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  • How to route tree-structured URLs with ASP.NET Routing?

    - by Venemo
    Hello Everyone, I would like to achieve something very similar to this question, with some enhancements. There is an ASP.NET MVC web application. I have a tree of entities. For example, a Page class which has a property called Children, which is of type IList<Page>. (An instance of the Page class corresponds to a row in a database.) I would like to assign a unique URL to every Page in the database. I handle Page objects with a Controller called PageController. Example URLs: http://mysite.com/Page1/ http://mysite.com/Page1/SubPage/ http://mysite.com/Page/ChildPage/GrandChildPage/ You get the picture. So, I'd like every single Page object to have its own URL that is equal to its parent's URL plus its own name. In addition to that, I also would like the ability to map a single Page to the / (root) URL. I would like to apply these rules: If a URL can be handled with any other route, or a file exists in the filesystem in the specified URL, let the default URL mapping happen If a URL can be handled by the virtual path provider, let that handle it If there is no other, map the other URLs to the PageController class I also found this question, and also this one and this one, but they weren't of much help, since they don't provide an explanation about my first two points. I see the following possible soutions: Map a route for each page invidually. This requires me to go over the entire tree when the application starts, and adding an exact match route to the end of the route table. I could add a route with {*path} and write a custom IRouteHandler that handles it, but I can't see how could I deal with the first two rules then, since this handler would get to handle everything. So far, the first solution seems to be the right one, because it is also the simplest. I would really appreciate your thoughts on this. Thank you in advance!

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  • accessing object variables in javascript

    - by user1452370
    So, I just started javascript and everything was working fine till i came to objects. This peace of code is supposed to create a bouncing ball in a html canvas with javascript but it doesn't work. var canvas = document.getElementById("myCanvas"); var ctx = canvas.getContext("2d"); //clear function clear() { ctx.clearRect(0, 0, canvas.width, canvas.height); } here is my ball object //ball var ball = { x: canvas.width / 2, getX: function() { return x; }, setX: function(a) { x = a; }, y: canvas.height / 2, getY: function() { return y; }, setY: function(a) { y = a; }, mx: 2, getMx: function() { return mx; }, my: 4, getMy: function() { return my; }, r: 10, getR: function() { return r; } }; code to draw my ball function drawBall() { ctx.beginPath(); ctx.arc(ball.getX, ball.getY, ball.getR, 0, Math.PI * 2, true); ctx.fillStyle = "#83F52C"; ctx.fill(); } function circle(x, y, r) { ctx.beginPath(); ctx.arc(x, y, r, 0, Math.PI * 2, true); ctx.fillStyle = "#83F52C"; ctx.fill(); } //draws ball and updates x,y cords function draw() { clear(); drawBall(); if (ball.getX() + ball.getMx() >= canvas.width || ball.getX()+ ball.getMx() <= 0) { ball.setMx(-ball.getMx()); } if (ball.getY() + ball.getMy() >= canvas.height|| ball.getY()+ ball.getMy() <= 0) { ball.setMy(-ball.getMy()); } ball.setX(ball.getX() + ball.getMx()); ball.setY(ball.getY() + ball.getMy()); } set interval function init() { return setInterval(draw, 10); } init();

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  • accessing parsed JSON on the iPhone SDK

    - by itai alter
    Hello All! I've been following the great tutorial about (iPhone, json and Flickr API and I did manage to access the parsed json info just fine. Now I'm trying to do the same thing with the Twitter API, and I am able to get the json info and parse it, but I can't seem to access it like in Flickr. I noticed that the json info that is retrieved from Twitter is a little different from Flickr. The Flickr json info starts straight with a curly braces ({), while the Twitter json info starts with a square bracket and then a curly braces ([{). I understand that it means it's an array inside the json info, but I don't know how to access it. In the Flickr example, I access the objects like so (the second line takes the number of pages Flickr has reported): NSDictionary *results = [jsonString JSONValue]; pagesString = [[results objectForKey:@"photos"] objectForKey:@"pages"]; but I can't seem to access the Twitter response in the same way... Does anyone know of a solution? (here's an example of the Twitter JSON response: api.twitter.com/1/statuses/public_timeline.json ) Thanks a bunch!

