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  • Having the same texture data in different ID3D11Texture2D

    - by bdmnd
    Sorry if this has been answered elsewhere - I'm rather new to DX. My question concerns conservation of resources - specifically textures in VRAM. I assume that upon returning from a call to CreateTexture2D, a copy of any textures data supplied has been copied elsewhere, likely VRAM. Does DX11 have any facility for having multiple ID3D11Texture2D objects which point to the same data? This might at first seem silly, but imagine a ID3D11Texture2D which is an array of textures. In one material, an artist has chosen to blend three identically sized maps, saved on disk as A.dds, B.dds, and C.dds. Then imagine they have another material which also uses three maps, but this time A.dds, B.dds, and D.dds. The shader code knows the diffuse texture is a texture array, and also has the number of layers baked (three in each case). I would essentially like to set up just two ID3D11Texture2D objects, one for each material, but I don't want to waste VRAM for two identical copies of A.dds and B.dds. I could use explicit texture arrays, of course, but this reduces the number of resources available to the shader and can complicate code somewhat more than would otherwise be needed.

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  • How would you model an objects representing different phases of an entity life cycle?

    - by Ophir Yoktan
    I believe the scenario is common mostly in business workflows - for example: loan management the process starts with a loan application, then there's the loan offer, the 'live' loan, and maybe also finished loans. all these objects are related, and share many fields all these objects have also many fields that are unique for each entity the variety of objects maybe large, and the transformation between the may not be linear (for example: a single loan application may end up as several loans of different types) How would you model this? some options: an entity for each type, each containing the relevant fields (possibly grouping related fields as sub entities) - leads to duplication of data. an entity for each object, but instead of duplicating data, each object has a reference to it's predecessor (the loan doesn't contain the loaner details, but a reference to the loan application) - this causes coupling between the object structure, and the way it was created. if we change the loan application, it shouldn't effect the structure of the loan entity. one large entity, with fields for the whole life cycle - this can create 'mega objects' with many fields. it also doesn't work well when there's a one to many or many to many relation between the phases.

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  • Clustering Strings on the basis of Common Substrings

    - by pk188
    I have around 10000+ strings and have to identify and group all the strings which looks similar(I base the similarity on the number of common words between any two give strings). The more number of common words, more similar the strings would be. For instance: How to make another layer from an existing layer Unable to edit data on the network drive Existing layers in the desktop Assistance with network drive In this case, the strings 1 and 3 are similar with common words Existing, Layer and 2 and 4 are similar with common words Network Drive(eliminating stop word) The steps I'm following are: Iterate through the data set Do a row by row comparison Find the common words between the strings Form a cluster where number of common words is greater than or equal to 2(eliminating stop words) If number of common words<2, put the string in a new cluster. Assign the rows either to the existing clusters or form a new one depending upon the common words Continue until all the strings are processed I am implementing the project in C#, and have got till step 3. However, I'm not sure how to proceed with the clustering. I have researched a lot about string clustering but could not find any solution that fits my problem. Your inputs would be highly appreciated.

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  • Preferred way for dealing with customer-defined data in enterprise application

    - by Axarydax
    Let's say that we have a small enterprise web (intranet) application for managing data for car dealers. It has screens for managing customers, inventory, orders, warranties and workshops. This application is installed at 10 customer sites for different car dealers. First version of this application was created without any way to provide for customer-specific data. For example, if dealer A wanted to be able to attach a photo to a customer, dealer B wanted to add e-mail contact to each workshop, and dealer C wanted to attach multiple PDF reports to a warranty, each and every feature like this was added to the application, so all of the customers received everything on new update. However, this will inevitably lead to conflicts as the number of customers grow as their usage patterns are unique, and if, for instance, a specific dealer requested to have an ability to attach (for some reason) a color of inventory item (and be able to search by this color) as a required item, others really wouldn't need this feature, and definitely will not want it to be a required item. Or, one dealer would like to manage e-mail contacts for their employees on a separate screen of the application. I imagine that a solution for this is to use a kind of plugin system, where we would have a core of the application that provides for standard features like customers, inventory, etc, and all of the customer's installed plugins. There would be different kinds of plugins - standalone screens like e-mail contacts for employees, with their own logic, and customer plugin which would extend or decorate inventory items (like photo or color). Inventory (customer,order,...) plugins would require to have installation procedure, hooks for plugging into the item editor, item displayer, item filtering for searching, backup hook and such. Is this the right way to solve this problem?

