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  • Reading a C/C++ data structure in C# from a byte array

    - by Chris Miller
    What would be the best way to fill a C# struct from a byte[] array where the data was from a C/C++ struct? The C struct would look something like this (my C is very rusty): typedef OldStuff { CHAR Name[8]; UInt32 User; CHAR Location[8]; UInt32 TimeStamp; UInt32 Sequence; CHAR Tracking[16]; CHAR Filler[12];} And would fill something like this: [StructLayout(LayoutKind.Explicit, Size = 56, Pack = 1)]public struct NewStuff{ [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)] [FieldOffset(0)] public string Name; [MarshalAs(UnmanagedType.U4)] [FieldOffset(8)] public uint User; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)] [FieldOffset(12)] public string Location; [MarshalAs(UnmanagedType.U4)] [FieldOffset(20)] public uint TimeStamp; [MarshalAs(UnmanagedType.U4)] [FieldOffset(24)] public uint Sequence; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)] [FieldOffset(28)] public string Tracking;} What is best way to copy OldStuff to NewStuff, if OldStuff was passed as byte[] array? I'm currently doing something like the following, but it feels kind of clunky. GCHandle handle;NewStuff MyStuff;int BufferSize = Marshal.SizeOf(typeof(NewStuff));byte[] buff = new byte[BufferSize];Array.Copy(SomeByteArray, 0, buff, 0, BufferSize);handle = GCHandle.Alloc(buff, GCHandleType.Pinned);MyStuff = (NewStuff)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(NewStuff));handle.Free(); Is there better way to accomplish this?

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  • Confusion about Nullable<T> constraints

    - by n535
    Greetings everybody. I am sorry, if this was already asked before (searched in vain) or is really very simple, but i just can't get it. The MSDN definition of a Nullable type, states, that it is defined in a following manner: [SerializableAttribute] public struct Nullable<T> where T : struct, new() So the question is quite straightforward: How is this definition possible? Or this is just a typo? Every value type already has a default constructor. Indeed, when i try to compile something like this, the compiler reasonably says, that it is illegal to apply both constraints at the same time, because the second one is implicitly included in a first one. Thanks in advance.

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  • Ruby on Rails: building a model with an attribute not in the database?

    - by randombits
    I have a model that sets one of its attributes based off of a form parameter that a user submits. The model is a child resource to a parent resource Home. A hypothetical example is the following: A class Person has an age attribute. The user submits a birthdate as an HTTP POST parameter and from that, I need to derive the age of the user. So I'd do something like this: @home.people.build(:name => params[:name], :birthdate => params[:birthdate]) Rails would barf on that for obvious reasons, complaining it doesn't know what the attribute birthdate is. What's the proper way of going about this? Is it possible to use the build constructor with the supplied solution so that my foreign key relations are also setup properly? If not, what's a better way to work around this problem?

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  • How to set default values to the properties of dynamically loaded types at runtime for XML serializa

    - by Erkan Y.
    I need to serialize dynamically loaded types' classes using XMLSerializer. When using XML serializer non initialized values are not being serialized. I dont have control over the assemblies I am working with so can not use XML attributes for specifying default values on properties. So I think I need to set all properties and sub properties to their default values recursively and then serialize. ( Please let me know if there is any better way ) Followed this : Activator.CreateInstance(propType); but above line complains about not having a parameterless constructor for some types. Tried this : subObject = FormatterServices.GetUninitializedObject(propType); but this one gives an error "value was invalid" with no inner exception. Please let me know if you need any further information.

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  • Can there be two public section in a class? If yes then why ? And in which circumstances we do so?

    - by Abhi
    Dear all I have a doubt related to class. For example class A { public: A() { ..... ..... } void cleanup() { .... .... .... } public: UINT a; ULONG b; }; In the above example there are two public section, In first section i am defining constructor and the method and in the second section i am declaring data members. Does the above class i.e. A is correct. Can we do so? If yes then why we needed and in which circumstances we should use it? Also we can do the entire thing in one section then why un necessary we r taking two section...? Thanks and regards Abhineet Agarwal

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  • Can anyone recommend a .Net XML Serialization library?

