Search Results

Search found 9894 results on 396 pages for 'primary interop assembly'.

Page 344/396 | < Previous Page | 340 341 342 343 344 345 346 347 348 349 350 351  | Next Page >

  • iPhone - Using sql database - insert statement failing

    - by Satyam svv
    Hi, I'm using sqlite database in my iphone app. I've a table which has 3 integer columns. I'm using following code to write to that database table. -(BOOL)insertTestResult { NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString* documentsDirectory = [paths objectAtIndex:0]; NSString* dataBasePath = [documentsDirectory stringByAppendingPathComponent:@"test21.sqlite3"]; BOOL success = NO; sqlite3* database = 0; if(sqlite3_open([dataBasePath UTF8String], &database) == SQLITE_OK) { BOOL res = (insertResultStatement == nil) ? createStatement(insertResult, &insertResultStatement, database) : YES; if(res) { int i = 1; sqlite3_bind_int(insertResultStatement, 0, i); sqlite3_bind_int(insertResultStatement, 1, i); sqlite3_bind_int(insertResultStatement, 2, i); int err = sqlite3_step(insertResultStatement); if(SQLITE_ERROR == err) { NSAssert1(0, @"Error while inserting Result. '%s'", sqlite3_errmsg(database)); success = NO; } else { success = YES; } sqlite3_finalize(insertResultStatement); insertResultStatement = nil; } } sqlite3_close(database); return success;} The command sqlite3_step is always giving err as 19. I'm not able to understand where's the issue. Tables are created using following queries: CREATE TABLE [Patient] (PID integer NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,PFirstName text NOT NULL,PLastName text,PSex text NOT NULL,PDOB text NOT NULL,PEducation text NOT NULL,PHandedness text,PType text) CREATE TABLE PatientResult(PID INTEGER,PFreeScore INTEGER NOT NULL,PForcedScore INTEGER NOT NULL,FOREIGN KEY (PID) REFERENCES Patient(PID)) I've only one entry in Patient table with PID = 1 BOOL createStatement(const char* query, sqlite3_stmt** stmt, sqlite3* database){ BOOL res = (sqlite3_prepare_v2(database, query, -1, stmt, NULL) == SQLITE_OK); if(!res) NSLog( @"Error while creating %s => '%s'", query, sqlite3_errmsg(database)); return res;}

    Read the article

  • C#: Non-constructed generics as properties (eg. List<T>)

    - by Dav
    The Problem It's something I came across a while back and was able to work around it somehow. But now it came back, feeding on my curiosity - and I'd love to have a definite answer. Basically, I have a generic dgv BaseGridView<T> : DataGridView where T : class. Constructed types based on the BaseGridView (such as InvoiceGridView : BaseGridView<Invoice>) are later used in the application to display different business objects using the shared functionality provided by BaseGridView (like virtual mode, buttons, etc.). It now became necessary to create a user control that references those constructed types to control some of the shared functionality (eg. filtering) from BaseGridView. I was therefore hoping to create a public property on the user control that would enable me to attach it to any BaseGridView in Designer/code: public BaseGridView<T> MyGridView { get; set; }. The trouble is, it doesn't work :-) When compiled, I get the following message: The type or namespace name 'T' could not be found (are you missing a using directive or an assembly reference?) Solutions? I realise I could extract the shared functionality to an interface, mark BaseGridView as implementing that interface, and then refer to the created interface in my uesr control. But I'm curious if there exists some arcane C# command/syntax that would help me achieve what I want - without polluting my solution with an interface I don't really need :-)

    Read the article

  • design pattern for related inputs

    - by curiousMo
    My question is a design question : let's say i have a data entry web page with 4 drop down lists, each depending on the previous one, and a bunch of text boxes. ddlCountry (DropDownList) ddlState (DropDownList) ddlCity (DropDownList) ddlBoro (DropDownList) txtAddress (TxtBox) txtZipcode(TxtBox) and an object that represents a datarow with a value for each: countrySeqid stateSeqid citySeqid boroSeqid address zipCode naturally the country, state, city and boro values will be values of primary keys of some lookup tables. when the user chooses to edits that record, i would load it from database and load it into the page. the issue that I have is how to streamline loading the DropDownLists. i have some code that would grab the object,look thru its values and move them to their corresponding input controls in one shot. but in this case i will have to load the ddlCountry with possible values, then assign values, then do the same thing for the rest of the ddls. I guess i am looking for an elegant solution. i am using asp.net, but i think it is irrelevant to the question. i am looking more into a design pattern.

