Search Results

Search found 8818 results on 353 pages for 'undefined behavior'.

Page 98/353 | < Previous Page | 94 95 96 97 98 99 100 101 102 103 104 105  | Next Page >

• EXEC_BAD_ACCESS error comes in my applicatoin in iphone

  - by Jaimin

  when i print dictionary i got this error.. here my dictTf is mutabledictionay.. when i m in home page i selct few fields and click find. so new view comes with the result.. now i go back and again click find without changing anything.. now comes proper.. now at this moment when i go back it shows this in the dictionay and EXEC_BAD_ACCESS eror comes... Printing description of dictTf: The program being debugged was signaled while in a function called from GDB. GDB has restored the context to what it was before the call. To change this behavior use "set unwindonsignal off" Evaluation of the expression containing the function (CFShow) will be abandoned. The program being debugged was signaled while in a function called from GDB. GDB has restored the context to what it was before the call. To change this behavior use "set unwindonsignal off" Evaluation of the expression containing the function (CFShow) will be abandoned. (gdb)

  Read the article

• MFC (C++) CDialog DoModal() not working as expected

  - by krebstar

  Hi, I have a plugin that is loaded by this application.. This plugin calls some dialog boxes with DoModal(). I'm expecting these dialog boxes to function like this: If I click on the application window behind the dialog box, the dialog box flashes and does not allow the application to be in focus. However, in one of the other dialog boxes, called with DoModal(), if I click on the application window, it doesn't do the flashing thing, and after a while the application's close/minimize buttons become active (well, just the color). They're not really active and the window turns somewhat white and the title bar says (Not Responding)... What could possibly be wrong and how do I fix it? I've tried setting the dialog box's properties to System Modal: True, and Set Foreground: True but it doesn't seem to work.. :( Thanks.. EDIT: I'd like to note that the in the Windows taskbar, there is only one entry for the application for the correct behavior, but when the dialog box with the incorrect behavior is launched, another "window" is launched.. So it looks like (Application)(Dialog box title).. The effect I'm trying to achieve is just (Application)..

  Read the article

• Is `List<Dog>` a subclass of `List<Animal>`? Why aren't Java's generics implicitly polymorphic?

  - by froadie

  I'm a bit confused about how Java generics handle inheritance / polymorphism. Assume the following hierarchy - Animal (Parent) Dog - Cat (Children) So suppose I have a method doSomething(List<Animal> animals). By all the rules of inheritance and polymorphism, I would assume that a List<Dog> is a List<Animal> and a List<Cat> is a List<Animal> - and so either one could be passed to this method. Not so. If I want to achieve this behavior, I have to explicitly tell the method to accept a list of any subset of Animal by saying doSomething(List<? extends Animal> animals). I understand that this is Java's behavior. My question is why? Why is polymorphism generally implicit, but when it comes to generics it must be specified?

  Read the article

• Delegate Methods Not Firing on Search Results Table

  - by Slinky

  All, I have a UITableView w/detail, with a Search bar, created from code. Works fine on selected items except it doesn't work when an item is clicked from the search results; no delegate methods fire. Never seen this type of behavior before so I don't know where the issue lies. I get the same behavior with standard table cells as well as custom table cells. Appreciate any guidance on this and thanks. Just Hangs Here //ViewController.h @interface SongsViewController : UITableViewController <UISearchBarDelegate,UISearchDisplayDelegate> { NSMutableArray *searchData; UISearchBar *searchBar; UISearchDisplayController *searchDisplayController; UITableViewCell *customSongCell; } //ViewController.m -(void)viewDidLoad { [super viewDidLoad]; CGRect screenRect = [[UIScreen mainScreen] bounds]; CGFloat screenWidth = screenRect.size.width; searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, screenWidth, 88)]; [searchBar setShowsScopeBar:YES]; [searchBar setScopeButtonTitles:[[NSArray alloc] initWithObjects:@"Title",@"Style", nil]]; searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:searchBar contentsController:self]; searchDisplayController.delegate = self; searchDisplayController.searchResultsDataSource = self; self.tableView.tableHeaderView = searchBar; //Load custom table cell UINib *songCellNib = [UINib nibWithNibName:@"SongItem" bundle:nil]; //Register this nib, which contains the cell [[self tableView] registerNib:songCellNib forCellReuseIdentifier:@"SongItemCell"]; // create a filtered list that will contain products for the search results table. SongStore *ps = [SongStore defaultStore]; NSArray *songObjects = [ps allSongs]; self.filteredListContent = [NSMutableArray arrayWithCapacity: [songObjects count]]; self.masterSongArr = [[NSMutableArray alloc] initWithArray:[ps allSongs]]; [self refreshData]; [self.tableView reloadData]; self.tableView.scrollEnabled = YES; }