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  • Why is my USB data transfer so slow?

    - by Dave M G
    Whenever I do any kind of file transfer using USB, whether to a USB stick, or with my Android phone, or anything else, it is ridiculously slow. It says 59.8 KB/sec, which would be an awesome speed if this were 1991 and I was using a modem to dial up to my local BBS. Surely USB technology is better than that...? 37 seconds to move less data than the equivelent of 1 MP3 file? Also, regardless of what it says about speed and time, the reality is much, much slower. I routinely see it say something like "37 seconds left" and have to wait for minutes. Sometimes, if I want to move large amounts of files, it can say it will take 8 hours or more. Is this normal? My computer may not be the most awesome on the market, and about a year old, but it's an i5 with 4GB RAM and modern components, so surely this isn't the hardware's fault. What can I do to get better USB data transfer performance? Also, I did look at this question, but my newbie eyes don't see anything that look like an actual solution, just a lot of discussion about what transfer rates could or should be. Update: As requested in the comments, I've generated a whole bunch of output from the command line, and put it on Ubuntu Pastebin. Please see it here.

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  • Storing large array of tiles, but allowing easy access to data

    - by Cyral
    I've been thinking about this for a while. I have a 2D tile bases platformer in XNA with a large array of tile data, I've been running into memory problems with large maps. (I will add chunks soon!) Currently, Each tile contains an Item along with other properties like how its rotated, if it has forground / background, etc. An Item is static and has properties like the name, tooltip, type of item, how much light it emits, the collision it does to player, etc. Examples: public class Item { public static List<Item> Items; public Collision blockCollisionType; public string nameOfItem; public bool someOtherVariable,etc,etc public static Item Air public static Item Stone; public static Item Dirt; static Item() { Items = new List<Item>() { (Stone = new Item() { nameOfItem = "Stone", blockCollisionType = Collision.Solid, }), (Air = new Item() { nameOfItem = "Air", blockCollisionType = Collision.Passable, }), }; } } Would be an Item, The array of Tiles would contain a Tile for each point, public class Tile { public Item item; //What type it is public bool onBackground; public int someOtherVariables,etc,etc } Now, Most would probably use an enum, or a form of ID to identify blocks. Well my system is really nice just to find out about an item. I can simply do tiles[x,y].item.Name To get the name for example. I realized my Item property of the tile is over 1000 Bytes! Wow! What I'm looking for is a way to use an ID (Int or byte depending on how many items) instead of an Item but still have a method for retreiving data about the type of item a tile contains.

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  • How to quickly search through a very large list of strings / records on a database

    - by Giorgio
    I have the following problem: I have a database containing more than 2 million records. Each record has a string field X and I want to display a list of records for which field X contains a certain string. Each record is about 500 bytes in size. To make it more concrete: in the GUI of my application I have a text field where I can enter a string. Above the text field I have a table displaying the (first N, e.g. 100) records that match the string in the text field. When I type or delete one character in the text field, the table content must be updated on the fly. I wonder if there is an efficient way of doing this using appropriate index structures and / or caching. As explained above, I only want to display the first N items that match the query. Therefore, for N small enough, it should not be a big issue loading the matching items from the database. Besides, caching items in main memory can make retrieval faster. I think the main problem is how to find the matching items quickly, given the pattern string. Can I rely on some DBMS facilities, or do I have to build some in-memory index myself? Any ideas? EDIT I have run a first experiment. I have split the records into different text files (at most 200 records per file) and put the files in different directories (I used the content of one data field to determine the directory tree). I end up with about 50000 files in about 40000 directories. I have then run Lucene to index the files. Searching for a string with the Lucene demo program is pretty fast. Splitting and indexing took a few minutes: this is totally acceptable for me because it is a static data set that I want to query. The next step is to integrate Lucene in the main program and use the hits returned by Lucene to load the relevant records into main memory.