    Read the article

  • how can access public properties of MasterPage from external Class ?

    - by eugeneK
    Why i can't access MasterPage's public property (MessagePlaceholder) from other Class (Errors) ? Error compiler gives me is "Error 1 The type or namespace name 'MyMasterPage' could not be found (are you missing a using directive or an assembly reference?)" my master page code behind using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class MyMasterPage : System.Web.UI.MasterPage { public string MessagePlaceholder { get { return messagePlaceholder.InnerHtml; } set { messagePlaceholder.InnerHtml = value; } } protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { messagePlaceholder.InnerHtml = Errors.getMessage(); } } } my Errors Class public static string getMessage() { HttpContext c = HttpContext.Current; string messageType = ""; if (c.Session["errorMessage"] != null) { messageType = "errorMessage"; } else if (c.Session["successMessage"] != null) { messageType = "successMessage"; } if (!string.IsNullOrEmpty(messageType)) { StringBuilder userMessageSb = new StringBuilder(); userMessageSb.Append(string.Format("<div id=\"{0}\" title=\"{1}\">{2}</div>", messageType, messageType.Replace("Message",string.Empty), c.Session[messageType])); // fix so message will not re-appear c.Session.Remove(messageType); messageType = userMessageSb.ToString(); } return messageType; } public static void setSuccess(string successMessage, bool isRedirect) { HttpContext.Current.Session["successMessage"] = successMessage; } public static void setError(string errorMessage, bool isRedirect) { HttpContext.Current.Session["errorMessage"] = errorMessage; if (!isRedirect) { ((HttpContext.Current.CurrentHandler as System.Web.UI.Page).Master as MyMasterPage).MessagePlaceholder = getMessage(); } } this is how i set error if (true) { Errors.setError("this is an error demo", false); return; } or with redirect after error if (true) { Errors.setError("yet another error", true); Response.Redirect("~/error.aspx"); }

    Read the article

  • How can I concisely copy multiple SQL rows, with minor modifications?

    - by Steve Jessop
    I'm copying a subset of some data, so that the copy will be independently modifiable in future. One of my SQL statements looks something like this (I've changed table and column names): INSERT Product( ProductRangeID, Name, Weight, Price, Color, And, So, On ) SELECT @newrangeid AS ProductRangeID, Name, Weight, Price, Color, And, So, On FROM Product WHERE ProductRangeID = @oldrangeid and Color = 'Blue' That is, we're launching a new product range which initially just consists of all the blue items in some specified current range, under new SKUs. In future we may change the "blue-range" versions of the products independently of the old ones. I'm pretty new at SQL: is there something clever I should do to avoid listing all those columns, or at least avoid listing them twice? I can live with the current code, but I'd rather not have to come back and modify it if new columns are added to Product. In its current form it would just silently fail to copy the new column if I forget to do that, which should show up in testing but isn't great. I am copying every column except for the ProductRangeID (which I modify), the ProductID (incrementing primary key) and two DateCreated and timestamp columns (which take their auto-generated values for the new row). Btw, I suspect I should probably have a separate join table between ProductID and ProductRangeID. I didn't define the tables. This is in a T-SQL stored procedure on SQL Server 2008, if that makes any difference.

    Read the article

  • AngularJS not validating email field in form

    - by idipous
    I have the html below where I have a form that I want to submit to the AngularJS Controller. <div class="newsletter color-1" id="subscribe" data-ng-controller="RegisterController"> <form name="registerForm"> <div class="col-md-6"> <input type="email" placeholder="[email protected]" data-ng-model="userEmail" required class="subscribe"> </div> <div class="col-md-2"> <button data-ng-click="register()" class="btn btn-primary pull-right btn-block">Subsbcribe</button> </div> </form> </div> And the controller is below app.controller('RegisterController', function ($scope,dataFactory) { $scope.users = dataFactory.getUsers(); $scope.register = function () { var userEmail = $scope.userEmail; dataFactory.insertUser(userEmail); $scope.userEmail = null; $scope.ThankYou = "Thank You!"; } }); The problem is that no validation is taking place when I click the button. It is always routed to the controller although I do not supply a correct email. So every time I click the button I get the {{ThankYou}} variable displayed. Maybe I do not understand something.

    Read the article

  • What does P mean in Sort(Expression<Func<T, P>> expr, ListSortDirection direction)?

