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  • Learning C++ from scratch in Visual Studio?

    - by flesh
    I need to get up to speed with C++ quite quickly (I've never used it previously) - is learning through Visual Studio (i.e. Managed C++) going to be any use? Or will I end up learning the extensions and idiosyncracies of C++ in VS, rather then the language itself? If learning in VS is not recommended, what platform / IDE do you guys suggest? Edit: Can anyone elaborate on what VS will hide or manage for me when coding unmanaged C++? I really need to be learning things like pointers, garbage collection and all the nuts and bolts of the low level language.. does VS abstract or hide any of this kind of stuff from you? Thanks for all the suggestions..

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  • Android: How to put ListView in XML?

    - by FloIancu
    I want to make a simple app that shows a list of contacts (name, surname). My code: package lista.android; import java.util.*; import android.app.ListActivity; import android.os.Bundle; import android.widget.*; class Contact{ String nume; String prenume; Contact(String nume, String prenume){ this.nume=nume; this.prenume=prenume; } public String toString(){ return prenume +" "+ nume; } } public class Lista1Activity extends ListActivity { /** Called when the activity is first created. */ ArrayList <Contact> lista; ArrayAdapter <Contact> adaptor; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); setListAdapter(adaptor); lista=new ArrayList<Contact>(); adaptor=new ArrayAdapter<Contact>(this, R.id.element, lista); adaugaContact("Florian", "Iancu"); adaugaContact("Ioana", "Constantina"); } public void adaugaContact(String nume, String prenume){ lista.add(new Contact(nume, prenume)); adaptor.notifyDataSetChanged(); } } In the XML I have the LinearLayout and a TextView that is the list element. When I run it, the simulator says "Sorry, the application [...] has stopped unexpectedly. Please try again." The LogCat tells me I have to have a ListView whose id is android.R.id.lista. If I create a random ListView field in the XML file and give it the "lista" id, it still doesn't work. How to I call that ListView from XML to match something in my Java code? In other words, I know I'm wrong, but where and how do I fix it?

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  • JFrame that has multiple layers

    - by phunehehe
    Hello, I have a window that has two layers: a static background and a foreground that contains moving objects. My idea is to draw the background just once (because it's not going to change), so I make the changing panel transparent and add it on top of the static background. Here is the code for this: public static void main(String[] args) { JPanel changingPanel = new JPanel() { @Override public void paintComponent(Graphics g) { super.paintComponent(g); g.setColor(Color.RED); g.fillRect(100, 100, 100, 100); } }; changingPanel.setOpaque(false); JPanel staticPanel = new JPanel(); staticPanel.setBackground(Color.BLUE); staticPanel.setLayout(new BorderLayout()); staticPanel.add(changingPanel); JFrame frame = new JFrame(); frame.add(staticPanel); frame.setSize(800, 600); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } This piece of code gives me the correct image I want, but every time I repaint changingPanel, staticPanel gets repainted as well (which is obviously against the whole idea of painting the static panel just once). Can somebody show me what's wrong? FYI I am using the javax.swing.Timer to recalculate and repaint the changing panel 24 times every second.

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  • how to set the output image use com.android.camera.action.CROP

    - by adi.zean
    I have code to crop an image, like this : public void doCrop(){ Intent intent = new Intent("com.android.camera.action.CROP"); intent.setType("image/"); List<ResolveInfo> list = getPackageManager().queryIntentActivities(intent,0); int size = list.size(); if (size == 0 ){ Toast.makeText(this, "Cant find crop app").show(); return; } else{ intent.setData(selectImageUri); intent.putExtra("outputX", 300); intent.putExtra("outputY", 300); intent.putExtra("aspectX", 1); intent.putExtra("aspectY", 1); intent.putExtra("scale", true); intent.putExtra("return-data", true); if (size == 1) { Intent i = new Intent(intent); ResolveInfo res = list.get(0); i.setComponent(new ComponentName(res.activityInfo.packageName, res.activityInfo.name)); startActivityForResult(i, CROP_RESULT); } } } public void onActivityResult (int requestCode, int resultCode, Intent dara){ if (resultCode == RESULT_OK){ if (requestCode == CROP_RESULT){ Bundle extras = data.getExtras(); if (extras != null){ bmp = extras.getParcelable("data"); } File f = new File(selectImageUri.getPath()); if (f.exists()) f.delete(); Intent inten3 = new Intent(this, tabActivity.class); startActivity(inten3); } } } from what i have read, the code intent.putExtra("outputX", 300); intent.putExtra("outputY", 300); is use to set the resolution of crop result, but why i can't get the result image resolution higer than 300x300? when i set the intent.putExtra("outputX", 800); intent.putExtra("outputY", 800); the crop function has no result or crash, any idea for this situation? the log cat say "! ! ! FAILED BINDER TRANSACTION ! ! !

