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  • Division of text follow the cursor via Javascript/Jquery

    - by webzide
    Dear experts, I wanted have a dynamic division of content follow you with the cursor in the web browser space. I am not a pro at JS so I spent 2 hours to finally debugged a very stupid way to accomplish this. $(document).ready(function () { function func(evt) { var evt = (evt) ? evt : event; var div = document.createElement('div'); div.style.position = "absolute"; div.style.left = evt.clientX + "px"; div.style.top = evt.clientY + "px"; $(div).attr("id", "current") div.innerHTML = "CURSOR FOLLOW TEXT"; $(this).append($(div)); $(this).unbind() $(this).bind('mousemove', function () { $('div').remove("#current"); }); $(this).bind('mousemove', func); } $("body").bind('mousemove', func) }); As you can see this is pretty much Brute force and it slows down the browser quite a bit. I often experience a lag on the browser as a drag my mouse from one place to another. Is there a way to accomplish this easier and faster and more intuitive. I know you can use the cursor image technique but thats something I'm looking to avoid. Thanks in advance.

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  • Reading HTML header info of files via JS

    - by Morten Repsdorph Husfeldt
    I have a product list that is generated in ASP. I have product descriptions for each product in an HTML file. Each HTML file is named: <product.id>.html. Each HTML file size is only 1-3 kb. Within the HTML file is <title> and <meta name="description" content="..." />. I want to access these in an efficient way so that I can output this as e.g.: document.write(<product.id>.html.title);<br/> document.write(<product.id>.html.description); I have a working solution for the individual products, where I use the description file - but I hope to find a more efficient / simple approach. Preferably, I want to avoid having 30+ hidden iframes - Google might think that I am trying to tamper with search result and blacklist my page. Current code: <script type="text/javascript"> document.getElementById('produkt').onload = function(){ var d = window.frames[frame].document; document.getElementById('pfoto').title = d.title : ' '; document.getElementById('pfoto').alt = d.getElementsByName('description')[0].getAttribute('content', 0) : ' '; var keywords = d.getElementsByName('keywords')[0].getAttribute('content', 0) : ' '; }; </script>

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  • Is Subversion's 'Lazy Copy' still lazy when overwriting a previously deleted file?

    - by JW
    Is Subversion's 'Lazy Copy' still lazy when overwriting a previously deleted file? I store my externals in a separate folder for each version: i.e say for dojo I'd have: webroot\ scripts\ dojo-v-1.0.0\ dojo-v-1.1.0\ etc. By doing this, for me at least, I feel it makes it easier to switch over to a new version. By only adding each new version i am not really giving svn the history it needs to do lazy copies. So one tactic I have used is to svn copy over the old version over to where the new one will be then svn delete that whole folder then unpack my newer version into that place then svn add them The idea is to avoid having a massive amount of duplicated data in my repo. I hope svn is looking at the new files and saying, "hey, i already had this once, copied, then deleted...so i am only going to be lazy store the changes". That was my theory - but does that happen in practice? p.s. Yes I know an alternative is to set the 'externals properties on the folder' - but that's another question.

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  • Freetype2 (error-)return value documentation

    - by Awaki
    In short, I'm looking for documentation that would limit the error situations to check for after a Freetype library function failed, much like the OpenGL and Win32 APIs document the error codes generated by their respective functions. I can't seem to find such documentation though, so I was wondering how to best handle translation of Freetype errors to typed exceptions. Background: I am currently in the process of implementing font-rendering capability (using Freetype) for my GUI framework, which makes strong use of typed exceptions to indicate error situations. However, the Freetype docs seem to completely omit what errors can be expected from what functions. That, if such documentation does indeed not exist, would basically leave me with two options: either guessing which errors make sense for a certain Freetype function (obviously prone to mistakes on my part), or considering every error code for translation into appropriate exceptions (less verbose since I would have to write the translation only once). Performance isn't really critical in the code that calls the Freetype library, so even the latter option would probably be acceptable, but surely there must be some kind of documentation on which library calls may return what Freetype error? Is there any such documentation which I just somehow managed to not find? Should I go the route of generically expecting every error code for translation? Or are there other ways to approach this problem? By the way, I wanted to avoid introducing some kind of generic FreetypeException (containing a description of the Freetype error) since I intended to completely hide what libraries I'm using (not from a legal point-of-view, mind you), but I guess I can be convinced to do this anyway if the consensus is that it would be the best option. I don't think it matters for this question, but I'm writing in C++.

