_stok) ' Fill Dataset and Get Data Table da_1.Fill(Stock_checkDataSet1, "item") Dim dt_1 As DataTable = Stock_checkDataSet1.Tables("item") If i >= DataGridView_stockout.Rows.Count Then 'MessageBox.Show("Sorry, DataGridView_stockout doesn't any row at index " & i.ToString()) Exit Sub End If If 1 >= Stock_checkDataSet1.Tables.Count Then 'MessageBox.Show("Sorry, Stock_checkDataSet1 doesn't any table at index 1") Exit Sub End If If i >= Stock_checkDataSet1.Tables(1).Rows.Count Then 'MessageBox.Show("Sorry, Stock_checkDataSet1.Tables(1) doesn't any row at index " & i.ToString()) Exit Sub End If If Not Stock_checkDataSet1.Tables(1).Columns.Contains("os") Then 'MessageBox.Show("Sorry, Stock_checkDataSet1.Tables(1) doesn't any column named 'os'") Exit Sub End If 'DataGridView_stockout.Item("cs_stockout", i).Value = Stock_checkDataSet1.Tables(0).Rows(i).Item("os") Dim ab As String = Stock_checkDataSet1.Tables(0).Rows(i)(0).ToString() End Sub I keep on getting the error saying "Object reference not set to an instance of an object" I dont know where I'm going wrong. Help really appreciated!!

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  • -[UITableViewRowData isEqualToString:]: unrecognized selector sent to instance 0x391dce0

    - by tak
    I have a datatable which shows the list of contacts. when I start the application all the data is loaded correctly.But after selecting a contact, I am sometimes getting this exception :- Program received signal: “EXC_BAD_ACCESS”. and sometimes -[UITableViewRowData isEqualToString:]: unrecognized selector sent to instance 0x391dce0 most probably for this code:- - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; } ExpenseTrackerAppDelegate *appDelegate = (ExpenseTrackerAppDelegate *)[[UIApplication sharedApplication] delegate]; Person *person = (Person *)[appDelegate.expensivePersonsList objectAtIndex:indexPath.row]; NSString *name = (NSString *)[NSMutableString stringWithFormat:@"%@ %@" ,person.lastName , person.firstName]; cell.textLabel.text = name; //cell.detailTextLabel.text = person.lastName; // Configure the cell. return cell; } If I replace these lines of code NSString *name = (NSString *)[NSMutableString stringWithFormat:@"%@ %@" ,person.lastName , person.firstName]; cell.textLabel.text = name; with this code cell.textLabel.text = person.lastName; then everything works fine? I dont know what exactly happens?

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  • Right way to return proxy model instance from a base model instance in Django ?

    - by sotangochips
    Say I have models: class Animal(models.Model): type = models.CharField(max_length=255) class Dog(Animal): def make_sound(self): print "Woof!" class Meta: proxy = True class Cat(Animal): def make_sound(self): print "Meow!" class Meta: proxy = True Let's say I want to do: animals = Animal.objects.all() for animal in animals: animal.make_sound() I want to get back a series of Woofs and Meows. Clearly, I could just define a make_sound in the original model that forks based on animal_type, but then every time I add a new animal type (imagine they're in different apps), I'd have to go in and edit that make_sound function. I'd rather just define proxy models and have them define the behavior themselves. From what I can tell, there's no way of returning mixed Cat or Dog instances, but I figured maybe I could define a "get_proxy_model" method on the main class that returns a cat or a dog model. Surely you could do this, and pass something like the primary key and then just do Cat.objects.get(pk = passed_in_primary_key). But that'd mean doing an extra query for data you already have which seems redundant. Is there any way to turn an animal into a cat or a dog instance in an efficient way? What's the right way to do what I want to achieve?

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  • How to fix: unrecognized selector sent to instance

    - by Matt
    I am having a problem that may be simple to fix, but not simple for me to debug. I simple have a button inside a view in IB; the file's owner is set to the view controller class I am using and when making the connections, everything seems fine, ie. the connector is finding the method I am trying to call etc. however, I am receiving this error: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[UIApplication getStarted:]: unrecognized selector sent to instance 0x3d19130' My code is as follows: RootViewController.h @interface RootViewController : UIViewController { IBOutlet UIButton* getStartedButton; } @property (nonatomic, retain) UIButton* getStartedButton; - (IBAction) getStarted: (id)sender; @end RootViewController.m #import "RootViewController.h" #import "SimpleDrillDownAppDelegate.h" @implementation RootViewController @synthesize getStartedButton; - (void)viewDidLoad { [super viewDidLoad]; } - (IBAction) getStarted: (id)sender { NSLog(@"Button Tapped!"); //[self.view removeFromSuperview]; } - (void)dealloc { [getStartedButton release]; [super dealloc]; } @end Seems simple enough...any thoughs?

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  • "no inclosing instance error " while getting top term frequencies for document from Lucene index

    - by Julia
    Hello ! I am trying to get the most occurring term frequencies for every particular document in Lucene index. I am trying to set the treshold of top occuring terms that I care about, maybe 20 However, I am getting the "no inclosing instance of type DisplayTermVectors is accessible" when calling Comparator... So to this function I pass vector of every document and max top terms i would like to know protected static Collection getTopTerms(TermFreqVector tfv, int maxTerms){ String[] terms = tfv.getTerms(); int[] tFreqs = tfv.getTermFrequencies(); List result = new ArrayList(terms.length); for (int i = 0; i < tFreqs.length; i++) { TermFrq tf = new TermFrq(terms[i], tFreqs[i]); result.add(tf); } Collections.sort(result, new FreqComparator()); if(maxTerms < result.size()){ result = result.subList(0, maxTerms); } return result; } /Class for objects to hold the term/freq pairs/ static class TermFrq{ private String term; private int freq; public TermFrq(String term,int freq){ this.term = term; this.freq = freq; } public String getTerm(){ return this.term; } public int getFreq(){ return this.freq; } } /*Comparator to compare the objects by the frequency*/ class FreqComparator implements Comparator{ public int compare(Object pair1, Object pair2){ int f1 = ((TermFrq)pair1).getFreq(); int f2 = ((TermFrq)pair2).getFreq(); if(f1 > f2) return 1; else if(f1 < f2) return -1; else return 0; } } Explanations and corrections i will very much appreciate, and also if someone else had experience with term frequency extraction and did it better way, I am opened to all suggestions! Please help!!!! Thanx!

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