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• How to not persist NSManagedObjects retrieved from NSManagedObjectContext

  - by RickiG

  Hi I parse an xml file containing books, for each new node I go: Book *book = (Book*)[NSEntityDescription insertNewObjectForEntityForName:@"Book" inManagedObjectContext:managedObjectContext]; To obtain an NSManagedObject of my Core Data Book Entity, I then proceed to populate the managed Book object with data, add it to an array, rinse, repeat. When I am done, I present the list of books to the user. I have not yet executed the save: NSError *error; if (![managedObjectContext save:&error]) { NSLog(@"%@", [error domain]); } The user now selects one of the books, this one I would like to persist, but only this one, all the other books are of no interest to me any more. The Book Entity does not have/or is part of any relationships. It is just a "single" Entity. If I pull the "save lever" every Book object will be persisted and I will have to delete everything but my desired one. How would I get around this challenge, I can't really seem to find that particular use-case in the Core Data Programming Guide, which sort of also bugs me a bit, am I going against best practice here? Thanks for any help given.

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• Does RabbitMq do round-robin from the exchange to the queues

  - by Lancelot

  Hi, I am currently evaluating message queue systems and RabbitMq seems like a good candidate, so I'm digging a little more into it. To give a little context I'm looking to have something like one exchange load balancing the message publishing to multiple queues. I don't want to replicate the messages, so a fanout exchange is not an option. Also the reason I'm thinking of having multiple queues vs one queue handling the round-robin w/ the consumers, is that I don't want our single point of failure to be at the queue level. Sounds like I could add some logic on the publisher side to simulate that behavior by editing the routing key and having the appropriate bindings in place. But that's kind of a passive approach that wouldn't take the pace of the message consumption on each queue into account, potentially leading to fill up one queue if the consumer applications for that queue are dead. I was looking for a more pro-active way from the exchange entity side, that would decide where to send the next message based on each queue size or something of that nature. I read about Alice and the available RESTful APIs but that seems kind of a heavy duty solution to implement fast routing decisions. Anyone knows if round-robin between the exchange the queues is feasible w/ RabbitMQ then? Thanks.

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• How to Convert using of SqlLit to Simple SQL command in C#

  - by Nasser Hajloo

  I want to get start with DayPilot control I do not use SQLLite and this control documented based on SQLLite. I want to use SQL instead of SQL Lite so if you can, please do this for me. main site with samples http://www.daypilot.org/calendar-tutorial.html The database contains a single table with the following structure CREATE TABLE event ( id VARCHAR(50), name VARCHAR(50), eventstart DATETIME, eventend DATETIME); Loading Events private DataTable dbGetEvents(DateTime start, int days) { SQLiteDataAdapter da = new SQLiteDataAdapter("SELECT [id], [name], [eventstart], [eventend] FROM [event] WHERE NOT (([eventend] <= @start) OR ([eventstart] >= @end))", ConfigurationManager.ConnectionStrings["db"].ConnectionString); da.SelectCommand.Parameters.AddWithValue("start", start); da.SelectCommand.Parameters.AddWithValue("end", start.AddDays(days)); DataTable dt = new DataTable(); da.Fill(dt); return dt; } Update private void dbUpdateEvent(string id, DateTime start, DateTime end) { using (SQLiteConnection con = new SQLiteConnection(ConfigurationManager.ConnectionStrings["db"].ConnectionString)) { con.Open(); SQLiteCommand cmd = new SQLiteCommand("UPDATE [event] SET [eventstart] = @start, [eventend] = @end WHERE [id] = @id", con); cmd.Parameters.AddWithValue("id", id); cmd.Parameters.AddWithValue("start", start); cmd.Parameters.AddWithValue("end", end); cmd.ExecuteNonQuery(); } }