  Read the article

• Adding a button bar at the bottom of ListView upon checkbox select (as in gmail app)??

  - by elto

  I have a ListView with custom adapter. In each row there is a checkbox and couple of textviews. I want user to give option to delete the check marked items, so as soon as soon clicks on one of the checkbox, I want a button bar to slide in from the bottom and stay at the bottom regardless of listview scroll. This is something like the email app behavior of Motorola Cliq and to some extent gmail app itself. I have tried adding a relativelayout (containing buttons) below the listview, which has visibility set to gone initially, but as soon as user checks a button, the visibility changes to "visible". I have added a slide-in animation to it too. It is working but problem is that it is overlapping the last element of the listview which user can not checkmark if the button bar has already become visible. So I tried to set the bottom margin of the listview equal to the height of the button bar when I'm changing the button bar visibility, which solves the problem of overlap, but now the checkbox behavior has gone weird. Clicking on one checkmark tries to checkmark another checkmark in the list for some weird reason. I noticed that this happens because as soon as I change the listview margin, list redraws itself, and during this new call to getView() method of adapter, things mess up. I wanted to ask if anyone has done something like this. What is the best method to add such button bar below list while keeping the slide-in animation intact. Also, What is the footer-view of listview and can that solve my problem?

  Read the article

• How to deal with a flaw in System.Data.DataTableExtensions.CopyToDataTable()

  - by andy

  Hey guys, so I've come across something which is perhaps a flaw in the Extension method .CopyToDataTable. This method is used by Importing (in VB.NET) System.Data.DataTableExtensions and then calling the method against an IEnumerable. You would do this if you want to filter a Datatable using LINQ, and then restore the DataTable at the end. i.e: Imports System.Data.DataRowExtensions Imports System.Data.DataTableExtensions Public Class SomeClass Private Shared Function GetData() As DataTable Dim Data As DataTable Data = LegacyADO.NETDBCall Data = Data.AsEnumerable.Where(Function(dr) dr.Field(Of Integer)("SomeField") = 5).CopyToDataTable() Return Data End Function End Class In the example above, the "WHERE" filtering might return no results. If this happens CopyToDataTable throws an exception because there are no DataRows. Why? The correct behavior should be to return a DataTable with Rows.Count = 0. Can anyone think of a clean workaround to this, in such a way that whoever calls CopyToDataTable doesn't have to be aware of this issue? System.Data.DataTableExtensions is a Static Class so I can't override the behavior....any ideas? Have I missed something? cheers UPDATE: I have submitted this as an issue to Connect. I would still like some suggestions, but if you agree with me, you could vote up the issue at Connect via the link above cheers

  Read the article

• Using the Queue class in Python 2.6

  - by voipme

  Let's assume I'm stuck using Python 2.6, and can't upgrade (even if that would help). I've written a program that uses the Queue class. My producer is a simple directory listing. My consumer threads pull a file from the queue, and do stuff with it. If the file has already been processed, I skip it. The processed list is generated before all of the threads are started, so it isn't empty. Here's some pseudo-code. import Queue, sys, threading processed = [] def consumer(): while True: file = dirlist.get(block=True) if file in processed: print "Ignoring %s" % file else: # do stuff here dirlist.task_done() dirlist = Queue.Queue() for f in os.listdir("/some/dir"): dirlist.put(f) max_threads = 8 for i in range(max_threads): thr = Thread(target=consumer) thr.start() dirlist.join() The strange behavior I'm getting is that if a thread encounters a file that's already been processed, the thread stalls out and waits until the entire program ends. I've done a little bit of testing, and the first 7 threads (assuming 8 is the max) stop, while the 8th thread keeps processing, one file at a time. But, by doing that, I'm losing the entire reason for threading the application. Am I doing something wrong, or is this the expected behavior of the Queue/threading classes in Python 2.6?