    - by Grasshopper
    I am attempting to use the answer in post: How do you sort an EntitySet<T> to expose an interface so that I can sort an EntitySet with a Binding list. I have created the class below and I get the following compiler error: "The type or namespace 'P' could not be found (are you missing a using directive or assembly reference?). Can someone tell me what the P means and which namespace I need to include to get the method below to compile? I am very new to delegates and lamba expressions. Also, can someone confirm that if I create a BindingList from my EntitySet that any modifications I make to the BindingList will be made to the EntitySet? Basically, I have an EntitySet that I need to sort and make changes to. Then, I will need to persist these changes using the original Entity that the BindingList came from. public class EntitySetBindingWrapper<T> : BindingList<T> { public EntitySetBindingWrapper(BindingList<T> root) : base(root) { } public void Sort(Expression<Func<T, P>> expr, ListSortDirection direction) { if (expr == null) base.RemoveSortCore(); MemberExpression propExpr = expr as MemberExpression; if (propExpr == null) throw new ArgumentException("You must provide a property", "expr"); PropertyDescriptorCollection descriptorCol = TypeDescriptor.GetProperties(typeof(T)); IEnumerable<PropertyDescriptor> descriptors = descriptorCol.Cast<PropertyDescriptor>(); PropertyDescriptor descriptor = descriptors.First(pd => pd.Name == propExpr.Member.Name); base.ApplySortCore(descriptor, direction); } }

    Read the article

  • How did My Object Get into ASP.NET Page State?

    - by Paul Knopf
    I know what this error is, how to fix it, etc. My question is that I don't know why my current page I am developing is throwing this error when I am not using the foo class directly in any way, nor am I setting anything to the viewstate. I am using postbacks alot, but like I said, I am not storing anything in the viewstate etc one integer. I am using nhibernate if that is relevant. Any idea why I need to mark this classes as serializable that arent being used? Where should I start investigating? [SerializationException: Type 'FlexiCommerce.Persistence.NH.ContentPersister' in Assembly 'FlexiCommerce.Persistence.NH, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.] System.Runtime.Serialization.FormatterServices.InternalGetSerializableMembers(RuntimeType type) +9434541 System.Runtime.Serialization.FormatterServices.GetSerializableMembers(Type type, StreamingContext context) +247 System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitMemberInfo() +160 System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder) +218 System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Write(WriteObjectInfo objectInfo, NameInfo memberNameInfo, NameInfo typeNameInfo) +388 System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, Header[] inHeaders, __BinaryWriter serWriter, Boolean fCheck) +444 System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph, Header[] headers, Boolean fCheck) +133 System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph) +13 System.Web.UI.ObjectStateFormatter.SerializeValue(SerializerBinaryWriter writer, Object value) +2937 [ArgumentException: Error serializing value 'Music#2' of type 'FlexiCommerce.Components.Category.'] System.Web.UI.ObjectStateFormatter.SerializeValue(SerializerBinaryWriter writer, Object value) +3252 System.Web.UI.ObjectStateFormatter.SerializeValue(SerializerBinaryWriter writer, Object value) +2276 [ArgumentException: Error serializing value 'System.Object[]' of type 'System.Object[].'] System.Web.UI.ObjectStateFormatter.SerializeValue(SerializerBinaryWriter writer, Object value) +3252 System.Web.UI.ObjectStateFormatter.Serialize(Stream outputStream, Object stateGraph) +116 System.Web.UI.ObjectStateFormatter.Serialize(Object stateGraph) +57 System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter.Serialize(Object state) +4 System.Web.UI.Util.SerializeWithAssert(IStateFormatter formatter, Object stateGraph) +37 System.Web.UI.HiddenFieldPageStatePersister.Save() +79 System.Web.UI.Page.SavePageStateToPersistenceMedium(Object state) +108 System.Web.UI.Page.SaveAllState() +315 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2492

    Read the article

  • Has anyone ever had OpenCV work with Python 2.7 on MacOS 10.6?