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  • Silverlight - rebinding to a property?

    - by bplus
    Hello, I'm just getting started with silverlight. Basically I have a silverlight user control that has various dataGrids and a combobox, their item sources set to the properties of a custom plain c# object. My problem is that I have a dropdown list that when a user selects an item from the list a new row should appear in one of the grids. All I'm doing is handling the SelectionChanged event and adding a new item to to a list in my custom object and setting the itemsource for the grid again. This doesnt seem to work; no row is added to the dataGrid I have no idea how to force my grid to "rebind" to this property. I've been reading about dependency properties, are these what I need? Any pointers would be really appreciated.

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  • run time error wats the wrong?

    - by javacode
    I am getting run time error import javax.mail.*; import javax.mail.internet.*; import java.util.*; public class SendMail { public static void main(String [] args)throws MessagingException { SendMail sm=new SendMail(); sm.postMail(new String[]{"[email protected]"},"hi","hello","[email protected]"); } public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException { boolean debug = false; //Set the host smtp address Properties props = new Properties(); props.put("mail.smtp.host", "webmail.emailmyname.com"); // create some properties and get the default Session Session session = Session.getDefaultInstance(props, null); session.setDebug(debug); // create a message Message msg = new MimeMessage(session); // set the from and to address InternetAddress addressFrom = new InternetAddress(from); msg.setFrom(addressFrom); InternetAddress[] addressTo = new InternetAddress[recipients.length]; for (int i = 0; i < recipients.length; i++) { addressTo[i] = new InternetAddress(recipients[i]); } msg.setRecipients(Message.RecipientType.TO, addressTo); // Optional : You can also set your custom headers in the Email if you Want msg.addHeader("MyHeaderName", "myHeaderValue"); // Setting the Subject and Content Type msg.setSubject(subject); msg.setContent(message, "text/plain"); Transport.send(msg); } } Error Exception in thread "main" java.lang.NoClassDefFoundError: SendMail Caused by: java.lang.ClassNotFoundException: SendMail at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) Could not find the main class: SendMail. Program will exit.

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  • Creating futures using Apple's GCD

    - by jer
    I'm working on a library which implements the actor model on top of Grand Central Dispatch (specifically the C level API libdispatch). Basically a brief overview of my system is as such: Communication happens between actors using messages Multicast communication only (one actor to many actors) Senders and receivers are decoupled from one another using a blackboard where messages are pushed to. Messages are sent in the default queue asynchronously using dispatch_group_async() once a message gets pushed onto the blackboard. I'm trying to implement futures in the language right now, so I've created a new type which holds some information: A group of its own The value being 'returned' However, I have a problem since dispatch_block_t is of type void (^)(void) so it doesn't return anything. So my idea of in my future_new() function of setting up another group which can be used to execute a block returning a result, which I can store in my "value" member in my future_t structure, isn't going to work. The rest of the futures implementation is very clear, except it all depends on being able to get the value into the future back from the actor, acting on the message. When using the library, it would greatly reduce its usefulness if I had to ask users (and myself) to be aware when futures were going to be used by other parts of the system—It just isn't practical. I'm wondering if anyone can think of a way around this?

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  • Objective-C protocol vs inheritance vs extending?