  Read the article

• Snapshot agent obliterates conflicts

  - by mwolfe02

  We are using merge replication in SQL Server 2000. We have a snapshot agent that runs every night that updates the publication snapshot. About six months ago we updated from SQL Server 7.0 to 2000 (that's not a typo). We noticed a sharp decline in conflicts at that time but could not track down the reason. We finally found that the daily snapshot agent is recreating the conflict tables every night. This seems to be a change in functionality from SQL Server 7.0. We were running the snapshot agent before and the conflicts would accumulate. Is there some way to prevent the data in the conflict tables from being lost when the snapshot runs? Can anyone confirm a change in behavior between 7.0 and 2000? Our current plan is to simply stop automatically updating the publication snapshot. Is that a reasonable workaround? Here is the line from the script that is adding the snapshot: exec sp_addpublication_snapshot @publication = N'MyPub' , @frequency_type = 4 , @frequency_interval = 1 , @frequency_relative_interval = 1 , @frequency_recurrence_factor = 0 , @frequency_subday = 1 , @frequency_subday_interval = 5 , @active_start_date = 0 , @active_end_date = 0 , @active_start_time_of_day = 500 , @active_end_time_of_day = 235959 Here is the step that runs in the agent job: Step Name: Run agent. Type: Replication Snapshot Command: -Publisher [WCDBS02] -PublisherDB [TaxDB] -Distributor [WCDBS02] -Publication [TaxDB] -ReplicationType 2 -DistributorSecurityMode 1 This appears to be running the Replication Snapshot Agent Utility. There is no mention on that link about dropping and recreating system conflict tables, nor is there any flag that can be set to alter this behavior.

  Read the article

• CREATE VIEW called multiple times not creating all views

  - by theninepoundhammer

  Noticing strange behavior in SQL 2005, both Express and Enterprise Edition: In my code I need to loop through a series of values (about five in a row), and for each value, I need to insert the value into a table and dynamically create a new view using that value as part of the where clause and the name of the view. The code runs pretty quickly, but what I'm noticing is that all the values are inserted into the table correctly but only the LAST view is being created. Every time. For example, if the values I'm using are X1, X2, X3, X4, and X5, I'll run the process, open up Mgmt Studio, and see five rows in the table with the correct five values, but only one view named MyView_x5 that has the correct WHERE clause. At first, I had this loop in an SSIS package as part of a larger data flow. When I started noticing this behavior, I created a stored proc that would create the CREATE VIEW statement dynamically after the insert and called EXECUTE to create the view. Same result. Finally, I created some C# code using the Enterprise Library DAAB, and did the insert and CREATE VIEW statements from my DLL. Same result every time. Most recently, I turned on Profiler while running against the Enterprise Edition and was able to verify that the Batch Started and Batch Completed events were being fired off for each instance of the view. However, like I said, only the last view is actually being created. Does anyone have any idea why this might be happening? Or any suggestions about what else to check or profile? I've profiled for error messages, exceptions, etc. but don't see any in my trace file. My express edition is 9.00.1399.06. Not sure about the Enterprise edition but think it is SP2.

  Read the article

• Testing When Correctness is Poorly Defined?

  - by dsimcha

  I generally try to use unit tests for any code that has easily defined correct behavior given some reasonably small, well-defined set of inputs. This works quite well for catching bugs, and I do it all the time in my personal library of generic functions. However, a lot of the code I write is data mining code that basically looks for significant patterns in large datasets. Correct behavior in this case is often not well defined and depends on a lot of different inputs in ways that are not easy for a human to predict (i.e. the math can't reasonably be done by hand, which is why I'm using a computer to solve the problem in the first place). These inputs can be very complex, to the point where coming up with a reasonable test case is near impossible. Identifying the edge cases that are worth testing is extremely difficult. Sometimes the algorithm isn't even deterministic. Usually, I do the best I can by using asserts for sanity checks and creating a small toy test case with a known pattern and informally seeing if the answer at least "looks reasonable", without it necessarily being objectively correct. Is there any better way to test these kinds of cases?

