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  • Is it possible to create a C++ factory system that can create an instance of any "registered" object

    - by chrensli
    Hello, I've spent my entire day researching this topic, so it is with some scattered knowledge on the topic that i come to you with this inquiry. Please allow me to describe what I am attempting to accomplish, and maybe you can either suggest a solution to the immediate question, or another way to tackle the problem entirely. I am trying to mimic something related to how XAML files work in WPF, where you are essentially instantiating an object tree from an XML definition. If this is incorrect, please inform. This issue is otherwise unrelated to WPF, C#, or anything managed - I solely mention it because it is a similar concept.. So, I've created an XML parser class already, and generated a node tree based on ObjectNode objects. ObjectNode objects hold a string value called type, and they have an std::vector of child ObjectNode objects. The next step is to instantiate a tree of objects based on the data in the ObjectNode tree. This intermediate ObjectNode tree is needed because the same ObjectNode tree might be instantiated multiple times or delayed as needed. The tree of objects that is being created is such that the nodes in the tree are descendants of a common base class, which for now we can refer to as MyBase. Leaf nodes can be of any type, not necessarily derived from MyBase. To make this more challenging, I will not know what types of MyBase derived objects might be involved, so I need to allow for new types to be registered with the factory. I am aware of boost's factory. Their docs have an interesting little design paragraph on this page: o We may want a factory that takes some arguments that are forwarded to the constructor, o we will probably want to use smart pointers, o we may want several member functions to create different kinds of objects, o we might not necessarily need a polymorphic base class for the objects, o as we will see, we do not need a factory base class at all, o we might want to just call the constructor - without #new# to create an object on the stack, and o finally we might want to use customized memory management. I might not be understanding this all correctly, but that seems to state that what I'm trying to do can be accomplished with boost's factory. But all the examples I've located, seem to describe factories where all objects are derived from a base type. Any guidance on this would be greatly appreciated. Thanks for your time!

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  • Blackberry - Programmatically extract/open zip file

    - by KKlucznik
    I have looked online with mixed results, but is there a way to programmatically extract a zip file on the BB? Very basic my app will display different encrypted file types, and those files are delivered in a zip file. My idea was to have the user browse to the file on their SDCard, select it, and I extract what i need as a stream from the file. is this possible?

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  • How to emulate OOP with C?

    - by Francisco Garcia
    I would like to know which articles or books are good to use OOP concepts in C. I mean things like using function pointers to emulate classes, strict naming conventions to emulate namespaces, and things like that. Also a reference about how to code in C different types of UML diagrams would be great.

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  • VB.NET SqlException Was Unhandled

    - by Daniel
    I am trying some SQL code but I get an error when I try this code. Main.database.ExecuteCommand("UPDATE Contacts SET first_name='" + c.first_name + _ "', middle='" + c.middle + _ "', last_name='" + c.last_name + _ "', age='" + c.age + _ "', mobile_phone='" + c.mobile_phone + _ "', home_phone='" + c.home_phone + _ "', work_phone='" + c.work_phone + _ "', home_street='" + c.home_street + _ "', home_city='" + c.home_city + _ "', home_state='" + c.home_state + _ "', home_zip='" + c.home_zip + _ "', work_street='" + c.work_street + _ "', work_city='" + c.work_city + _ "', work_state='" + c.work_state + _ "', work_zip='" + c.work_zip + _ "', home_www='" + c.home_www + _ "', work_www='" + c.work_www + _ "', home_email='" + c.home_email + _ "', work_email='" + c.work_email + _ "' WHERE first_name='" + c.first_name + _ "' AND last_name='" + c.last_name + "'") I get the following error Sql Exception was unhandled The data types text and varchar are incompatible in the equal to operator.

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  • How do I control the amount of JavaScript Ajax Control Toolkit spits out?

    - by RyanKeeter
    With the Ajax Control Toolkit, one can easily drag and drop all types of great extender onto controls, but they register a boatload of JavaScript to do it. How do I control this? If the ScriptManager is in the MasterPage, is there anyway to control the loading of a script on one page that isn't in another? For example: calendar extender is on one page, but the script for it gets loaded on every page that is a child of the master page.

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  • Add custom method to string object [closed]

    - by cru3l
    Possible Duplicate: Can I add custom methods/attributes to built-in Python types? In Ruby you can override any built-in object class with custom method, like this: class String def sayHello return self+" is saying hello!" end end puts 'JOHN'.downcase.sayHello # >>> 'john is saying hello!' How can i do that in python? Is there a normally way or just hacks?

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  • C# Automatic Properties - Still null after +=?

