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  • Which way is preferred when doing asynchronous WCF calls?

    - by Mikael Svenson
    When invoking a WCF service asynchronous there seems to be two ways it can be done. 1. public void One() { WcfClient client = new WcfClient(); client.BegindoSearch("input", ResultOne, null); } private void ResultOne(IAsyncResult ar) { WcfClient client = new WcfClient(); string data = client.EnddoSearch(ar); } 2. public void Two() { WcfClient client = new WcfClient(); client.doSearchCompleted += TwoCompleted; client.doSearchAsync("input"); } void TwoCompleted(object sender, doSearchCompletedEventArgs e) { string data = e.Result; } And with the new Task<T> class we have an easy third way by wrapping the synchronous operation in a task. 3. public void Three() { WcfClient client = new WcfClient(); var task = Task<string>.Factory.StartNew(() => client.doSearch("input")); string data = task.Result; } They all give you the ability to execute other code while you wait for the result, but I think Task<T> gives better control on what you execute before or after the result is retrieved. Are there any advantages or disadvantages to using one over the other? Or scenarios where one way of doing it is more preferable?

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  • difference in using virtual and not using virtual

    - by numerical25
    In C++, whether you choose to use virtual or not, you can still override the base class function. The following compiles just fine... class Enemy { public: void SelectAnimation(); void RunAI(); void Interact() { cout<<"Hi I am a regular Enemy"; } private: int m_iHitPoints; }; class Boss : public Enemy { public: void Interact() { cout<<"Hi I am a evil Boss"; } }; So my question is what is the difference in using or not using the virtual function. And what is the disadvantage.

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  • Nested bind expressions

    - by user328543
    This is a followup question to my previous question. #include <functional> int foo(void) {return 2;} class bar { public: int operator() (void) {return 3;}; int something(int a) {return a;}; }; template <class C> auto func(C&& c) -> decltype(c()) { return c(); } template <class C> int doit(C&& c) { return c();} template <class C> void func_wrapper(C&& c) { func( std::bind(doit<C>, std::forward<C>(c)) ); } int main(int argc, char* argv[]) { // call with a function pointer func(foo); func_wrapper(foo); // error // call with a member function bar b; func(b); func_wrapper(b); // call with a bind expression func(std::bind(&bar::something, b, 42)); func_wrapper(std::bind(&bar::something, b, 42)); // error // call with a lambda expression func( [](void)->int {return 42;} ); func_wrapper( [](void)->int {return 42;} ); return 0; } I'm getting a compile errors deep in the C++ headers: functional:1137: error: invalid initialization of reference of type ‘int (&)()’ from expression of type ‘int (*)()’ functional:1137: error: conversion from ‘int’ to non-scalar type ‘std::_Bind(bar, int)’ requested func_wrapper(foo) is supposed to execute func(doit(foo)). In the real code it packages the function for a thread to execute. func would the function executed by the other thread, doit sits in between to check for unhandled exceptions and to clean up. But the additional bind in func_wrapper messes things up...

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  • NDK app onDestroy cleanup - how to DetachCurrentThread

    - by Aristarhys
    So if we attach we must detach thread after after it finish, right? JNIEnv* get_jni_env() { JNIEnv* res; JAVA_VM->GetEnv((void**) &res, JNI_VERSION_1_6);//Using cached JavaVM JAVA_VM->AttachCurrentThread(&res, NULL); return res; } I call next native method from @Override protected void onDestroy() of my Activity class void free_jni_manager() { JNIEnv* env = get_jni_env(); ... //Here i delete global refs (jclass) //JAVA_VM->DetachCurrentThread(); } ERROR: detaching thread with interp frames (count=16) - main thread still running and we try to detach it. Even if we take any function that use JNIEnv (for example calling java methods), putting DetachCurrentThread will cause same error. DetachCurrentThread works flawlessly if used in pthread function static void* thread_func(void* arg) { get_jni_env(); // attach new thread //Do thread stuff JAVA_VM->DetachCurrentThread();//thread done detached it with ok return NULL; } Do we need detach main thread then we done with JNI, there do it? Or then activity will be destroyed, it will freed itself with JavaVM? Do we need do call DestroyJavaVM() (just doing crash if use onDestroy), how free cached JavaVM or garbage cleaner will handle this? P.S. What benefits of using AttachCurrentThreadAsDaemon()

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  • how to run TimerTask off main UI thread?