    - by ?????
    I've been trying on and off for the past 6 months to get OpenCV to work with Python on MacOS. Every time there's a new release, I try again and fail. I've tried both 64-bit and 32-bit, and both the xcode gcc and gcc installed via macports. I just spend the past two days on it, hopeful that the latest OpenCV release, that appears to include Python support directly would work. It doesn't. I've also tried and failed to use this: http://code.google.com/p/pyopencv/ I've been using OpenCV with C++ or Microsoft C++/CLI for the past few years, but I'd love to use it with Python on a Mac because that is my primary development environment. I'd love to hear from anyone who's actually been able to get the opencv python examples to run under Mac OS 10.6, either 32 or 64-bit. My last attempt was to follow the instructions on this page http://recursive-design.com/blog/2010/12/14/face-detection-with-osx-and-python/ with a clean, fresh install of 10.6 on a 64-bit capable Mac. My PYTHONPATH is set, and I can see the cv library in it. But an "import cv" from python fails. Previously, the closest I've ever gotten (again, staring on a clean, fresh 10.6 install) was this: Python 2.7.1 (r271:86882M, Nov 30 2010, 10:35:34) [GCC 4.2.1 (Apple Inc. build 5664)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> import cv Fatal Python error: Interpreter not initialized (version mismatch?) Abort trap thrilllap-2:~ swirsky$ I've seen a lot of folks answering similar questions here, but have never seen an definitive answer for it.

    Read the article

  • @ManyToMany Duplicate Entry Exception

    - by zp26
    I have mapped a bidirectional many-to-many exception between the entities Course and Trainee in the following manner: Course { ... private Collection<Trainee> students; ... @ManyToMany(targetEntity = lesson.domain.Trainee.class, cascade = {CascadeType.All}, fetch = {FetchType.EAGER}) @Jointable(name="COURSE_TRAINEE", joincolumns = @JoinColumn(name="COURSE_ID"), inverseJoinColumns = @JoinColumn(name = "TRAINEE_ID")) @CollectionOfElements public Collection<Trainee> getStudents() { return students; } ... } Trainee { ... private Collection<Course> authCourses; ... @ManyToMany(cascade = {CascadeType.All}, fetch = {FetchType.EAGER}, mappedBy = "students", targetEntity = lesson.domain.Course.class) @CollectionOfElements public Collection<Course> getAuthCourses() { return authCourses; } ... } Instead of creating a table where the Primary Key is made of the two foreign keys (imported from the table of the related two entities), the system generates the table "COURSE_TRAINEE" with the following schema: I am working on MySQL 5.1 and my App. Server is JBoss 5.1. Does anyone guess why?

    Read the article

  • Stored procedure for generic MERGE

    - by GilliVilla
    I have a set of 10 tables in a database (DB1). And there are 10 tables in another database (DB2) with exact same schema on the same SQL Server 2008 R2 database server machine. The 10 tables in DB1 are frequently updated with data. I intend to write a stored procedure that would run once every day for synchronizing the 10 tables in DB1 with DB2. The stored procedure would make use of the MERGE statement. Now, my aim is to make this as generic and parametrized as possible. That is, accommodate for more tables down the line... and accommodate different source and target DB names. Definitely no hard coding is intended. This is my algorithm so far: Have the database names as parameters Have the first query within the stored procedure... result in giving the names of the 10 tables from a lookup table (this can be 10, 20 or whatever) Have a generic MERGE statement that does the sync for each of the above set of tables (based on primary key?) This is where I need more inputs on. What is the best way to achieve this stored procedure? SQL syntax would be helpful.

    Read the article

  • Question about using an access database as a resource file in Visual Studio.

    - by user354303
    Hi I am trying to embed a Microsoft Access database file into my Class assembly DLL. I want my code to reference the resource file and use it with a ADODB.Connection object. Any body know a simpler way, or an easier way? Or what is wrong with my code, when i added the resource file it added me dataset definitions, but i have no idea what to do with those. The connection string I am trying below is from an automatically generated app.config. I did add the item as a resource... using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; using ConsoleApplication1.Resources;//SPPrinterLicenses using System.Data.OleDb; using ADODB; using System.Configuration; namespace ConsoleApplication1 { class SharePointPrinterManager { public static bool IsValidLicense(string HardwareID) { OleDbDataAdapter da = new OleDbDataAdapter(); DataSet ds = new DataSet(); ADODB.Connection adoCn = new Connection(); ADODB.Recordset adoRs = new Recordset(); //**open command below fails** adoCn.Open( @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Resources\SPPrinterLicenses.accdb;Persist Security Info=True", "", "", 1); adoRs.Open("Select * from AllWorkstationLicenses", adoCn, ADODB.CursorTypeEnum.adOpenForwardOnly, ADODB.LockTypeEnum.adLockReadOnly, 1); da.Fill(ds, adoRs, "AllworkstationLicenses"); adoCn.Close(); DataTable dt = new DataTable(); //ds.Tables. return true; } } }

    Read the article

  • FluentNHibernate error -- "Invalid object name"