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  • Authentication and Security in my website - need advice please.

    - by Ichirichi
    Hi, I am using database with a list of username/passwords, and a simple web form that allows for users to enter their username/password. When they submit the page, I simply do a stored procedure check to authenticate. If they are authorised, then their user details (e.g. username, dob, address, company address, other important info) are stored in a custom User object and then in a session. This custom User object that I created is used throughout the web application, and also in a sub-site (session sharing). My question/problems are: Is my method of authentication the correct way to do things? I find users complaining that their session have expired although they "were not idle", possibly due the app pool recycling? They type large amounts of text and find that their session had expired and thus lose all the text typed in. I am uncertain whether the session does really reset sporadically but will Forms Authentication using cookies/cookiless resolve the issue? Alternatively should I build and store the User Object in a session, cookie or something else instead in order to be more "correct" and avoid cases like in point #2. If I go down the Forms Authentication route, I believe I cannot store my custom User object in a Forms Authentication cookie so does it mean I would store the UserID and then recreate the user object on every page? Would this not be a huge increase on the server load? Advice and answers much appreciated. L

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  • Migrating MachineKey from iis6 on old server to iis7 on new server

    - by MaseBase
    I am migrating our hosting environment to a totally new data center with new boxes and hardware and software... the whole deal. Our website cookies are encrypted using the machineKey, so when I make a request to my domain and point it to the new web server (by overriding the local hosts file), I get an error because the cookie cannot be decrypted, since the Machine Key is different. I'd like to avoid any problems a frequent user might have when they arrive at the new server for the first time. To the best of my knowledge, at this point I think I need to set the same MachineKey from our current servers on our new servers. This way when past visitors with a cookie arrive at our website served by the new server, the cookie will be decrypted properly with the MachineKey it was encrypted with and then log them in properly. My question is where do I find my MachineKey value (in IIS 6 win2k3 server) so I can use that value to set it statically on my new servers? I've pulled up my machine.config file, but it doesn't specify the key, it only specifies a configSection where the key can be defined. It's not in my web.config for the app or elsewhere. I did find this great article on some MachineKey and Web Garden woes (which could explain some other bugs I've been experiencing with regard to the machineKey). Update I am back to this issue and am still faced with a similar problem. I have the MachineKey auto-generated on the IIS6 server but I need to get that exact key so I can set it explicitly and not have it auto-generated anymore. Any help is appreciated...

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  • Unable to delete inherited entity class in EF4

    - by Coding Gorilla
    I have two entities in an EF4 model (using Model First), let's call them EntityA and EntityB. EntityA is marked as abstract, and EntityB inherits from EntityA. They are similar to the following: public class EntityA { public Guid Id; public string Name; public string Uri; } public class EntityB : EntityA { public string AnotherProperty; } The generated database tables look as I would expect them, with EntityA as on table, and then another table like: EntityA_EntityB Id (PK, FK, uniqueidentifier) AnotherProperty (varchar) There is a foreign key constraint on EntityA_EntityB that references EntityA's Id property, no cascades are configured (although I did try changing these myself). The problem is that when I attempt to do something like: Context.DeleteObject(EntityA_EntityB); EF attempts to delete the EntityA_EntityB table record before deleting the EntityA table record, which of course violates the foreign key constraint on EntityA_EntityB table. Using EFProfiler I see the following commands being sent to the database: delete [dbo].[EntityA_EntityB] where (([Id] = '5c02899f-09ea-2ed9-d44b-01aef80f6b64' /* @0 */) followed by delete [dbo].[EntityA] where ([Id] = '5c02899f-09ea-2ed9-d44b-01aef80f6b64' /* @0 */) I'm completely stumped as to how to get around this problem. I would think the EF should know that it needs to delete the base class first, before deleting the inherited class. I know I could do some triggers or other database type solutions, but I'd rather avoid doing that if I can. All my classes are POCO built using some customized T4 templates. I don't want to paste in a lot of extraneous code, but if you need more information I'll provide what I can.