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• Nonblocking Tcp server

  - by hoodoos

  It's not a question really, i'm just looking for some guidelines :) I'm currently writing some abstract tcp server which should use as low number of threads as it can. Currently it works this way. I have a thread doing listening and some worker threads. Listener thread is just sits and wait for clients to connect I expect to have a single listener thread per server instance. Worker threads are doing all read/write/processing job on clients socket. So my problem is in building efficient worker process. And I came to some problem I can't really solve yet. Worker code is something like that(code is really simple just to show a place where i have my problem): List<Socket> readSockets = new List<Socket>(); List<Socket> writeSockets = new List<Socket>(); List<Socket> errorSockets = new List<Socket>(); while( true ){ Socket.Select( readSockets, writeSockets, errorSockets, 10 ); foreach( readSocket in readSockets ){ // do reading here } foreach( writeSocket in writeSockets ){ // do writing here } // POINT2 and here's the problem i will describe below } it works all smothly accept for 100% CPU utilization because of while loop being cycling all over again, if I have my clients doing send-receive-disconnect routine it's not that painful, but if I try to keep alive doing send-receive-send-receive all over again it really eats up all CPU. So my first idea was to put a sleep there, I check if all sockets have their data send and then putting Thread.Sleep in POINT2 just for 10ms, but this 10ms later on produces a huge delay of that 10ms when I want to receive next command from client socket.. For example if I don't try to "keep alive" commands are being executed within 10-15ms and with keep alive it becomes worse by atleast 10ms :( Maybe it's just a poor architecture? What can be done so my processor won't get 100% utilization and my server to react on something appear in client socket as soon as possible? Maybe somebody can point a good example of nonblocking server and architecture it should maintain?

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• Complex data types in WCF?

  - by Hojou

  I've run into a problem trying to return an object that holds a collection of childobjects that again can hold a collection of grandchild objects. I get an error, 'connection forcibly closed by host'. Is there any way to make this work? I currently have a structure resembling this: pseudo code: Person: IEnumerable<Order> Order: IEnumberable<OrderLine> All three objects have the DataContract attribute and all public properties i want exposed (including the IEnumerable's) have the DataMember attribute. I have multiple OperationContract's on my service and all the methods returning a single object OR an IEnumerable of an object works perfectly. It's only when i try to nest IEnumerable that it turns bad. Also in my client service reference i picked the generic list as my collection type. I just want to emphasize, only one of my operations/methods fail with this error - the rest of them work perfectly. EDIT (more detailed error description): [SocketException (0x2746): An existing connection was forcibly closed by the remote host] [IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.] [WebException: The underlying connection was closed: An unexpected error occurred on a receive.] [CommunicationException: An error occurred while receiving the HTTP response to http://myservice.mydomain.dk/MyService.svc. This could be due to the service endpoint binding not using the HTTP protocol. This could also be due to an HTTP request context being aborted by the server (possibly due to the service shutting down). See server logs for more details.] I tried looking for logs but i can't find any... also i'm using a WSHttpBinding and an http endpoint.

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• Visual Studio project using the Quality Center API remains in memory

  - by Traveling Tech Guy

  Hi, Currently developing a connector DLL to HP's Quality Center. I'm using their (insert expelative) COM API to connect to the server. An Interop wrapper gets created automatically by VStudio. My solution has 2 projects: the DLL and a tester application - essentially a form with buttons that call functions in the DLL. Everything works well - I can create defects, update them and delete them. When I close the main form, the application stops nicely. But when I call a function that returns a list of all available projects (to fill a combo box), if I close the main form, VStudio still shows the solution as running and I have to stop it. I've managed to pinpoint a single function in my code that when I call, the solution remains "hung" and if I don't, it closes well. It's a call to a property in the TDC object get_VisibleProjects that returns a List (not the .Net one, but a type in the COM library) - I just iterate over it and return a proper list (that I later use to fill the combo box): public List<string> GetAvailableProjects() { List<string> projects = new List<string>(); foreach (string project in this.tdc.get_VisibleProjects(qcDomain)) { projects.Add(project); } return projects; } My assumption is that something gets retained in memory. If I run the EXE outside of VStudio it closes - but who knows what gets left behind in memory? My question is - how do I get rid of whatever calling this property returns? Shouldn't the GC handle this? Do I need to delve into pointers? Things I've tried: getting the list into a variable and setting it to null at the end of the function Adding a destructor to the class and nulling the tdc object Stepping through the tester function application all the way out, whne the form closes and the Main function ends - it closes, but VStudio still shows I'm running. Thanks for your assistance!