    - by huskyd97
    I am having trouble with a TimerTask Interfering with In App Purchasing (Async Tasks). I am weak with Threads, so I believe it is running on the main UI thread, eating up resources. How can I run this outside the UI thread? I have searched, and tried some suggestions using handlers. but seems like I get the same result, app gets really laggy. when I don't run this task (refreshes every 500mS), the activity runs smoothly, and there are no hangs during In app purchases. Your help is appreciated, code snippet below: public class DummyButtonClickerActivity extends Activity { protected Timer timeTicker = new Timer("Ticker"); private Handler timerHandler = new Handler(); protected int timeTickDown = 20; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.mainhd); // start money earned timer handler TimerTask tick = new TimerTask() { public void run() { myTickTask(); } }; timeTicker.scheduleAtFixedRate(tick, 0, 500); // 500 ms each } // End OnCreate protected void myTickTask() { if (timeTickDown == 0) { /// run my code here //total = total + _Rate; timerHandler.post(doUpdateTimeout); } else if(timeTickDown < 0) { // do nothing } timeTickDown--; } private Runnable doUpdateTimeout = new Runnable() { public void run() { updateTimeout(); } }; private void updateTimeout() { // reset tick timeTickDown = 2; // 2* 500ms == once a second } }

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  • Explain the code: c# locking feature and threads

    - by Mendy
    I used this pattern in a few projects, (this snipped of code is from CodeCampServer), I understand what it does, but I'm really interesting in an explanation about this pattern. Specifically: Why is the double check of _dependenciesRegistered. Why to use lock (Lock){}. Thanks. public class DependencyRegistrarModule : IHttpModule { private static bool _dependenciesRegistered; private static readonly object Lock = new object(); public void Init(HttpApplication context) { context.BeginRequest += context_BeginRequest; } public void Dispose() { } private static void context_BeginRequest(object sender, EventArgs e) { EnsureDependenciesRegistered(); } private static void EnsureDependenciesRegistered() { if (!_dependenciesRegistered) { lock (Lock) { if (!_dependenciesRegistered) { new DependencyRegistrar().ConfigureOnStartup(); _dependenciesRegistered = true; } } } } }

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  • Android - dialer icon gets placed in recently used apps after finish()

    - by Donal Rafferty
    In my application I detect the out going call when a call is dialled from the dialer or contacts. This works fine and I then pop up a dialog saying I have detected the call and then the user presses a button to close the dialog which calls finish() on that activity. It all works fine except that when I then hold the home key to bring up the recently used apps the dialer icon is there. And when it is clicked the dialog is brought back into focus in the foreground when the dialog activity should be dead and gone and not be able to be brought back to the foreground. Here is a picture of what I mean. So two questions arise, why would the dialer icon be getting placed there and why would it be recalling my activity to the foreground? Here is the code for that Activity which has a dialog theme: public class CallDialogActivity extends Activity{ boolean isRecording; AudioManager audio_service; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.dialog); audio_service = (AudioManager) getSystemService(Context.AUDIO_SERVICE); getWindow().addFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND); Bundle b = this.getIntent().getExtras(); String number = b.getString("com.networks.NUMBER"); String name = b.getString("com.networks.NAME"); TextView tv = (TextView) findViewById(R.id.voip) ; tv.setText(name); Intent service = new Intent(CallAudio.CICERO_CALL_SERVICE); startService(service); final Button stop_Call_Button = (Button) findViewById(R.id.widget35); this.setVolumeControlStream(AudioManager.STREAM_VOICE_CALL); stop_Call_Button.setOnClickListener(new View.OnClickListener(){ public void onClick(View v){ Intent service = new Intent(CallAudio._CALL_SERVICE); //this is for Android 1.5 (sets speaker going for a few seconds before shutting down) stopService(service); Intent setIntent = new Intent(Intent.ACTION_MAIN); setIntent.addCategory(Intent.CATEGORY_HOME); setIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(setIntent); finish(); isRecording = false; } }); final Button speaker_Button = (Button) findViewById(R.id.widget36); speaker_Button.setOnClickListener(new View.OnClickListener(){ public void onClick(View v){ if(true){ audio_service.setSpeakerphoneOn(false); } else{ audio_service.setSpeakerphoneOn(true); } } }); } @Override protected void onResume() { super.onResume(); } @Override protected void onPause() { super.onPause(); } public void onCofigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); } } It calls a service that uses AudioRecord to record from the Mic and AudioTrack to play it out the earpiece, nothing in the service to do with the dialler. Has anyone any idea why this might be happening?

