Search Results

Search found 19541 results on 782 pages for 'event handling'.

Page 24/782 | < Previous Page | 20 21 22 23 24 25 26 27 28 29 30 31  | Next Page >

  • Handling SQL Server Errors

    This article covers the basics of TRY CATCH error handling in T-SQL introduced in SQL Server 2005. It includes the usage of common functions to return information about the error and using the TRY CATCH block in stored procedures and transactions.

    Read the article

  • C# .Net Serial DataReceived Event response too slow for high-rate data.

    - by Matthew
    Hi, I have set up a SerialDataReceivedEventHandler, with a forms based program in VS2008 express. My serial port is set up as follows: 115200, 8N1 Dtr and Rts enabled ReceivedBytesThreshold = 1 I have a device I am interfacing with over a BlueTooth, USB to Serial. Hyper terminal receives the data just fine at any data rate. The data is sent regularly in 22 byte long packets. This device has an adjustable rate at which data is sent. At low data rates, 10-20Hz, the code below works great, no problems. However, when I increase the data rate past 25Hz, there starts to recieve mulitple packets on one call. What I mean by this is that there should be a event trigger for every incoming packet. With higher output rates, I have tested the buffer size (BytesToRead command) immediatly when the event is called and there are multiple packets in the buffer then. I think that the event fires slowly and by the time it reaches the code, more packes have hit the buffer. One test I do is see how many time the event is trigger per second. At 10Hz, I get 10 event triggers, awesome. At 100Hz, I get something like 40 event triggers, not good. My goal for data rate is 100HZ is acceptable, 200Hz preferred, and 300Hz optimum. This should work because even at 300Hz, that is only 52800bps, less than half of the set 115200 baud rate. Anything I am over looking? public Form1() { InitializeComponent(); serialPort1.DataReceived += new SerialDataReceivedEventHandler(serialPort1_DataReceived); } private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e) { this.Invoke(new EventHandler(Display_Results)); } private void Display_Results(object s, EventArgs e) { serialPort1.Read(IMU, 0, serial_Port1.BytesToRead); }

    Read the article

  • How do I add and remove an event listener using a function with parameters?

    - by Bungle
    Sorry if this is a common question, but I couldn't find any answers that seemed pertinent through searching. If I attach an event listener like this: window.addEventListener('scroll', function() { check_pos(box); }, false); it doesn't seem to work to try to remove it later, like this: window.removeEventListener('scroll', function() { check_pos(box); }, false); I assume this is because the addEventListener and removeEventListener methods want a reference to the same function, while I've provided them with anonymous functions, which, while identical in code, are not literally the same. How can I change my code to get the call to removeEventListener to work? The "box" argument refers to the name of an <iframe> that I'm tracking on the screen; that is, I want to be able to subscribe to the scroll event once for each <iframe> that I have (the quantity varies), and once the check_pos() function measures a certain position, it will call another function and also remove the event listener to free up system resources. My hunch is that the solution will involve a closure and/or naming the anonymous function, but I'm not sure exactly what that looks like, and would appreciate a concrete example. Hope that makes sense. Thanks for any help!

    Read the article

  • What is wrong with the JavaScript event handling in this example? (Using click() and hover() jQuery

    - by Bungle
    I'm working on a sort of proof-of-concept for a project that approximates Firebug's inspector tool. For more details, please see this related question. Here is the example page. I've only tested it in Firefox: http://troy.onespot.com/static/highlight.html The idea is that, when you're mousing over any element that can contain text, it should "highlight" with a light gray background to indicate the boundaries of that element. When you then click on the element, it should alert() a CSS selector that matches it. This is somewhat working in the example linked above. However, there's one fundamental problem. When mousing over from the top of the page to the bottom, it will pick up the paragraphs, <h1> element, etc. But, it doesn't get the <div>s that encompass those paragraphs. However, for example, if you "sneak up" on the <div> that contains the two paragraphs "The area was settled..." and "Austin was selected..." from the left - tracing down the left edge of the page and entering the <div> just between the two paragraphs (see this screenshot) - then it is picked up. I assume this has something to do with the fact that I haven't attached an event handler to the <body> element (where you're entering the <div> from if you enter from the left), but I have attached handlers to the <p>s (where you're entering from if you come from the top or bottom). There are also other issues with mousing in and out elements - background colors that "stick" and the like - that I think are also related. As indicated in the related question posted above, I suspect there is something about event bubbling that I don't understand that is causing unexpected behavior. Can anyone spot what's wrong with my code? Thanks in advance for any help!