  Read the article

• Python : How to close a UDP socket while is waiting for data in recv ?

  - by alexroat

  Hello, let's consider this code in python: import socket import threading import sys import select class UDPServer: def __init__(self): self.s=None self.t=None def start(self,port=8888): if not self.s: self.s=socket.socket(socket.AF_INET, socket.SOCK_DGRAM) self.s.bind(("",port)) self.t=threading.Thread(target=self.run) self.t.start() def stop(self): if self.s: self.s.close() self.t.join() self.t=None def run(self): while True: try: #receive data data,addr=self.s.recvfrom(1024) self.onPacket(addr,data) except: break self.s=None def onPacket(self,addr,data): print addr,data us=UDPServer() while True: sys.stdout.write("UDP server> ") cmd=sys.stdin.readline() if cmd=="start\n": print "starting server..." us.start(8888) print "done" elif cmd=="stop\n": print "stopping server..." us.stop() print "done" elif cmd=="quit\n": print "Quitting ..." us.stop() break; print "bye bye" It runs an interactive shell with which I can start and stop an UDP server. The server is implemented through a class which launches a thread in which there's a infinite loop of recv/*onPacket* callback inside a try/except block which should detect the error and the exits from the loop. What I expect is that when I type "stop" on the shell the socket is closed and an exception is raised by the recvfrom function because of the invalidation of the file descriptor. Instead, it seems that recvfrom still to block the thread waiting for data even after the close call. Why this strange behavior ? I've always used this patter to implements an UDP server in C++ and JAVA and it always worked. I've tried also with a "select" passing a list with the socket to the xread argument, in order to get an event of file descriptor disruption from select instead that from recvfrom, but select seems to be "insensible" to the close too. I need to have a unique code which maintain the same behavior on Linux and Windows with python 2.5 - 2.6. Thanks.

  Read the article

• Slider with buttons. How to improve?

  - by Kalinin

  I need to make slider. I have content (which should shift horizontally) and two buttons - "right" and "left". If you press the button and hold it, the content starts to move (in the appropriate direction). If you not hold the button, then the movement stops. This behavior is copies the behavior of usual window scrollbar. I wrote code: var animateTime = 1, offsetStep = 5; //event handling for buttons "left", "right" $('.bttR, .bttL') .mousedown(function() { scrollContent.data('loop', true).loopingAnimation($(this)); }) .bind("mouseup mouseout", function(){ scrollContent.data('loop', false); }); $.fn.loopingAnimation = function(el){ if(this.data('loop') == true){ var leftOffsetStr; leftOffsetInt = parseInt(this.css('marginLeft').slice(0, -2)); if(el.attr('class') == 'bttR') leftOffsetStr = (leftOffsetInt - offsetStep).toString() + 'px'; else if(el.attr('class') == 'bttL') leftOffsetStr = (leftOffsetInt + offsetStep).toString() + 'px'; this.animate({marginLeft: leftOffsetStr}, animateTime, function(){ $(this).loopingAnimation(el); }) } return this; } But it does have a few things that I do not like: Always call the function animation (loopingAnimation) - I think that this is an extra load (not good). When moving content he "twitches and trembling" - (it's not pretty). How can I solve this problem more elegantly and without the drawbacks of my code?

  Read the article

• JavaScript window object element properties

  - by Timothy

  A coworker showed me the following code and asked me why it worked. <span id="myspan">Do you like my hat?</span> <script type="text/javascript"> var spanElement = document.getElementById("myspan"); alert("Here I am! " + spanElement.innerHTML + "\n" + myspan.innerHTML); </script> I explained that a property is attached to the window object with the name of the element's id when the browser parses the document which then contains a reference to the appropriate dom node. It's sort of as if window.myspan = document.getElementById("myspan") is called behind the scenes as the page is being rendered. The ensuing discussion we had raised a few of questions: The window object and most of the DOM are not part of the official JavaScript/ECMA standards, but is the above behavior documented in any other official literature, perhaps browser-related? The above works in a browser (at least the main contenders) because there is a window object, but fails in something like rhino. Is writing code that relys on this considered bad practice because it makes too many assumptions about the execution environment? Are there any browsers in which the above would fail, or is this considered standard behavior across the board? Does anyone here know the answers to those questions and would be willing to enlighten me? I tried a quick internet search, but I admit I'm not sure how to even properly phrase the query. Pointers to references and documentation are welcome.

