Search Results

Search found 30347 results on 1214 pages for 'public speaking'.

Page 521/1214 | < Previous Page | 517 518 519 520 521 522 523 524 525 526 527 528  | Next Page >

• Can I pass a child class to a reference of a parent class?

  - by michael

  Hi, I have a class A which takes a reference of B in its constructor. class A { public: A(B& b); } And I have a class SubB which is a child class of B: class SubB : public B { //omitted... } In my code, I create a SubB and pass it to A: SubB subB; A a(subB); But I get this compile Error: error: ‘B’ is an inaccessible base of ‘SubB’ Can I pass a reference of SubB as B? Thank you.

  Read the article

• C#: are ranges possible with enums?

  - by Craig Johnston

  In C#, can you use number ranges in enum types, for example public enum BookType { Novel = 1, Journal = 2, Reference = 3, TextBook = 4 .. 10 }

  Read the article

• Using FindAll on a List<List<T>> type

  - by Ken Foster

  Assuming public class MyClass { public int ID {get; set; } public string Name {get; set; } } and List<MyClass> classList = //populate with MyClass instances of various IDs I can do List<MyClass> result = classList.FindAll(class => class.ID == 123); and that will give me a list of just classes with ID = 123. Works great, looks elegant. Now, if I had List<List<MyClass>> listOfClassLists = //populate with Lists of MyClass instances How do I get a filtered list where the lists themselves are filtered. I tried List<List<MyClass>> result = listOfClassLists.FindAll (list => list.FindAll(class => class.ID == 123).Count > 0); it looks elegant, but doesn't work. It only includes Lists of classes where at least one class has an ID of 123, but it includes ALL MyClass instances in that list, not just the ones that match. I ended up having to do List<List<MyClass>> result = Results(listOfClassLists, 123); private List<List<MyClass>> Results(List<List<MyClass>> myListOfLists, int id) { List<List<MyClass>> results = new List<List<MyClass>>(); foreach (List<MyClass> myClassList in myListOfLists) { List<MyClass> subList = myClassList.FindAll(myClass => myClass.ID == id); if (subList.Count > 0) results.Add(subList); } return results; } which gets the job done, but isn't that elegant. Just looking for better ways to do a FindAll on a List of Lists. Ken

  Read the article

• Is this a correct Interlocked synchronization design?

  - by Dan Bryant

  I have a system that takes Samples. I have multiple client threads in the application that are interested in these Samples, but the actual process of taking a Sample can only occur in one context. It's fast enough that it's okay for it to block the calling process until Sampling is done, but slow enough that I don't want multiple threads piling up requests. I came up with this design (stripped down to minimal details): public class Sample { private static Sample _lastSample; private static int _isSampling; public static Sample TakeSample(AutomationManager automation) { //Only start sampling if not already sampling in some other context if (Interlocked.CompareExchange(ref _isSampling, 0, 1) == 0) { try { Sample sample = new Sample(); sample.PerformSampling(automation); _lastSample = sample; } finally { //We're done sampling _isSampling = 0; } } return _lastSample; } private void PerformSampling(AutomationManager automation) { //Lots of stuff going on that shouldn't be run in more than one context at the same time } } Is this safe for use in the scenario I described?

  Read the article

• How to load secure S3 images into Flex with temporary URLs

  - by Yarin

  I have some secure images on S3 that I need to load into Flex. I was expecting to be able to do this using signed temporary URLs but can't get it working. I know the URLs I'm generating are correct, because they load fine in my browsers' address bar. Moreover, Flex has no problem loading my images with a non-signed url when they are public, but as soon as I try signing the urls all the images fail, whether public or not. I've tried image.source = signedURL, image.load(signedURL), etc. If I try loading the file with URLLoader/URLStream, it looks like I'm getting the data OK, but I'm not sure how to translate those results to an Image control. Is this just an issue with the Image control not being able to recognize signed urls? Do I have to load the image from a byte array? What would that look like?

  Read the article

• Implement INotifyPropertyChanged

  - by yossharel

  Hi all, I want to have Dictionary that would be 'Observable' in order to throw events when its item changing.(Remove or Add). In other class I created such dictionary and set Binding to ListBox.ItemsSourseProperty. The Binding work well. I can see the items. But something wrong. the event 'PropertyChanged' always null. Can anyone help? Thanks in advance! class ObservableDictionary<TKey, TValue>:Dictionary<TKey, TValue>, INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public new void Remove(TKey obj) { base.Remove(obj); if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs("Remove")); } } }

  Read the article

• How to pass content in response from Exception filter in Asp.net WebAPI?