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  • Profiling help required

    - by Mick
    I have a profiling issue - imagine I have the following code... void main() { well_written_function(); badly_written_function(); } void well_written_function() { for (a small number) { highly_optimised_subroutine(); } } void badly_written_function() { for (a wastefully and unnecessarily large number) { highly_optimised_subroutine(); } } void highly_optimised_subroutine() { // lots of code } If I run this under vtune (or other profilers) it is very hard to spot that anything is wrong. All the hotspots will appear in the section marked "// lots of code" which is already optimised. The badly_written_function() will not be highlighted in any way even though it is the cause of all the trouble. Is there some feature of vtune that will help me find the problem? Is there some sort of mode whereby I can find the time taken by badly_written_function() and all of its sub-functions?

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  • Command Not working in separate thread in J2me.

    - by RishiPatel
    I am creating a bluetooth application. I created a simple midlet with a exit command and i create a thread for finding the service and discovering the device. While doing so it displays a animated screen on which i added the parent commandListener for exit command. After successful connection both user is represented with greetings(Current screen calls the parent Display method setCurrent for displaying itself). This screen also have CommandListener set to the parent. Now i want to add few more commands. I Implemented the CommandLIstener Interface in this class, added few commands but the commands are not working. I dont whats wen wrong. I am giving u Code snippets to fully describle my issue : - package name Imports here public class MyMidlet extends MIDlet implements CommandListener { public CommandListener theListener; public Display theDisplay; public Command exitCommand; public MyMidlet() { // Retrieve the display for this MIDlet //Create the initial screen } public void startApp() throws MIDletStateChangeException { } public void pauseApp() { } public void destroyApp(boolean unconditional) { } public void commandAction(Command c, Displayable d) { // Determine if the exit command was selected if (c == exitCommand) { //End application here notifyDestroyed(); } else { //Start the new thread here } } } Now here is the code for the class which is invoked by the above midlet in a separate thread; package here; imports here public class MyService implements Runnable, CommandListener { private MyMidlet parent; private StreamConnection conn; private OutputStream output; private InputStream input; public Command sendCommand; private TextField messageToSend Form form; public BChatService(boolean isServer, BChatMidlet parent) { //some stuff here this.parent = parent; } public void run() { //functino for showing animation here try { input = conn.openInputStream(); output = conn.openOutputStream(); } catch (IOException e) { displayError("IO Error", "An error occurred while opening " + "the input and output streams" + "(IOException: " + e.getMessage() + ")"); try { conn.close(); } catch (Exception ex) { } return; } // Create the Form here when service is discoverd and greets the users Command sendCommand = new Command("Send", Command.ITEM, 2); exitCommand = new Command("Exit", Command.EXIT, 1); form.addCommand(exitCommand); form.addCommand(sendCommand); parent.theDisplay.setCurrent(form); form.setCommandListener(this); public void commandAction(Command c, Displayable d) { if (c == exitCommand) { // End the game parent.destroyApp(true); parent.notifyDestroyed(); } if(c == sendCommand) { form.append("SOme text here"); } } } When i select the Send command, the string doesnt append in form neither exit command works. What can be the possible cause for it?? I need to implement this functionality...Is there any other way to achieve this??

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  • How to call a method in another class using the arraylist index in java?