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  • RSACryptoServiceProvider CryptographicException System Cannot Find the File Specified under ASP.NET

    - by Will Hughes
    I have an application which is making use of the RSACryptoServiceProvider to decrypt some data using a known private key (stored in a variable). When the IIS Application Pool is configured to use Network Service, everything runs fine. However, when we configure the IIS Application Pool to run the code under a different Identity, we get the following: System.Security.Cryptography.CryptographicException: The system cannot find the file specified. at System.Security.Cryptography.Utils.CreateProvHandle(CspParameters parameters, Boolean randomKeyContainer) at System.Security.Cryptography.RSACryptoServiceProvider.ImportParameters(RSAParameters parameters) at System.Security.Cryptography.RSA.FromXmlString(String xmlString) The code is something like this: byte[] input; byte[] output; string private_key_xml; var provider = new System.Cryptography.RSACryptoServiceProvider(this.m_key.Key_Size); provider.FromXmlString(private_key_xml); // Fails Here when Application Pool Identity != Network Service ouput = provider.Decrypt(input, false); // False = Use PKCS#1 v1.5 Padding There are resources which attempt to answer it by stating that you should give the user read access to the machine key store - however there is no definitive answer to solve this issue. Environment: IIS 6.0, Windows Server 2003 R2, .NET 3.5 SP1

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  • Error: Expected specifier-qualifier-list before ... in XCode Core Data

    - by Doron Katz
    Hi guys, I keep on getting this error "error: expected specifier-qualifier-list for core data code im working with, in the app delegate. Now when i get this error and about 40 other errors relating to managedobjectcontext etc, i thought maybe the library needs to be imported. Now i havent done this before, but i went to Frameworks group and add existing frameworks and it added CoreData.framework. I re-build and it still came up with the error. Do I need to import anything in the headers explicitly or is there some other step i need to do? Thanks

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  • Start/Stop Window Service from ASP.NET page

    - by kaushalparik27
    Last week, I needed to complete one task on which I am going to blog about in this entry. The task is "Create a control panel like webpage to control (Start/Stop) Window Services which are part of my solution installed on computer where the main application is hosted". Here are the important points to accomplish:[1] You need to add System.ServiceProcess reference in your application. This namespace holds ServiceController Class to access the window service.[2] You need to check the status of the window services before you explicitly start or stop it.[3] By default, IIS application runs under ASP.NET account which doesn't have access rights permission to window service. So, Very Important part of the solution is: Impersonation. You need to impersonate the application/part of the code with the User Credentials which is having proper rights and permission to access the window service. If you try to access window service it will generate "access denied" error.The alternatives are: You can either impersonate whole application by adding Identity tag in web.cofig as:        <identity impersonate="true" userName="" password=""/>This tag will be under System.Web section. the "userName" and "password" will be the credentials of the user which is having rights to access the window service. But, this would not be a wise and good solution; because you may not impersonate whole website like this just to have access window service (which is going to be a small part of code).Second alternative is: Only impersonate part of code where you need to access the window service to start or stop it. I opted this one. But, to be fair; I am really unaware of the code part for impersonation. So, I just googled it and injected the code in my solution in a separate class file named as "Impersonate" with required static methods. In Impersonate class; impersonateValidUser() is the method to impersonate a part of code and undoImpersonation() is the method to undo the impersonation. Below is one example:  You need to provide domain name (which is "." if you are working on your home computer), username and password of appropriate user to impersonate.[4] Here, it is very important to note that: You need to have to store the Access Credentials (username and password) which you are going to user for impersonation; to some secured and encrypted format. I have used Machinekey Encryption to store the value encrypted value inside database.[5] So now; The real part is to start or stop a window service. You are almost done; because ServiceController class has simple Start() and Stop() methods to start or stop a window service. A ServiceController class has parametrized constructor that takes name of the service as parameter.Code to Start the window service: Code to Stop the window service: Isn't that too easy! ServiceController made it easy :) I have attached a working example with this post here to start/stop "SQLBrowser" service where you need to provide proper credentials who have permission to access to window service.  hope it would helps./.

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  • System.Windows.Ria.Controls and POCO

    - by jvcoach23
    I'm trying to figure out how to use POCO for silverlight use. I found an article that appears it will step me through the basics. However, it has in it a reference to the System.Windows.Ria.Controls. i don't have that on my machine.. i found System.Windows.Ria but not one that has teh control on it. I just downloaded teh RIA beta today and installed it.. so should have the latest and greatest. Anyway.. Here is the link to the article... link text and here is the code in the xaml they refer to. <UserControl x:Class="Try1Silverlight.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data" xmlns:riaControls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Ria.Controls" xmlns:domain="clr-namespace:Try1Silverlight.Web" mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480" <data:DataGrid x:Name="CustomerList" ItemsSource="{Binding Data, ElementName=CustomerSource}"> </data:DataGrid> What have i done wrong that the Ria.Control is not there. thanks shannon

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  • Are some data structures more suitable for functional programming than others?