  Read the article

• How do i set the Transaction Isolation in EJB?

  - by Nitesh Panchal

  Hello, I am not able to find a way to set TransactionIsolation in ejb. Can anybody tell me how do i set it? I am using persistence. I have looked the following classes : EntityManager , EntityManagerFactory, UserTransaction. None of them seems to have any method like setTransactionIsolation or such. Do we need to change persistence.xml? I just read a book named Mastering EJB 3.0 4th edition. They gave a full 10 page theory about Isolation level that this problems occur and that occurs and such things but at the end they gave this paragraph :- "As we now know, the EJB standard does not deal with isolation levels directly, and rightly so. EJB is a component specification. It defines the behavior and contracts of a business component with clients and middleware infrastructure (containers) such that the component can be rendered as various middleware services properly. EJBs therefore are transactional components that interact with resource managers, such as the JDBC resource manager or JMS resource manager, via JTS, as part of a transaction. They are not, hence, resource components in themselves. Since isolation levels are very specific to the behavior and capabilities of the underlying resources, they should therefore be specified at the resource API levels. " What exactly does it mean? What is meant by resource level APIs? Please help me. If persistence has no way to set Isolation Level then why do they give such huge theory in an EJB book and make it heavy in weight unnecessarily :(

  Read the article

• Invoking code both before and after WebControl.Render method

  - by Dirk

  I have a set of custom ASP.NET server controls, most of which derive from CompositeControl. I want to implement a uniform look for "required" fields across all control types by wrapping each control in a specific piece of HTML/CSS markup. For example: <div class="requiredInputContainer"> ...custom control markup... </div> I'd love to abstract this behavior in such a way as to avoid having to do something ugly like this in every custom control, present and future: public class MyServerControl : TextBox, IRequirableField { public IRequirableField.IsRequired {get;set;} protected override void Render(HtmlTextWriter writer){ RequiredFieldHelper.RenderBeginTag(this, writer) //render custom control markup RequiredFieldHelper.RenderEndTag(this, writer) } } public static class RequiredFieldHelper{ public static void RenderBeginTag(IRequirableField field, HtmlTextWriter writer){ //check field.IsRequired, render based on its values } public static void RenderEndTag(IRequirableField field, HtmlTextWriter writer){ //check field.IsRequired , render based on its values } } If I was deriving all of my custom controls from the same base class, I could conceivably use Template Method to enforce the before/after behavior;but I have several base classes and I'd rather not end up with really a convoluted class hierarchy anyway. It feels like I should be able to design something more elegant (i.e. adheres to DRY and OCP) by leveraging the functional aspects of C#, but I'm drawing a blank.

  Read the article

• Deleting elements from stl set while iterating through it does not invalidate the iterators.

  - by pedromanoel

  I need to go through a set and remove elements that meet a predefined criteria. This is the test code I wrote: #include <set> #include <algorithm> void printElement(int value) { std::cout << value << " "; } int main() { int initNum[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; std::set<int> numbers(initNum, initNum + 10); // print '0 1 2 3 4 5 6 7 8 9' std::for_each(numbers.begin(), numbers.end(), printElement); std::set<int>::iterator it = numbers.begin(); // iterate through the set and erase all even numbers for (; it != numbers.end(); ++it) { int n = *it; if (n % 2 == 0) { // wouldn't invalidate the iterator? numbers.erase(it); } } // print '1 3 5 7 9' std::for_each(numbers.begin(), numbers.end(), printElement); return 0; } At first, I thought that erasing an element from the set while iterating through it would invalidate the iterator, and the increment at the for loop would have undefined behavior. Even though, I executed this test code and all went well, and I can't explain why. My question: Is this the defined behavior for std sets or is this implementation specific? I am using gcc 4.3.3 on ubuntu 10.04 (32-bit version), by the way. Thanks!