  - by jaffa

  Consider following code: My problem is: 1) I can't seem to cast the errors to HttpContent 2) I can't use the CreateContent extension method as this doesn't exist on the context.Response.Content.CreateContent public class ServiceLayerExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { if (context.Response == null) { var exception = context.Exception as ModelValidationException; if ( exception != null ) { var modelState = new ModelStateDictionary(); modelState.AddModelError(exception.Key, exception.Description); var errors = modelState.SelectMany(x => x.Value.Errors).Select(x => x.ErrorMessage); // Cannot cast errors to HttpContent?? // var resp = new HttpResponseMessage(HttpStatusCode.BadRequest) {Content = errors}; // throw new HttpResponseException(resp); // Cannot create response from extension method?? //context.Response.Content.CreateContent } else { context.Response = new HttpResponseMessage(context.Exception.ConvertToHttpStatus()); } } base.OnException(context); } }

  Read the article

• static array in c++ forgets its size

  - by Karel Bílek

  In this small example, c++ forgets size of an array, passed to a constructor. I guess it is something simple, but I cannot see it. In classes.h, there is this code: #ifndef CLASSES_INC #define CLASSES_INC #include <iostream> class static_class { public: static_class(int array[]) { std::cout<<sizeof(array)/sizeof(int)<<"\n"; } }; class my_class{ public: static static_class s; static int array[4]; }; #endif In classes.cpp, there is this code: #include "classes.h" int my_class::array[4]={1, 2, 3, 4}; static_class my_class::s = static_class(my_class::array); In main.cpp, there is only simple #include "classes.h" int main () { return 0; } Now, the desired output (from the constructor of static_class) is 4. But what I get is 1. Why is that?

  Read the article

• Writing to a comet stream using tomcat 6.0

  - by user301247

  Hey I'm new to java servlets and I am trying to write one that uses comet so that I can create a long polling Ajax request. I can successfully start the stream and perform operations but I can't write anything out. Here is my code: public class CometTestServlet extends HttpServlet implements CometProcessor { /** * */ private static final long serialVersionUID = 1070949541963627977L; private MessageSender messageSender = null; protected ArrayList<HttpServletResponse> connections = new ArrayList<HttpServletResponse>(); public void event(CometEvent cometEvent) throws IOException, ServletException { HttpServletRequest request = cometEvent.getHttpServletRequest(); HttpServletResponse response = cometEvent.getHttpServletResponse(); //final PrintWriter out = response.getWriter(); if (cometEvent.getEventType() == CometEvent.EventType.BEGIN) { PrintWriter writer = response.getWriter(); writer.println("<!doctype html public \"-//w3c//dtd html 4.0 transitional//en\">"); writer.println("<head><title>JSP Chat</title></head><body bgcolor=\"#FFFFFF\">"); writer.println("</body></html>"); writer.flush(); cometEvent.setTimeout(10 * 1000); //cometEvent.close(); } else if (cometEvent.getEventType() == CometEvent.EventType.ERROR) { log("Error for session: " + request.getSession(true).getId()); synchronized(connections) { connections.remove(response); } cometEvent.close(); } else if (cometEvent.getEventType() == CometEvent.EventType.END) { log("End for session: " + request.getSession(true).getId()); synchronized(connections) { connections.remove(response); } PrintWriter writer = response.getWriter(); writer.println("</body></html>"); cometEvent.close(); } else if (cometEvent.getEventType() == CometEvent.EventType.READ) { //handleReadEvent(cometEvent); InputStream is = request.getInputStream(); byte[] buf = new byte[512]; do { int n = is.read(buf); //can throw an IOException if (n > 0) { log("Read " + n + " bytes: " + new String(buf, 0, n) + " for session: " + request.getSession(true).getId()); } else if (n < 0) { //error(cometEvent, request, response); return; } } while (is.available() > 0); } } Any help would be appreciated.