    - by Rob Lachlan
    In Real World Haskell, there is a section titled "Life without arrays or hash tables" where the authors suggest that list and trees are preferred in functional programming, whereas an array or a hash table might be used instead in an imperative program. This makes sense, since it's much easier to reuse part of an (immutable) list or tree when creating a new one than to do so with an array. So my questions are: Are there really significantly different usage patterns for data structures between functional and imperative programming? If so, is this a problem? What if you really do need a hash table for some application? Do you simply swallow the extra expense incurred for modifications?

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  • What are the "Navigation Properties" in this data model for?

    - by d03boy
    I've been wondering how to properly set up many-to-many relationships in ASP.NET MVC 2 using Linq2Sql for quite some time now. I found this blog post that seems to have a similar model layout as mine. If you take a look at the first screenshot showing the data model you can see that each model has "Navigation Properties" at the bottom of it. What exactly is this and why don't my models have them? I have the proper foreign keys put in to place. Most specifically, I am looking at the relationship between the Article and Category models since that is the only many-to-many relationship that I see and that's what I'm trying to model. Obviously I use an intermediary joining table between these two tables but I am having trouble understanding the proper methodology for modeling that relationship and I'm not finding this information anywhere on The Google.

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  • loading data from file into 2d array

    - by Chris
    I am just starting with perl and would like some help with arrays please. I am reading lines from a data file and splitting the line into fields: open (INFILE, $infile); do { my $linedata = <INFILE>; my @data= split ',',$linedata; .... } until eof; I then want to store the individual field values (in @data) in and array so that the array looks like the input data file ie, the first "row" of the array contains the first line of data from INFILE etc. Each line of data from the infile contains 4 values, x,y,z and w and once the data are all in the array, I have to pass the array into another program which reads the x,y,z,w and displays the w value on a screen at the point determined by the x,y,z value. I can not pas the data to the other program on a row-by-row basis as the program expects the data to in a 2d matrtix format. Any help greatly appreciated. Chris

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  • How to retrieve JSON Data Array from ExtJS Store

    - by user291928
    Is there a method allowing me to return my stored data in an ExtJS Grid Panel exactly the way I loaded it using: var data = ["value1", "value2"] Store.loadData(data); I would like to have a user option to reload the Grid, but changes to the store need to be taken into account. The user can make changes and the grid is dynamically updated, but if I reload the grid, the data that was originally loaded is shown even though the database has been updated with the new changes. I would prefer not to reload the page and just let them reload the grid data itself with the newly changed store. I guess im looking for something like this: var data = Store.getData(); //data = ["value1", "value2"] after its all said and done. Or is there a different way to refresh the grid with new data that I am not aware of. Even using the proxy still uses the "original" data, not the new store. Thanks in advance

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  • Best way to store a large amount of game objects and update the ones onscreen