  Read the article

• force refresh of part of page in browser

  - by Jeremy

  I have the following html: <ul class="scr"> <li class="scr"> <input type="checkbox" class="chkscr"/> <h3>Item Name</h3> <div class="scr">Contents</div> </li> .... </ul> And the following jQuery: //Set initial state of each scr section $('.chkscr input, input.chkscr').each(function() { chkSCR_Click($(this)); }); //Setup click event $('.chkscr input, input.chkscr').click(function() { chkSCR_Click($(this)); }); //Toggle corresponding scr section for the checkbox function chkSCR_Click(ctl) { if (ctl.attr('checked')) { ctl.parents('li.scr').find('div.scr').stop().show(); } else { ctl.parents('li.scr').find('div.scr').stop().hide(); } } My issue is that when I toggle the last li element to display, the h3 element contents disapear, until I click somewhere else on the page, or scroll the page up and down to cause the browse to repaint that portion of the window. I don't get this behavior in Opera for example, and even in IE the behavior only happens on the last li element, so I'm pretty sure it's an IE quirk and not my code. Is there any workaround I can do through jquery/javascript to force it to repaint the h3 element?

  Read the article

• Regular expression test can't decide between true and false (JavaScript)

  - by nw

  I get this behavior in both Chrome (Developer Tools) and Firefox (Firebug). Note the regex test returns alternating true/false values: > var re = /.*?\bbl.*\bgr.*/gi; undefined > re /.*?\\bbl.*\\bgr.*/gi > re.test("Blue-Green"); true > re.test("Blue-Green"); false > re.test("Blue-Green"); true > re.test("Blue-Green"); false However, testing the same regex as a literal: > /.*?\bbl.*\bgr.*/gi.test("Blue-Green"); true > /.*?\bbl.*\bgr.*/gi.test("Blue-Green"); true > /.*?\bbl.*\bgr.*/gi.test("Blue-Green"); true > /.*?\bbl.*\bgr.*/gi.test("Blue-Green"); true I can't explain this and it's making debugging very difficult. Can anyone explain this behavior?

  Read the article

• .NET framework execution aborted while executing CLR stored procedure?

  - by Sean Ochoa

  I constructed a stored procedure that does the equivalent of FOR XML AUTO in SQL Server 2008. Now that I'm testing it, it gives me a really unhelpful error message. What does this error mean? Msg 10329, Level 16, State 49, Procedure ForXML, Line 0 .NET Framework execution was aborted. System.Threading.ThreadAbortException: Thread was being aborted. System.Threading.ThreadAbortException: at System.Runtime.InteropServices.Marshal.PtrToStringUni(IntPtr ptr, Int32 len) at System.Data.SqlServer.Internal.CXVariantBase.WSTRToString() at System.Data.SqlServer.Internal.SqlWSTRLimitedBuffer.GetString(SmiEventSink sink) at System.Data.SqlServer.Internal.RowData.GetString(SmiEventSink sink, Int32 i) at Microsoft.SqlServer.Server.ValueUtilsSmi.GetValue(SmiEventSink_Default sink, ITypedGettersV3 getters, Int32 ordinal, SmiMetaData metaData, SmiContext context) at Microsoft.SqlServer.Server.ValueUtilsSmi.GetValue200(SmiEventSink_Default sink, SmiTypedGetterSetter getters, Int32 ordinal, SmiMetaData metaData, SmiContext context) at System.Data.SqlClient.SqlDataReaderSmi.GetValue(Int32 ordinal) at System.Data.SqlClient.SqlDataReaderSmi.GetValues(Object[] values) at System.Data.ProviderBase.DataReaderContainer.CommonLanguageSubsetDataReader.GetValues(Object[] values) at System.Data.ProviderBase.SchemaMapping.LoadDataRow() at System.Data.Common.DataAdapter.FillLoadDataRow(SchemaMapping mapping) at System.Data.Common.DataAdapter.FillFromReader(DataSet dataset, DataTable datatable, String srcTable, DataReaderContainer dataReader, Int32 startRecord, Int32 maxRecords, DataColumn parentChapterColumn, Object parentChapterValue) at System.Data.Common.DataAdapter.Fill(DataTable[] dataTables, IDataReader dataReader, Int32 startRecord, Int32 maxRecords) at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataTable[] dataTables, Int32 startRecord, Int32 maxRecords, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataTable dataTable) at ForXML.GetXML...