  Read the article

• Changing a limited user account in XP fails

  - by javamonkey79

  I have the following: using System; using System.DirectoryServices.AccountManagement; public class ChangePassword { public static void Main() { PrincipalContext context = new PrincipalContext(ContextType.Machine); UserPrincipal user = UserPrincipal.FindByIdentity(context, "someLimitedAccount"); user.ChangePassword( "xxx", "zzz" ); } } This works just fine with administrator accounts, but seems to crash like so when I try to change limited accounts in XP: Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object. at ChangePassword.Main() Is what I am trying to do possible? If so, how? EDIT #1: I added the following: Console.WriteLine( "user: " + user ); Below this line: UserPrincipal user = UserPrincipal.FindByIdentity(context, "someLimitedAccount"); And I get this: user: It doesn't look like user is null when I print it, but then again I'm not really a .Net guy - I seem to remember this being expected behavior.

  Read the article

• Differences between query using LINQ and IQueryable interface directly?

  - by JohnMetta

  Using Entity Framework 4, and given: ObjectSet<Thing> AllThings = Context.CreateObjectSet<Thing>; public IQueryable<Thing> ByNameA(String name) { IQueryable<Thing> query = from o in AllThings where o.Name == name select o; return query; } public IQueryable<Thing> ByNameB(String name) { return AllThings.Where((o) => o.Name == name); } Both return IQueryable< instances, and thus the query doesn't hit the server until something like ToList() is called, right? Is it purely readability that is the difference, or are the using fundamentally different technologies on the back-end?

  Read the article

• What is the best way, if possible, to send information from a Java PrintStream to a JTextPane?

  - by Daniel Reeves

  In Java, I have a package that translates XML metadata from one standard to another. This package is ultimately accessed through a single function and sends all of its output through a PrintStream object. The output sent is just a status of each file and whether or not it was translated. This is pretty fine and dandy if I'm just printing to System.out, but I'm actually wanting to print this to a JTextPane while it translates (kind of like a progress text box). It wouldn't be a big deal to just print the status after it was done translating the XML, but since there may be thousands of XML files, that's just not feasible. One thing that I've tried is to use a thread that takes all of the information from the PrintStream (which is attached to a ByteArrayOutputStream) and let it send any new information to the text pane. Unfortunately, this still sends the information all at once at the end of the translation. This does work correctly for System.out. Here's the code that does the translation and tries to show the output: public class ConverterGUI extends javax.swing.JFrame { boolean printToResultsBox = false; PrintStream printStream = null; ByteArrayOutputStream baos = null; private class ResultsPrinter implements Runnable { public ResultsPrinter() { baos = new ByteArrayOutputStream(); printStream = new PrintStream(baos); } public void run() { String tempString = ""; while (printToResultsBox) { try { if (!baos.toString().equals(tempString)) { tempString = baos.toString(); resultsBox.setText(tempString); } } catch (Exception ex) { } } } } ... ResultsPrinter rp = new ResultsPrinter(); Thread thread = new Thread(rp); thread.start(); // Do the translation. try { printToResultsBox = true; boolean success = false; TranslationEngine te = new TranslationEngine(); // fileOrFolderToConvert is a text box in the GUI. // linkNeeded and destinationFile are just parameters for the translation process. success = te.translate(fileOrFolderToConvert.getText(), linkNeeded, destinationFile, printStream); if (success) { printStream.println("File/folder translation was a success."); } resultsBox.setText(baos.toString()); } catch (Exception ex) { printStream.println("File translation failed."); } finally { printToResultsBox = false; } ... } Ultimately, this code prints out to the JTextPane just fine after all the translation is done but not during. Any suggestions? Do I need to change the PrintStream to something else?

  Read the article

• Understanding Thread/BeginInvoke? [beginner]

  - by Moberg

  Consider the code: class Work { public void DoStuff(string s) { Console.WriteLine(s); // .. whatever } } class Master { private readonly Work work = new Work(); public void Execute() { string hello = "hello"; // (1) is this an ugly hack ? var thread1 = new Thread(new ParameterizedThreadStart(o => this.work.DoStuff((string)o))); thread1.Start(hello); thread1.Join(); // (2) is this similar to the one above? new Action<string>(s => this.work.DoStuff(s)).BeginInvoke(hello, null, null); } } Is (1) an acceptable way of easy starting some work in a seperate thread? If not a better alternative would be much appreciated. Is (2) doing the same? I guess what I ask is if a new thread is started, or.. Hope you can help a beginner to a better understanding :) /Moberg

  Read the article

• How to set Foreground Color in a ListBox single element?