    - by James
    Can anyone recommend a .Net XML Serialization library (ideally open source). I am looking for a robust XML serialization library that I can throw any object at, which will produce a human readable XML representation of the public properties for logging purposes. I never need to be able to deserialize. XmlSerializer's requirement of an object having a parameter constructor is too restrictive for what I want. DataContractSerializer does not give enough control over the output (which is not particularly human-readable). Any recommendations appreciated! Thanks

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  • Relvance of 'public' contructor in abstract class.

    - by Amby
    Is there any relevance of a 'public' constructor in an abstract class? I can not think of any possible way to use it, in that case shouldn't it be treated as error by compiler (C#, not sure if other languages allow that). Sample Code: internal abstract class Vehicle { public Vehicle() { } } The C# compiler allows this code to compile, while there is no way i can call this contructor from the outside world. It can be called from derived classes only. So shouldn't it allow 'protected' and 'private' modifiers only. Please comment.

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  • How can I access and modify objects inside frames with AS3 in a permanent way?

    - by curro
    I have a MovieClip symbol created with flash in a fla file library. There is a textfield in frame one of this movieclip's timeline . There is another frame in the movieclip timeline. There is a custon class definition for this symbol. It is a flipping card in a memory game. I access the textfield by going to frame 2 (gotoAndStop(2)) and setting the textfield's text property ( this.field.text = "hello" ). However if I go to frame 1 and then return to frame 2, the text becomes the original one in the library's symbol. I have to modify the text propery again in a showFace method I've written. Besides, I cannot pass parameters in the constructor because it is a symbol in the library and that would give errors. I find this behaviour of flash extremely weird. Is there a way I can set properties inside frames permanently? Thank you

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  • 2 Classes need each other declared C++

    - by Prodigga
    I have a "Game" class which holds all the games settings and manages the game. I have a "Grid" class which is the grid the game is played on. The "Game" class initializes a "Grid" object as one of its members (passing itself ("this") as one of the parameters for "Grid"s constructor).. The "Grid" object therefor needs to deal with a "Game*" pointer. To do this it needs to know what "Game" is; i need to declare it before "Grid". But "Game" uses "Grid"...so it also needs "Grid" declared before it. so confused on how to include headers/etc correctly here..

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  • C# property in a form class only accessable after formload event

    - by Spooky2010
    using vs2008, c# Howdy, Im instantiating and calling Form B from Form A. FormB has some custom properties, to allow me to pass it things like sqlAdaptors and dataset instances. When i instantiate and show Form B from Form A as a dialog form with a Using statement, it all works fine, but i find the properties i pass are not available in Form B until after the form_load event has fired. I was under the impression the properties when passed to a instantiated class should be available from a constructor, but this is not the case. If it try to access the properties before the form load event i get a null reference exception. Is this correct behavior ? It is very annoying. thanks for any help

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  • Android and Google Maps API - Icons

    - by oriharel
    I want to place markers on the map. I want to use the standard Google Maps icons for markers. how do I use them? I don't want to create my own icons. I'm developing for Android. in the documentation they tell me to create a class that overrides ItemizedOverlay but in the constructor I'm asked to provide a drawable object. how do I point to the standard Google Maps ones? thanks.

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  • Singletons and other design issues

    - by Ahmed Saleh
    I have worked using different languages like C++/Java and currently AS3. Most applications were computer vision, and small 2D computer games. Most companies that I have worked for, they use Singletons in a language like AS3, to retrieve elements or classes in an easy way. Their problem is basically they needs some variables or to call other functions from other classes. In a language like AS3, there is no private constructor, and they write a hacky code to prevent new instances. In Java and C++ I also faced the situation that I need to use other classe's members or to call their functions in different classes. The question is, is there a better or another design, to let other classes interact with each others without using singletons? I feel that composition is the answer, but I need more detailed solutions or design suggestions.