  Read the article

• Modules vs. Classes and their influence on descendants of ActiveRecord::Base

  - by Chris

  Here's a Ruby OO head scratcher for ya, brought about by this Rails scenario: class Product < ActiveRecord::Base has_many(:prices) # define private helper methods end module PrintProduct attr_accessor(:isbn) # override methods in ActiveRecord::Base end class Book < Product include PrintProduct end Product is the base class of all products. Books are kept in the products table via STI. The PrintProduct module brings some common behavior and state to descendants of Product. Book is used inside fields_for blocks in views. This works for me, but I found some odd behavior: After form submission, inside my controller, if I call a method on a book that is defined in PrintProduct, and that method calls a helper method defined in Product, which in turn calls the prices method defined by has_many, I'll get an error complaining that Book#prices is not found. Why is that? Book is a direct descendant of Product! More interesting is the following.. As I developed this hierarchy PrintProduct started to become more of an abstract ActiveRecord::Base, so I thought it prudent to redefine everything as such: class Product < ActiveRecord::Base end class PrintProduct < Product end class Book < PrintProduct end All method definitions, etc. are the same. In this case, however, my web form won't load because the attributes defined by attr_accessor (which are "virtual attributes" referenced by the form but not persisted in the DB) aren't found. I'll get an error saying that there is no method Book#isbn. Why is that?? I can't see a reason why the attr_accessor attributes are not found inside my form's fields_for block when PrintProduct is a class, but they are found when PrintProduct is a Module. Any insight would be appreciated. I'm dying to know why these errors are occurring!

  Read the article

• Is the C++ compiler optimizer allowed to break my destructor ability to be called multiple times?

  - by sharptooth

  We once had an interview with a very experienced C++ developer who couldn't answer the following question: is it necessary to call the base class destructor from the derived class destructor in C++? Obviously the answer is no, C++ will call the base class destructor automagically anyway. But what if we attempt to do the call? As I see it the result will depend on whether the base class destructor can be called twice without invoking erroneous behavior. For example in this case: class BaseSafe { public: ~BaseSafe() { } private: int data; }; class DerivedSafe { public: ~DerivedSafe() { BaseSafe::~BaseSafe(); } }; everything will be fine - the BaseSafe destructor can be called twice safely and the program will run allright. But in this case: class BaseUnsafe { public: BaseUnsafe() { buffer = new char[100]; } ~BaseUnsafe () { delete[] buffer; } private: char* buffer; }; class DerivedUnsafe { public: ~DerivedUnsafe () { BaseUnsafe::~BaseUnsafe(); } }; the explicic call will run fine, but then the implicit (automagic) call to the destructor will trigger double-delete and undefined behavior. Looks like it is easy to avoid the UB in the second case. Just set buffer to null pointer after delete[]. But will this help? I mean the destructor is expected to only be run once on a fully constructed object, so the optimizer could decide that setting buffer to null pointer makes no sense and eliminate that code exposing the program to double-delete. Is the compiler allowed to do that?

  Read the article

• UIAlertView Will not show

  - by John

  I have a program that is requesting a JSON string. I have created a class that contains the connect method below. When the root view is coming up, it does a request to this class and method to load up some data for the root view. When I test the error code (by changing the URL host to 127.0.0.1), I expect the Alert to show. Behavior is that the root view just goes black, and the app aborts with no alert. No errors in debug mode on the console, either. Any thoughts as to this behavior? I've been looking around for hints to this for hours to no avail. Thanks in advance for your help. Note: the conditional for (error) is called, as well as the UIAlertView code. - (NSString *)connect:(NSString *)urlString { NSString *jsonString; UIApplication *app = [UIApplication sharedApplication]; app.networkActivityIndicatorVisible = YES; NSError *error = nil; NSURLResponse *response = nil; NSURL *url = [[NSURL alloc] initWithString:urlString]; NSURLRequest *req = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:10]; NSData *_response = [NSURLConnection sendSynchronousRequest: req returningResponse: &response error: &error]; if (error) { /* inform the user that the connection failed */ //AlertWithMessage(@"Connection Failed!", message); UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Oopsie!" message:@"Unable to connect! Try later, thanks." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil]; [alert show]; [alert release]; } else { jsonString = [[[NSString alloc] initWithData:_response encoding:NSUTF8StringEncoding] autorelease]; } app.networkActivityIndicatorVisible = NO; [url release]; return jsonString; }

  Read the article

• What's the best way to communicate the purpose of a string parameter in a public API?