  - by user1038056

  I'm doing a game. I have a list of users (nicks): List<string> users; This list is used to show to the users on a ListBox, call listaJogadores. public delegate void actualizaPlayersCallback(List<string> users); public void actualizaPlayers(List<string> users) { listaJogadores.BeginInvoke(new actualizaPlayersCallback(this.actualizarListaPlayers), new object[] { users }); } public void actualizarListaPlayers(List<string> users) { listaJogadores.Items.Clear(); for (int i = 0; i < users.Count; i++) { listaJogadores.Items.Add(users.ElementAt(i)); } } When a user is playing, then it have is nick on the list of games: List<Game> games; What I want is when a player enter in a game, the color of is nick show in listaJogadores, must be Red! When I have only one player in a game, everything is ok, all the players see the nick of that player in red, but when another player go to a game, then I get an ArgumentOutOfRangeException in the instruction string nick = tmp.players.ElementAt(i).getNick(); This is my code... Give me some ideas/help please! I think that the problem is the for(), but how can I manipulate an entire list without doing a loop? listaJogadores.DrawMode = DrawMode.OwnerDrawFixed; private void listaJogadores_DrawItem(object sender, DrawItemEventArgs e) { e.DrawBackground(); Brush textBrush = SystemBrushes.ControlText; Font drawFont = e.Font; for (int i = 0; i < games.Count; i++) { Game tmp; tmp = games.ElementAt(i); for (int j = 0; j < tmp.players.Count; j++) { string nick = tmp.players.ElementAt(i).getNick(); if (listaJogadores.Items[e.Index].ToString() == nick) { textBrush = Brushes.Red;//RED.... if ((e.State & DrawItemState.Selected) > 0) drawFont = new Font(drawFont.FontFamily, drawFont.Size, FontStyle.Bold); } else if ((e.State & DrawItemState.Selected) > 0) { textBrush = SystemBrushes.HighlightText; } } } e.Graphics.DrawString(listaJogadores.Items[e.Index].ToString(), drawFont, textBrush, e.Bounds); }

  Read the article

• Overriding Page class constructor in ASP.NET code-behind file -- when is it called?

  - by CSharp Noob

  If I override the System.Web.UI.Page constructor, as shown, when does DoSomething() get called in terms of the page lifecycle? I can't seem to find this documented anywhere. namespace NameSpace1 { public partial class MyClass : System.Web.UI.Page { public MyClass() { DoSomething(); } protected void Page_Load(object sender, EventArgs e) { } } } For reference, here is the ASP.NET Page Lifecycle Overview: http://msdn.microsoft.com/en-us/library/ms178472.aspx Turns out the best answer was right in the MSDN article. I just had to look carefully at the diagram.

  Read the article

• How to save the content of Textbox into a textfile

  - by Owais Wani

  I have a textbox which has some content. I also have a button (SAVE) which shud open the FileSaveDialog and allow the content to be saved in a .txt file. XAML: <TextBox Height="93" IsReadOnly="True" Text="{Binding Path=ReadMessage, Mode=TwoWay}" Name="MessageRead" /> <Button Content="Save" Command="{Binding Path=SaveFileCommand}" Name="I2CSaveBtn" /> ViewModel: private string _readMessage = string.Empty; public string ReadMessage { get { return _readMessage; } set { _readMessage = value; NotifyPropertyChanged("ReadMessage"); } } public static RelayCommand SaveFileCommand { get; set; } private void RegisterCommands() { SaveFileCommand = new RelayCommand(param => this.ExecuteSaveFileDialog()); } private void ExecuteSaveFileDialog() { //What To Do HERE??? } What I basically need is to read the content of textbox, open a file save dialog and store it in a text file to be saved in my system.

  Read the article

• Question regarding inheritance in wxWidgets.