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  • Retrieve only the superclass from a class hierarchy

    - by user1792724
    I have an scenario as the following: @Entity @Table(name = "ANIMAL") @Inheritance(strategy = InheritanceType.JOINED) public class Animal implements Serializable { @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "S_ANIMAL") @SequenceGenerator(name = "S_ANIMAL", sequenceName = "S_ANIMAL", allocationSize = 1) public int getNumero() { return numero; } public void setNumero(int numero) { this.numero = numero; } . . . } and as the subclass: @Entity @Table(name = "DOG") public class Dog extends Animal { private static final long serialVersionUID = -7341592543130659641L; . . . } I have a JPA Select statement like this: SELECT a FROM Animal a; I'm using Hibernate 3.3.1 As I can see the framework retrieves instances of Animal and also of Dog using a left outer join. Is there a way to Select only the "part" Animal? I mean, the previous Select will get all the Animals, those that are only Animals but not Dogs and those that are Dogs. I want them all, but in the case of Dogs I want to only retrieve the "Animal part" of them. I found the @org.hibernate.annotations.Entity(polymorphism = PolymorphismType.EXPLICIT) but as I could see this only works if Animal isn't an @Entity. Thanks a lot.

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  • Trouble dragging and dropping gui components onto other .net forms using NHibernate

    - by IsaacB
    Hi, using VS2008, here. I have a GUI component that loads some stuff from a database mapped by nhibernate in its constructor. When I drag and drop this component onto another form from the toolbox, NHibernate complains that it can't find the config file in program files\visual studio 9\common7\ide. Why is it looking here for the cfg file? I'm actually calling database stuff through another project in the same solution, and the cfg file is located at the root of that project. copy/pasting the cfg file over to there does work, but I'm working with svn here and I don't want to have configuration files outside the repository. Something else that would help would be turning off how it tries to load the data in the form design screen. How would I do that?

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  • different explanation

    - by Delirium tremens
    The following code echoes 5, not 10: $global_obj = null; class my_class { var $value; function my_class() { global $global_obj; $global_obj = &$this; } } $a = new my_class; $a->my_value = 5; $global_obj->my_value = 10; echo $a->my_value; "Upon first examination, it would seem that the constructor of my_class stores a reference to itself inside the $global_obj variable. Therefore, one would expect that, when we later change the value of $global_obj-my_value to 10, the corresponding value in $a would change as well. Unfortunately, the new operator does not return a reference, but a copy of the newly created object." Please, give me a different explanation.

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  • Doubt in abstract classes

    - by mohit
    public abstract class Person { private String name; public Person(String name) { this.name = name; System.out.println("Person"); } public String getName() { return name; } abstract public String getDescription(); } public class Student extends Person { private String major; public Student(String name, String major) { super(name); this.major = major; } public String getMajor() { return major; } @Override public String getDescription() { return "student" + super.getName() + " having" + major; } } public class PersonTest { public static void main(String[] args) { Person person = new Student("XYZ", "ABC"); System.out.println(person.getDescription()); } } Ques: We cannot create objects of abstract classes, then why Person Constructor has been invoked, even its an abstract class?

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  • Implementing implicitly shared classes outside of Qt

    - by Timothy Baldridge
    I'm familiar with the way Qt uses D-pointers for managing data. How do I do this in my code? I tried this method: 1) move all data into a struct 2) add a QAtomicInt to the struct 3) implement a = operator and change my constructor/deconstructor to check-up on the reference count. The issue is, when I go to do a shallow copy of the object, I get an error about QObject declaring = as private. How then do I accomplish this? Here's an example of my copy operator: HttpRequest & HttpRequest::operator=(const HttpRequest &other) { other.d->ref.ref(); if (!d->ref.deref()) delete d; d = other.d; return *this; } Am I going about this the wrong way?

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  • Big-O for calculating all routes from GPS data

    - by HH
    A non-critical GPS module use lists because it needs to be modifiable, new routes added, new distances calculated, continuos comparisons. Well so I thought but my team member wrote something I am very hard to get into. His pseudo code int k =0; a[][] <- create mapModuleNearbyDotList -array //CPU O(n) for(j = 1 to n) // O(nlog(m)) for(i =1 to n) for(k = 1 to n) if(dot is nearby) adj[i][j]=min(adj[i][j], adj[i][k] + adj[k][j]); His ideas transformations of lists to tables His worst case time complexity is O(n^3), where n is number of elements in his so-called table. Exception to the last point with Finite structure: O(mlog(n)) where n is number of vertices and m is the amount of neighbour vertices. Questions about his ideas why to waste resources to transform constantly-modified lists to table? Fast? only point where I to some extent agree but cannot understand the same upper limits n for each for-loops -- perhaps he supposed it circular why does the code take O(mlog(n)) to proceed in time as finite structure? The term finite may be wrong, explicit?