    - by user3002473
    Good afternoon guys! I'm a young beginner game developer working on my first large scale game project and I've run into a situation where I'm not quite sure what the best solution may be (if there is a lone solution). The question may be vague (if anyone can think of a better title after having read the question, please edit it) or broad but I'm not quite sure what to do and I thought it would help just to discuss the problem with people more educated in the field. Before we get started, here are some of the questions I've looked at for help in the past: Best way to keep track of game objects Elegant way to simulate large amounts of entities within a game world What is the most efficient container to store dynamic game objects in? I've also read articles about different data structures commonly used in games to store game objects such as this one about slot maps, but none of them are really what I'm looking for. Also, if it helps at all I'm using Python 3 to design the game. It has to be Python 3, if I could I would use C++ or Unityscript or something else, but I'm restricted to having to use Python 3. My game will be a form of side scroller shooter game. In said game the player will traverse large rooms with large amounts of enemies and other game objects to update (think some of the larger areas in Cave Story or Iji). The player obviously can't see the entire room all at once, so there is a viewport that follows the player around and renders only a selection of the room and the game objects that it contains. This is not a foreign concept. The part that's getting me confused has to do with how certain game objects are updated. Some of them are to be updated constantly, regardless of whether or not they can be seen. Other objects however are only to be updated when they are onscreen (for example, an enemy would only be updated to react to the player when it is onscreen or when it is in a certain range of the screen). Another problem is that game objects have to be easily referable by other game objects; something that happens in the player's update() method may affect another object in the world. Collision detection in games is always a serious problem. I need a way of containing the game objects such that it minimizes the number of cases when testing for collisions against one another. The final problem is that of creating and destroying game objects. I think this problem is pretty self explanatory. To store the game objects then I've considered a number of different methods. The original method I had was to simply store all the objects in a hash table by an id. This method was simple, and decently fast as it allows all the objects to be looked up in O(1) complexity, and also allows them to be deleted fairly easily. Hash collisions would not be a major problem; I wasn't originally planning on using computer generated ids to store the game objects I was going to rely on them all using ids given to them by the game designer (such names would be strings like 'Player' or 'EnemyWeapon4'), and even if I did use computer generated ids, if I used a decent hashing algorithm then the chances of collisions would be around 1 in 4 billion. The problem with using a hash table however is that it is inefficient in checking to see what objects are in range of the viewport. Considering the fact that certain game objects move (as well as the viewport itself), the only solution I could think of in order to only update objects that are in the viewport would be to iterate through every object in the hash table and check if it is in the viewport or not, updating only the ones that are in the valid area. This would be incredibly slow in scenarios where the amount of game objects exceeds 500, or even 200. The second solution was to store everything in a 2-d list. The world is partitioned up into cells (a tilemap essentially), where each cell or tile is the same size and is square. Each cell would contain a list of the game objects that are currently occupying it (each game object would be inserted into a cell depending on the center of the object's collision mask). A 2-d list would allow me to take the top-left and bottom-right corners of the viewport and easily grab a rectangular area of the grid containing only the cells containing entities that are in valid range to be updated. This method also solves the problem of collision detection; when I take an entity I can find the cell that it is currently in, then check only against entities in it's cell and the 8 cells around it. One problem with this system however is that it prohibits easy lookup of game objects. One solution I had would be to simultaneously keep a hash table that would contain all the positions of the objects in the 2-d list indexed by the id of said object. The major problem with a 2-d list is that it would need to be rebuilt every single game frame (along with the hash table of object positions), which may be a serious detriment to game speed. Both systems have ups and downs and seem to solve some of each other's problems, however using them both together doesn't seem like the best solution either. If anyone has any thoughts, ideas, suggestions, comments, opinions or solutions on new data structures or better implementations of the existing data structures I have in mind, please post, any and all criticism and help is welcome. Thanks in advance! EDIT: Please don't close the question because it has a bad title, I'm just bad with names!

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  • System.out.println() does not operate in Akka actor

    - by faisal abdulai
    I am kind of baffled by this encointer. I am working an akka project that was created as a maven projecct and imported into eclipse using the mvn eclipse:eclipse command. the akka actor has the system println method just to make it easy to do read the functions and methods invoked. However any time I run the akka system, the println command does not print any thing to the eclipse console but I do not get any error messages. does any one have any idea about this. below is a code snippet. public class MasterActor extends UntypedActor { /** * */ ActorSystem system = ActorSystem.create("container"); ActorRef worker1; //public MasterActor(){} @Override public void onReceive(Object message) throws Exception { System.out.println(" Master Actor 5"); if(message instanceof GesturePoints) { //GesturePoints gp = (GesturePoints) message; System.out.println(" Master Actor 1"); try { worker1.tell(message, getSelf()); System.out.println(" Master Actor 2"); } catch (Exception e) { getSender().tell(new akka.actor.Status.Failure(e), getSelf()); throw e; } } else{ unhandled(message);} } public void preStart() { worker1 = getContext().actorFor("akka://[email protected]:2553/user/workerActor"); } } don't know whether it is a bug in eclipse. thank you.

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  • how to format date when i load data from google-app-engine..