    - by Sam Schutte
    This seems like a bug to me... I accept that automatic properties, defined as such: public decimal? Total { get; set; } Will be null when they are first accessed. They haven't been initialized, so of course they are null. But, even after setting their value through +=, this decimal? still remains null. So after: Total += 8; Total is still null. How can this be correct? I understand that it's doing a (null + 8), but seems strange that it doesn't pick up that it means it should just be set to 8... Addendums: I made the "null + 8" point in my question - but notice that it works with strings. So, it does null + "hello" just fine, and returns "hello". Therefore, behind the scenes, it is initializing the string to a string object with the value of "hello". The behavior should be the same for the other types, IMO. It might be because a string can accept a null as a value, but still, a null string is not an initialized object, correct? Perhaps it's just because a string isn't a nullable...

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  • Will this only allow certain extensions?

    - by Dr Hydralisk
    I found this snippet that says will only allow certain file types. Will it work and could someone bypass it to upload what ever file type they want? And could someone explain the substr part, i don't get how it works.. <?php function CheckExt($filename, $ext) { $name = strtolower($filename); if(substr($name, strlen($name) -3, 3) == $ext) return true; else return false; } ?>

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  • Dynamically created jagged "rectangle" array

    - by gagar1n
    In my project I have a lot of code like this: int[][] a = new int[firstDimension][]; for (int i=0; i<firstDimension; i++) { a[i] = new int[secondDimension]; } Types of elements are different. Is there any way of writing a method like createArray(typeof(int), firstDimension, secondDimension); and getting new int[firstDimension][secondDimension]? Once again, type of elements is known only at runtime.

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  • Any tips for how to build a LED sytem thet will light up to music?

    - by daniels
    So basically I would like somehow that given an audio file as input (most likely mp3 or I can use some audio engine that will handle other types too) from my computer to control some LED lights so they will be something like an oscilloscope, like the one in winamp. What would I need to be able to do this? I'm interested in building thing up all by myself, coding, hardware, etc.. I'm going with C++ on Windows.

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  • Entity Framework does not map 2 columns from a SqlQuery calling a stored procedure

    - by user1783530
    I'm using Code First and am trying to call a stored procedure and have it map to one of my classes. I created a stored procedure, BOMComponentChild, that returns details of a Component with information of its hierarchy in PartsPath and MyPath. I have a class for the output of this stored procedure. I'm having an issue where everything except the two columns, PartsPath and MyPath, are being mapped correctly with these two properties ending up as Nothing. I searched around and from my understanding the mapping bypasses any Entity Framework name mapping and uses column name to property name. The names are the same and I'm not sure why it is only these two columns. The last part of the stored procedure is: SELECT t.ParentID ,t.ComponentID ,c.PartNumber ,t.PartsPath ,t.MyPath ,t.Layer ,c.[Description] ,loc.LocationID ,loc.LocationName ,CASE WHEN sup.SupplierID IS NULL THEN 1 ELSE sup.SupplierID END AS SupplierID ,CASE WHEN sup.SupplierName IS NULL THEN 'Scinomix' ELSE sup.SupplierName END AS SupplierName ,c.Active ,c.QA ,c.IsAssembly ,c.IsPurchasable ,c.IsMachined ,t.QtyRequired ,t.TotalQty FROM BuildProducts t INNER JOIN [dbo].[BOMComponent] c ON c.ComponentID = t.ComponentID LEFT JOIN [dbo].[BOMSupplier] bsup ON bsup.ComponentID = t.ComponentID AND bsup.IsDefault = 1 LEFT JOIN [dbo].[LookupSupplier] sup ON sup.SupplierID = bsup.SupplierID LEFT JOIN [dbo].[LookupLocation] loc ON loc.LocationID = c.LocationID WHERE (@IsAssembly IS NULL OR IsAssembly = @IsAssembly) ORDER BY t.MyPath and the class it maps to is: Public Class BOMComponentChild Public Property ParentID As Nullable(Of Integer) Public Property ComponentID As Integer Public Property PartNumber As String Public Property MyPath As String Public Property PartsPath As String Public Property Layer As Integer Public Property Description As String Public Property LocationID As Integer Public Property LocationName As String Public Property SupplierID As Integer Public Property SupplierName As String Public Property Active As Boolean Public Property QA As Boolean Public Property IsAssembly As Boolean Public Property IsPurchasable As Boolean Public Property IsMachined As Boolean Public Property QtyRequired As Integer Public Property TotalQty As Integer Public Property Children As IDictionary(Of String, BOMComponentChild) = New Dictionary(Of String, BOMComponentChild) End Class I am trying to call it like this: Me.Database.SqlQuery(Of BOMComponentChild)("EXEC [BOMComponentChild] @ComponentID, @PathPrefix, @IsAssembly", params).ToList() When I run the stored procedure in management studio, the columns are correct and not null. I just can't figure out why these won't map as they are the important information in the stored procedure. The types for PartsPath and MyPath are varchar(50).