    - by Puchatek
    Currently I have two classes. A Classroom class and a School class. public void addTeacherToClassRoom(Classroom myClassRoom, String TeacherName) I would like my method addTeacherToClassRoom to use the Classroom Arraylist index number to setTeacherName e.g. int 0 = maths int 1 = science I would like to setTeacherName "Daniel" in int 1 science. many, thanks public class Classroom { private String classRoomName; private String teacherName; public void setClassRoomName(String newClassRoomName) { classRoomName = newClassRoomName; } public String returnClassRoomName() { return classRoomName; } public void setTeacherName(String newTeacherName) { teacherName = newTeacherName; } public String returnTeacherName() { return teacherName; } } import java.util.ArrayList; public class School { private ArrayList<Classroom> classrooms; private String classRoomName; private String teacherName; public School() { classrooms = new ArrayList<Classroom>(); } public void addClassRoom(Classroom newClassRoom, String theClassRoomName) { classrooms.add(newClassRoom); classRoomName = theClassRoomName; } public void addTeacherToClassRoom(Classroom myClassRoom, String TeacherName) { myClassRoom.setTeacherName(TeacherName); } }

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  • DoWork of BackgroundWorker is called twice when RunWorkerAsync is called once?

    - by Power-Mosfet
    I have create a backgroundworker in an class it works, but if i call and wait until the end run, call it for the second time it will do the same process twice i thinks there is somthing wrong with bw.DoWork += private void button1_Click(object sender, EventArgs e) { nptest.test.start("null", "null"); } namespace nptest { class test { public static void start(string str, string strb) { if (bw.IsBusy != true) { bw.WorkerSupportsCancellation = true; bw.DoWork += (obj, e) => bw_DoWork(str, strb); bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted); bw.RunWorkerAsync(); } } private static BackgroundWorker bw = new BackgroundWorker(); private static void bw_DoWork(string str, string strb) { System.Windows.Forms.MessageBox.Show("initializing BackgroundWorker"); } private static void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { if ((e.Cancelled == true)) { Console.WriteLine("Canceled"); } else if (!(e.Error == null)) { Console.WriteLine("Error: " + e.Error.Message); } bw.Dispose(); } } }

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  • How can I determine whether or not to add project items using IWizard?

    - by taarskog
    Hi, I am generating entity wrappers in VS2010 based on dynamic objects in a CRM system. In addition to the entity code, I want to add an EntityBase of which all entities inherit from. If the file exists in the project from before, it should not be added. I am using an IWizard implementation to give the generator the object names etc. Is it possible in the IWizard implementation to determine whether or not to add an item if it exists in the project from before? How do I get a hold of the project handle and its items in or before the ShouldAddProjectItem method? My code so far (not completed): public class EntityWizardImplementation : IWizard { public void BeforeOpeningFile(ProjectItem projectItem) { //Note: Nothing here. } public void ProjectFinishedGenerating(Project project) { //Note: Nothing here. } public void ProjectItemFinishedGenerating(ProjectItem projectItem) { //Note: Nothing here. } public void RunFinished() { //Note: Nothing here. } public void RunStarted(object automationObject, Dictionary<string, string> replacementsDictionary, WizardRunKind runKind, object[] customParams) { try { var window = new WizardWindow(); // Replace parameters gathered from the wizard replacementsDictionary.Add("$crmEntity$", window.CrmEntity); replacementsDictionary.Add("$crmOrganization$", window.CrmOrganization); replacementsDictionary.Add("$crmMetadataServiceUrl$", window.CrmMetadataUrl); window.Close(); } catch (SoapException se) { MessageBox.Show(se.ToString()); } catch (Exception e) { MessageBox.Show(e.ToString()); } } public bool ShouldAddProjectItem(string filePath) { // This is where I assume it is correct to handle the preexisting file. return true; } }

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  • How solve consumer/producer task using semaphores