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• simple Stata program

  - by Cyrus S

  I am trying to write a simple program to combine coefficient and standard error estimates from a set of regression fits. I run, say, 5 regressions, and store the coefficient(s) and standard error(s) of interest into vectors (Stata matrix objects, actually). Then, I need to do the following: Find the mean value of the coefficient estimates. Combine the standard error estimates according to the formula suggested for combining results from "multiple imputation". The formula is the square root of the formula for "T" on page 6 of the following document: http://bit.ly/b05WX3 I have written Stata code that does this once, but I want to write this as a function (or "program", in Stata speak) that takes as arguments the vector (or matrix, if possible, to combine multiple estimates at once) of regression coefficient estimates and the vector (or matrix) of corresponding standard error estimates, and then generates 1 and 2 above. Here is the code that I wrote: (breg is a 1x5 vector of the regression coefficient estimates, and sereg is a 1x5 vector of the associated standard error estimates) mat ones = (1,1,1,1,1) mat bregmean = (1/5)*(ones*breg’) scalar bregmean_s = bregmean[1,1] mat seregmean = (1/5)*(ones*sereg’) mat seregbtv = (1/4)*(breg - bregmean#ones)* (breg - bregmean#ones)’ mat varregmi = (1/5)*(sereg*sereg’) + (1+(1/5))* seregbtv scalar varregmi_s = varregmi[1,1] scalar seregmi = sqrt(varregmi_s) disp bregmean_s disp seregmi This gives the right answer for a single instance. Any pointers would be great! UPDATE: I completed the code for combining estimates in a kXm matrix of coefficients/parameters (k is the number of parameters, m the number of imputations). Code can be found here: http://bit.ly/cXJRw1 Thanks to Tristan and Gabi for the pointers.

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• Android:Multi touch doesn't work as expected?

  - by user187532

  Hi folks, Help me in resolving the below issue. I have three image buttons on screen. All these three buttons controlled under ontouchlistner as below. buttonOne.setOnTouchListener(this); buttonTwo.setOnTouchListener(this); buttonThree.setOnTouchListener(this); I override "public boolean onTouch(View v, MotionEvent event)". Under this i check for these three image buttons touch events like below. ImageButton imageBtn = (ImageButton) v; if ( imageBtn == buttonOne ) // first button touch ..Log.. else if ( imageBtn == buttonTwo ) ..Log.. else if ( imageBtn == buttonThree ) // first button touch ..Log.. My problem is, as it is under multi touch event handler like above, it does not detect when touch all three button at a time to try to produce multi touch effect, instead it detects only one imagebutton touch at a time even though i touch all three image buttons. As i am developing this project on Android 1.6 SDK, is there any problem accessing my requirement(multi touch) (or) it is a known issue? I am hoping that, when it works for single button touch, why shouldn't it work when clicking three imagebuttons at a time to produce three logs printed as per my above code? How do i resolve it for my case? Please don't question me why i am still developing on 1.6 for such a requirement. Thank you. Appreciate your suggestions !

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• C# wrapper and Callbacks

  - by fergs

  I'm in the process of writing a C# wrapper for Dallmeier Common API light (Camera & Surviellance systems) and I've never written a wrapper before, but I have used the Canon EDSDK C# wrapper. So I'm using the Canon wrapper as a guide to writing the Dallmeier wrapper. I'm currently having issues with wrapping a callback. In the API manual it has the following: dlm_connect int(unsigned long uLWindowHandle, const char * strIP, const char* strUser1, const char* strPwd1, const char* strUser2, const char* strPwd2, void (*callback)(void *pParameters, void *pResult, void *pInput), void * pInput) Arguments - ulWindowhandle - handle of the window that is passed to the ViewerSDK to display video and messages there - strUser1/2 - names of the users to log in. If only single user login is used strUser2 is - NULL - strPwd1/2 - passwords of both users. If strUser2 is NULL strPwd2 is ignored. Return This function creates a SessionHandle that has to be passed Callback pParameters will be structured: - unsigned long ulFunctionID - unsigned long ulSocketHandle, //handle to socket of the established connection - unsigned long ulWindowHandle, - int SessionHandle, //session handle of the session created - const char * strIP, - const char* strUser1, - const char* strPwd1, - const char* strUser2, - const char * strPWD2 pResult is a pointer to an integer, representing the result of the operation. Zero on success. Negative values are error codes. So from what I've read on the Net and Stack Overflow - C# uses delegates for the purpose of callbacks. So I create a my Callback function : public delegate uint DallmeierCallback(DallPparameters pParameters, IntPtr pResult, IntPtr pInput); I create the connection function [DllImport("davidapidis.dll")] public extern static int dlm_connect(ulong ulWindowHandle, string strIP, string strUser1, string strPwd1, string strUser2, string strPwd2, DallmeierCallback inDallmeierFunc And (I think) the DallPParameters as a struct : [StructLayout(LayoutKind.Sequential)] public struct DallPParameters { public ulong ulfunctionID; public ulong ulsocketHandle; public ulong ulWindowHandle; ... } All of this is in my wrapper class. Am I heading in the right direction or is this completely wrong?