    - by ryanjm.mp
    I have a couple classes that have nearly identical code. Only a string or two is different between them. What I would like to do is to make them "x" from another class that defines those functions and then uses constants or something else to define those strings that are different. I'm not sure if "x" is inheritance or extending or what. That is what I need help with. For example: objectA.m: -(void)helloWorld { NSLog("Hello %@",child.name); } objectBob.m: #define name @"Bob" objectJoe.m #define name @"Joe" (I'm not sure if it's legal to define strings, but this gets the point across) It would be ideal if objectBob.m and objectJoe.m didn't have to even define the methods, just their relationship to objectA.m. Is there any way to do something like this? It is kind of like protocol, except in reverse, I want the "protocol" to actually define the functions. If all else fails I'll just make objectA.m: -(void)helloWorld:(NSString *name) { NSLog("Hello %@",name); } And have the other files call that function (and just #import objectA.m).

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  • What is a good DBMS for archiving?

    - by Thomas.Winsnes
    I've been stuck in a MsSql/MySql world now for a few years, and I've decided to spread my wings a little further. At the moment I'm researching which DBMS is good at things needed when archiving data. Eg. lots of writes and low reads. I've seen the NoSQL crusade, but I have a very RDBMS mindset, so I'm a bit skeptical. Anyone have any suggestions? Or even any pointers to where there are some benchmarks etc for this kind of stuff. Thank you :) Thomas

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  • Google App Engine how to get an object from the servlet ?

    - by Frank
    I have the following class objects in Google App Engine's dadastore, I can see them from the "Datastore Viewer " : import javax.jdo.annotations.IdGeneratorStrategy; import javax.jdo.annotations.IdentityType; import javax.jdo.annotations.PersistenceCapable; import javax.jdo.annotations.Persistent; import javax.jdo.annotations.PrimaryKey; @PersistenceCapable(identityType=IdentityType.APPLICATION) public class Contact_Info_Entry implements Serializable { @PrimaryKey @Persistent(valueStrategy=IdGeneratorStrategy.IDENTITY) Long Id; public static final long serialVersionUID=26362862L; String Contact_Id="",First_Name="",Last_Name="",Company_Name="",Branch_Name="",Address_1="",Address_2="",City="",State="",Zip="",Country=""; double D_1,D_2; boolean B_1,B_2; Vector<String> A_Vector=new Vector<String>(); public Contact_Info_Entry() { } ...... } How can my java applications get the object from a servlet url ? For instance if have an instance of Contact_Info_Entry who's Contact_Id is "ABC-123", and my App Id is : nm-java When my java program accesses the url : "http://nm-java.appspot.com/Check_Contact_Info?Contact_Id=ABC-123 How will the Check_Contact_Info servlet get the object from datastore and return it to my app ? public class Check_Contact_Info_Servlet extends HttpServlet { static boolean Debug=true; public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException { } ... protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException { doGet(request,response); } } Frank

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  • Import data from .xls File

    - by tek3
    HI, I am developing an application in which i have to get data from .xls file. I am fairly new to iPhone development so any pointers in direction to getting started will be very much helpful. The steps that i am thinking are : 1) First i need to convert .xls to .csv Format. 2)Import the data from .csv file to SQlite Databse or Core Data.(I am not familier with any one of them, so kindly suggest which one to choose. I am looking forward to use Core Data) Am I thinking in the right direction. Will be greatful for any kind of assistance.. Thanx in advance..

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  • How to open a pdf on the iPad from an AIR for iOS app

    - by Dennis Flood
    I am making an AIR for iOS app that can download pdfs. I do not want to display the pdf in the app itself but want the default pdf-viewer (iBooks) to launch and show the pdf. How can this be done. I am aware that navigateToURL can be used to open a file with the uri scheme of iBooks. But i dont know how to tell iBooks to look in the app-directory of my app. (Or is there some secret directory to place the file in from within the app - where iBooks can find it) Any pointers or help would be greatly appreciated as this is somewhat of a show stopper.

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  • Can I get rid of this read lock?