    - by user1074896
    I have SimpleProducerConsumer class that illustrate consumer/producer problem (I am not sure that it's correct). public class SimpleProducerConsumer { private Stack<Object> stack = new Stack<Object>(); private static final int STACK_MAX_SIZE = 10; public static void main(String[] args) { SimpleProducerConsumer pc = new SimpleProducerConsumer(); new Thread(pc.new Producer(), "p1").start(); new Thread(pc.new Producer(), "p2").start(); new Thread(pc.new Consumer(), "c1").start(); new Thread(pc.new Consumer(), "c2").start(); new Thread(pc.new Consumer(), "c3").start(); } public synchronized void push(Object d) { while (stack.size() >= STACK_MAX_SIZE) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } stack.push(new Object()); System.out.println("push " + Thread.currentThread().getName() + " " + stack.size()); notify(); } public synchronized Object pop() { while (stack.size() == 0) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(50); } catch (InterruptedException e) { e.printStackTrace(); } stack.pop(); System.out.println("pop " + Thread.currentThread().getName() + " " + stack.size()); notify(); return null; } class Consumer implements Runnable { @Override public void run() { while (true) { pop(); } } } class Producer implements Runnable { @Override public void run() { while (true) { push(new Object()); } } } } I found simple realization of semaphore(here:http://docs.oracle.com/javase/tutorial/essential/concurrency/guardmeth.html I know that there is concurrency package) How I need to change code to exchange java objects monitors to my custom semaphore. (To illustrate C/P problem using semaphores) Semaphore: class Semaphore { private int counter; public Semaphore() { this(0); } public Semaphore(int i) { if (i < 0) throw new IllegalArgumentException(i + " < 0"); counter = i; } public synchronized void release() { if (counter == 0) { notify(); } counter++; } public synchronized void acquire() throws InterruptedException { while (counter == 0) { wait(); } counter--; } }

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  • Android: Unable to access a local website over HTTPS

    - by user1253789
    I am trying to access a locally hosted website and get its HTML source to parse. I have few questions: 1) Can I use "https://An IP ADDRESS HERE" as a valid URL to try and access. I do not want to make changes in the /etc/hosts file so I want to do it this way. 2) I cannot get the html, since it is giving me Handshake exceptions and Certificate issues. I have tried a lot of help available over the web , but am not successful. Here is the code I am using: public class MainActivity extends Activity { private TextView textView; String response = ""; String finalresponse=""; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); textView = (TextView) findViewById(R.id.TextView01); System.setProperty("javax.net.ssl.trustStore","C:\\User\\*" ); System.setProperty("javax.net.ssl.trustStorePassword", "" ); } private class DownloadWebPageTask extends AsyncTask<String, Void, String> { @Override protected String doInBackground(String... urls) { TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager() { public java.security.cert.X509Certificate[] getAcceptedIssuers() { return null; } public void checkClientTrusted(java.security.cert.X509Certificate[] certs, String authType) { } public void checkServerTrusted(java.security.cert.X509Certificate[] certs, String authType) { } } }; try { SSLContext sc = SSLContext.getInstance("SSL"); sc.init(null, trustAllCerts, new java.security.SecureRandom()); HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory()); } catch (Exception e) { } try { URL url = new URL("https://172.27.224.133"); HttpsURLConnection con =(HttpsURLConnection)url.openConnection(); con.setHostnameVerifier(new AllowAllHostnameVerifier()); finalresponse=readStream(con.getInputStream()); } catch (Exception e) { e.printStackTrace(); } return finalresponse; } private String readStream(InputStream in) { BufferedReader reader = null; try { reader = new BufferedReader(new InputStreamReader(in)); String line = ""; while ((line = reader.readLine()) != null) { response+=line; } } catch (IOException e) { e.printStackTrace(); } finally { if (reader != null) { try { reader.close(); } catch (IOException e) { e.printStackTrace(); } } } return response; } @Override protected void onPostExecute(String result) { textView.setText(finalresponse); } } public void readWebpage(View view) { DownloadWebPageTask task = new DownloadWebPageTask(); task.execute(new String[] { "https://172.27.224.133" }); } }

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  • Win32 reset event like synchronization class with boost C++