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• Mapping parent-child relationships with iBatis

  - by agnul

  I have the classic setup public class Parent { Integer id; ... // No generics Collection someCollectionAttribute; ... public void setChildren(Collection c) { ... } } public class Child { Integer id; ... } and I'm trying to map this on the usual table setup using iBatis (version 2.30... don't ask). create table parents ( ID integer primary key ... ) create table children ( ID integer primary key PARENT_ID integer references parents(id) ... ) My mapping file looks like this <resultMap id="ParentResult" groupBy="id"> <result property="id" column="ID" /> ... <result property="children" resultMap="ChildResult" /> </resultMap> <resultMap id="ChildResult"> <result property="id" column="ID" /> <result property="parentId" column="PARENT_ID" /> ... </result> <sql id="loadParent" resultMap="ParentResult"> select P.ID as p1, ..., C.ID as c1, C.PARENT_ID as c2 ... from parents P join children C on (P.ID = C.PARENT_ID) where P.ID = #id# order by P.ID </sql> Doing the usual sqlMap.queryForObject("loadParent", new Integer(42)) at first caused a NullPointerException inside the setChildren setter which apparently is called with a null argument (my bad). Fixing the setter everything works fine, but the logs show that setChildren is called only once before even running a single SQL statement, still with a null argument, so I'm wondering what's going on here. Anyone has any clues?

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• Java Simple Chat Box

  - by Allen

  I am trying to create a very simple chat window that simply has the ability to display some text, which i add to from time to time. However I get the following run time error when attempting to append text to the window: java.lang.ClassCastException: javax.swing.JViewport cannot be cast to javax.swing.JTextPane at ChatBox.getTextPane(ChatBox.java:41) at ChatBox.getDocument(ChatBox.java:45) at ChatBox.addMessage(ChatBox.java:50) at ImageTest2.main(ImageTest2.java:160) Here is the class to handle the basic operations: public class ChatBox extends JScrollPane { private Style style; public ChatBox() { StyleContext context = new StyleContext(); StyledDocument document = new DefaultStyledDocument(context); style = context.getStyle(StyleContext.DEFAULT_STYLE); StyleConstants.setAlignment(style, StyleConstants.ALIGN_LEFT); StyleConstants.setFontSize(style, 14); StyleConstants.setSpaceAbove(style, 4); StyleConstants.setSpaceBelow(style, 4); JTextPane textPane = new JTextPane(document); textPane.setEditable(false); this.add(textPane); } public JTextPane getTextPane() { return (JTextPane) this.getComponent(0); } public StyledDocument getDocument() { return (StyledDocument) getTextPane().getStyledDocument(); } public void addMessage(String speaker, String message) { String combinedMessage = speaker + ": " + message; StyledDocument document = getDocument(); try { document.insertString(document.getLength(), combinedMessage, style); } catch (BadLocationException badLocationException) { System.err.println("Oops"); } } } if there is a simpler way to do this, by all means let me know. I only need the text to be of a single font type, and uneditable by the user. Aside from that, I just need to be able to append text on the fly.

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• Proving f (f bool) = bool

  - by Marcus Whybrow

  How can I in coq, prove that a function f that accepts a bool true|false and returns a bool true|false (shown below), when applied twice to a single bool true|false would always return that same value true|false: (f:bool -> bool) For example the function f can only do 4 things, lets call the input of the function b: Always return true Always return false Return b (i.e. returns true if b is true vice versa) Return not b (i.e. returns false if b is true and vice vera) So if the function always returns true: f (f bool) = f true = true and if the function always return false we would get: f (f bool) = f false = false For the other cases lets assum the function returns not b f (f true) = f false = true f (f false) = f true = false In both possible input cases, we we always end up with with the original input. The same holds if we assume the function returns b. So how would you prove this in coq? Goal forall (f:bool -> bool) (b:bool), f (f b) = f b.