  - by celestialorb

  Currently I'm attempting to write my own wxObject, and I would like for the class to be based off of the wxTextCtrl class. Currently this is what I have: class CommandTextCtrl : public wxTextCtrl { public: void OnKey(wxKeyEvent& event); private: DECLARE_EVENT_TABLE() }; Then later on I have this line of code, which is doesn't like: CommandTextCtrl *ctrl = new CommandTextCtrl(panel, wxID_ANY, *placeholder, *origin, *size); ...and when I attempt to compile the program I receive this error: error: no matching function for call to ‘CommandTextCtrl::CommandTextCtrl(wxPanel*&, <anonymous enum>, const wxString&, const wxPoint&, const wxSize&)’ It seems that it doesn't inherit the constructor method with wxTextCtrl. Does anyone happen to know why it doesn't inherit the constructor? Thanks in advance for any help!

  Read the article

• Checking if an int is prime more efficiently

  - by SipSop

  I recently was part of a small java programming competition at my school. My partner and I have just finished our first pure oop class and most of the questions were out of our league so we settled on this one (and I am paraphrasing somewhat): "given an input integer n return the next int that is prime and its reverse is also prime for example if n = 18 your program should print 31" because 31 and 13 are both prime. Your .class file would then have a test case of all the possible numbers from 1-2,000,000,000 passed to it and it had to return the correct answer within 10 seconds to be considered valid. We found a solution but with larger test cases it would take longer than 10 seconds. I am fairly certain there is a way to move the range of looping from n,..2,000,000,000 down as the likely hood of needing to loop that far when n is a low number is small, but either way we broke the loop when a number is prime under both conditions is found. At first we were looping from 2,..n no matter how large it was then i remembered the rule about only looping to the square root of n. Any suggestions on how to make my program more efficient? I have had no classes dealing with complexity analysis of algorithms. Here is our attempt. public class P3 { public static void main(String[] args){ long loop = 2000000000; long n = Integer.parseInt(args[0]); for(long i = n; i<loop; i++) { String s = i +""; String r = ""; for(int j = s.length()-1; j>=0; j--) r = r + s.charAt(j); if(prime(i) && prime(Long.parseLong(r))) { System.out.println(i); break; } } System.out.println("#"); } public static boolean prime(long p){ for(int i = 2; i<(int)Math.sqrt(p); i++) { if(p%i==0) return false; } return true; } } ps sorry if i did the formatting for code wrong this is my first time posting here. Also the output had to have a '#' after each line thats what the line after the loop is about Thanks for any help you guys offer!!!

  Read the article

• Loopj Android Async Http - onFailure not fired

  - by Ashley Staggs

  I am using the great async http library from loopj, but I have run into a small snag. If the user has no internet connection or loses their connection, the app just won't return anything. This part is expected, but it also doesn't fire the onFailure method. Also, the code I have used when there is an internet connection does work so there is no problem on the server end. Here is some code that is stripped down to the minimum. It also doesn't work (I have tested this too) String url = getString(R.string.baseurl) + "/appconnect.php"; client.getHttpClient().getParams().setParameter(ClientPNames.ALLOW_CIRCULAR_REDIRECTS, true); client.get(url, null, new JsonHttpResponseHandler() { @Override public void onSuccess(JSONArray response) { Toast.makeText(getApplicationContext(), "Success", Toast.LENGTH_SHORT).show(); } @Override public void onFailure(Throwable e, JSONArray errorResponse) { Toast.makeText(getApplicationContext(), "Failure", Toast.LENGTH_SHORT).show(); } }); Thanks, Ashley

  Read the article

• Extending both T and SomeInterface<T> in Java

  - by Graeme Moss

  I want to create a class that takes two parameters. One should be typed simply as T. The other should be typed as something that extends both T and SomeInterface. When I attempt this with public class SomeClass<T, S extends SomeInterface<T> & T> then Java complains with "The type T is not an interface; it cannot be specified as a bounded parameter" and if instead I attempt to create an interface for S with public interface TandSomeInterface<T> extends SomeInterface<T>, T then Java complains with "Cannot refer to the type parameter T as a supertype" Is there any way to do this in Java? I think you can do it in C++...?

  Read the article

• What is an example of MVC in PHP?

  - by waiwai933

  I'm trying to understand the MVC pattern. Here's what I think MV is: Model: <?php if($a == 2){ $variable = 'two'; } else{ $variable = 'not two'; } $this->output->addContent($variable); $this->output->displayContent(); ?> View: <?php class output{ private $content; public function addContent($var){ $this->content = 'The variable is '.$var; } public function displayContent(){ include 'header.php'; echo $content; include 'footer.php'; } } ?> Is this right? If so, what is the controller?