    - by fgungor
    I need some mechanism reminiscent of Win32 reset events that I can check via functions having the same semantics with WaitForSingleObject() and WaitForMultipleObjects() (Only need the ..SingleObject() version for the moment) . But I am targeting multiple platforms so all I have is boost::threads (AFAIK) . I came up with the following class and wanted to ask about the potential problems and whether it is up to the task or not. Thanks in advance. class reset_event { bool flag, auto_reset; boost::condition_variable cond_var; boost::mutex mx_flag; public: reset_event(bool _auto_reset = false) : flag(false), auto_reset(_auto_reset) { } void wait() { boost::unique_lock<boost::mutex> LOCK(mx_flag); if (flag) return; cond_var.wait(LOCK); if (auto_reset) flag = false; } bool wait(const boost::posix_time::time_duration& dur) { boost::unique_lock<boost::mutex> LOCK(mx_flag); bool ret = cond_var.timed_wait(LOCK, dur) || flag; if (auto_reset && ret) flag = false; return ret; } void set() { boost::lock_guard<boost::mutex> LOCK(mx_flag); flag = true; cond_var.notify_all(); } void reset() { boost::lock_guard<boost::mutex> LOCK(mx_flag); flag = false; } }; Example usage; reset_event terminate_thread; void fn_thread() { while(!terminate_thread.wait(boost::posix_time::milliseconds(10))) { std::cout << "working..." << std::endl; boost::this_thread::sleep(boost::posix_time::milliseconds(1000)); } std::cout << "thread terminated" << std::endl; } int main() { boost::thread worker(fn_thread); boost::this_thread::sleep(boost::posix_time::seconds(1)); terminate_thread.set(); worker.join(); return 0; } EDIT I have fixed the code according to Michael Burr's suggestions. My "very simple" tests indicate no problems. class reset_event { bool flag, auto_reset; boost::condition_variable cond_var; boost::mutex mx_flag; public: explicit reset_event(bool _auto_reset = false) : flag(false), auto_reset(_auto_reset) { } void wait() { boost::unique_lock<boost::mutex> LOCK(mx_flag); if (flag) { if (auto_reset) flag = false; return; } do { cond_var.wait(LOCK); } while(!flag); if (auto_reset) flag = false; } bool wait(const boost::posix_time::time_duration& dur) { boost::unique_lock<boost::mutex> LOCK(mx_flag); if (flag) { if (auto_reset) flag = false; return true; } bool ret = cond_var.timed_wait(LOCK, dur); if (ret && flag) { if (auto_reset) flag = false; return true; } return false; } void set() { boost::lock_guard<boost::mutex> LOCK(mx_flag); flag = true; cond_var.notify_all(); } void reset() { boost::lock_guard<boost::mutex> LOCK(mx_flag); flag = false; } };

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  • I'm confused about Polymorphism

    - by Vtanathip
    I'm know polymorphism rule that we can send it via parameter like this code interface Animal { void whoAmI(); } class A implements Animal{ @Override public void whoAmI() { // TODO Auto-generated method stub System.out.println("A"); } } class B implements Animal{ @Override public void whoAmI() { // TODO Auto-generated method stub System.out.println("B"); } } class RuntimePolymorphismDemo { public void WhoRU(List t){ System.out.println(t.getClass()); } public static void main(String[] args) { A a = new A(); B b = new B(); RuntimePolymorphismDemo rp = new RuntimePolymorphismDemo(); rp.WhoRU(a); rp.WhoRU(b); } } but List<Example> examples = new ArrayList<Example>(); This code,I'm don't understand why we must use List. why we can't use like this? ArrayList<Example> examples = new ArrayList<Example>(); Because when we use List we can't use method that only have in ArrayList class like trimToSize() and How I know when to use or not use?

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  • Polymorphism and c#

    - by saurabh
    Here one more basic question asked in MS interview recently Class A { public virtual void Method1(){} public void Method2() { Method1(); } } class B:A { public override void Method1() { } } Class main { A obk = new B(); obk.Method2(); } now tell me which function gets called ? sorry for the typos.