    - by Pieter
    I have the following helper class (simplified): public static class Cache { private static readonly object _syncRoot = new object(); private static Dictionary<Type, string> _lookup = new Dictionary<Type, string>(); public static void Add(Type type, string value) { lock (_syncRoot) { _lookup.Add(type, value); } } public static string Lookup(Type type) { string result; lock (_syncRoot) { _lookup.TryGetValue(type, out result); } return result; } } Add will be called roughly 10/100 times in the application and Lookup will be called by many threads, many of thousands of times. What I would like is to get rid of the read lock. How do you normally get rid of the read lock in this situation? I have the following ideas: Require that _lookup is stable before the application starts operation. The could be build up from an Attribute. This is done automatically through the static constructor the attribute is assigned to. Requiring the above would require me to go through all types that could have the attribute and calling RuntimeHelpers.RunClassConstructor which is an expensive operation; Move to COW semantics. public static void Add(Type type, string value) { lock (_syncRoot) { var lookup = new Dictionary<Type, string>(_lookup); lookup.Add(type, value); _lookup = lookup; } } (With the lock (_syncRoot) removed in the Lookup method.) The problem with this is that this uses an unnecessary amount of memory (which might not be a problem) and I would probably make _lookup volatile, but I'm not sure how this should be applied. (John Skeets' comment here gives me pause.) Using ReaderWriterLock. I believe this would make things worse since the region being locked is small. Suggestions are very welcome.

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  • Ninject giving NullReferenceException

    - by Iceman
    I'm using asp.net MVC 2 and Ninject 2. The setup is very simple. Controller calls service that calls repository. In my controller I use inject to instantiate the service classes with no problem. But the service classes don't instantiate the repositories, giving me NullReferenceException. public class BaseController : Controller { [Inject] public IRoundService roundService { get; set; } } This works. But then this does not... public class BaseService { [Inject] public IRoundRepository roundRepository { get; set; } } Giving a NullReferenceException, when I try to use the roundRepository in my RoundService class. IList<Round> rounds = roundRepository.GetRounds( ); Module classes... public class ServiceModule : NinjectModule { public override void Load( ) { Bind( ).To( ).InRequestScope( ); } } public class RepositoryModule : NinjectModule { public override void Load( ) { Bind<IRoundRepository>( ).To<RoundRepository>( ).InRequestScope( ); } } In global.axax.cs protected override IKernel CreateKernel( ) { return new StandardKernel( new ServiceModule( ), new RepositoryModule( ) ); }

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  • Add UIView Above All Other Views, Including StatusBar

    - by Mike Stead
    I'm wanting to create a view (UIControl) which blocks all input and shows a UIActivityIndicatorView while authenticating a user. The UIActionSheet and UIAlertView both manage to add a black semi-transparent view over the top of all other views to block input and I'd like to do similar. I've tried adding my view to the top UIWindow in the [[UIApplication sharedApplication] windows] array, and while this does place it above the UIKeyboard if it's visible, it doesn't place it over the StatusBar (which makes sense). My next attempt was to extend UIAlertView, remove all of its subviews and set its layer.contents = nil, then add the ActivityIndicator as a subview. This works well, but I can't seem to kill the default bouncy transition of the UIAlertView when you call it to "show". Does anyone have any pointers towards the best way tackle this problem that gives me full control? Oh and I know blocking input is not great but I do ensure it's for a short period of time and it has the benefit of making it clear to the user that their action, which must complete for them to progress, is processing.

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  • Binary Tree operator overloading and recursion

    - by furious.snail
    I was wondering how to overload the == operator for a binary tree to compare if two trees have identical data at same nodes. So far this is what I have: bool TreeType::operator==(const TreeType& otherTree) const { if((root == NULL) && (otherTree.root == NULL)) return true; //two null trees are equal else if((root != NULL) && (otherTree.root != NULL)) { return((root-info == otherTree.root-info) && //this part doesn't actually do anything recursively... //(root-left == otherTree.root-left) && //(root-right == otherTree.root-right)) } else return false; //one tree is null the other is not } I have a similar function that takes two TreeNode pointers as parameters but I've been stuck on how to convert it to this function.