    - by goober
    I'm attempting to do the most simple of mappings with FluentNHibernate & Sql2005. Basically, I have a database table called "sv_Categories". I'd like to add a category, setting the ID automatically, and adding the userid and title supplied. Database table layout: CategoryID -- int -- not-null, primary key, auto-incrementing UserID -- uniqueidentifier -- not null Title -- varchar(50) -- not null Simple. My SessionFactory code (which works, as far as I can tell): _SessionFactory = Fluently.Configure().Database( MsSqlConfiguration.MsSql2005 .ConnectionString(c => c.FromConnectionStringWithKey("SVTest"))) .Mappings(x => x.FluentMappings.AddFromAssemblyOf<CategoryMap>()) .BuildSessionFactory(); My ClassMap code: public class CategoryMap : ClassMap<Category> { public CategoryMap() { Id(x => x.ID).Column("CategoryID").Unique(); Map(x => x.Title).Column("Title").Not.Nullable(); Map(x => x.UserID).Column("UserID").Not.Nullable(); } } My Class code: public class Category { public virtual int ID { get; private set; } public virtual string Title { get; set; } public virtual Guid UserID { get; set; } public Category() { // do nothing } } And the page where I save the object: public void Add(Category catToAdd) { using (ISession session = SessionProvider.GetSession()) { using (ITransaction Transaction = session.BeginTransaction()) { session.Save(catToAdd); Transaction.Commit(); } } } I receive the error Invalid object name 'Category'. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.SqlClient.SqlException: Invalid object name 'Category'. I think it might be that I haven't told the CategoryMap class to use the "sv_Categories" table, but I'm not sure how to do that. Any help would be appreciated. Thanks!

    Read the article

  • Multiple generic types in one container

    - by Lirik
    I was looking at the answer of this question regarding multiple generic types in one container and I can't really get it to work: the properties of the Metadata class are not visible, since the abstract class doesn't have them. Here is a slightly modified version of the code in the original question: public abstract class Metadata { } public class Metadata<T> : Metadata { // ... some other meta data public T Function{ get; set; } } List<Metadata> metadataObjects; metadataObjects.Add(new Metadata<Func<double,double>>()); metadataObjects.Add(new Metadata<Func<int,double>>()); metadataObjects.Add(new Metadata<Func<double,int>>()); foreach( Metadata md in metadataObjects) { var tmp = md.Function; // <-- Error: does not contain a definition for Function } The exact error is: error CS1061: 'Metadata' does not contain a definition for 'Function' and no extension method 'Function' accepting a first argument of type 'Metadata' could be found (are you missing a using directive or an assembly reference?) I believe it's because the abstract class does not define the property Function, thus the whole effort is completely useless. Is there a way that we can get the properties?

    Read the article

  • Extracting DCT coefficients from encoded images and video

    - by misha
    Is there a way to easily extract the DCT coefficients (and quantization parameters) from encoded images and video? Any decoder software must be using them to decode block-DCT encoded images and video. So I'm pretty sure the decoder knows what they are. Is there a way to expose them to whomever is using the decoder? I'm implementing some video quality assessment algorithms that work directly in the DCT domain. Currently, the majority of my code uses OpenCV, so it would be great if anyone knows of a solution using that framework. I don't mind using other libraries (perhaps libjpeg, but that seems to be for still images only), but my primary concern is to do as little format-specific work as possible (I don't want to reinvent the wheel and write my own decoders). I want to be able to open any video/image (H.264, MPEG, JPEG, etc) that OpenCV can open, and if it's block DCT-encoded, to get the DCT coefficients. In the worst case, I know that I can write up my own block DCT code, run the decompressed frames/images through it and then I'd be back in the DCT domain. That's hardly an elegant solution, and I hope I can do better. Presently, I use the fairly common OpenCV boilerplate to open images: IplImage *image = cvLoadImage(filename); // Run quality assessment metric The code I'm using for video is equally trivial: CvCapture *capture = cvCaptureFromAVI(filename); while (cvGrabFrame(capture)) { IplImage *frame = cvRetrieveFrame(capture); // Run quality assessment metric on frame } cvReleaseCapture(&capture); In both cases, I get a 3-channel IplImage in BGR format. Is there any way I can get the DCT coefficients as well?

    Read the article

  • Why does VS2005 skip execution of lines when debugging managed C++ without optimizations?