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  • Question about WeakReferences

    - by Impz0r
    Hey there, I've got a question regarding WeakReferences. I'm right now in the process of writing a "Resource Manager" who hast to keep references to created texture objects. I have a Dictionary like: Dictionary<uint, WeakReference> Where the first is, as you allready may guessed, the Resource Id and the second param is a WeakReference to the Resource itself. Right now my Resources do have a method to free themselfes from their Owner (i.e. Resource Manager). They do so in calling a method at the Resource Manger while passing a this reference to it. The ResMgr does lookup if it is a resource he keeps bookmark of and if so, does something like this: WeakReference result; if (m_Resources.TryGetValue(ResourceId, out result)) { if (result.IsAlive) return; (result.Target as Resource).free(); // free for good m_Resources.Remove(ResourceId); } The Problem I'm having is that the part after: if (result.IsAlive) is never reached because there are still leftover references to the Resource. The thing is, I do only have one Reference of the Resource in question and it releases itself like: resource.free(); // calls internally its owner (i.e. ResMgr) resource = null; I guess the left over reference would be the "resource" variable, but I cannot set it to null, because I do have to call free first. Quite a dilema... Well what I wanted to achive with this is a Resource Manager who keeps references to its owning Resources and release them ONLY if there is no reference left to not screw up something. Any idea how I may solve this in a clean fashion? Thanks in advance! Mfg Imp

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  • Ruby custom class to and from YAML;

    - by Sanarothe
    Hi. I'm having trouble deserializing a ruby class that I wrote to YAML. Where I want to be I want to be able to pass one object around as a full 'question' which includes the question text, some possible answers (For multi. choice) and the correct answer. One module (The encoder) takes input, builds a 'question' class out of it and appends it to the question pool. Another module reads a question pool and builds an array of 'question' objects. Where I am currently Sample Question Pool --- | --- !ruby/object:MultiQ a: "no" answer: "no" b: "no" c: "no" d: "no" text: "yes?" Encoder dump to YAML file. Object is a MultiQ filled up with input. (See below.) def dump(file, object) File.open(file, 'a') do |out| YAML.dump(object.to_yaml, out) end object = nil end MultiQ Class definition class MultiQ attr_accessor :text, :answer, :a, :b, :c, :d def initialize(text, answer, a, b, c, d) @text = text @answer = answer @a = a @b = b @c = c @d = d end end The decoder (I've been trying different things, so what's here wasn't my first or best guess. But I'm at a loss and the documentation doesn't really explain things thoroughly enough.) File.open( "test_set.yaml" ) do |yf| YAML.load_documents( yf ) { |item| new = YAML.object_maker( MultiQ, item) puts new } end Questions you can answer How do I achieve my goal? What methods should I use, between parsing, loading files or documents, to successfully deserialize a Ruby class? I've already looked over the YAML Rdoc, and I didn't absorb very much, so please don't just link me to it. What other methods would you suggest using? Is there a better way to store questions like this? Should I be using document db, relational db, xml? Some other format?

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  • Force compile-time linking of all classes in a SWC

    - by aaaidan
    Using Flash CS4, I am making a game that has a dozen or so sounds and a couple of music tracks. To cut down on publish/compile time, I have moved the sounds and music into an (external) SWC, which is located in a "Library Path" for the project. This works, but with a caveat... Until before I externalised the assets, I had been dynamically instantiating the Sound objects of the embedded sound by getting their classes with getDefinitionByName. // something like... var soundSubClass:Class = Class(getDefinitionByName(soundClassName)); var mySound:Sound = new soundSubClass(); But now that they're located in an external SWC, I need to have "concrete" references to the classes in order to load them like this, otherwise they are not included in the published SWF, and there is a runtime error when getDefinitionByName tries to get a class that doesn't exist. So, my question: in Flash Professional CS4, is there any way to force a library's assets to be included, regardless of whether they are statically linked? FlashDevelop has a compiler option "SWC Include Libraries", which is exactly what I want, and is distinct from the "SWC Libraries" option. The description of the "SWC Include Libraries" option is "Links all classes inside a SWC file to the resulting application SWF file, regardless of whether or not they are used." (Also, it's important to me that all the assets are contained within the one compiled SWF. Linking at runtime isn't what I'm after.)