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  • C++ variable to const expression

    - by user1344784
    template <typename Real> class A{ }; template <typename Real> class B{ }; //... a few dozen more similar template classes class Computer{ public slots: void setFrom(int from){ from_ = from; } void setTo(int to){ to_ = to; } private: template <int F, int T> void compute(){ using boost::fusion::vector; using boost::fusion::at_c; vector<A<float>, B<float>, ...> v; at_c<from_>(v).operator()(at_c<to_>(v)); //error; needs to be const-expression. }; This question isn't about Qt, but there is a line of Qt code in my example. The setFrom() and setTo() are functions that are called based on user selection via the GUI widget. The root of my problem is that 'from' and 'to' are variables. In my compute member function I need to pick a type (A, B, etc.) based on the values of 'from' and 'to'. The only way I know how to do what I need to do is to use switch statements, but that's extremely tedious in my case and I would like to avoid. Is there anyway to convert the error line to a constant-expression?

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  • How to best manage multi-frame MovieClips with classes?

    - by Arms
    After switching to AS3, I've been having a hell of a time figuring out the best way to manage MovieClips that have UI elements spread across multiple frames with a single class. An example that I am working on now is a simple email form. I have a MovieClip with two frames: the 1st frame has the form elements (text inputs, submit button) the 2nd frame has a "thank you" message and a button to go back to the first frame (to send another email) In the library I have linked the MovieClip to a custom class (Emailer). My immediate problem is how do I assign a MouseEvent.CLICK event to the button on the 2nd frame? I should note at this point that I am trying to avoid putting code on the timeline (except for stop() calls). This is how I am 'solving' the problem now: Emailer registers an event listener for a frame change ( addEventListener("frame 2", onFrameChange) ) On the 2nd frame of the MovieClip I am calling dispatchEvent(new Event("frame 2")); (I would prefer to not have this code on the frame, but I don't know what else to do) My two complaints with this method are that, first I have calls to addEventListener spread out across different class methods (I would rather have all UI event listeners registered in one method), and second that I have to dispatch those custom "onFrameChange" events. The second complaint grows exponentially for MovieClips that have more than just 2 frames. My so called solution feels makes me feel dirty and makes my brain hurt. I am looking for any advice on what to do differently. Perhaps there's a design pattern I should be looking at? Should I swallow my pride and write timeline code even though the rest of my application is written in class files (and I abhor the Flash IDE code editor)? I absolutely LOVE the event system, and have no problem coding applications with it, but I feel like I'm stuck thinking in terms of AS2 when working with mutl-frame movieclips and code. Any and all help would be greatly appreciated.

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  • Proper API Design for Version Independence?

    - by Justavian
    I've inherited an enormous .NET solution of about 200 projects. There are now some developers who wish to start adding their own components into our application, which will require that we begin exposing functionality via an API. The major problem with that, of course, is that the solution we've got on our hands contains such a spider web of dependencies that we have to be careful to avoid sabotaging the API every time there's a minor change somewhere in the app. We'd also like to be able to incrementally expose new functionality without destroying any previous third party apps. I have a way to solve this problem, but i'm not sure it's the ideal way - i was looking for other ideas. My plan would be to essentially have three dlls. APIServer_1_0.dll - this would be the dll with all of the dependencies. APIClient_1_0.dll - this would be the dll our developers would actual refer to. No references to any of the mess in our solution. APISupport_1_0.dll - this would contain the interfaces which would allow the client piece to dynamically load the "server" component and perform whatever functions are required. Both of the above dlls would depend upon this. It would be the only dll that the "client" piece refers to. I initially arrived at this design, because the way in which we do inter process communication between windows services is sort of similar (except that the client talks to the server via named pipes, rather than dynamically loading dlls). While i'm fairly certain i can make this work, i'm curious to know if there are better ways to accomplish the same task.

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  • Word Automation : Replace do not work after TypeText

    - by wishper
    I need to generate doc (real doc, not docx) files, the "best" way i have found is to use word automation (Word 2010). I have files that I open, and then replace values inside before saving it on a new name. (Ex : I replace "" with "155023"). To do this, I use the Application.Selection.Find. I just had a problem when the new value had more than 255 characters (Thanks Microsofts limitations ...). To avoid this problem, i use TypeText in this case. My problem now is once I use TypeText, the Replace do not work anymore .. And I can't find why. Any idea will be greatly appreciated. My code is in a function, called in a foreach with each values to replace : private void Replace(Application app, string name, string newValue) { Selection selection = app.Selection; Find find = selection.Find; Replacement replacement = find.Replacement; find.ClearFormatting(); find.Text = "<" + name + ">"; // Word limitation : can't replace with more than 255 characters, // use another way to do it if that's the case if (tempNewValue.Length < 255) { replacement.ClearFormatting(); replacement.Text = tempNewValue; find.Execute(Replace: replaceAll); } else { while (find.Execute()) { selection.TypeText(tempNewValue); } } Marshal.ReleaseComObject(replacement); Marshal.ReleaseComObject(find); Marshal.ReleaseComObject(selection); }