    - by Sakin
    I ran into a rather odd behavior that I don't even know how to start describing. I wrote a piece of managed C++ code that makes calls to native methods. A (very) simplified version of the code would look like this (I know it looks like a full native function, just assume there is managed stuff being done all over the place): int somefunction(ptrHolder x) { // the accessptr method returns a native pointer if (x.accessptr() != nullptr) // I tried this with nullptr, NULL, 0) { try { x->doSomeNativeVeryImportantStuff(); // or whatever, doesn't matter } catch (SomeCustomExceptionClass &) { return 0; } } SomeOtherNativeClass::doStaticMagic(); return 1; } I compiled this code without optimizations using the /clr flag (VS.NET 2005, SP2) and when running it in the debugger I get to the if statement, since the pointer is actually null, I don't enter the if, but surprisingly, the cursor jumps directly to the return 1 statement, ignoring the doStaticMagic() method completely!!! When looking at the assembly code, I see that it really jumps directly to that line. If I force the debugger to enter the if block, I also jump to the return 1 statement after I press F10. Any ideas why this is happening? Thanks, Ariel

    Read the article

  • Best (Java) book for understanding 'under the bonnet' for programming?

    - by Ben
    What would you say is the best book to buy to understand exactly how programming works under the hood in order to increase performance? I've coded in assembly at university, I studied computer architecture and I obviously did high level programming, but what I really dont understand is things like: -what is happening when I perform a cast -whats the difference in performance if I declare something global as opposed to local? -How does the memory layout for an ArrayList compare with a Vector or LinkedList? -Whats the overhead with pointers? -Are locks more efficient than using synchronized? -Would creating my own array using int[] be faster than using ArrayList -Advantages/disadvantages of declaring a variable volatile I have got a copy of Java Performance Tuning but it doesnt go down very low and it contains rather obvious things like suggesting a hashmap instead of using an ArrayList as you can map the keys to memory addresses etc. I want something a bit more Computer Sciencey, linking the programming language to what happens with the assembler/hardware. The reason im asking is that I have an interview coming up for a job in High Frequency Trading and everything has to be as efficient as possible, yet I cant remember every single possible efficiency saving so i'd just like to learn the fundamentals. Thanks in advance

    Read the article

  • Questions about openid and dotnetauthentication

    - by chobo2
    Hi I am looking into openid and dotnetauthentication library. However I still go some outstanding questions. the id that comes back is that unique for each user? Can I store this id in a database as the userId(currently this field is a primary key and unique identifier) I read that you can try to request information such as email address but you may not give it to you. What happens if you need this information? I think it kinda sucks if I have to popup another field right away and ask for their email address and whatever else fields I need. Sort of seems to defeat the purpose a bit as I always considered a benefit of openid is that you don't have to fill out registration forms. Is it better to only have some predefined choices(google,yahoo,openid,facebook). Then letting them type in their own ones(ie gray out the field to let them type in a url). I am thinking of this because it goes back to point number 2 if they type in a provider that does not give me the information that I need I am then stuck. How do you a log person out? Do you just kill the form authentication ticket?

    Read the article

  • Paperclip: Stay put on edit

    - by EricR
    When a user edits something in my application, they're forced to re-upload their image via paperclip even if they aren't changing it. Failing to do so will cause an error, since I validate_presence_of :image. This is quite annoying. How can I make it so Paperclip won't update its attributes if a user simply doesn't supply a new image on an edit? The photo controller is fresh out of Rails' scaffold generator. The rest of the source code is provided below. models/accommodation.rb class Accommodation < ActiveRecord::Base attr_accessible :photo validates_presence_of :photo has_one :photo has_many :notifications belongs_to :user accepts_nested_attributes_for :photo, :allow_destroy => true end controllers/accommodation_controller.rb class AccommodationsController < ApplicationController def index @accommodations = Accommodation.all end def show @accommodation = Accommodation.find(params[:id]) rescue ActiveRecord::RecordNotFound flash[:error] = "Accommodation not found." redirect_to :home end def new @accommodation = current_user.accommodations.build @accommodation.build_photo end def create @accommodation = current_user.accommodations.build(params[:accommodation]) if @accommodation.save flash[:notice] = "Successfully created your accommodation." redirect_to @accommodation else @accommodation.build_photo render :new end end def edit @accommodation = Accommodation.find(params[:id]) @accommodation.build_photo rescue ActiveRecord::RecordNotFound flash[:error] = "Accommodation not found." redirect_to :home end def update @accommodation = Accommodation.find(params[:id]) if @accommodation.update_attributes(params[:accommodation]) flash[:notice] = "Successfully updated accommodation." redirect_to @accommodation else @accommodation.build_photo render :edit end end def destroy @accommodation = Accommodation.find(params[:id]) @accommodation.destroy flash[:notice] = "Successfully destroyed accommodation." redirect_to :inkeep end end models/photo.rb class Photo < ActiveRecord::Base attr_accessible :image, :primary belongs_to :accommodation has_attached_file :image, :styles => { :thumb=> "100x100#", :small => "150x150>" } end