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  • Designing a class in such a way that it doesn't become a "God object"

    - by devoured elysium
    I'm designing an application that will allow me to draw some functions on a graphic. Each function will be drawn from a set of points that I will pass to this graphic class. There are different kinds of points, all inheriting from a MyPoint class. For some kind of points it will be just printing them on the screen as they are, others can be ignored, others added, so there is some kind of logic associated to them that can get complex. How to actually draw the graphic is not the main issue here. What bothers me is how to make the code logic such that this GraphicMaker class doesn't become the so called God-Object. It would be easy to make something like this: class GraphicMaker { ArrayList<Point> points = new ArrayList<Point>(); public void AddPoint(Point point) { points.add(point); } public void DoDrawing() { foreach (Point point in points) { if (point is PointA) { //some logic here else if (point is PointXYZ) { //...etc } } } } How would you do something like this? I have a feeling the correct way would be to put the drawing logic on each Point object (so each child class from Point would know how to draw itself) but two problems arise: There will be kinds of points that need to know all the other points that exist in the GraphicObject class to know how to draw themselves. I can make a lot of the methods/properties from the Graphic class public, so that all the points have a reference to the Graphic class and can make all their logic as they want, but isn't that a big price to pay for not wanting to have a God class?

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  • flood fill algorithm

    - by user335593
    i want to implement the flood fill algorthm...so that when i get the x and y co-od of a point...it should start flooding from that point and fill till it finds a boundary but it is not filling the entire region...say a pentagon this is the code i am using void setpixel(struct fill fillcolor,int x,int y) { glColor3f(fillcolor.r,fillcolor.g,fillcolor.b); glBegin(GL_POINTS); glVertex2i(x,y); glEnd(); glFlush(); } struct fill getpixcol(int x,int y) { struct fill gotpixel; glReadPixels(x,y,1,1,GL_RGB,GL_UNSIGNED_BYTE,pick_col); gotpixel.r =(float) pick_col[0]/255.0; gotpixel.g =(float) pick_col[1]/255.0; gotpixel.b =(float) pick_col[2]/255.0; return(gotpixel); } void floodFill(int x, int y,struct fill fillcolor,struct fill boundarycolor) { struct fill tmp; // if ((x < 0) || (x >= 500)) return; // if ((y < 0) || (y >= 500)) return; tmp=getpixcol(x,y); while (tmp.r!=boundarycolor.r && tmp.g!=boundarycolor.g && tmp.b!=boundarycolor.b) { setpixel(fillcolor,x,y); setpixel(fillcolor,x+1,y); setpixel(fillcolor,x,y+1); setpixel(fillcolor,x,y-1); setpixel(fillcolor,x-1,y); floodFill(x-1,y+1,fillcolor,boundarycolor); floodFill(x-1,y,fillcolor,boundarycolor); floodFill(x-1,y-1,fillcolor,boundarycolor); floodFill(x,y+1,fillcolor,boundarycolor); floodFill(x,y-1,fillcolor,boundarycolor); floodFill(x+1,y+1,fillcolor,boundarycolor); floodFill(x+1,y,fillcolor,boundarycolor); floodFill(x+1,y-1,fillcolor,boundarycolor); } }

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  • No "redefinition of default parameter error" for class template member function?

    - by STingRaySC
    Why does the following give no compilation error?: // T.h template<class T> class X { public: void foo(int a = 42); }; // Main.cpp #include "T.h" #include <iostream> template<class T> void X<T>::foo(int a = 13) { std::cout << a << std::endl; } int main() { X<int> x; x.foo(); // prints 42 } It seems as though the 13 is just silently ignored by the compiler. Why is this? The cooky thing is that if the template declaration is in Main.cpp instead of a header file, I do indeed get the default parameter redefinition error. Now I know the compiler will complain about this if it were just an ordinary (non-template) function. What does the standard have to say about default parameters in class template member functions or function templates?