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  • Rails fields_for parameters for a has_many relation don't yield an Array in params

    - by user1289061
    I have a model Sensor with has_many and accepts_nested_attributes_for relationships to another model Watch. In a form to update a Sensor, I have something like the following <%= sensor_form.fields_for :watches do |watches_form| %> <%= watches_form.label :label %><br /> <%= watches_form.text_field :label %> <% end %> This is indended to allow editting of the already-created Watches belonging to a Sensor. This call spits form inputs as so: <input name="sensor[watches_attributes][0][label]" ... /> <input name="sensor[watches_attributes][0][id]" ... /> When this gets submitted, the params object in the Sensor controller gets an assoc like "sensor" => { "id"=>"1", "watches_attributes"=> { "0"=>{"id" => "1", "label" => "foo"}, "1"=>{"id" => "2", "label" => "bar"} } } For a has_many, accepts_nested_attributes_for update to work upon the @sensor.update_attributes call, it seems that that attributes key really must map to an Array. From what I've seen in the examples, the combination of has_many, accepts_nested_attributes_for, and sensor_form.fields_for should allow me to pass the resulting params object directly to @sensor.update_attributes and update each related object as intended. Instead the Sensor takes place, with no errors, but the Watch objects are not updated (since "watches_attributes" maps to a Hash instead of an Array?) Have I missed something?

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  • How to avoid game rendering component circular references?

    - by CodexArcanum
    I'm working on a simple game design, and I wanted to break up my game objects into more reusable components. But I'm getting stuck on how exactly to implement the design I have in mind. Here's an example: I have a Logger object, whose job is simply to store a list of messages and render them to screen. You know, logging. Originally the Logger just held the list, and the game loop rendered it's contents. Then I moved the rendering logic into the Logger.Draw() method, and now I want to move it further into a LoggerRenderer object. In effect, I want to have the game loop call RenderAll, which will then call Logger.Render, which will in turn call the LoggerRenderer.Render and finally output the text. So the Logger needs to contain a Renderer object, but the Renderer needs access to the Logger's state (the message queue) in order to render. How do I resolve that? Should I be passing in the message queue and other state information explicitly to the Render method? Or should the game loop be calling the Renderer directly and it links back to the logger, but the RenderAll method never actually sees the logger object itself? This feels kind of like Command pattern, but I'm botching it up terribly.

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  • Setting database-agnostic default column timestamp using Hibernate

    - by unsquared
    I'm working on a java project full of Hibernate (3.3.1) mapping files that have the following sort of declaration for most domain objects. <property name="dateCreated" generated="insert"> <column name="date_created" default="getdate()" /> </property> The problem here is that getdate() is an MSSQL specific function, and when I'm using something like H2 to test subsections of the project, H2 screams that getdate() isn't a recognized function. It's own timestamping function is current_timestamp(). I'd like to be able to keep working with H2 for testing, and wanted to know whether there was a way of telling Hibernate "use this database's own mechanism for retrieving the current timestamp". With H2, I've come up with the following solution. CREATE ALIAS getdate AS $$ java.util.Date now() { return new java.util.Date(); } $$; CALL getdate(); It works, but is obviously H2 specific. I've tried extending H2Dialect and registering the function getdate(), but that doesn't seem to be invoked when Hibernate is creating tables. Is it possible to abstract the idea of a default timestamp away from the specific database engine?

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  • Comparing two collections for equality

    - by Crossbrowser
    I would like to compare two collections (in C#), but I'm not sure of the best way to implement this efficiently. I've read the other thread about Enumerable.SequenceEqual, but it's not exactly what I'm looking for. In my case, two collections would be equal if they both contain the same items (no matter the order). Example: collection1 = {1, 2, 3, 4}; collection2 = {2, 4, 1, 3}; collection1 == collection2; // true What I usually do is to loop through each item of one collection and see if it exists in the other collection, then loop through each item of the other collection and see if it exists in the first collection. (I start by comparing the lengths). if (collection1.Count != collection2.Count) return false; // the collections are not equal foreach (Item item in collection1) { if (!collection2.Contains(item)) return false; // the collections are not equal } foreach (Item item in collection2) { if (!collection1.Contains(item)) return false; // the collections are not equal } return true; // the collections are equal However, this is not entirely correct, and it's probably not the most efficient way to do compare two collections for equality. An example I can think of that would be wrong is: collection1 = {1, 2, 3, 3, 4} collection2 = {1, 2, 2, 3, 4} Which would be equal with my implementation. Should I just count the number of times each item is found and make sure the counts are equal in both collections? The examples are in some sort of C# (let's call it pseudo-C#), but give your answer in whatever language you wish, it does not matter. Note: I used integers in the examples for simplicity, but I want to be able to use reference-type objects too (they do not behave correctly as keys because only the reference of the object is compared, not the content).