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  • Flex 3 - Remove image flickering

    - by BS_C3
    Hello Community! I have an application with different components that are accessible through a viewstack in the main application. The main application looks like that: <Application> <Viewstack> <myComponent1/> <myComponent2/> <myComponent3/> . . . </Viewstack> </Application> In myComponent1, I have a horizontalList where the user can select a product. In myComponent2, I have 2 containers inside the component. A left container with a larger image of the product selected in myComponent1 and a right container with all characteristics of the product. Both containers have an embed background image. When I select a product in myComponent1, the application displays myComponent2. When the component is displayed, I first see the page without the large image of the product, then both containers flickers and the product image is displayed. How could I avoid this flickering? It's really annoying _< Thanks in advance for your help =) Regards. BS_C3

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  • Check a list of packages to install with apt-get

    - by Joel
    I am writing a post-install script for Ubuntu in Perl (same script as seen here). One of the steps is to install a list of packages. The problem is that if apt-get install fails in some of many different ways for any one of the packages the script dies badly. I would like to prevent that from happening. This happens because of the ways that apt-get install fails for packages that it doesn't like. For example when I try to install a nonsense word (i.e. typed in the wrong package name) $ sudo apt-get install oblihbyvl Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package oblihbyvl but if instead the package name has been obsoleted (installing handbrake from ppa) $ sudo apt-get install handbrake Reading package lists... Done Building dependency tree Reading state information... Done Package handbrake is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package 'handbrake' has no installation candidate $ apt-cache search handbrake handbrake-cli - versatile DVD ripper and video transcoder - command line handbrake-gtk - versatile DVD ripper and video transcoder - GTK GUI I have tried parsing the results of apt-cache and apt-get -s install to try to catch all possibilities before doing the install, but I seem to keep finding new ways to allow failures to continue to the actual install system command. My question is, is there some facility either in Perl (e.g. a module, though I would like to avoid installing modules if possible as this is supposed to be the first thing run after a new install of Ubuntu) or apt-* or dpkg that would let me be sure that the packages are all available to be installed before installing and if not fail gracefully in some way that lets the user decide what to do?

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  • UpdatePanel reloads the whole page

    - by Emil D
    Hi.I'm building an asp.net cutom control inside which I have two dropdownlists: companyIdSelection and productFamilySelection.I populate the companyIdSelection at Page_Load and in order to populate the productFamilySelection depending on the selected item in companyIdSelection.I'm using UpdatePanels to achieve this, but for some reason every time I update companyIdSelection Page_Load is being called ( which as far as I know should happen only when the entire page is reloaded ), the list is being reloaded again and the item the user selected is lost( the selected item is always the top one ).Here's the code <asp:UpdatePanel ID="updateFamilies" runat="server" UpdateMode="Always"> <ContentTemplate> Company ID:<br> <br></br> <asp:DropDownList ID="companyIdSelection" runat="server" AutoPostBack="True" OnSelectedIndexChanged="companyIdSelection_SelectedIndexChanged"> </asp:DropDownList> <br></br> Product Family: <br></br> <asp:DropDownList ID="productFamilySelection" runat="server" AutoPostBack="True" onselectedindexchanged="productFamilySelection_SelectedIndexChanged"> </asp:DropDownList> <br> </ContentTemplate> </asp:UpdatePanel> protected void Page_Load(object sender, EventArgs e) { this.companyIdSelection.DataSource = companyIds(); //companyIds returns the object containing the initial data items this.companyIdSelection.DataBind(); } protected void companyIdSelection_SelectedIndexChanged(object sender, EventArgs e) { // Page_Load is called again for some reason before this method is called, so it // resets the companyIdSelection EngDbService s = new EngDbService(); productFamilySelection.DataSource = s.getProductFamilies(companyIdSelection.Text); productFamilySelection.DataBind(); } Also, I tried setting the UpdateMode of the UpdatePanel to "Conditional" and adding an asyncpostback trigger but the result was the same. What am I doing wrong? PS: I fixed the updating problem, by using Page.IsPostBack in the Page_Load method, but I would still want to avoid a full postback if possible