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  • extension method phone format with country code as parameter

    - by frenchie
    Hi, I'm writing an extension method called ToPhoneFormat that formats a string of digits to phone numbers. Is it possible to add a parameter to the method that would enable me to call it like this: MyPhoneString.ToPhoneFormat(international code) That way, I could write MyPhoneString.ToPhoneFormat(1); to format a US phone number and MyPhoneString.ToPhoneFormat(33) to format a French phone number. I already wrote the method that does the formatting but I'm wondering how to build the constructor so that it works with a parameter when I'm calling it. Thanks.

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  • How do I toggle CSS with jQuery?

    - by marcamillion
    I have the following code: $('#bc' + $.trim($this) + ' span.dashed-circle').css({ 'border' : '5px solid #000'}); That is triggered by a click.function(). I would like that to be a toggle - so when I click the element, it changes the border to what I have above...but when it is clicked again it disappears or rather sets the border to ' '. Thoughts? Edit: I should have been explicit...but I don't want to create a CSS class. The reason being is because when I do that, it messes up the formatting of the element being styled. I am sure that it is some small quirk somewhere that would fix it, but I am not interested in wading through the entire code base to fix little positioning issues with a new class. I would much rather just edit the css attribute directly - because it doesn't interfere with the layout. Edit2: Here is the jsfiddle of the code I am trying to edit. If you notice, I have the CSS attributes last. But how do I let that be toggled ? Edit3: If anyone is interested...the UI that this will be used in is for my webapp - http://www.compversions.com

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  • Vector of Object Pointers, general help and confusion

    - by Staypuft
    Have a homework assignment in which I'm supposed to create a vector of pointers to objects Later on down the load, I'll be using inheritance/polymorphism to extend the class to include fees for two-day delivery, next day air, etc. However, that is not my concern right now. The final goal of the current program is to just print out every object's content in the vector (name & address) and find it's shipping cost (weight*cost). My Trouble is not with the logic, I'm just confused on few points related to objects/pointers/vectors in general. But first my code. I basically cut out everything that does not mater right now, int main, will have user input, but right now I hard-coded two examples. #include <iostream> #include <string> #include <vector> using namespace std; class Package { public: Package(); //default constructor Package(string d_name, string d_add, string d_zip, string d_city, string d_state, double c, double w); double calculateCost(double, double); void Print(); ~Package(); private: string dest_name; string dest_address; string dest_zip; string dest_city; string dest_state; double weight; double cost; }; Package::Package() { cout<<"Constucting Package Object with default values: "<<endl; string dest_name=""; string dest_address=""; string dest_zip=""; string dest_city=""; string dest_state=""; double weight=0; double cost=0; } Package::Package(string d_name, string d_add, string d_zip, string d_city, string d_state, string r_name, string r_add, string r_zip, string r_city, string r_state, double w, double c){ cout<<"Constucting Package Object with user defined values: "<<endl; string dest_name=d_name; string dest_address=d_add; string dest_zip=d_zip; string dest_city=d_city; string dest_state=d_state; double weight=w; double cost=c; } Package::~Package() { cout<<"Deconstructing Package Object!"<<endl; delete Package; } double Package::calculateCost(double x, double y){ return x+y; } int main(){ double cost=0; vector<Package*> shipment; cout<<"Enter Shipping Cost: "<<endl; cin>>cost; shipment.push_back(new Package("tom r","123 thunder road", "90210", "Red Bank", "NJ", cost, 10.5)); shipment.push_back(new Package ("Harry Potter","10 Madison Avenue", "55555", "New York", "NY", cost, 32.3)); return 0; } So my questions are: I'm told I have to use a vector of Object Pointers, not Objects. Why? My assignment calls for it specifically, but I'm also told it won't work otherwise. Where should I be creating this vector? Should it be part of my Package Class? How do I go about adding objects into it then? Do I need a copy constructor? Why? What's the proper way to deconstruct my vector of object pointers? Any help would be appreciated. I've searched for a lot of related articles on here and I realize that my program will have memory leaks. Using one of the specialized ptrs from boost:: will not be available for me to use. Right now, I'm more concerned with getting the foundation of my program built. That way I can actually get down to the functionality I need to create. Thanks.