    - by zjm1126
    i use remote_api to load data from google-app-engine. appcfg.py download_data --config_file=helloworld/GreetingLoad.py --filename=a.csv --kind=Greeting helloworld the setting is: class AlbumExporter(bulkloader.Exporter): def __init__(self): bulkloader.Exporter.__init__(self, 'Greeting', [('author', str, None), ('content', str, None), ('date', str, None), ]) exporters = [AlbumExporter] and i download a.csv is : the date is not readable , and the date in appspot.com admin is : so how to get the full date ?? thanks i change this : class AlbumExporter(bulkloader.Exporter): def __init__(self): bulkloader.Exporter.__init__(self, 'Greeting', [('author', str, None), ('content', str, None), ('date', lambda x: datetime.datetime.strptime(x, '%m/%d/%Y').date(), None), ]) exporters = [AlbumExporter] but the error is :

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  • How to handle concurrency control in ASP.NET Dynamic Data?

    - by Andrew
    I've been quite impressed with dynamic data and how easy and quick it is to get a simple site up and running. I'm planning on using it for a simple internal HR admin site for registering people's skills/degrees/etc. I've been watching the intro videos at www.asp.net/dynamicdata and one thing they never mention is how to handle concurrency control. It seems that DD does not handle it right out of the box (unless there is some setting I haven't seen) as I manually generated a change conflict exception and the app failed without any user friendly message. Anybody know if DD handles it out of the box? Or do you have to somehow build it into the site?

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  • The best way to display data in a table view?

    - by LawVS
    Hey guys, I'm trying to display nutritional information in a table view but am struggling about the best way to show the info. I don't want to create unique views for each page as that would take up a lot of space. My ideal avenue would be like a website having links to data pages instead of individual views for each page. How would I best implement that? For example, I would want the first page to be a list of restaurants, then as you press the restaurant it would list the different types of food...the next page would be a list of those foods and then the final page would be the nutrition info itself. Thanks

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  • How do I display non-normalized data in a hierarchical structure?

    - by rofly
    My issue is that I want to display data in a hierarchal structure as so: Democrat County Clerk Candidate 1 Candidate 2 Magistrate Candidate 1 Candidate 2 Candidate 3 But I'm retrieving the dataset like this: Party | Office | Candidate Democrat | County Clerk | Candidate 1 Democrat | County Clerk | Candidate 2 Democrat | Magistrate | Candidate 1 Democrat | Magistrate | Candidate 2 Democrat | Magistrate | Candidate 3 I planned on using nested repeaters, but I need a distinct value of Party, and then distinct values of office name within that party in order to do it. Are there any .NET functions to easily do what I'm attempting to? Would there be a better way of displaying the information other than repeaters? Thanks in advance!

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  • What is the best data structure and algorithm for comparing a list of strings?

    - by Chiraag E Sehar
    I want to find the longest possible sequence of words that match the following rules: Each word can be used at most once All words are Strings Two strings sa and sb can be concatenated if the LAST two characters of sa matches the first two characters of sb. In the case of concatenation, it is performed by overlapping those characters. For example: sa = "torino" sb = "novara" sa concat sb = "torinovara" For example, I have the following input file, "input.txt": novara torino vercelli ravenna napoli liverno messania noviligure roma And, the output of the above file according to the above rules should be: torino novara ravenna napoli livorno noviligure since the longest possible concatenation is: torinovaravennapolivornovilligure Can anyone please help me out with this? What would be the best data structure for this?

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  • Core Data: Fetch all entities in a to-many-relationship of a particular object?

