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  • EntityFramework how to Override properties

    - by plotnick
    I've just started using EF in VS2010. That thing is just amazin'. I frankly can't understand something. For example I have EntityType with property, they generated from database structure. Now, I have to simply override that property in my code. I don't need to save value of the property back into DB, but everytime when it gets read from DB it should be substituted with run-time calculated value. Of course I can create derived class based on my EntityType but I've tried and found kinda difficulties, I'm not sure this is kinda right way to do. Anyway even when I try to change the whole EntityType to Abstract, damn Visual Studio doesn't want to validate that and says something like: "Error 2078: The EntityType 'AssetsModel.Asset' is Abstract and can be mapped only using IsTypeOf." "Error 2063: At least one property must be mapped in the set mapping for 'Assets'" What the hell is this suppose to mean I dunno.. Any ideas gentlemen?

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  • C# Asynchronous Sockets questions.

    - by ccppjava
    Based on my reading and testing, with asynchronous sockets, the socket itself can be passed using state object (IAsyncResult result), also if store the socket as a private field, it would be captured by the callback methods. I am wondering how the IAysnResult is kepted between the BeginXXX and ReceiveXXX? It looks to me that after the BeginXXX call and the method ends, the state object would be disposed by GC if there is no reference to it. In the case of private field, how the private field is shared between threads? (As far as I know, a callback is executed using a thread from the default thread pool, which would be considered as a new thread.) Many thanks, hope the questions themselves are clear.

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  • Accessing items from a dictionary using pickle efficiently in Python

    - by user248237
    I have a large dictionary mapping keys (which are strings) to objects. I pickled this large dictionary and at certain times I want to pull out only a handful of entries from it. The dictionary has usually thousands of entries total. When I load the dictionary using pickle, as follows: from cPickle import * # my dictionary from pickle, containing thousands of entries mydict = open(load('mypickle.pickle')) # accessing only handful of entries here for entry in relevant_entries: # find relevant entry value = mydict[entry] I notice that it can take up to 3-4 seconds to load the entire pickle, which I don't need, since I access only a tiny subset of the dictionary entries later on (shown above.) How can I make it so pickle only loads those entries that I have from the dictionary, to make this faster? Thanks.

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  • "No row with the given identifier exists" although it DOES exist!

    - by roesslerj
    Hello all! I am using Hibernate and getting Exception in thread "main" org.hibernate.ObjectNotFoundException: No row with the given identifier exists: [<MyDbObject>#271] What is pretty weird about this error is, that the object with the given id exists in the database. I inserted the problematic record in another run of the application. If I access it in the same run (i.e. same hibernate session) there seem to be no problems retrieving the data. Just because it could be a fault of the mapping: public class ProblemClass { @ManyToOne(optional = false) private MyDbObject myDbObject; } public class MyDbObject { @OneToMany(mappedBy = "myDbObject") private List<ProblemClass> problemClasses; } I have absolutely no clue even where to look at. Any hints highly appreciated!

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  • Using locks inside a loop

    - by Xaqron
    // Member Variable private readonly object _syncLock = new object(); // Now inside a static method foreach (var lazyObject in plugins) { if ((string)lazyObject.Metadata["key"] = "something") { lock (_syncLock) { if (!lazyObject.IsValueCreated) lazyObject.value.DoSomething(); } return lazyObject.value; } } Here I need synchronized access per loop. There are many threads iterating this loop and based on the key they are looking for, a lazy instance is created and returned. lazyObject should not be created more that one time. Although Lazy class is for doing so and despite of the used lock, under high threading I have more than one instance created (I track this with a Interlocked.Increment on a volatile shared int and log it somewhere). The problem is I don't have access to definition of Lazy and MEF defines how the Lazy class create objects. My questions: 1) Why the lock doesn't work ? 2) Should I use an array of locks instead of one lock for performance improvement ?

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  • Does std::multiset guarantee insertion order?