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  • Linked list example using threads

    - by Carl_1789
    I have read the following code of using CRITICAL_SECTION when working with multiple threads to grow a linked list. what would be the main() part which uses two threads to add to linked list? #include <windows.h> typedef struct _Node { struct _Node *next; int data; } Node; typedef struct _List { Node *head; CRITICAL_SECTION critical_sec; } List; List *CreateList() { List *pList = (List*)malloc(sizeof(pList)); pList->head = NULL; InitializeCriticalSection(&pList->critical_sec); return pList; } void AddHead(List *pList, Node *node) { EnterCriticalSection(&pList->critical_sec); node->next = pList->head; pList->head = node; LeaveCriticalSection(&pList->critical_sec); } void Insert(List *pList, Node *afterNode, Node *newNode) { EnterCriticalSection(&pList->critical_sec); if (afterNode == NULL) { AddHead(pList, newNode); } else { newNode->next = afterNode->next; afterNode->next = newNode; } LeaveCriticalSection(&pList->critical_sec); } Node *Next(List *pList, Node *node) { Node* next; EnterCriticalSection(&pList->critical_sec); next = node->next; LeaveCriticalSection(&pList->critical_sec); return next; }

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  • Problems with Json Serialize Dictionary<Enum, Int32>

    - by dbemerlin
    Hi, whenever i try to serialize the dictionary i get the exception: System.ArgumentException: Type 'System.Collections.Generic.Dictionary`2[[Foo.DictionarySerializationTest+TestEnum, Foo, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]' is not supported for serialization/deserialization of a dictionary, keys must be strings or object My Testcase is: public class DictionarySerializationTest { private enum TestEnum { A, B, C } public void SerializationTest() { Dictionary<TestEnum, Int32> data = new Dictionary<TestEnum, Int32>(); data.Add(TestEnum.A, 1); data.Add(TestEnum.B, 2); data.Add(TestEnum.C, 3); JavaScriptSerializer serializer = new JavaScriptSerializer(); String result = serializer.Serialize(data); // Throws } public void SerializationStringTest() { Dictionary<String, Int32> data = new Dictionary<String, Int32>(); data.Add(TestEnum.A.ToString(), 1); data.Add(TestEnum.B.ToString(), 2); data.Add(TestEnum.C.ToString(), 3); JavaScriptSerializer serializer = new JavaScriptSerializer(); String result = serializer.Serialize(data); // Succeeds } } Of course i could use .ToString() whenever i enter something into the Dictionary but since it's used quite often in performance relevant methods i would prefer using the enum. My only solution is using .ToString() and converting before entering the performance critical regions but that is clumsy and i would have to change my code structure just to be able to serialize the data. Does anyone have an idea how i could serialize the dictionary as <Enum, Int32>? I use the System.Web.Script.Serialization.JavaScriptSerializer for serialization.

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  • Why is my UITableView not being set?

    - by Jamie L
    I checked using the debbuger in the viewDidLoad method and tracerTableView is 0x0 which i assume means it is nil. I don't understand. I should go ahaed say yes I have already checked my nib file and yes all the connections are correct. Here is the header file and the begging of the .m. ///////////// .h file //////////// @interface TrackerListController : UITableViewController { // The mutable (modifiable) dictionary days holds all the data for the days tab NSMutableArray *trackerList; UITableView *tracerTableView; } @property (nonatomic, retain) NSMutableArray *trackerList; @property (nonatomic, retain) IBOutlet UITableView. *tracerTableView; //The addPackage: method is invoked when the user taps the addbutton created at runtime. -(void) addPackage : (id) sender; @end /////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////// .m file ////////////////////////////////////// @implementation TrackerListController @synthesize trackerList, tracerTableView; (void)viewDidLoad { [super viewDidLoad]; self.title = @"Package Tracker"; self.navigationItem.leftBarButtonItem = self.editButtonItem; UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(addPackage:)]; // Set up the Add custom button on the right of the navigation bar self.navigationItem.rightBarButtonItem = addButton; [addButton release]; // Release the addButton from memory since it is no longer needed }

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  • iphone NSMutableArray loses objects at end of method