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  • Using XmlSerializer deserialize complex type elements are null

    - by Jean Bastos
    I have the following schema: <?xml version="1.0"?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:tipos="http://www.ginfes.com.br/tipos_v03.xsd" targetNamespace="http://www.ginfes.com.br/servico_consultar_situacao_lote_rps_resposta_v03.xsd" xmlns="http://www.ginfes.com.br/servico_consultar_situacao_lote_rps_resposta_v03.xsd" attributeFormDefault="unqualified" elementFormDefault="qualified"> <xsd:import schemaLocation="tipos_v03.xsd" namespace="http://www.ginfes.com.br/tipos_v03.xsd" /> <xsd:element name="ConsultarSituacaoLoteRpsResposta"> <xsd:complexType> <xsd:choice> <xsd:sequence> <xsd:element name="NumeroLote" type="tipos:tsNumeroLote" minOccurs="1" maxOccurs="1"/> <xsd:element name="Situacao" type="tipos:tsSituacaoLoteRps" minOccurs="1" maxOccurs="1"/> </xsd:sequence> <xsd:element ref="tipos:ListaMensagemRetorno" minOccurs="1" maxOccurs="1"/> </xsd:choice> </xsd:complexType> </xsd:element> </xsd:schema> and the following class: [System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "2.0.50727.3038")] [System.SerializableAttribute()] [System.Diagnostics.DebuggerStepThroughAttribute()] [System.ComponentModel.DesignerCategoryAttribute("code")] [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true, Namespace = "http://www.ginfes.com.br/servico_consultar_situacao_lote_rps_envio_v03.xsd")] [System.Xml.Serialization.XmlRootAttribute(Namespace = "http://www.ginfes.com.br/servico_consultar_situacao_lote_rps_envio_v03.xsd", IsNullable = false)] public partial class ConsultarSituacaoLoteRpsEnvio { [System.Xml.Serialization.XmlElementAttribute(Order = 0)] public tcIdentificacaoPrestador Prestador { get; set; } [System.Xml.Serialization.XmlElementAttribute(Order = 1)] public string Protocolo { get; set; } } Use the following code to deserialize the object: XmlSerializer respSerializer = new XmlSerializer(typeof(ConsultarSituacaoLoteRpsResposta)); StringReader reader = new StringReader(resp); ConsultarSituacaoLoteRpsResposta respModel = (ConsultarSituacaoLoteRpsResposta)respSerializer.Deserialize(reader); does not occur any error but the properties of objects are null, anyone know what is happening?

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  • Are lambda expressions/delegates in C# "pure", or can they be?

    - by Bob
    I recently asked about functional programs having no side effects, and learned what this means for making parallelized tasks trivial. Specifically, that "pure" functions make this trivial as they have no side effects. I've also recently been looking into LINQ and lambda expressions as I've run across examples many times here on StackOverflow involving enumeration. That got me to wondering if parallelizing an enumeration or loop can be "easier" in C# now. Are lambda expressions "pure" enough to pull off trivial parallelizing? Maybe it depends on what you're doing with the expression, but can they be pure enough? Would something like this be theoretically possible/trivial in C#?: Break the loop into chunks Run a thread to loop through each chunk Run a function that does something with the value from the current loop position of each thread For instance, say I had a bunch of objects in a game loop (as I am developing a game and was thinking about the possibility of multiple threads) and had to do something with each of them every frame, would the above be trivial to pull off? Looking at IEnumerable it seems it only keeps track of the current position, so I'm not sure I could use the normal generic collections to break the enumeration into "chunks". Sorry about this question. I used bullets above instead of pseudo-code because I don't even know enough to write pseudo-code off the top of my head. My .NET knowledge has been purely simple business stuff and I'm new to delegates and threads, etc. I mainly want to know if the above approach is good for pursuing, and if delegates/lambdas don't have to be worried about when it comes to their parallelization.