    - by Naveen
    I have a std::multiset which stores elements of class A. I have provided my own implementation of operator< for this class. My question is if I insert two equivalent objects into this multiset is their order guaranteed? For example, first I insert a object a1 into the set and then I insert an equivalent object a2 into this set. Can I expect the a1 to come before a2 when I iterate through the set? If no, is there any way to achieve this using multiset?

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  • Confusion using MYSQLI

    - by user1020069
    I just started using mysqli API for PHP. Apparently, every time an object of the class MYSQLI is instantiated, it can setup a connection to the database as it connects to the server unlike mysql_connect, which connects to the server first and then you are required to specify the database to query. Now this is a good problem if the db exists, in my case, the db does not exist on the first ever connection to the server/execution of the problem, hence I must connect without specifying the database, which is fine, since the msyqli constructor does not make this database mandatory. My challenge is essentially, how do I check if the database exists before attempting the first connection. The only way to really do this would be to establish a conection to the server and then use the result of the following query to gauge if the database exists: SELECT COUNT(*) AS `exists` FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMATA.SCHEMA_NAME="dbname" ; If this returns true, then the database exists, but now the challenge is how do I get the mysqli object to query this database rather than having to prefix the name of the database in the query. Thanks much

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  • Help needed to write a LINQ with GROUP bY(C#3.0)

    - by Newbie
    I have a datatable whose structure is as under Week Dates Key_Factors Factor_Values --- ----- ----------- ------------- 1 29/12/2000 Factor_1 19.20 1 29/12/2000 Factor_2 20.67 1 29/12/2000 Factor_3 10 2 21/12/2007 Factor_1 20.54 2 21/12/2007 Factor_4 21.70 I have a Object model like WeekNumber(int) Dates(Datetime) FactorDictionary (Dictionary<string,double>) I am trying to populate the data from DataTable to my Object Model whose needed output is as under Desired Output ---------------- WeekNumber : 1 Dates : 29/12/2000 FactorDictionary: Key_Factors: Factor_1 Factor_Values:19.20 Key_Factors: Factor_2 Factor_Values:20.67 Key_Factors: Factor_3 Factor_Values:10 WeekNumber : 2 Dates : 21/12/2007 FactorDictionary: Key_Factors: Factor_1 Factor_Values:20.54 Key_Factors: Factor_4 Factor_Values:21.70 i.e. The result is grouped by weeks. Can I achieve the same by using LINQ. I am using C#(3.0) with framework(3.5) Thanks

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  • Multi-threading concept and lock in c#

    - by Neeraj
    I read about lock, though not understood nothing at all. My question is why do we use a un-used object and lock that and how this makes something thread-safe or how this helps in multi-threading ? Isn't there other way to make thread-safe code. public class test { private object Lock { get; set; } ... lock (this.Lock) { ... } ... } Sorry is my question is very stupid, but i don't understand, although i've used it many times.

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  • Two way binding when setter is overriden

    - by Nicolas Goy
    I have an NSTextField bound to some object "zoom" property. In this object's class implementation, I have the following - (void)setZoom:(CGFloat)zoom { _zoom = MAX(0, MIN(10, zoom)); } If I write "-5" in the textfield, setZoom: will be called with "-5" as argument and _zoom will be set to 0. Then problem is that the textfield is not updating itself and it shows "-5" instead of re-reading the property value it has just set. If I do myObject.zoom = -5; in code, the text field will display 0 correctly. I tried to wrap _zoom =... inside willChangeValueForKey/didChangeValueForKey calls but it didn't change anything.