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• What is the most important thing you weren't taught in school?

  - by Alexandre Brisebois

  What is the most important thing you weren't taught in school? What topics are missing from the CS/IS education? Posted so far How to sell an idea Principles: Often, good enough is better than perfect. Making mistakes is actually a Good Thing™ -- as long as they're new mistakes. If a user can break your code they will. In the Real World™ they're all open-book exams Self confidence is way more important in getting ahead than intelligence. Always prefer simplicity over complexity. The best code is the code that you don't write. You never know when you'll meet someone again ... or where. It's always worthwhile to treat people with respect and kindness. Be aware of what you don't know and don't be afraid to ask questions when you need to Missing knowledge: How to communicate effectively. Lack of source control Lack of Softskills experience How to productize code How to write secure code How to formulate problems How to self-measurement. To evaluate ones true competences and market worth. How to debug code How important is backup How to read code on a large scale (being able to adapt and build upon existing projects) Good Regular expressions comprehension How to teach others effectively TDD/Unit testing Critical thinking How to integrate different skills and languages in a single project

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• Mutability design patterns in Objective C and C++

  - by Mac

  Having recently done some development for iPhone, I've come to notice an interesting design pattern used a lot in the iPhone SDK, regarding object mutability. It seems the typical approach there is to define an immutable class NSFoo, and then derive from it a mutable descendant NSMutableFoo. Generally, the NSFoo class defines data members, getters and read-only operations, and the derived NSMutableFoo adds on setters and mutating operations. Being more familiar with C++, I couldn't help but notice that this seems to be a complete opposite to what I'd do when writing the same code in C++. While you certainly could take that approach, it seems to me that a more concise approach is to create a single Foo class, mark getters and read-only operations as const functions, and also implement the mutable operations and setters in the same class. You would then end up with a mutable class, but the types Foo const*, Foo const& etc all are effectively the immutable equivalent. I guess my question is, does my take on the situation make sense? I understand why Objective-C does things differently, but are there any advantages to the two-class approach in C++ that I've missed? Or am I missing the point entirely? Not an overly serious question - more for my own curiosity than anything else.

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• Is there more to HTML forms than http://www.w3schools.com/html/html_forms.asp ?

  - by mawg

  I am creating a form designer. It will generate PHP code which will produce an HTML form. Users will fill in fields and the PHP will store user input in a MySql database (and, of course, they can use the designer to generate forms which query the database). I am using Borland C++ Builder (very similar to Delphi & and you can get the same idea from VB, MSVC, Qt ... any IDE with a RAD GUI designer). Looking at the W3C page http://www.w3schools.com/html/html_forms.asp it seems that the components I can use for my form and retrieve data from are - edit box / TEdit / <input type="text" - memo / TMemo / <input type="textarea" - check box / TCheckBox / <input type="CheckBox" - Combo box / TComboBox / <select ... <option... - Radio group / TRadioGroup / <input type="radio" - Group box / TGroupBox / <fieldset ... <legend ... - Panel / TPanel / <fieldset ... I am unsure whether to allow button / TButton/ input type="button" - other than a single submit button which my form designer program automatically adds to the end of the generated form. But my real question is - did I miss any? It might be nice to have masked edit which only accepts numbers, or maybe some form of "spin control" (TUpDown, or slider + linked read only TEdit), so that the user can click & hold to increment/decrement an integer value. And a calendar component would be nice. Very important: I want to implement it all server-side in PHP, so no client-side JS or Ajax or the likes. If there anything else that I can add to make my generated forms look more impressive in the browser?