    Read the article

  • How to increment the string value during run time without using dr.read() and store it in the oledb

    - by sameer
    Here is my code, everything is working fine the only problem is with the ReadData() method in which i want the string value to be increment i.e AM0001,AM0002,AM0003 etc. This is happening but only one time the value is getting increment to AM0001, the second time the same value i.e AM0001 is getting return. Due to this i am getting a error from oledb because of AM0001 is a primary key field. enter code here: class Jewellery : Connectionstr { string lmcode = null; public string LM_code { get { return lmcode;} set { lmcode = ReadData();} } string mname; public string M_Name { get { return mname; } set { mname = value;} } string desc; public string Desc { get { return desc; } set { desc = value; } } public string ReadData() { string jid = string.Empty; string displayString = string.Empty; String query = "select max(LM_code)from Master_Accounts"; Datamanager.RunExecuteReader(Constr,query); if (string.IsNullOrEmpty(jid)) { jid = "AM0000";//This string value has to increment at every time, but it is getting increment only one time. } int len = jid.Length; string split = jid.Substring(2, len - 2); int num = Convert.ToInt32(split); num++; displayString = jid.Substring(0, 2) + num.ToString("0000"); return displayString; } public void add() { String query ="insert into Master_Accounts values ('" + LM_code + "','" + M_Name + "','" + Desc + "')"; Datamanager.RunExecuteNonQuery(Constr , query); } Any help will be appreciated.

    Read the article

  • after assembling jar - No Persistence provider for EntityManager named ....

    - by alabalaa
    im developing a standalone application and it works fine when starting it from my ide(intellij idea), but after creating an uberjar and start the application from it javax.persistence.spi.PersistenceProvider is thrown saying "No Persistence provider for EntityManager named testPU" here is my persistence.xml which is placed under meta-inf directory: <persistence-unit name="testPU" transaction-type="RESOURCE_LOCAL"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <class>test.model.Configuration</class> <properties> <property name="hibernate.connection.username" value="root"/> <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/> <property name="hibernate.connection.password" value="root"/> <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/test"/> <property name="hibernate.show_sql" value="true"/> <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLInnoDBDialect"/> <property name="hibernate.c3p0.timeout" value="300"/> <property name="hibernate.hbm2ddl.auto" value="update"/> </properties> </persistence-unit> and here is how im creating the entity manager factory: emf = Persistence.createEntityManagerFactory("testPU"); im using maven and tried the assembly plug-in with the default configuration fot it, i dont have much experience with assembling jars and i dont know if im missing something, so if u have any ideas ill be glad to hear them

    Read the article

  • What's the proper approach for writing multi-path "story" flows?

    - by Basiclife
    Hi, I wonder if you can help me. I'm writing a game (2d) which allows players to take multiple routes, some of which branch/merge - perhaps even loop. Each section of the game will decide which section is loaded next. I'm calling each section an IStoryElement - And I'm wondering how best to link these elements up in a way that is easily changed/configured and at the same time, graphable I'm going to have an engine/factory assembly which will load the appropriate StoryElement(s) based on various config options. I initially planned to give each StoryElement a NextElement() As IStoryElement property and a Completed() event. When the vent fires, the engine reads the NextElement property to find the next StoryElement. The downside to this is that if I ever wanted to graph all the routes through the game, I would be unable to - I couldn't determine all possible targets for each StoryElement. I considered a couple of other solutions but they all feel a little clunky - eg Do I need an additional layer of abstraction? ie StoryElementPlayers or similar - Each one would be responsible for stringing together multiple StoryElement perhaps a Series and a ChoicePlayer with each responsible for graphing its own StoryElement - But this will just move the problem up a layer. In short, I need some way of emulating a simple but dynamic workflow (but I'd rather not actually use WWF). Is there a pattern for something this simple? All the ones I've managed to find relate to more advanced control flow (parallel processing, etc.)