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  • Cannot understand the behaviour of dotnet compiler while instantiating a class thru interface(C#)

    - by Newbie
    I have a class that impelemnts an interface. The interface is public interface IRiskFactory { void StartService(); void StopService(); } The class that implements the interface is public class RiskFactoryService : IRiskFactory { } Now I have a console application and one window service. From the console application if I write the following code static void Main(string[] args) { IRiskFactory objIRiskFactory = new RiskFactoryService(); objIRiskFactory.StartService(); Console.ReadLine(); objIRiskFactory.StopService(); } It is working fine. However, when I mwrite the same piece of code in Window service public partial class RiskFactoryService : ServiceBase { IRiskFactory objIRiskFactory = null; public RiskFactoryService() { InitializeComponent(); objIRiskFactory = new RiskFactoryService(); <- ERROR } /// <summary> /// Starts the service /// </summary> /// <param name="args"></param> protected override void OnStart(string[] args) { objIRiskFactory.StartService(); } /// <summary> /// Stops the service /// </summary> protected override void OnStop() { objIRiskFactory.StopService(); } } It throws error: Cannot implicitly convert type 'RiskFactoryService' to 'IRiskFactory'. An explicit conversion exists (are you missing a cast?) When I type casted to the interface type, it started working objIRiskFactory = (IRiskFactory)new RiskFactoryService(); My question is why so? Thanks.(C#)

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  • How to call a method after asynchronous task is complete

    - by doctordoder
    I have a class called WikiWebView which is a subclass of UIWebView which loads Wikipedia subjects and is designed to fetch all the links of the webpage, in order to create a sort of site map for the subject. My problem is that I can only create the links once the web page has loaded, but the loading isn't done right after [self loadRequest:requestObj] is called. - (void)loadSubject:(NSString *)subject { // load the actual webpage NSString *wiki = @"http://www.wikipedia.org/wiki/"; NSString *fullURL = [wiki stringByAppendingString:subject]; NSURL *url = [NSURL URLWithString:fullURL]; NSURLRequest *requestObj = [NSURLRequest requestWithURL:url]; [self loadRequest:requestObj]; // [self createLinks]; // need this to be called after the view has loaded } - (void)createLinks { NSString *javascript = @"var string = \"\";" "var arr = document.getElementsByClassName(\"mw-redirect\");" "for (var i = 0; i < arr.length; ++i)" "{" "var redirectLink = arr[i].href;" "string = string + redirectLink + \" \";" "}" "string;"; NSString *links = [self stringByEvaluatingJavaScriptFromString:javascript]; self.links = [links componentsSeparatedByString:@" "]; } I tried the normal delegation technique, which lead to this code being added: - (id)init { if (self = [super init]) { self.delegate = self; // weird } return self; } #pragma mark - UIWebViewDelegate - (void)webViewDidStartLoad:(UIWebView *)webView { ++_numProcesses; } - (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error { --_numProcesses; } - (void)webViewDidFinishLoad:(UIWebView *)webView { --_numProcesses; if (_numProcesses == 0) { [self createLinks]; } } However, the delegate methods are never called.. I've seen similar questions where the answers are to use blocks, but how would I do that in this case?

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  • Why doesn't g++ pay attention to __attribute__((pure)) for virtual functions?

    - by jchl
    According to the GCC documentation, __attribute__((pure)) tells the compiler that a function has no side-effects, and so it can be subject to common subexpression elimination. This attribute appears to work for non-virtual functions, but not for virtual functions. For example, consider the following code: extern void f( int ); class C { public: int a1(); int a2() __attribute__((pure)); virtual int b1(); virtual int b2() __attribute__((pure)); }; void test_a1( C *c ) { if( c->a1() ) { f( c->a1() ); } } void test_a2( C *c ) { if( c->a2() ) { f( c->a2() ); } } void test_b1( C *c ) { if( c->b1() ) { f( c->b1() ); } } void test_b2( C *c ) { if( c->b2() ) { f( c->b2() ); } } When compiled with optimization enabled (either -O2 or -Os), test_a2() only calls C::a2() once, but test_b2() calls b2() twice. Is there a reason for this? Is it because, even though the implementation in class C is pure, g++ can't assume that the implementation in every subclass will also be pure? If so, is there a way to tell g++ that this virtual function and every subclass's implementation will be pure?

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  • I have a following gcc compilation warning

    - by thetna
    symbol.h:179: note: expected ‘uintptr_t *’ but argument is of type ‘PRECEDENCE’ The corresponding code is : 176 void symbol_SetCount(SYMBOL, unsigned long); 177 unsigned long symbol_GetCount(SYMBOL); 178 179 size_t symbol_Ordering(uintptr_t*, SYMBOL); 180 181 void symbol_CheckIndexInRange(int); 182 void symbol_CheckNoVariable(SYMBOL); SYMBOL is defined as: typedef size_t SYMBOL Any effort will be highly appreciated.