  Read the article

• Inheritance in Java

  - by stevebot

  If I have an abstract class in java named Foo and it has an implementor named Bar then I want to know the following. lets say Foo looks something like public abstract class Foo { Service serviceFoo ... } And Bar is public class Bar extends Foo { ... } Also, lets assume I have an instance with Foo, named foo, currently that has serviceFoo instantiated If I then declare: Foo foo = new Bar(); will this create a a new instance of Bar that has serviceFoo instantiated or not? E.g. will that field be inherited and instantiated or just inherited?

  Read the article

• Android: roatating images in a loop.

  - by user573736

  Hello, I am trying with no success to modify the code example from: http://www.inter-fuser.com/2009/08/android-animations-3d-flip.html so it will rotate the images in a loop, when clicking on the image once. (second click should pause). I tried using Handler and threading but cannot update the view since only the main thread can update UI. Exception I get from the code below: android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views. [in 'image1.startAnimation(rotation);' ('applyRotation(0, 90);' from the main thread)] package com.example.flip3d; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.animation.AccelerateInterpolator; import android.widget.ImageView; public class Flip3d extends Activity { private ImageView image1; private ImageView image2; private boolean isFirstImage = true; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); image1 = (ImageView) findViewById(R.id.image01); image2 = (ImageView) findViewById(R.id.image02); image2.setVisibility(View.GONE); image1.setOnClickListener(new View.OnClickListener() { public void onClick(View view) { if (isFirstImage) { applyRotation(0, 90); isFirstImage = !isFirstImage; } else { applyRotation(0, -90); isFirstImage = !isFirstImage; } } }); } private void applyRotation(float start, float end) { // Find the center of image final float centerX = image1.getWidth() / 2.0f; final float centerY = image1.getHeight() / 2.0f; // Create a new 3D rotation with the supplied parameter // The animation listener is used to trigger the next animation final Flip3dAnimation rotation = new Flip3dAnimation(start, end, centerX, centerY); rotation.setDuration(500); rotation.setFillAfter(true); rotation.setInterpolator(new AccelerateInterpolator()); rotation.setAnimationListener(new DisplayNextView(isFirstImage, image1, image2)); if (isFirstImage) { image1.startAnimation(rotation); } else { image2.startAnimation(rotation); } } } How can I manage to update the UI and control the rotation within onClick listener? Thank you, Oakist

  Read the article

• TreeNodes don't get collected with weakevent solution

  - by Marcus

  Hi, When I use this method http://stackoverflow.com/questions/1089309/weak-events-in-net (by Egor) to hook up a event i a inherited treenode, the tree node never gets collected, is there any speciall case with tree nodes and GC? public class MyTreeNode : TreeNode { public MyTreeNode(Entity entity) { entity.Children.ListChanged += new ListChangedEventHandler(entityChildren_ListChanged).MakeWeak(eh => entity.Children.ListChanged -= eh); } } Entity.Children is a bindinglist. I made tests with a destructor on MyTreeNode and invoking GC.Collect(), with the weak eventhandler the treenode never gets collected but i DOES get collected WIHTOUT the weak eventhandler.