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  • Exception wrapping and HTML pages

    - by dotnetdev
    Hi, We have a sharepoint 2007 project at work. The exception handling policy is to log to the Sharepoint logs. In this case, would the best approach be to call that method and then rethrow the exception higher up? Except if I rethrow it to be caught higher up, there is no other exception handling code so what would happen in this case? Also, if you are going to display a more friendly error to the user (which uses information in the exception object), then this would be a good use of exception wrapping. Would it be a good idea to make a custom aspx page and add these to customerrors, so that on init (not sure of the exact event), I can display exception info in the passed parameter on the page. However, a static html page can't do this so I don't see the point in wrapping exceptions (unless there is a page or alert which uses the exception object). So if a project uses html pages for errors, is there a point in wrapping exceptions? Thanks

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  • is there a way to add a variable/property to a DOM element (eg, an element returned by a jQuery sele

    - by bt
    Hi there, I am looking for an alternative to using an object/variable in global scope -- I would like to associate key/value pairs with specific DOM elements (eg, a DIV), so that I can use them as input for logic that processes other elements (eg, child elements of said DIV). I tried something naive like: $('[foo=bar]').key='value' , and $('[foo=bar]')[key]='value', but it puked. Doing something like: var foobar = $('[foo=bar]'); foobar.key = 'value' -- works, but the new property/value only affects the new object (ie, foobar, not $('[foo=bar]')) Most likely there's something terribly basic I am overlooking. Any help is appreciated, thanks!

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  • C++: conjunction of binds?

    - by Helltone
    Suppose the following two functions: #include <iostream> #include <cstdlib> // atoi #include <cstring> // strcmp #include <boost/bind.hpp> bool match1(const char* a, const char* b) { return (strcmp(a, b) == 0); } bool match2(int a, const char* b) { return (atoi(b) == a); } Each of these functions takes two arguments, but can be transformed into a callable object that takes only one argument by using (std/boost)bind. Something along the lines of: boost::bind(match1, "a test"); boost::bind(match2, 42); I want to be able to obtain, from two functions like these that take one argument and return bool, a callable object that takes two arguments and returns the && of the bools. The type of the arguments is arbitrary. Something like an operator&& for functions that return bool.

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  • Linq to SQL inheritance and Table per Class - approach needed for multiple roles

    - by Ash Machine
    I am using L2S and an inheritance model for mapping Persons against certain roles. Guy Burstein's excellent blog post explains how to accomplish this: http://blogs.microsoft.co.il/blogs/bursteg/archive/2007/10/01/linq-to-sql-inheritance.aspx However, I have a specific case where a Person has multiple roles. For example 'Jane Doe' is a Contact and a Programmer. In this model, she would need two rows in the People table, one as Contact (PersonType = 1) and one as Programmer (PersonType = 3). If she changes her last name, and that update happens in her role as Contact, I would need to change all instances of 'Jane Doe' to reflect the name change everywhere. What sort of best approach (improved data structure) could be used to change last name within all roles? Finally, I am hoping to avoid overriding each general form update events to include all instances, but that may be the only way. Any suggestions or approaches appreciated.

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  • Help understanding this stack trace

    - by user80632
    Hi I have health monitoring turned on, and i have the following error i'm trying to understand: Exception: Exception information: Exception type: System.InvalidCastException Exception message: Specified cast is not valid. Thread information: Thread ID: 5 Thread account name: NT AUTHORITY\NETWORK SERVICE Is impersonating: False Stack trace: at _Default.Repeater1_ItemDataBound(Object sender, RepeaterItemEventArgs e) at System.Web.UI.WebControls.Repeater.CreateControlHierarchy(Boolean useDataSource) at System.Web.UI.WebControls.Repeater.OnDataBinding(EventArgs e) at _Default.up1_Load() at _Default.Timer1_Tick(Object sender, EventArgs e) at System.Web.UI.Timer.OnTick(EventArgs e) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) I'm just trying to figure out exactly where the problem is happening and what it is - is it happening in the Repeater1_ItemDataBound sub routine, or in the Timer1_Tick sub routine? Is the last thing that happened before the error occured at the top or bottom of the trace? any help much appreciated thanks

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  • Select one column from a row in hibernate

    - by ComfortablyNumb
    I am trying to do a simple query to get a unique result back in hibernate here is my code. public String getName(Integer id) { Session session = getSessionFactory().openSession(); String name = (String)session.createSQLQuery("SELECT name FROM users WHERE user_id = :userId").setParameter("userId", id).uniqueResult(); return name; } The name that is being returned is stored as HTML text that includes html syntacx language. I think this is what is causing the problem but it doesnt make sense I just want to return it as a string. It is only happening on this one field name, I can get every other field in the row but this one it gives me the error. I am getting an exception. The exception I am getting is No Dialect mapping for JDBC type: -1; nested exception is org.hibernate.HibernateException How do you query for a specific column on a row in hibernate?