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  • boost thread pool

    - by Dtag
    I need a threadpool for my application, and I'd like to rely on standard (C++11 or boost) stuff as much as possible. I realize there is an unofficial(!) boost thread pool class, which basically solves what I need, however I'd rather avoid it because it is not in the boost library itself -- why is it still not in the core library after so many years? In some posts on this page and elsewhere, people suggested using boost::asio to achieve a threadpool like behavior. At first sight, that looked like what I wanted to do, however I found out that all implementations I have seen have no means to join on the currently active tasks, which makes it useless for my application. To perform a join, they send stop signal to all the threads and subsequently join them. However, that completely nullifies the advantage of threadpools in my use case, because that makes new tasks require the creation of a new thread. What I want to do is: ThreadPool pool(4); for (...) { for (int i=0;i<something;i++) pool.pushTask(...); pool.join(); // do something with the results } Can anyone suggest a solution (except for using the existing unofficial thread pool on sourceforge)? Is there anything in C++11 or core boost that can help me here? Thanks a lot

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  • Tree iterator, can you optimize this any further?

    - by Ron
    As a follow up to my original question about a small piece of this code I decided to ask a follow up to see if you can do better then what we came up with so far. The code below iterates over a binary tree (left/right = child/next ). I do believe there is room for one less conditional in here (the down boolean). The fastest answer wins! The cnt statement can be multiple statements so lets make sure this appears only once The child() and next() member functions are about 30x as slow as the hasChild() and hasNext() operations. Keep it iterative <-- dropped this requirement as the recursive solution presented was faster. This is C++ code visit order of the nodes must stay as they are in the example below. ( hit parents first then the children then the 'next' nodes). BaseNodePtr is a boost::shared_ptr as thus assignments are slow, avoid any temporary BaseNodePtr variables. Currently this code takes 5897ms to visit 62200000 nodes in a test tree, calling this function 200,000 times. void processTree (BaseNodePtr current, unsigned int & cnt ) { bool down = true; while ( true ) { if ( down ) { while (true) { cnt++; // this can/will be multiple statesments if (!current->hasChild()) break; current = current->child(); } } if ( current->hasNext() ) { down = true; current = current->next(); } else { down = false; current = current->parent(); if (!current) return; // done. } } }

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  • streaming xml pretty printer in C/C++ using expat or libxml2?

    - by Mark Zeren
    I have a library that outputs xml without whitespace all on one line. In some cases I'd like to pretty print that output. I'm looking for a BSD-ish licensed C/C++ library or sample code that will take a raw xml byte stream and pretty print it. Here's some pseudo code showing one way that I might use this functionality: void my_write(const char* buf, int len); PrettyPrinter pp(bind(&my_write)); while (...) { // ... get some more xml ... const char* buf = xmlSource.get_buf(); int len = xmlSource.get_buf_len(); int written = pp.write(buf, len); // calls my_write with pretty printed xml // ... error handling, maybe call write again, etc. ... } I'd like to avoid instantiating a DOM representation. I already have dependencies on the expat and libxml2 shared libraries, and I'd rather not add any more shared library dependencies.

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  • Handling Denormalized Schema with Eclipselink

    - by iamrohitbanga
    Hello All I have a denormalized table containing employee information. The fields are employee id, name and department name. The primary key is a composite one consisting of all three fields. An employee can belong to multiple departments. I want to read/write the objects in the table using the Eclipselink Dynamic Persistence API (which is infact a wrapper on top of JPA descriptors etc.). Example Data: 1 e1 dep1 2 e1 dep2 3 e2 dep1 4 e2 dep3 5 e3 dep1 5 e3 dep2 5 e3 dep3 A normal ReadAllQuery (select query) on the table returns a DynamicEntity corresponding to each row in the table. However I want to club all entities based on the emp id and return all the departments he belongs to as a list. I can merge the entities after retrieving them but if I can use some Eclipselink feature out of the box then it would be better. One way to do the read is the following: I create two dynamic types corresponding to employee: Having id,name as the primary key Having id, department as the primary key, I create a OneToManyMapping from the first type to the second one. Then when I query the first type it does return the departments to which employee belongs as a list of DynamicEntity of the second type. This satisfies the read scenario. Is there a better way of doing this? Is this inherently supported by Eclipselink or JPA? I cannot get the same dynamic type configuration working for the write scenario. This is because when I write the changes using the writeObject method of UnitOfWork, it generates insert queries which enter the following entries in the table id name department 102 emp_102 102 st 102 dep_102 102 dep_102 102 dep_102 instead of: id name department 102 emp_102 st 102 emp_102 dep_102 102 emp_102 dep_102 102 emp_102 dep_102 Is there any way I can get write to work with this schema using eclipselink? I want to avoid doing the heavy lifting of merging the rows for such a denormalized schema or generating each row before doing a write. Is there no clean way of doing this using Eclipselink or JPA? Thanks in Advance.