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• Creating a WCF ServiceHost object takes three to four minutes on some PCs

  - by Steve

  Hello, I have created a WCF service which does not use the app.config to configure itself. However, it takes three to four minutes on some PCs to construct the ServiceHost object. Thinking there was something wrong with my service, I constructed a simple Hello, World service and tried it with that. I have the same issue. According to the profiler, all this time is spent reading in configuration for the service. So I have two questions really. Is it possible to disable reading config from the XML? More importantly, does anyone have any idea why this might be taking such an inordinate amount of time? Here is the sample service: [ServiceContract] public interface IMyService { [OperationContract] string GetString(); } [ServiceBehavior(InstanceContextMode=InstanceContextMode.Single)] public class MyService : IMyService { public string GetString() { return "Hello, world!"; } } class Program { static void Main(string[] args) { Uri epAddress = new Uri("http://localhost:8731/Test"); Uri[] uris = new Uri[] { epAddress }; MyService srv = new MyService(); ServiceHost host = new ServiceHost(srv, uris); // this line takes 3-4 minutes host.AddServiceEndpoint(typeof(IMyService), new WSHttpBinding(), "Test"); ServiceMetadataBehavior smb = new ServiceMetadataBehavior(); smb.HttpGetEnabled = true; host.Description.Behaviors.Add(smb); host.Open(); return; } } I need for design reasons to create the service and pass it in as an object, rather than passing it in as a type. If there's any more information that can be of use, please let me know. Many thanks.

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• Plot in GNU PLOT

  - by guddi

  I have to plot many lines in GNU PLOT.No problem with the X axis. The problem that I am facing is that most of the plotted lines are at yscale [0-0.05] ,few at range 60-70 and rest at 600-700. These numbers correspond to the y axis scale values. But after I plot I can see only 3 sets of lines all messed up. There is no clearity between the lines. Line at 0 and the line at 0.003 look like one single line. If I set yrange[0:0.05], the lines between this range are clearly vissible. But I want all the lines in the same graph. I have heard of breaking axis's and multi plotting..Can they be useful? how to implement them. Anyone pls help me. Below is the sript set terminal png size 1300,1200 enhanced font 'Verdana,20 set output ' output .png’ set key font 'Verdana,16' set key bottom outside set yrange[500:1000] set xtics("25k" 25000,"50k" 50000,"75k" 75000,"100k" 100000) set grid set title 'Performance Metrics' set ylabel 'Metrices' set xlabel 'FES' plot ' input ' using 1:2 title ' A' with linespoints linewidth 4, ' input ' using 1:3 title B'with linespoints linewidth 4, 'input ' using 1:4 title ' c' with linespoints linewidth 4, 'input ' using 1:5 title 'D' with linespoints linewidth 4, ' input ' using 1:6 title 'E' with linespoints linewidth 4, ' input ' using 1:7 title 'F' with linespoints linewidth 4, ' input ' using 1:8 title 'G' with linespoints linewidth 4, ' input ' using 1:9 title ' H ' with linespoints linewidth 4, ' input ' using 1:10 title ' I' Metric ' with linespoints linewidth 4 set output set terminal windows input.dat is something like this: 25 0.002 0.05 899 455 444 0.08 0.00004 900 700 0.003 This way i have other rows. I have shown only the first one

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• ASP.NET MVC Concurrency with RowVersion in Edit Action

  - by Jorin

  I'm wanting to do a simple edit form for our Issue Tracking app. For simplicity, the HttpGet Edit action looks something like this: // Issues/Edit/12 public ActionResult Edit(int id) { var thisIssue = edmx.Issues.First(i => i.IssueID == id); return View(thisIssue); } and then the HttpPost action looks something like this: [HttpPost] public ActionResult Edit(int id, FormCollection form) { // this is the dumb part where I grab the object before I update it. // concurrency is sidestepped here. var thisIssue = edmx.Issues.Single(c => c.IssueID == id); TryUpdateModel(thisIssue); if (ModelState.IsValid) { edmx.SaveChanges(); TempData["message"] = string.Format("Issue #{0} successfully modified.", id); return RedirectToAction("Index"); } return View(thisIssue); } Which works wonderfully. However, the concurrency check doesn't work because in the Post, I'm re-retreiving the current entity right before I attempt to update it. However, with EF, I don't know how to use the fanciness of SaveChanges() but attach my thisIssue to the context. I tried to call edmx.Issues.Attach(thisIssue) but I get The object cannot be attached because it is already in the object context. An object can only be reattached when it is in an unchanged state. How do I handle concurrency in MVC with EF and/or how do I properly Attach my edited object to the context? Thanks in advance