  Read the article

• SetWindowHookEx and execution blocking

  - by Kalaz

  Hello, I just wonder... I mainly use .NET but now I started to investigate WINAPI calls. For example I am using this piece of code to hook to the API functions. It starts freezing, when I try to debug the application... using System; using System.Diagnostics; using System.Runtime.InteropServices; using System.Threading; using System.Windows.Forms; public class Keyboard { private const int WH_KEYBOARD_LL = 13; private const int WM_KEYDOWN = 0x0100; private static LowLevelKeyboardProc _proc = HookCallback; private static IntPtr _hookID = IntPtr.Zero; public static event Action<Keys,bool, bool> KeyDown; public static void Hook() { new Thread(new ThreadStart(()=> { _hookID = SetHook(_proc); Application.Run(); })).Start(); } public static void Unhook() { UnhookWindowsHookEx(_hookID); } private static IntPtr SetHook(LowLevelKeyboardProc proc) { using (Process curProcess = Process.GetCurrentProcess()) using (ProcessModule curModule = curProcess.MainModule) { return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0); } } private delegate IntPtr LowLevelKeyboardProc( int nCode, IntPtr wParam, IntPtr lParam); private static IntPtr HookCallback( int nCode, IntPtr wParam, IntPtr lParam) { if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN) { int vkCode = Marshal.ReadInt32(lParam); Keys k = (Keys) vkCode; if (KeyDown != null) { KeyDown.BeginInvoke(k, IsKeyPressed(VirtualKeyStates.VK_CONTROL), IsKeyPressed(VirtualKeyStates.VK_SHIFT),null,null); } } return CallNextHookEx(_hookID, nCode, wParam, lParam); } private static bool IsKeyPressed(VirtualKeyStates virtualKeyStates) { return (GetKeyState(virtualKeyStates) & (1 << 7))==128; } [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId); [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] private static extern bool UnhookWindowsHookEx(IntPtr hhk); [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam); [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern IntPtr GetModuleHandle(string lpModuleName); [DllImport("user32.dll")] static extern short GetKeyState(VirtualKeyStates nVirtKey); } enum VirtualKeyStates : int { VK_LBUTTON = 0x01, VK_RBUTTON = 0x02, VK_CANCEL = 0x03, VK_MBUTTON = 0x04, // VK_XBUTTON1 = 0x05, VK_XBUTTON2 = 0x06, // VK_BACK = 0x08, VK_TAB = 0x09, // VK_CLEAR = 0x0C, VK_RETURN = 0x0D, // VK_SHIFT = 0x10, VK_CONTROL = 0x11, VK_MENU = 0x12, VK_PAUSE = 0x13, VK_CAPITAL = 0x14, // VK_KANA = 0x15, VK_HANGEUL = 0x15, /* old name - should be here for compatibility */ VK_HANGUL = 0x15, VK_JUNJA = 0x17, VK_FINAL = 0x18, VK_HANJA = 0x19, VK_KANJI = 0x19, // VK_ESCAPE = 0x1B, // VK_CONVERT = 0x1C, VK_NONCONVERT = 0x1D, VK_ACCEPT = 0x1E, VK_MODECHANGE = 0x1F, // VK_SPACE = 0x20, VK_PRIOR = 0x21, VK_NEXT = 0x22, VK_END = 0x23, VK_HOME = 0x24, VK_LEFT = 0x25, VK_UP = 0x26, VK_RIGHT = 0x27, VK_DOWN = 0x28, VK_SELECT = 0x29, VK_PRINT = 0x2A, VK_EXECUTE = 0x2B, VK_SNAPSHOT = 0x2C, VK_INSERT = 0x2D, VK_DELETE = 0x2E, VK_HELP = 0x2F, // VK_LWIN = 0x5B, VK_RWIN = 0x5C, VK_APPS = 0x5D, // VK_SLEEP = 0x5F, // VK_NUMPAD0 = 0x60, VK_NUMPAD1 = 0x61, VK_NUMPAD2 = 0x62, VK_NUMPAD3 = 0x63, VK_NUMPAD4 = 0x64, VK_NUMPAD5 = 