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  • Multiple "ObjectChangeTracker" getting created, can it be avoided?

    - by user555937
    Hi, We are working on a POC where we have following architecture (MVVM), WPF(Client) + WCF + Model(DataAccess)+ ADO.Net Entity Framework 4.0 (with SQL Server 2008 R2 as DB) All are different projects. In the DataAccess layer we have created different Entity Models(edmx) based on the functionality. The tables under perticular flow are grouped and created different entity models. We are using self tracking entities to and fro to communicate with the WPF client through wcf service. For Single model everything works fine. But when we created a Multiple models then few issues started coming. Mutliple models have few duplicate tables/entities. Two probels are, 1) When we try to access entities from different models mutiple objects "ObjectChangeTracker" are getting created. E.g. CompanyModel(edmx) - Company(Entity) - ObjectChangeTracker, ObjectState ProductModel(edmx) - Customer(Entity) - ObjectChangeTracker1, ObjectState1 OrderModel(edmx) - Oder(Entity) - ObjectChangeTracker2, ObjectState2 Is there any way to avoid this? 2) There are few tables which shared across the Models, E.g. Company(Entity) is used in All above mdoels. During compile time it does not thow any error. But run time It gives error saying "Schema specified is not valid. Errors: The mapping of CLR type to EDM type is ambiguous because multiple CLR types match the EDM type "Company"".. To resolve this, we renamed the entities with some prefix to make them Unique. Is there any other way we can resolve this without changing the name of the entity in the same assembly? Thanks in advance and appreciate if anyone has approach for these issues. Thanks, Kiran

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  • How to lazy load a data structure (python)

    - by Anton Geraschenko
    I have some way of building a data structure (out of some file contents, say): def loadfile(FILE): return # some data structure created from the contents of FILE So I can do things like puppies = loadfile("puppies.csv") # wait for loadfile to work kitties = loadfile("kitties.csv") # wait some more print len(puppies) print puppies[32] In the above example, I wasted a bunch of time actually reading kitties.csv and creating a data structure that I never used. I'd like to avoid that waste without constantly checking if not kitties whenever I want to do something. I'd like to be able to do puppies = lazyload("puppies.csv") # instant kitties = lazyload("kitties.csv") # instant print len(puppies) # wait for loadfile print puppies[32] So if I don't ever try to do anything with kitties, loadfile("kitties.csv") never gets called. Is there some standard way to do this? After playing around with it for a bit, I produced the following solution, which appears to work correctly and is quite brief. Are there some alternatives? Are there drawbacks to using this approach that I should keep in mind? class lazyload: def __init__(self,FILE): self.FILE = FILE self.F = None def __getattr__(self,name): if not self.F: print "loading %s" % self.FILE self.F = loadfile(self.FILE) return object.__getattribute__(self.F, name) What might be even better is if something like this worked: class lazyload: def __init__(self,FILE): self.FILE = FILE def __getattr__(self,name): self = loadfile(self.FILE) # this never gets called again # since self is no longer a # lazyload instance return object.__getattribute__(self, name) But this doesn't work because self is local. It actually ends up calling loadfile every time you do anything.

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  • What's the best approach for getting into VS2010, C# 4, and WPF if my background is in C++/MFC

    - by Canacourse
    All my past programming experience has been in C++ on VS2003/8, Mostly service based and completely self taught. 2 Years ago I had to create my first real GUI app and (Foolishly) choose MFC. I got the app working but it took a long time & was a bit of a nightmare to learn MCF (and its many shortcomings) but I ended up with a reliable workable app which was difficult to change or extend. Again I have to create another GUI app more complex than the first and again this will be created from scratch and will only ever be used on windows. I had put off learning C# for a long time but not wishing to re-visit MFC have decided that the new application with be birthed in VS2010 and WPF 4 will be the midwife. Trying to avoid the several expensive (Time wise) mistakes I made previously. Im looking for for good books/tutorials on the current versions of C# 4 & WPF 4 and also general advice on the best approach. The application will do several things one of them would persisting info in a SQL DB. So Im thinking LINQ for that? Please chip in...