    - by Brodie4598
    Hello - in my app, an NSMutableArray is populated with an object in viewDidLoad (eventually there will be many objects but I'm just doing one til I get it working right). I also start a timer that starts a method that needs to access the NSMutableArray every few seconds. The NSMutableArray works fine in viewDidLoad, but as soon as that method is finished, it loses the object. myApp.h @interface MyApp : UIViewController { NSMutableArray *myMutableArray; NSTimer *timer; } @property (nonatomic, retain) NSMutableArray *myMutableArray; @property (nonatomic, retain) NSTimer *timer; @end myApp.m #import "MyApp.h" @implementation MyApp @synthesize myMutableArray; - (void) viewDidLoad { cycleTimer = [NSTimer scheduledTimerWithTimeInterval:4.0 target:self selector:@selector(newCycle) userInfo: nil repeats:YES]; MyObject *myCustomUIViewObject = [[MyObject alloc]init]; [myMutableArray addObject:myCustomUIViewObject]; [myCustomUIViewObject release]; NSLog(@"%i",[myMutableArray count]); /////outputs "1" } -(void) newCycle { NSLog(@"%i",[myMutableArray count]); /////outputs "0" ?? why is this?? }

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  • Improving field get and set performance with ASM

    - by ng
    I would like to avoid reflection in an open source project I am developing. Here I have classes like the following. public class PurchaseOrder { @Property private Customer customer; @Property private String name; } I scan for the @Property annotation to determine what I can set and get from the PurchaseOrder reflectively. There are many such classes all using java.lang.reflect.Field.get() and java.lang.reflect.Field.set(). Ideally I would like to generate for each property an invoker like the following. public interface PropertyAccessor<S, V> { public void set(S source, V value); public V get(S source); } Now when I scan the class I can create a static inner class of PurchaseOrder like so. static class customer_Field implements PropertyAccessor<PurchaseOrder, Customer> { public void set(PurchaseOrder order, Customer customer) { order.customer = customer; } public Customer get(PurchaseOrder order) { return order.customer; } } With these I totally avoid the cost of reflection. I can now set and get from my instances with native performance. Can anyone tell me how I would do this. A code example would be great. I have searched the net for a good example but can find nothing like this. The ASM examples are pretty poor also. The key here is that I have an interface that I can pass around. So I can have various implementations, perhaps one with Java Reflection as a default, one with ASM, and maybe one with Javassist? Any help would be greatly appreciated.

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  • ObjectDisposedException when .Show()'ing a form that shouldn't be disposed.

    - by user320781
    ive checked out some of the other questions and obviously the best solution is to prevent the behavior that causes this issue in the first place, but the problem is very intermittent, and very un-reproduceable. I basically have a main form, with sub forms. The sub forms are shown from menus and/or buttons from the main form like so: private void myToolStripMenuItem_Click(object sender, EventArgs e) { try { xDataForm.Show(); xDataForm.Activate(); } catch (ObjectDisposedException) { MessageBox.Show("ERROR 10103"); ErrorLogging newLogger = new ErrorLogging("10103"); Thread errorThread = new Thread(ErrorLogging.writeErrorToLog); errorThread.Start(); } } and the sub forms are actually in the main form(for better or worse. i would actually like to change this but would be a considerable amount of time to do so): public partial class FormMainScreen : Form { Form xDataForm = new xData(); ...(lots more here) public FormMainScreen(int pCount, string pName) { InitializeComponent(); ... } ... } The Dispose function for the sub form is modified so that, the 'close' and 'X' buttons actually hide the form so we dont have to re-create it every time. When the main screen closes, it sets a "flag" to 2, so the other forms know that it is actually ok to close; protected override void Dispose(bool disposing) { if (FormMainScreen.isExiting == 2) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } else { if (xData.ActiveForm != null) { xData.ActiveForm.Hide(); } } } So, the question is, why would this work over and over and over again flawlessly, but, literally, about every 1/1000 of the time, cause an exception, or rather, why is my form being disposed? I had a suspicion that the garbage collector was getting confused, because it occurs slightly more frequently after it has been running for many hours.

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