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• function getting wrong values

  - by frankie

  so i have this function in C to calculate a power, and i'm using visual c++ 2010 power.h void power(); float get_power(float a, int n); power.c void power() { float a, r; int n; printf("-POWER-\n"); printf("The base: "); scanf("%f", &a); n = -1; while (n < 0) { printf("The power: "); scanf("%d", &n); if (n < 0) { printf("Power must be equal or larger than 0!\n"); } else { r = get_power(a, n); printf("%.2f ^ %d = %.2f", a, n, r); } }; } float get_power(float a, int n) { if (n == 0) { return 1; } return a * get_power(a, n-1); } not the best way to do it, i know, but that's not it when i debug it the values are scanned correctly (that is, the values are correct until just before the function call) but then upon entering the function a becomes 0 and n becomes 1074790400, and you can guess what happens next... the first function is being called from the main file, i included the full code because i really have no idea what could be going on, and i can't even think on how to google for it... strangely, i wrote the function in a single file and it works fine, but it definitely should work both ways any idea why this is happening?

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• Android Runtime Layout Tutorial

  - by Ryan

  Does anyone know how to perform or have a good reference for doing an activity layout at runtime in android? Here is the code for my activity. I'm sure I'm just neglecting to do something here: package com.isi.sa; import android.app.Activity; import android.os.Bundle; import android.widget.LinearLayout; import android.widget.TextView; public class SimpleAssessmentTest extends Activity { LinearLayout layout; TextView question; @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); layout = new LinearLayout(this); question = new TextView(this); layout.setBackgroundColor(R.color.black); question.setTextColor(R.color.white); question.setText("This is question1"); layout.addView(question); } } As you can see I'm just trying to add a linear layout with a single text view (just for testing purposes) however, when the activity starts I just get a black screen with a title bar of my app name. Thanks

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• Sql Querying, group relationships

  - by Jordan

  Hi, Suppose I have two tables: Group ( id integer primary key, someData1 text, someData2 text ) GroupMember ( id integer primary key, group_id foreign key to Group.id, someData text ) I'm aware that my SQL syntax is not correct :) Hopefully is clear enough. My problem is this: I want to load a group record and all the GroupMember records associated with that group. As I see it, there are two options. A single query: SELECT Group.id, Group.someData1, Group.someData2 GroupMember.id, GroupMember.someData FROM Group INNER JOIN GroupMember ... WHERE Group.id = 4; Two queries: SELECT id, someData2, someData2 FROM Group WHERE id = 4; SELECT id, someData FROM GroupMember WHERE group_id = 4; The first solution has the advantage of only being one database round trip, but has the disadvantage of returning redundant data (All group data is duplicated for every group member) The second solution returns no duplicate data but involves two round trips to the database. What is preferable here? I suppose there's some threshold such that if the group sizes become sufficiently large, the cost of returning all the redundant data is going to be greater than the overhead involved with an additional database call. What other things should I be thinking about here? Thanks, Jordan

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• Broken tables in RichTextBox control (word wrap)

  - by Ben Robbins

  We are having problems with the Windows.Forms.RichTextBox control in Visual Studio 2008. We are trying to display text supplied as an RTF file by a 3rd party in a windows forms application (.NET 3.5). In this RTF text file there are tables, which contain text that spans multiple lines. The RTF file displays correctly when opened with either WordPad or Word 2003. However, when we load the RTF file into the RichTextBox control, or copy & paste the whole text (including the table) into the control, the table does not display correctly - the cells are only single line, without wrapping. Here are links to images showing the exact problem: Correctly displayed in WordPad Incorrectly displayed in RichTextBox control I have googled for solutions and 3rd party .net RTF controls without success. I have found this exact problem asked on another forum without an answer (in fact that's where the link to the images come from) so I'm hoping stack overflow does better ;-) My preferred solution would be to use code or a 3rd party control that can correctly render the RTF. However, I suspect the problem is that the RichTextBox control only supports a subset of the full RTF spec, so another option would be to modify the RTF directly to remove the unsupported control codes or otherwise fix the RTF file itself (in which case any information as to what control codes need to be removed or modified would be a huge help).