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  • Testing system where App-level and Request-level IoC containers exist

    - by Bobby
    My team is in the process of developing a system where we're using Unity as our IoC container; and to provide NHibernate ISessions (Units of work) over each HTTP Request, we're using Unity's ChildContainer feature to create a child container for each request, and sticking the ISession in there. We arrived at this approach after trying others (including defining per-request lifetimes in the container, but there are issues there) and are now trying to decide on a unit testing strategy. Right now, the application-level container itself is living in the HttpApplication, and the Request container lives in the HttpContext.Current. Obviously, neither exist during testing. The pain increases when we decided to use Service Location from our Domain layer, to "lazily" resolve dependencies from the container. So now we have more components wanting to talk to the container. We are also using MSTest, which presents some concurrency dilemmas during testing as well. So we're wondering, what do the bright folks out there in the SO community do to tackle this predicament? How does one setup an application that, during "real" runtime, relies on HTTP objects to hold the containers, but during test has the flexibility to build-up and tear-down the containers consistently, and have the ServiceLocation bits get to those precise containers. I hope the question is clear, thanks!

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  • Name Values in Excel Object model

    - by mcoolbeth
    I am using VSTO to create an Excel add-in. My plan is to persist objects inside of excel workbooks by serializing them to strings and assigning those strings to be the values of names in the workbook. However, when I call the API function to add the new name, I get a mysterious exception from the COM library. More precisely, I am calling _app.ActiveWorkbook.Names.Add(name, value, true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); where name = "an_object" and value = "TestTemplate|'Sheet1'!$A$1| 1Cube=(0,1):(1,2)| 2EntryNumber=(1,1):(2,2)| 3Description=(2,1):(3,2)| 4Group=(4,1):(5,2)| 5Repost=(3,1):(4,2)| 6Debit=(13,3):(16,4)| 7Credit=(13,2):(16,3)|Company=(6,1):(7,2)|Company Partner=(7,1):(8,2)|Time Monthly=(8,1):(9,2)|Currency=(9,1):(10,2)|Version=(10,1):(11,2)|Department=(13,0):(16,1)|Account=(13,1):(16,2)|" A hypothesis is that the value string does not qualify as a string that can be stored in a name (illegal characters, too long, etc) but I cannot find any documentation about what the restrictions are. Does anyone know what is going wrong here? The error message, in case anyone wants it, is Exception from HRESULT: 0x800A03EC Thanks alot.

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  • Qt Jambi: Accessing the content of QNetworkReply

    - by Richard
    Hi All, I'm having trouble accessing the content of QNetworkReply objects. Content appears to be empty or zero. According to the docs (translating from c++ to java) I think I've got this set up correctly, but to no avail. Additionally an "Unknown error" is being reported. Any ideas much appreciated. Code: public class Test extends QObject { private QWebPage page; public Test() { page = new QWebPage(); QNetworkAccessManager nac = new QNetworkAccessManager(); nac.finished.connect(this, "requestFinished(QNetworkReply)"); page.setNetworkAccessManager(nac); page.loadProgress.connect(this, "loadProgress(int)"); page.loadFinished.connect(this, "loadFinished()"); } public void requestFinished(QNetworkReply reply) { reply.reset(); reply.open(OpenModeFlag.ReadOnly); reply.readyRead.connect(this, "ready()"); // never gets called System.out.println("bytes: " + reply.url().toString()); // writes out asset uri no problem System.out.println("bytes: " + reply.bytesToWrite()); // 0 System.out.println("At end: " + reply.atEnd()); // true System.out.println("Error: " + reply.errorString()); // "Unknown error" } public void loadProgress(int progress) { System.out.println("Loaded " + progress + "%"); } public void loadFinished() { System.out.println("Done"); } public void ready() { System.out.println("Ready"); } public void open(String url) { page.mainFrame().load(new QUrl(url)); } public static void main(String[] args) { QApplication.initialize(new String[] { }); Test t = new Test(); t.open("http://news.bbc.co.uk"); QApplication.exec(); } }

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  • WCF Service instead of ASMX Web Service?