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  • Specializing a template member function of a template class?

    - by uj2
    I have a template class that has a template member function that needs to be specialized, as in: template <typename T> class X { public: template <typename U> void Y() {} template <> void Y<int>() {} }; Altough VC handles this correctly, apperantly this isn't standard and GCC complains: explicit specialization in non-namespace scope 'class X<T>' I tried: template <typename T> class X { public: template <typename U> void Y() {} }; template <typename T> // Also tried `template<>` here void X<T>::Y<int>() {} But this causes both VC and GCC to complain. What's the right way to do this?

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  • Could someone explain __declspec(naked) please?

    - by Scott
    I'm looking into porting a script engine written for Windows to Linux; it's for Winamp's visualization platform AVS. I'm not sure if it's even possible at the moment. From what I can tell the code is taking the addresses of the C functions nseel_asm_atan and nseel_asm_atan_end and storing them inside a table that it can reference during code execution. I've looked at MS's documentation, but I'm unsure what __declspec(naked) really does. What is prolog and epilog code mentioned in the documentation? Is that related to Windows calling conventions? Is this portable? Know of any Linux-based examples using similar techniques? static double (*__atan)(double) = &atan; __declspec ( naked ) void nseel_asm_atan(void) { FUNC1_ENTER *__nextBlock = __atan(*parm_a); FUNC_LEAVE } __declspec ( naked ) void nseel_asm_atan_end(void) {}

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  • How to notify ViewController on parse end with multiple ViewControllers using a single parser.

    - by objneodude
    Hello, I have created a RSS parser and 3 TableViews and it parses the RSS files fine but I don't know how to notify the TableViewController when parsing has ended so it can update the view. The TableViewController initiates the parser and the parsing of a feed. parser = [[RSSParser alloc] initWithURL:@"http://randomfeed.com"]; I can access the single feed items like [parser feedItems]; In parser.m i have implemented the delegate methods of NSXMLParser: - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName - (void)parserDidEndDocument:(NSXMLParser *)parser So how do i get parserDidEndDocument to notify my controllers so i can add the data to the tableview. Cheers from a obj-c beginner.

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  • Android: How to properly exit application when inconsistent condition is unavoidable?

    - by Bevor
    First of all I already read about all this discussion that it isn't a good idea to manually exit an Android application. But in my case it seems to be needed. I have an AsyncTask which does a lof of operations in background. That means downloading data, saving it to local storage and preparing it for usage in application. It could happen that there is no internet connection or something different happens. For all that cases I have an Exception handling which returns the result. And if there is an exception, the application is unusable so I need to exit it. My question is, do I have to do some unregistration unloading or unbinding tasks or something when I exit the application by code or is System.exit(0) ok? I do all this in an AsyncTask, see my example: public class InitializationTask extends AsyncTask<Void, Void, InitializationResult> { private ProcessController processController = new ProcessController(); private ProgressDialog progressDialog; private Activity mainActivity; public InitializationTask(Activity mainActivity) { this.mainActivity = mainActivity; } @Override protected void onPreExecute() { super.onPreExecute(); progressDialog = new ProgressDialog(mainActivity); progressDialog.setMessage("Die Daten werden aufbereitet.\nBitte warten..."); progressDialog.setIndeterminate(true); //means that the "loading amount" is not measured. progressDialog.setCancelable(false); progressDialog.show(); }; @Override protected InitializationResult doInBackground(Void... params) { return processController.initializeData(); } @Override protected void onPostExecute(InitializationResult result) { super.onPostExecute(result); progressDialog.dismiss(); if (!result.isValid()) { AlertDialog.Builder dialog = new AlertDialog.Builder(mainActivity); dialog.setTitle("Initialisierungsfehler"); dialog.setMessage(result.getReason()); dialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); //TODO cancel application System.exit(0); } }); dialog.show(); } } }

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