0x65, VK_NUMPAD6 = 0x66, VK_NUMPAD7 = 0x67, VK_NUMPAD8 = 0x68, VK_NUMPAD9 = 0x69, VK_MULTIPLY = 0x6A, VK_ADD = 0x6B, VK_SEPARATOR = 0x6C, VK_SUBTRACT = 0x6D, VK_DECIMAL = 0x6E, VK_DIVIDE = 0x6F, VK_F1 = 0x70, VK_F2 = 0x71, VK_F3 = 0x72, VK_F4 = 0x73, VK_F5 = 0x74, VK_F6 = 0x75, VK_F7 = 0x76, VK_F8 = 0x77, VK_F9 = 0x78, VK_F10 = 0x79, VK_F11 = 0x7A, VK_F12 = 0x7B, VK_F13 = 0x7C, VK_F14 = 0x7D, VK_F15 = 0x7E, VK_F16 = 0x7F, VK_F17 = 0x80, VK_F18 = 0x81, VK_F19 = 0x82, VK_F20 = 0x83, VK_F21 = 0x84, VK_F22 = 0x85, VK_F23 = 0x86, VK_F24 = 0x87, // VK_NUMLOCK = 0x90, VK_SCROLL = 0x91, // VK_OEM_NEC_EQUAL = 0x92, // '=' key on numpad // VK_OEM_FJ_JISHO = 0x92, // 'Dictionary' key VK_OEM_FJ_MASSHOU = 0x93, // 'Unregister word' key VK_OEM_FJ_TOUROKU = 0x94, // 'Register word' key VK_OEM_FJ_LOYA = 0x95, // 'Left OYAYUBI' key VK_OEM_FJ_ROYA = 0x96, // 'Right OYAYUBI' key // VK_LSHIFT = 0xA0, VK_RSHIFT = 0xA1, VK_LCONTROL = 0xA2, VK_RCONTROL = 0xA3, VK_LMENU = 0xA4, VK_RMENU = 0xA5, // VK_BROWSER_BACK = 0xA6, VK_BROWSER_FORWARD = 0xA7, VK_BROWSER_REFRESH = 0xA8, VK_BROWSER_STOP = 0xA9, VK_BROWSER_SEARCH = 0xAA, VK_BROWSER_FAVORITES = 0xAB, VK_BROWSER_HOME = 0xAC, // VK_VOLUME_MUTE = 0xAD, VK_VOLUME_DOWN = 0xAE, VK_VOLUME_UP = 0xAF, VK_MEDIA_NEXT_TRACK = 0xB0, VK_MEDIA_PREV_TRACK = 0xB1, VK_MEDIA_STOP = 0xB2, VK_MEDIA_PLAY_PAUSE = 0xB3, VK_LAUNCH_MAIL = 0xB4, VK_LAUNCH_MEDIA_SELECT = 0xB5, VK_LAUNCH_APP1 = 0xB6, VK_LAUNCH_APP2 = 0xB7, // VK_OEM_1 = 0xBA, // ';:' for US VK_OEM_PLUS = 0xBB, // '+' any country VK_OEM_COMMA = 0xBC, // ',' any country VK_OEM_MINUS = 0xBD, // '-' any country VK_OEM_PERIOD = 0xBE, // '.' any country VK_OEM_2 = 0xBF, // '/?' for US VK_OEM_3 = 0xC0, // '`~' for US // VK_OEM_4 = 0xDB, // '[{' for US VK_OEM_5 = 0xDC, // '\|' for US VK_OEM_6 = 0xDD, // ']}' for US VK_OEM_7 = 0xDE, // ''"' for US VK_OEM_8 = 0xDF, // VK_OEM_AX = 0xE1, // 'AX' key on Japanese AX kbd VK_OEM_102 = 0xE2, // "<>" or "\|" on RT 102-key kbd. VK_ICO_HELP = 0xE3, // Help key on ICO VK_ICO_00 = 0xE4, // 00 key on ICO // VK_PROCESSKEY = 0xE5, // VK_ICO_CLEAR = 0xE6, // VK_PACKET = 0xE7, // VK_OEM_RESET = 0xE9, VK_OEM_JUMP = 0xEA, VK_OEM_PA1 = 0xEB, VK_OEM_PA2 = 0xEC, VK_OEM_PA3 = 0xED, VK_OEM_WSCTRL = 0xEE, VK_OEM_CUSEL = 0xEF, VK_OEM_ATTN = 0xF0, VK_OEM_FINISH = 0xF1, VK_OEM_COPY = 0xF2, VK_OEM_AUTO = 0xF3, VK_OEM_ENLW = 0xF4, VK_OEM_BACKTAB = 0xF5, // VK_ATTN = 0xF6, VK_CRSEL = 0xF7, VK_EXSEL = 0xF8, VK_EREOF = 0xF9, VK_PLAY = 0xFA, VK_ZOOM = 0xFB, VK_NONAME = 0xFC, VK_PA1 = 0xFD, VK_OEM_CLEAR = 0xFE } It works well even if you put messagebox into the event or something that blocks execution. But it gets bad if you try to put breakpoint into the event. Why? I mean event is not run in the same thread that the windows hook is. That means that It shouldn't block HookCallback. It does however... I would really like to know why is this happening. My theory is that Visual Studio when breaking execution temporarily stops all threads and that means that HookCallback is blocked... Is there any book or valuable resource that would explain concepts behind all of this threading?

  Read the article

< Previous Page | 517 518 519 520 521 522 523 524 525 526 527 528  | Next Page >