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• Apache and backslashes in mod_rewrite

  - by NuCalTone

  I want to process all incoming requests through a single script (index.php in web-root). So, the following is what currently happens: http://localhost/foo/bar/baz Is routed by Apache (through .htaccess) to: http://localhost/index.php?url=foo/bar/baz This works well, however, in Firefox I am able to do this: http://localhost/foo\ - notice the backslash. And Apache, instead of doing: /index.php?url=foo\ Emits a generic error page saying: Object not found! The requested URL was not found on this server. If you entered the URL manually please check your spelling and try again. If you think this is a server error, please contact the webmaster. Error 404 localhost Apache/2.2.14 (Win32) DAV/2 mod_ssl/2.2.14 OpenSSL/0.9.8l mod_autoindex_color PHP/5.3.1 mod_apreq2-20090110/2.7.1 mod_perl/2.0.4 Perl/v5.10.1 Directly going to: http://localhost/index.php?url=foo\ works without issues, however. All the sites that I've seen on the internet seem to be able to handle backslashes gracefully (e.g., http://stackoverflow.com/tags/php\\\\\). I consider this behavior a bug and I want to force Apache to forward backslashes correctly. Here's my .htaccess file in its entirety: RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^(.*)$ index.php?url=$1 [L] How can I make this work properly?

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• Best way to convert wpf triggers to silverlight?

  - by Stewart Armbrecht

  I have developed several custom controls in a wpf application that use triggers. what is the fastest way to convert the code so that I have a single code base that works both in the wpf application and the silverlight applicaiton. Here is a sample of the code: <Style x:Key="sButtonAction" TargetType="Button"> <!--<Setter Property="BitmapEffect" Value="{StaticResource BannerEffect}" />--> <Setter Property="Height" Value="25" /> <Setter Property="Margin" Value="4" /> <Setter Property="Cursor" Value="Hand" /> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="Button"> <Border x:Name="PART_Border" CornerRadius="10" BorderThickness="{StaticResource sBorderThicknessStandard}" BorderBrush="{StaticResource bColorBorder}" Background="{StaticResource ButtonActionBackground}"> <TextBlock x:Name="PART_TextBlock" Margin="5,2,5,2" HorizontalAlignment="Center" VerticalAlignment="Center" Foreground="White"> <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" /></TextBlock> </Border> <ControlTemplate.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Setter TargetName="PART_TextBlock" Property="Foreground" Value="#990000"></Setter> </Trigger> <Trigger Property="IsPressed" Value="True"> <Setter TargetName="PART_Border" Property="Background" Value="{StaticResource ButtonActionBackgroundSelected}"></Setter> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style>

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• Which key:value store to use with Python?

  - by Kurt

  So I'm looking at various key:value (where value is either strictly a single value or possibly an object) stores for use with Python, and have found a few promising ones. I have no specific requirement as of yet because I am in the evaluation phase. I'm looking for what's good, what's bad, what are the corner cases these things handle well or don't, etc. I'm sure some of you have already tried them out so I'd love to hear your findings/problems/etc. on the various key:value stores with Python. I'm looking primarily at: memcached - http://www.danga.com/memcached/ python clients: http://pypi.python.org/pypi/python-memcached/1.40 http://www.tummy.com/Community/software/python-memcached/ CouchDB - http://couchdb.apache.org/ python clients: http://code.google.com/p/couchdb-python/ Tokyo Tyrant - http://1978th.net/tokyotyrant/ python clients: http://code.google.com/p/pytyrant/ Lightcloud - http://opensource.plurk.com/LightCloud/ Based on Tokyo Tyrant, written in Python Redis - http://code.google.com/p/redis/ python clients: http://pypi.python.org/pypi/txredis/0.1.1 MemcacheDB - http://memcachedb.org/ So I started benchmarking (simply inserting keys and reading them) using a simple count to generate numeric keys and a value of "A short string of text": memcached: CentOS 5.3/python-2.4.3-24.el5_3.6, libevent 1.4.12-stable, memcached 1.4.2 with default settings, 1 gig memory, 14,000 inserts per second, 16,000 seconds to read. No real optimization, nice. memcachedb claims on the order of 17,000 to 23,000 inserts per second, 44,000 to 64,000 reads per second. I'm also wondering how the others stack up speed wise.

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