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  • Dynamic proxies to auto-save models

    - by atomman
    I'm trying to make some auto-magic happen in java using proxies to track objects and saving them when a set* method is called. I started of using java's built in Proxy, and everything works just fine, but from what I can understand I need a interface for every model, which is something that I'm trying to avoid. This is where CGLIB comes in, it allows me to create proxies of my models without the use of interfaces. BUT, how can I now retrieve the original object, the one I am trying to save? The optimal solution to be would be something like the EntityManager interface used by hibernate, where you keep your original object, but it is still tracked.

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  • Fluent NHibernate CheckProperty and Dates

    - by Chris C
    I setup a NUnit test as such: new PersistenceSpecification<MyTable>(_session) .CheckProperty(c => c.ActionDate, DateTime.Now); When I run the test via NUnit I get the following error: SomeNamespace.MapTest: System.ApplicationException : Expected '2/23/2010 11:08:38 AM' but got '2/23/2010 11:08:38 AM' for Property 'ActionDate' The ActionDate field is a datetime field in a SQL 2008 database. I use Auto Mapping and declare the ActionDate as a DateTime property in C#. If I change the test to use DateTime.Today the tests pass. My question is why is the test failing with DateTime.Now? Is NHibernate losing some precision when saving the date to the database and if so how do prevent the lose? Thank you.

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  • VB6 debugging- doesn't go to error handling code.

    - by Can Ho
    Hi, I'm maintaining a vb6 project(ActiveX DLL). When debugging, the app run into the following function: Public Function HasValue(ByVal vValue) As Boolean On Error GoTo Err If IsMissing(vValue) Then HasValue = False ElseIf IsNull(vValue) Or Len(vValue) = 0 Then HasValue = False ElseIf isEmpty(vValue) Then HasValue = False Else HasValue = True End If Exit Function Err: If IsArray(vValue) Or IsObject(vValue) Then HasValue = True Else HasValue = False End If End Function and it stops at the line ElseIf IsNull(vValue) Or Len(vValue) = 0 Then vValue is a custom object, contains some properties(obviously, not null). Although I didn't put any break point there, the app stopped there and alerted error dialog saying that "Run-time error '438': Object doesn't support this property or method". We had error handling code but the app didn't run to error handling code. It just stopped at the line causing the error and I had to stop the application. Do you have any idea about that? Thank you very much.

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  • Java template classes using generator or similar?

    - by Hugh Perkins
    Is there some library or generator that I can use to generate multiple templated java classes from a single template? Obviously Java does have a generics implementation itself, but since it uses type-erasure, there are lots of situations where it is less than adequate. For example, if I want to make a self-growing array like this: class EasyArray { T[] backingarray; } (where T is a primitive type), then this isn't possible. This is true for anything which needs an array, for example high-performance templated matrix and vector classes. It should probably be possible to write a code generator which takes a templated class and generates multiple instantiations, for different types, eg for 'double' and 'float' and 'int' and 'String'. Is there something that already exists that does this? Edit: note that using an array of Object is not what I'm looking for, since it's no longer an array of primitives. An array of primitives is very fast, and uses only as much space a sizeof(primitive) * length-of-array. An array of object is an array of pointers/references, that points to Double objects, or similar, which could be scattered all over the place in memory, require garbage collection, allocation, and imply a double-indirection for access. Edit2: good god, voted down for asking for something that probably doesn't currently exist, but is technically possible and feasible? Does that mean that people looking for ways to improve things have already left the java community? Edit3: Here is code to show the difference in performance between primitive and boxed arrays: int N = 10*1000*1000; double[]primArray = new double[N]; for( int i = 0; i < N; i++ ) { primArray[i] = 123.0; } Object[] objArray = new Double[N]; for( int i = 0; i < N; i++ ) { objArray[i] = 123.0; } tic(); primArray = new double[N]; for( int i = 0; i < N; i++ ) { primArray[i] = 123.0; } toc(); tic(); objArray = new Double[N]; for( int i = 0; i < N; i++ ) { objArray[i] = 123.0; } toc(); Results: double[] array: 148 ms Double[] array: 4614 ms Not even close!