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  • Best way to test if a generic type is a string? (c#)

    - by Rex M
    I have a generic class that should allow any type, primitive or otherwise. The only problem with this is using default(T). When you call default on a value type or a string, it initializes it to a reasonable value (such as empty string). When you call default(T) on an object, it returns null. For various reasons we need to ensure that if it is not a primitive type, then we will have a default instance of the type, not null. Here is attempt 1: T createDefault() { if(typeof(T).IsValueType) { return default(T); } else { return Activator.CreateInstance<T>(); } } Problem - string is not a value type, but it does not have a parameterless constructor. So, the current solution is: T createDefault() { if(typeof(T).IsValueType || typeof(T).FullName == "System.String") { return default(T); } else { return Activator.CreateInstance<T>(); } } But this feels like a kludge. Is there a nicer way to handle the string case?

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  • Not loading associations without proxies in NHibernate

    - by Alice
    I don't like the idea of proxy and lazy loading. I don't need that. I want pure POCO. And I want to control loading associations explicitly when I need. Here is entity public class Post { public long Id { get; set; } public long OwnerId { get; set; } public string Content { get; set; } public User Owner { get; set; } } and mapping <class name="Post"> <id name="Id" /> <property name="OwnerId" /> <property name="Content" /> <many-to-one name="Owner" column="OwnerId" /> </class> However if I specify lazy="false" in the mapping, Owner is always eagerly fetched. I can't remove many-to-one mapping because that also disables explicit loading or a query like from x in session.Query<Comment>() where x.Owner.Title == "hello" select x; I specified lazy="true" and set use_proxy_validator property to false. But that also eager loads Owner. Is there any way to load only Post entity?

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  • asp file system object

    - by sushant
    i am using this code to access files and folders. <%@ Language=VBScript %<% option explicit dim sRoot, sDir, sParent, objFSO, objFolder, objFile, objSubFolder, sSize % <% sRoot = "D:Raghu" sDir = Request("Dir") sDir = sDir & "\" Response.Write "" & sDir & "" & vbCRLF Set objFSO = CreateObject("Scripting.FileSystemObject") on error resume next Set objFolder = objFSO.GetFolder(sRoot & sDir) if err.number < 0 then Response.Write "Could not open folder" Response.End end if on error goto 0 sParent = objFSO.GetParentFolderName(objFolder.Path) ' Remove the contents of sRoot from the front. This gives us the parent ' path relative to the root folder ' eg. if parent folder is "c:webfilessubfolder1subfolder2" then we just want "subfolder1subfolder2" sParent = mid(sParent, len(sRoot) + 1) Response.Write "" ' Give a link to the parent folder. This is just a link to this page only pssing in ' the new folder as a parameter Response.Write "Parent folder" & vbCRLF ' Now we want to loop through the subfolders in this folder For Each objSubFolder In objFolder.SubFolders ' And provide a link to them Response.Write "" & objSubFolder.Name & "" & vbCRLF Next ' Now we want to loop through the files in this folder For Each objFile In objFolder.Files if Clng(objFile.Size) < 1024 then sSize = objFile.Size & " bytes" else sSize = Clng(objFile.Size / 1024) & " KB" end if ' And provide a link to view them. This is a link to show.asp passing in the directory and the file ' as parameters Response.Write "" & objFile.Name & "" & sSize & "" & objFile.Type & "" & vbCRLF Next Response.Write "" % it works fine. but when i try to access something on shred path like: "\cvrdd0110:share" it gives error. how to access these files?

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  • my .jar file won't do anything.

    - by David
    I created a program that more or less holds an array of strings as an object and randomly prints one. so basicaly class Happy { string[] namestrings = new string[#] constructor() { fill with some strings} public static void main (String[]arg) { create instance of class do some junk with it method that prints it } method that prints it {} another method } when i compile and run it on the command line it works fine but when on the comand line i type in jar -cf Happy.jar Fun.class i get a .jar file called Happy and when i click on it i get an error message that reads "the java Jar file happy could not be launched read the consol for possible error messages" I have a mac i'm running lepord if that makes a diference. Whats going on?

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