    - by wchrisjohnson
    I'm writing a SOAP Server that will act as an endpoint for an external client. The external client expects SOAP 1.1. I'll be taking embedded business objects in the SOAP messages and passing them to an internal application, getting responses back and responding with SOAP messages to the eternal client. I did the traditional ASMX based web services several years ago. Now, I've been exploring WCF Services and wondering the best approach to take. 1) Should WCF be considered a superset of ASMX web services? 2) Is there any reason to still write new web services using ASMX instead of WCF? 3) Does WCF provide better facilities for working with SOAP messages, as opposed to SOAP Extensions? 4) Can I restrict communication to SOAP 1.1 using WCF, the way I can with a web.config change in ASMX? 5) Does WCF have an easy way to log or review the requests that hit the service without resorting to something like SOAP extensions? Sorry my questions are not very specific; still trying to get handle on what I need to know... Using VS2008, Windows Server 2008. Chris

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  • List.Sort in C#: comparer being called with null object

    - by cbp
    I am getting strange behaviour using the built-in C# List.Sort function with a custom comparer. For some reason it sometimes calls the comparer class's Compare method with a null object as one of the parameters. But if I check the list with the debugger there are no null objects in the collection. My comparer class looks like this: public class DelegateToComparer<T> : IComparer<T> { private readonly Func<T,T,int> _comparer; public int Compare(T x, T y) { return _comparer(x, y); } public DelegateToComparer(Func<T, T, int> comparer) { _comparer = comparer; } } This allows a delegate to be passed to the List.Sort method, like this: mylist.Sort(new DelegateToComparer<MyClass>( (x, y) => { return x.SomeProp.CompareTo(y.SomeProp); }); So the above delegate will throw a null reference exception for the x parameter, even though no elements of mylist are null. UPDATE: Yes I am absolutely sure that it is parameter x throwing the null reference exception! UPDATE: Instead of using the framework's List.Sort method, I tried a custom sort method (i.e. new BubbleSort().Sort(mylist)) and the problem went away. As I suspected, the List.Sort method passes null to the comparer for some reason.

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  • How do I send an XML document to an ASP.NET MVC page for manipuation

    - by Decker
    I have some hierarchical data stored as an multiple XML files on the server according to a vendor's schema. In my ASP.NET MVC (2!) application, I'd like the user to choose one of these hierarchies (i.e. file -- I provide a list in my controller's Index action). When the user selects one to "edit" my edit action should return a page that presents the XML hierarchy (it's a representation of a folder tree). So my thoughts are that the view would return HTML that contained a JQuery on load ajax call back to the server for the XML data -- at which point I would present the tree using one of the many JQuery tree controls. On the client side I'd like the user to manipulate the tree and when done, I'd like to post back the new hierarchy where I would replace the original XML file that represents that hierarchy. So my questions are: What form should I use to send the data down? XML or JSON?. If I send down XML then I would have to not only read the XML -- which JQuery can do -- but I would also have to be able to modify that XML and then send it back. Can I use JQuery to modify this XML DOM? And will all the namespace declarations be preserved? What form should I send the data back? If I originally sent the client the hierarchy as JSON (using JsonResult), then presumably I would have a hierarchy of javascript objects. What options would I have to post that back? Would I have to recreate the XML reprentation on the client and post that back? Or should I serialize back to JSON, post that to the server, and then have the server do the work of recreating the XML according to the schema. Thanks for any advice.

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  • Map element position in data file to class property

    - by Augusto
    I need to read/write files, following a format provided by a third party specification. The specification itself is pretty simple: it says the position and the size of the data that will be saved in the file. For example: Position Size Description -------------------------------------------------- 0001 10 Device serial number 0011 02 Hour 0013 02 Minute 0015 02 Second 0017 02 Day 0019 02 Month 0021 02 Year The list is very long, it has about 400 elements. But lots of them can be combined. For example, hour, minute, second, day, month and year can be combined in a single DateTime object. I've splitted the elements into about 4 categories, and created separeted classes for holding the data. So, instead of a big structure representing the data, I have some smaller classes. I've also created different classes for reading and writing the data. The problem is: how to map the positions in the file to the objects properties, so that I don't need to repeat the values in the reading/writing class? I could use some custom attributes and retrieve them via reflection. But since the code will be running on devices with small memory and processor, it would be nice to find another way. My current read code looks like this: public void Read() { DataFile dataFile = new DataFile(); // the arguments are: position, size dataFile.SerialNumber = ReadLong(1, 10); //... } Any ideas on this one? Thanks!