    - by Björn Marschollek
    Hi there, in my iPhone application I am using simple Core Data Model with two entities (Item and Property): Item name properties Property name value item Item has one attribute (name) and one one-to-many-relationship (properties). Its inverse relationship is item. Property has two attributes the according inverse relationship. Now I want to show my data in table views on two levels. The first one lists all items; when one row is selected, a new UITableViewController is pushed onto my UINavigationController's stack. The new UITableView is supposed to show all properties (i.e. their names) of the selected item. To achieve this, I use a NSFetchedResultsController stored in an instance variable. On the first level, everything works fine when setting up the NSFetchedResultsController like this: -(NSFetchedResultsController *) fetchedResultsController { if (fetchedResultsController) return fetchedResultsController; // goal: tell the FRC to fetch all item objects. NSFetchRequest *fetch = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Item" inManagedObjectContext:self.moContext]; [fetch setEntity:entity]; NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]; [fetch setSortDescriptors:[NSArray arrayWithObject:sort]]; [fetch setFetchBatchSize:10]; NSFetchedResultsController *frController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetch managedObjectContext:self.moContext sectionNameKeyPath:nil cacheName:@"cache"]; self.fetchedResultsController = frController; fetchedResultsController.delegate = self; [sort release]; [frController release]; [fetch release]; return fetchedResultsController; } However, on the second-level UITableView, I seem to do something wrong. I implemented the fetchedresultsController in a similar way: -(NSFetchedResultsController *) fetchedResultsController { if (fetchedResultsController) return fetchedResultsController; // goal: tell the FRC to fetch all property objects that belong to the previously selected item NSFetchRequest *fetch = [[NSFetchRequest alloc] init]; // fetch all Property entities. NSEntityDescription *entity = [NSEntityDescription entityForName:@"Property" inManagedObjectContext:self.moContext]; [fetch setEntity:entity]; // limit to those entities that belong to the particular item NSPredicate *predicate = [NSPredicate predicateWithFormat:[NSString stringWithFormat:@"item.name like '%@'",self.item.name]]; [fetch setPredicate:predicate]; // sort it. Boring. NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]; [fetch setSortDescriptors:[NSArray arrayWithObject:sort]]; NSError *error = nil; NSLog(@"%d entities found.",[self.moContext countForFetchRequest:fetch error:&error]); // logs "3 entities found."; I added those properties before. See below for my saving "problem". if (error) NSLog("%@",error); // no error, thus nothing logged. [fetch setFetchBatchSize:20]; NSFetchedResultsController *frController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetch managedObjectContext:self.moContext sectionNameKeyPath:nil cacheName:@"cache"]; self.fetchedResultsController = frController; fetchedResultsController.delegate = self; [sort release]; [frController release]; [fetch release]; return fetchedResultsController; } Now it's getting weird. The above NSLog statement returns me the correct number of properties for the selected item. However, the UITableViewDelegate method tells me that there are no properties: -(NSInteger) tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section { id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section]; NSLog(@"Found %d properties for item \"%@\". Should have found %d.",[sectionInfo numberOfObjects], self.item.name, [self.item.properties count]); // logs "Found 0 properties for item "item". Should have found 3." return [sectionInfo numberOfObjects]; } The same implementation works fine on the first level. It's getting even weirder. I implemented some kind of UI to add properties. I create a new Property instance via Property *p = [NSEntityDescription insertNewObjectForEntityForName:@"Property" inManagedObjectContext:self.moContext];, set up the relationships and call [self.moContext save:&error]. This seems to work, as error is still nil and the object gets saved (I can see the number of properties when logging the Item instance, see above). However, the delegate methods are not fired. This seems to me due to the possibly messed up fetchRequest(Controller). Any ideas? Did I mess up the second fetch request? Is this the right way to fetch all entities in a to-many-relationship for a particular instance at all?

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  • How do you delete a core data entry from the detail view?

    - by Sam
    I am working with an app similar to apple's core data recipes sample code. I want to be able to delete the entry from the detail view, much like apple's contacts app. The code below is deleting the 1st entry and not the selected entry. Not sure what I am doing wrong. NSIndexPath *indexPath = [myTableView indexPathForSelectedRow]; NSManagedObjectContext *context = [fetchedResultsController managedObjectContext]; [context deleteObject:[fetchedResultsController objectAtIndexPath:indexPath]]; [myTableView reloadData];

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  • NSArrayController that is sorted and unique (no duplicates) for use in a pop-up in a core-data app

    - by Douglas Weaver
    I have core data app with an entity OBSERVATION that has as one of its attributes DEALNAME. I want to reference through Interface Builder or by making custom modifications to an NSArrayController a list of unique sorted dealnames so that I can use them in a pop-up. I have attempted to use @distinctUnionOfSets (and @distinctUnionOfArrays) but am unable to locate the proper key sequence. I can sort the ArrayController by providing a sort descriptor, but do not know how to eliminate duplicates. Are the @distinct... keys the right methodology? It would seem to provide the easiest way to optimize the use of IB. Is there a predicate form for removing duplicates? Or do I need to use my custom controller to extract an NSSet of the specific dealnames, put them back in an array and sort it and reference the custom array from IB? Any help would be appreciated. I am astounded that other have not tried to create a sorted-unique pop-up in tableviews.

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