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  • C++ destructor problem with boost::scoped_ptr

    - by bb-generation
    I have a question about the following code: #include <iostream> #include <boost/scoped_ptr.hpp> class Interface { }; class A : public Interface { public: A() { std::cout << "A()" << std::endl; } virtual ~A() { std::cout << "~A()" << std::endl; } }; Interface* get_a() { A* a = new A; return a; } int main() { { std::cout << "1" << std::endl; boost::scoped_ptr<Interface> x(get_a()); std::cout << "2" << std::endl; } std::cout << "3" << std::endl; } It creates the following output: 1 A() 2 3 As you can see, it doesn't call the destructor of A. The only way I see to get the destructor of A being called, is to add a destructor for the Interface class like this: virtual ~Interface() { } But I really want to avoid any Implementation in my Interface class and virtual ~Interface() = 0; doesn't work (produces some linker errors complaining about a non existing implementation of ~Interface(). So my question is: What do I have to change in order to make the destructor being called, but (if possible) leave the Interface as an Interface (only abstract methods).

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  • A better way of getting a data table with various column types into string array

    - by Vlad
    This should be an easy one, looks like I got myself too confused. I get a table from a database, data ranges from varchar to int to Null values. Cheap and dirty way of converting this into a tab-delimited file that I already have is this (shrunken to preserve space, ugliness is kept on par with original): da.Fill(dt) ' da - DataAdapter ' ' dt - DataTable ' Dim lColumns As Long = dt.Columns.Count Dim arrColumns(dt.Columns.Count) As String Dim arrData(dt.Columns.Count) As Object Dim j As Long = 0 Dim arrData(dt.Columns.Count) As Object For i = 0 To dt.Rows.Count - 1 arrData = dt.Rows(i).ItemArray() For j = 0 To arrData.GetUpperBound(0) - 1 arrColumns(j) = arrData(j).ToString Next wrtOutput.WriteLine(String.Join(strFieldDelimiter, arrColumns)) Array.Clear(arrColumns, 0, arrColumns.GetLength(0)) Array.Clear(arrData, 0, arrData.GetLength(0)) Next Not only this is ugly and inefficient, it is also getting on my nerves. Besides, I want, if possible, to avoid the infamous double-loop through the table. I would really appreciate a clean and safe way of rewriting this piece. I like the approach that is used here - especially that is trying to solve the same problem that I have, but it crashes on me when I apply it to my case directly.

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  • C++ - Distributing different headers than development

    - by Ben
    I was curious about doing this in C++: Lets say I have a small library that I distribute to my users. I give my clients both the binary and the associated header files that they need. For example, lets assume the following header is used in development: #include <string> ClassA { public: bool setString(const std::string & str); private: std::string str; }; Now for my question. For deployment, is there anything fundamentally wrong with me giving a 'reduced' header to my clients? For example, could I strip off the private section and simply give them this: #include <string> ClassA { public: bool setString(const std::string & str); }; My gut instinct says "yes, this is possible, but there are gotchas", so that is why I am asking this question here. If this is possible and also safe, it looks like a great way to hide private variables, and thus even avoid forward declaration in some cases. I am aware that the symbols will still be there in the binary itself, and that this is just a visibility thing at the source code level. Thanks!

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  • Could I return a FileStream as a generic interface to a file?

    - by Eric
    I'm writing a class interface that needs to return references to binary files. Typically I would provide a reference to a file as a file path. However, I'm considering storing some of the files (such as a small thumbnail) in a database directly rather then on a file system. In this case I don't want to add the extra step of reading the thumbnail out of the database onto the disc and then returning a path to the file for my program to read. I'd want to stream the image directly out of the database into my program and avoid writing anything to the disc unless the user explicit wants to save something. Would having my interface return a FileStreamor even a Imagemake sense? Then it would be up to the implementing class to determine if the source of the FileStream or Image is a file on a disc or binary data in a database. public interface MyInterface { string Thumbnail {get;} string Attachment {get;} } vs public interface MyInterface { Image Thumbnail {get;} FileStream Attachment {get;} }

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