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  • instantiate python object within a c function called via ctypes

    - by gwk
    My embedded Python 3.3 program segfaults when I instantiate python objects from a c function called by ctypes. After setting up the interpreter, I can successfully instantiate a python Int (as well as a custom c extension type) from c main: #import <Python/Python.h> #define LOGPY(x) \ { fprintf(stderr, "%s: ", #x); PyObject_Print((PyObject*)(x), stderr, 0); fputc('\n', stderr); } // c function to be called from python script via ctypes. void instantiate() { PyObject* instance = PyObject_CallObject((PyObject*)&PyLong_Type, NULL); LOGPY(instance); } int main(int argc, char* argv[]) { Py_Initialize(); instantiate(); // works fine // run a script that calls instantiate() via ctypes. FILE* scriptFile = fopen("emb.py", "r"); if (!scriptFile) { fprintf(stderr, "ERROR: cannot open script file\n"); return 1; } PyRun_SimpleFileEx(scriptFile, scriptPath, 1); // close on completion return 0; } I then run a python script using PyRun_SimpleFileEx. It appears to run just fine, but when it calls instantiate() via ctypes, the program segfaults inside PyObject_CallObject: import ctypes as ct dy = ct.CDLL('./emb') dy.instantiate() # segfaults lldb output: instance: 0 Process 52068 stopped * thread #1: tid = 0x1c03, 0x000000010000d3f5 Python`PyObject_Call + 69, stop reason = EXC_BAD_ACCESS (code=1, address=0x18) frame #0: 0x000000010000d3f5 Python`PyObject_Call + 69 Python`PyObject_Call + 69: -> 0x10000d3f5: movl 24(%rax), %edx 0x10000d3f8: incl %edx 0x10000d3fa: movl %edx, 24(%rax) 0x10000d3fd: leaq 2069148(%rip), %rax ; _Py_CheckRecursionLimit (lldb) bt * thread #1: tid = 0x1c03, 0x000000010000d3f5 Python`PyObject_Call + 69, stop reason = EXC_BAD_ACCESS (code=1, address=0x18) frame #0: 0x000000010000d3f5 Python`PyObject_Call + 69 frame #1: 0x00000001000d5197 Python`PyEval_CallObjectWithKeywords + 87 frame #2: 0x0000000201100d8e emb`instantiate + 30 at emb.c:9 Why does the call to instantiate() fail from ctypes only? The function only crashes when it calls into the python lib, so perhaps some interpreter state is getting munged by the ctypes FFI call?

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  • ViewModel updates after Model server roundtrip

    - by Pavel Savara
    I have stateless services and anemic domain objects on server side. Model between server and client is POCO DTO. The client should become MVVM. The model could be graph of about 100 instances of 20 different classes. The client editor contains diverse tab-pages all of them live-connected to model/viewmodel. My problem is how to propagate changes after server round-trip nice way. It's quite easy to propagate changes from ViewModel to DTO. For way back it would be possible to throw away old DTO and replace it whole with new one, but it will cause lot of redrawing for lists/DataTemplates. I could gather the server side changes and transmit them to client side. But the names of fields changed would be domain/DTO specific, not ViewModel specific. And the mapping seems nontrivial to me. If I should do it imperative way after round-trip, it would break SOC/modularity of viewModels. I'm thinking about some kind of mapping rule engine, something like automappper or emit mapper. But it solves just very plain use-cases. I don't see how it would map/propagate/convert adding items to list or removal. How to identify instances in collections so it could merge values to existing instances. As well it should propagate validation/error info. Maybe I should implement INotifyPropertyChanged on DTO and try to replay server side events on it ? And then bind ViewModel to it ? Would binding solve the problems with collection merges nice way ? Is EventAgregator from PRISM useful for that ? Is there any event record-replay component ? Is there better client side pattern for architecture with server side logic ?

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  • Dependency Injection and decoupling of software layers

    - by cs31415
    I am trying to implement Dependency Injection to make my app tester friendly. I have a rather basic doubt. Data layer uses SqlConnection object to connect to a SQL server database. SqlConnection object is a dependency for data access layer. In accordance with the laws of dependency injection, we must not new() dependent objects, but rather accept them through constructor arguments. Not wanting to upset the DI gods, I dutifully create a constructor in my DAL that takes in SqlConnection. Business layer calls DAL. Business layer must therefore, pass in SqlConnection. Presentation layer calls Business layer. Hence it too, must pass in SqlConnection to business layer. This is great for class isolation and testability. But didn't we just couple the UI and Business layers to a specific implementation of the data layer which happens to use a relational database? Why do the Presentation and Business layers need to know that the underlying data store is SQL? What if the app needs to support multiple data sources other than SQL server (such as XML files, Comma delimited files etc.) Furthermore, what if I add another object upon which my data layer is dependent on (say, a second database). Now, I have to modify the upper layers to pass in this new object. How can I avoid this merry-go-round and reap all the benefits of DI without the pain?