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  • Oracle Insert via Select from multiple tables where one table may not have a row

    - by Mikezx6r
    I have a number of code value tables that contain a code and a description with a Long id. I now want to create an entry for an Account Type that references a number of codes, so I have something like this: insert into account_type_standard (account_type_Standard_id, tax_status_id, recipient_id) ( select account_type_standard_seq.nextval, ts.tax_status_id, r.recipient_id from tax_status ts, recipient r where ts.tax_status_code = ? and r.recipient_code = ?) This retrieves the appropriate values from the tax_status and recipient tables if a match is found for their respective codes. Unfortunately, recipient_code is nullable, and therefore the ? substitution value could be null. Of course, the implicit join doesn't return a row, so a row doesn't get inserted into my table. I've tried using NVL on the ? and on the r.recipient_id. I've tried to force an outer join on the r.recipient_code = ? by adding (+), but it's not an explicit join, so Oracle still didn't add another row. Anyone know of a way of doing this? I can obviously modify the statement so that I do the lookup of the recipient_id externally, and have a ? instead of r.recipient_id, and don't select from the recipient table at all, but I'd prefer to do all this in 1 SQL statement.

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  • website and protocol restriction (firewall application)

    - by Smith
    Am developing a firewall application that is suppose to restrict website/protocols/webs directories system wide that i choose for example restrict login.domain.com, but not domain.com restrict domain.com/passport not domain.com restrict .tld types e.g .org pls give me some ideas? [edit] Am developing on the windows plat form , from win 2000 to win7, using any vb language vb6 upwards also i want to be able to block any protocol http ftp etc.

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  • Import fixed width file to oracle

    - by Alex Blokha
    Is there an ability to import fixed width file to oracle? Preferably through .net(c#) for catching errors during import and showing them to user. P.S. File has 5 types of rows. For example 1 row has 5 columns, 2-nd has 50 columns.

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  • C#. Where struct methods code kept in memory?

    - by maxima120
    It is somewhat known where .NET keeps value types in memory (mostly in stack but could be in heap in certain circumstances etc)... My question is - where is the code of the struct? If I have say 16 byte of data fields in the struct and a massive computation method in it - I am presuming that 16 byte will be copied in stack and the method code is stored somewhere else and is shared for all instances of the struct. Are these presumptions correct?

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  • C# or windows equivalent of OS X's Core Data?

    - by Nektarios
    I'm late to the boat and have only just now started using Core Data in OS X / Cocoa - it's incredible and is really changing the way I look at things. Is there an equivalent technology in C# or the modern Windows frameworks? i.e. having managed data types where you get saving, data management, deleting, searching all for free? Also wondering if there's anything like this on Linux.

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  • Can we change the text/background color of an individual property in PropertyGrid

    - by Charvak
    I have a .NET PropertyGrid control which displays properties of some class. I want to change the color or font or background color(it doesn't matter just that they look different from the other displayed properties) of some property. I can do with writing custom editor but I was wondering If an easier method exists? If I use custom editor then how do i change the editor of built-in types like bool, int etc. Thanks

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  • Error exposing event througt interface

    - by carlos
    I have this interface Interface IProDataSource Delegate Sub DstartingHandler(ByVal sender As Object, ByVal e As EventArgs) Event starting_Sinc As DstartingHandler End Interface Trying to use the intarce like this Public Class DataSource : Implements IProDataSource Public Event starting_Sinc As DstartingHandler Implements IProDataSource.starting_Sinc Public Delegate Sub DstartingHandler(ByVal sender As Object, ByVal e As EventArgs) End Class Gives me the next error Event 'starting_Sinc' cannot implement event 'starting_Sinc' on interface 'IProDataSource' because their delegate types 'DstartingHandler' and 'IProDataSource.DstartingHandler' do not match.

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  • Google App Engine/Simple HTML, how to write input boxes with google autocomplete

    - by Calm Storm
    I am writing a GAE application and I would like to have an input box with google auto-suggest. Specifically, when a user types "Shawshank" I would like to see google's suggestions in my drop down. Can someone tell me what are the different ways of doing this? I understand I may have to use some javascript libraries so any code samples etc will help immensely. (Pure javascript/jquery kinda solutions will be more preferable)

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