  - by Dave

  According to the guidance published in New Recommendations for Using Strings in Microsoft .NET 2.0, the data in a string may exhibit one of the following types of behavior: A non-linguistic identifier, where bytes match exactly. A non-linguistic identifier, where case is irrelevant, especially a piece of data stored in most Microsoft Windows system services. Culturally-agnostic data, which still is linguistically relevant. Data that requires local linguistic customs. Given that, I'd like to know the best way to communicate which behavior is expected of a string parameter in a public API. I wasn't able to find an answer in the Framework Design Guidelines. Consider the following methods: f(string this_is_a_linguistic_string) g(string this_is_a_symbolic_identifier_so_use_ordinal_compares) Is variable naming and XML documentation the best I can do? Could I use attributes in some way to mark the requirements of the string? Now consider the following case: h(Dictionary<string, object> dictionary) Note that the dictionary instance is created by the caller. How do I communicate that the callee expects the IEqualityComparer<string> object held by the dictionary to perform, for example, a case-insensitive ordinal comparison?

  Read the article

• Why strings behave like ValueType

  - by AJP

  I was perplexed after executing this piece of code, where strings seems to behave as if they are value types. I am wondering whether the assignment operator is operating on values like equality operator for strings. Here is the piece of code I did to test this behavior. using System; namespace RefTypeDelimma { class Program { static void Main(string[] args) { string a1, a2; a1 = "ABC"; a2 = a1; //This should assign a1 reference to a2 a2 = "XYZ"; //I expect this should change the a1 value to "XYZ" Console.WriteLine("a1:" + a1 + ", a2:" + a2);//Outputs a1:ABC, a2:XYZ //Expected: a1:XYZ, a2:XYZ (as string being a ref type) Proc(a2); //Altering values of ref types inside a procedure //should reflect in the variable thats being passed into Console.WriteLine("a1: " + a1 + ", a2: " + a2); //Outputs a1:ABC, a2:XYZ //Expected: a1:NEW_VAL, a2:NEW_VAL (as string being a ref type) } static void Proc(string Val) { Val = "NEW_VAL"; } } } In the above code if I use a custom classes instead of strings, I am getting the expected behavior. I doubt is this something to do with the string immutability? welcoming expert views on this.

  Read the article

• Function Returning Negative Value

  - by Geowil

  I still have not run it through enough tests however for some reason, using certain non-negative values, this function will sometimes pass back a negative value. I have done a lot of manual testing in calculator with different values but I have yet to have it display this same behavior. I was wondering if someone would take a look at see if I am missing something. float calcPop(int popRand1, int popRand2, int popRand3, float pERand, float pSRand) { return ((((((23000 * popRand1) * popRand2) * pERand) * pSRand) * popRand3) / 8); } The variables are all contain randomly generated values: popRand1: between 1 and 30 popRand2: between 10 and 30 popRand3: between 50 and 100 pSRand: between 1 and 1000 pERand: between 1.0f and 5500.0f which is then multiplied by 0.001f before being passed to the function above Edit: Alright so after following the execution a bit more closely it is not the fault of this function directly. It produces an infinitely positive float which then flips negative when I use this code later on: pPMax = (int)pPStore; pPStore is a float that holds popCalc's return. So the question now is, how do I stop the formula from doing this? Testing even with very high values in Calculator has never displayed this behavior. Is there something in how the compiler processes the order of operations that is causing this or are my values simply just going too high? If the later I could just increase the division to 16 I think.

  Read the article

< Previous Page | 94 95 96 97 98 99 100 101 102 103 104 105  | Next Page >