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  • Automation Error when exporting Excel data to SQL Server

    - by brohjoe
    I'm getting an Automation error upon running VBA code in Excel 2007. I'm attempting to connect to a remote SQL Server DB and load data to from Excel to SQL Server. The error I get is, "Run-time error '-2147217843(80040e4d)': Automation error". I checked out the MSDN site and it suggested that this may be due to a bug associated with the sqloledb provider and one way to mitigate this is to use ODBC. Well I changed the connection string to reflect ODBC provider and associated parameters and I'm still getting the same error. Here is the code with ODBC as the provider: Dim cnt As ADODB.Connection Dim rst As ADODB.Recordset Dim stSQL As String Dim wbBook As Workbook Dim wsSheet As Worksheet Dim rnStart As Range Public Sub loadData() 'This was set up using Microsoft ActiveX Data Components version 6.0. 'Create ADODB connection object, open connection and construct the connection string object. Set cnt = New ADODB.Connection cnt.ConnectionString = "Driver={SQL Server}; Server=onlineSQLServer2010.foo.com; Database=fooDB;Uid=logonalready;Pwd='helpmeOB1';" cnt.Open On Error GoTo ErrorHandler 'Open Excel and run query to export data to SQL Server. strSQL = "SELECT * INTO SalesOrders FROM OPENDATASOURCE('Microsoft.ACE.OLEDB.12.0'," & _ "'Data Source=C:\Database.xlsx; Extended Properties=Excel 12.0')...[SalesOrders$]" cnt.Execute (strSQL) 'Error handling. ErrorExit: 'Reclaim memory from the connection objects Set rst = Nothing Set cnt = Nothing Exit Sub ErrorHandler: MsgBox Err.Description, vbCritical Resume ErrorExit 'clean up and reclaim memory resources. If CBool(cnt.State And adStateOpen) Then Set rst = Nothing Set cnt = Nothing cnt.Close End If End Sub

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  • Filter a date property between a begin and end Dates with JDOQL

    - by Sergio del Amo
    I want to code a function to get a list of Entry objects whose date field is between a beginPeriod and endPeriod I post below a code snippet which works with a HACK. I have to substract a day from the begin period date. It seems the condition great or equal does not work. Any idea why I have this issue? public static List<Entry> getEntries(Date beginPeriod, Date endPeriod) { /* TODO * The great or equal condition does not seem to work in the filter below * Substract a day and it seems to work */ Calendar calendar = Calendar.getInstance(); calendar.set(beginPeriod.getYear(), beginPeriod.getMonth(), beginPeriod.getDate() - 1); beginPeriod = calendar.getTime(); PersistenceManager pm = JdoUtil.getPm(); Query q = pm.newQuery(Entry.class); q.setFilter("this.date >= beginPeriodParam && this.date <= endPeriodParam"); q.declareParameters("java.util.Date beginPeriodParam, java.util.Date endPeriodParam"); List<Entry> entries = (List<Entry>) q.execute(beginPeriod,endPeriod); return entries; }

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  • DDD: Persisting aggregates

    - by Mosh
    Hello, Let's consider the typical Order and OrderItem example. Assuming that OrderItem is part of the Order Aggregate, it an only be added via Order. So, to add a new OrderItem to an Order, we have to load the entire Aggregate via Repository, add a new item to the Order object and persist the entire Aggregate again. This seems to have a lot of overhead. What if our Order has 10 OrderItems? This way, just to add a new OrderItem, not only do we have to read 10 OrderItems, but we should also re-insert all these 10 OrderItems again. (This is the approach that Jimmy Nillson has taken in his DDD book. Everytime he wants to persists an Aggregate, he clears all the child objects, and then re-inserts them again. This can cause other issues as the ID of the children are changed everytime because of the IDENTITY column in database.) I know some people may suggest to apply Unit of Work pattern at the Aggregate Root so it keeps track of what has been changed and only commit those changes. But this violates Persistence Ignorance (PI) principle because persistence logic is leaking into the Domain Model. Has anyone thought about this before? Mosh

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