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  • @Secured not working

    - by user3640507
    I am new to spring and trying to implement Role based authorization with the help of @Secured annotation. I have a method which is specifically for ADMIN and I have written @Secured ("ROLE_ADMIN") to secure it. @Secured ("ROLE_ADMIN") public void HelloUser(String name) { System.out.println("Hello ADMIN"); } Now when I call this method by creating a class object it gets called eventhough user dont have ADMIN authority But when I dont create an object and use @autowired annotation instead then it works i.e User is not allowed to access this method. In my security.xml as well as servlet.xml I have added <global-method-security secured-annotations="enabled" /> Can some one please tell me where I am going wrong or is this the natural behaviour in spring ?

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  • How are ambigous methods resolved in java ?

    - by Jijoy
    Hi, I have a question. package org.study.algos; public class Study { public static void main(String[] args) { A a = new A(); a.m1(null); } } class A { public void m1(String s) { System.out.println("String"); System.out.println(s); } public void m1(Object obj) { System.out.println("Object"); System.out.println(obj); } } Here, the output is String null Why does the JVM resolve the method to one with a String argument? Thanks in advance J

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  • How to create an image from canvas data?

    - by Jakub Hampl
    In my application I am trying to save an arbitrary part of a rendered HTML canvas to an image file. In my Javascript I call ctx.getImageData(x, y, w, h) and pass the resulting object to my macruby code (though if you know a solution in objc I am also very interested). There I'm trying to create a NSBitmapImageRep object so that I can then save to an image format the user desires. This is my code so far (the function gets a WebScriptObject as it's argument): def setimagedata(d) w = d.valueForKey("width").to_i h = d.valueForKey("height").to_i data = Pointer.new(:char, d.valueForKey("data").valueForKey("length").to_i) d.valueForKey("data").valueForKey("length").to_i.times do |i| data[i] = d.valueForKey("data").webScriptValueAtIndex(i).to_i end puts "data complete" # get's called @exported_image = NSBitmapImageRep.alloc.initWithBitmapDataPlanes(data, pixelsWide: w, pixelsHigh:h, bitsPerSample: 32, samplesPerPixel: 4, hasAlpha: true, isPlanar: false, colorSpaceName: NSCalibratedRGBColorSpace, bitmapFormat: NSAlphaNonpremultipliedBitmapFormat, bytesPerRow: 0, bitsPerPixel: 0) puts "done" # doesn't get called end The code doesn't seem to get through the initWithBitmapDataPlanes function but gives no error. My question is: what am I doing wrong? Is this approach reasonable (if not, what would be better?).

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  • When we run an aspx page with client side scripting on IIS, we get an ActiveX control error?

    - by Ananya
    we have implemented the code for installing the messenger theme pack using the client side scripting in a web page. We are creating an object of the messenger using the classid .Using this object we call the installcontent() method and try to install the messenger theme pack hosted at following path: http://www.messengerexpressions.com/assets/worldCup/cabs/en-gb.cab Our code initially checks whether the messenger is installed on the user machine or not. Then it checks for the user login ,once the messenger is installed on the machine. And if the user is signed-in , the messenger theme pack is installed. The code currently when hosted on IIS checks the “Sign-In of the user” but when it tries to install the theme pack an error is thrown “An ActiveX control on this page is unsafe.Your current security settings prohibit running unsafe control on this page.As a result,this page may not be display as intended.” Please let us know if any setting is required on IIS for running this piece of codeor anything that we are missing out.

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