    Read the article

  • NHibernate class referencing discriminator based subclass

    - by Rich
    I have a generic class Lookup which contains code/value properties. The table PK is category/code. There are subclasses for each category of lookup, and I've set the discriminator column in the base class and its value in the subclass. See example below (only key pieces shown): public class Lookup { public string Category; public string Code; public string Description; } public class LookupClassMap { CompositeId() .KeyProperty(x = x.Category, "CATEGORY_ID") .KeyProperty(x = x.Code, "CODE_ID"); DiscriminateSubclassesBasedOnColumn("CATEGORY_ID"); } public class MaritalStatus: Lookup {} public class MartialStatusClassMap: SubclassMap { DiscriminatorValue(13); } This all works. Here's the problem. When a class has a property of type MaritalStatus, I create a reference based on the contained code ID column ("MARITAL_STATUS_CODE_ID"). NHibernate doesn't like it because I didn't map both primary key columns (Category ID & Code ID). But with the Reference being of type MaritalStatus, NHibernate should already know what the value of the category ID is going to be, because of the discriminator value. What am I missing?

    Read the article

  • How to replace auto-implemented c# get body at runtime or compile time?

    - by qstarin
    I've been trying to figure this out all night, but I guess my knowledge of the .Net Framework just isn't that deep and the problem doesn't exactly Google well, but if I can get a nod in the right direction I'm sure I can implement it, one way or another. I'd like to be able to declare a property decorated with a custom attribute as such: public MyClass { [ReplaceWithExpressionFrom(typeof(SomeOtherClass))] public virtual bool MyProperty { get; } } public SomeOtherClass : IExpressionHolder<MyClass, bool> { ... } public interface IExpressionHolder<TArg, TResult> { Expression<Func<TArg, TResult>> Expression { get; } } And then somehow - this is the part I'm having trouble figuring - replace the automatically generated implementation of that getter with a piece of custom code, something like: Type expressionHolderType = LookupAttributeCtorArgTypeInDeclarationOfPropertyWereReplacing(); return ReplaceWithExpressionFromAttribute.GetCompiledExpressionFrom(expressionHolderType)(this); The main thing I'm not sure how to do is replace the automatic implementation of the get. The first thing that came to mind was PostSharp, but that's a more complicated dependency than I care for. I'd much prefer a way to code it without using post-processing attached to the build (I think that's the jist of how PostSharp sinks its hooks in anyway). The other part of this I'm not so sure about is how to retrieve the type parameter passed to the particular instantiation of the ReplaceWithExpressionFrom attribute (where it decorates the property whose body I want to replace; in other words, how do I get typeof(SomeOtherClass) where I'm coding the get body replacement). I plan to cache compiled expressions from concrete instances of IExpressionHolder, as I don't want to do that every time the property gets retrieved. I figure this has just got to be possible. At the very least I figure I should be able to search an assembly for any method decorated with the attribute and somehow proxy the class or just replace the IL or .. something? And I'd like to make the integration as smooth as possible, so if this can be done without explicitly calling a registration or initialization method somewhere that'd be super great. Thanks!

    Read the article

  • Building argv and argc

    - by Wylie Coyote SG.
    I'm a student programmer using Qt to build a GUI application for work. The primary purpose of this application is to open some of our old style files, allows better editing and then save the file in a new format and file extension. Recently I have been asked to allow this conversion to take place from a terminal. While I do know what argv and argc are along with what they represent I am unsure how to accomplish what they want. For instance how to handle relative paths vs. absolute... maybe how to get absolute from relative; perhaps none of that is even needed. My programming experience has been primarily with guis so this is a little new to me. Users would like the following to be ran from the terminal application -o /fileLocation /fileDestination template(to determine new format) I began to use for loops and if statements to begin accomplishing this when I relized that I might be taking the worng approach to all of this. I WOULD ALSO BE REALLY INTERESTED IF QT HAS SOMETHING FOR THIS! Here is what I have began coming up with: int main(int argc, char *argv[]) { if(argc > 1) { for(int i = 0; i < argc; i++) { if(argv[i] == "-c") { QString fileName = QString::fromStdString(argv[i+1]); QString fileDestination = QString::fromStdString(argv[i+2]); QString templateName = QString::fromStdString(argv[i+3]); QFile fileToConvert(fileName); if(fileToConvert.open(QFile::ReadOnly)) { //do stuff Thanks for reading my post and a big thanks for any contributions you make to helping me overcome this issue.

    Read the article

< Previous Page | 340 341 342 343 344 345 346 347 348 349 350 351  | Next Page >