    Read the article

  • Determine image src in onload and onerror event handlers in IE

    - by Bill
    How can I determine the image src of the image that triggered the event in the onload and onerror event handlers in IE? This example code I threw together: <script language="javascript" type="text/javascript" src="jquery.js"></script> <script language="javascript" type="text/javascript"> function loadImages() { var goodImage = new Image(); var missingImage = new Image(); $(goodImage).bind('load', function(event){ $("#log").append( $(event.target).attr('src') + ' WAS FOUND <br>'); }); $(missingImage).bind('load', function(event){ $("#log").append( $(event.target).attr('src') + ' WAS FOUND <br>' ); }); $(goodImage).bind('error', function(event){ $("#log").append( $(event.target).attr('src') + ' IS MISSING <br>'); }); $(missingImage).bind('error', function(event){ $("#log").append( $(event.target).attr('src') + ' IS MISSING <br>'); }); goodImage.src = 'GOOD-IMAGE.GIF'; // this image exists missingImage.src = 'MISSING-IMAGE.GIF'; // this image doesn't exist } </script> </head> <body onload="loadImages();"> <div id="log"></div> works in FF but in IE8 it prints out undefined for the $(event.target).attr('src') part. I thought jQuery was supposed to normalize the event object for IE so that it acted like other browsers? I've tried a number of permutations but haven't been able to get anything to work in IE8. Anyway if anyone has a suggestion on how to figure out the image src in the onload and onerror event handlers that works in IE I would really appreciate it. Or even how to figure out after the images have loaded which have loaded and which haven't (but not graphically - I need to generate an array containing the filenames of the images that didn't load). Thanks!

    Read the article

  • Call event from original thread ??

    - by user311883
    Hi all, Here is my problem, I have a class which have a object who throw an event and in this event I throw a custom event from my class. But unfortunately the original object throw the event from another thread and so my event is also throw on another thread. This cause a exception when my custom event try to access from controls. Here is a code sample to better understand : class MyClass { // Original object private OriginalObject myObject; // My event public delegate void StatsUpdatedDelegate(object sender, StatsArgs args); public event StatsUpdatedDelegate StatsUpdated; public MyClass() { // Original object event myObject.AnEvent += new EventHandler(myObject_AnEvent); } // This event is called on another thread private void myObject_AnEvent(object sender, EventArgs e) { // Throw my custom event here StatsArgs args = new StatsArgs(..........); StatsUpdated(this, args); } } So when on my windows form I call try to update a control from the event StatsUpdated I get a cross thread exception cause it has been called on another thread. What I want to do is throw my custom event on the original class thread, so control can be used within it. Anyone can help me ?

    Read the article

  • Prevent event from parent element to child element in jquery

    - by sonam
    I have binded event as below: $(document).delegate('.budget', 'click', function(e){ if ($(this).hasClass('collapsed')) { $(this).removeClass('collapsed'); $(this).addClass('expanded'); } else if ($(this).hasClass('expanded')) { $(this).removeClass('expanded'); $(this).addClass('collapsed'); } }); Basically this toggles between expand and collapse. I have another event binded as below: $('[id^="tree"]').delegate('.collapsed', 'click', function(e){ var elementId = $(this).attr('id'); hideChildElement(elementId); }); The elements binded by the second event binding are parents of elements binded by first event binding. What happens is that on clicking on the element from the first binding event method also triggers the event binded by second event binding. I want to prevent any events from binding from second event binding to 1st event binding method. If element A is binded to click event from first event binding and B is binded to second event binding (A is inside B or A is child of B), I dont want any event of B to propagate to A. Note I tried e.stopImmediatePropagation(); but did not worked

    Read the article

  • How can I set up .NET UnhandledException handling in a Windows service?

    - by Mike Pateras
    protected override void OnStart(string[] args) { AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException); Thread.Sleep(10000); throw new Exception(); } void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e) { } I attached a debugger to the above code in my windows service, setting a breakpoint in CurrentDomain_UnhandledException, but it was never hit. The exception pops up saying that it is unhandled, and then the service stops. I even tried putting some code in the event handler, in case it was getting optimized away. Is this not the proper way to set up unhandled exception handling in a windows service?

    Read the article

  • How can I set up .Net unhanlded exception handling in a windows service?

    - by Mike Pateras
    protected override void OnStart(string[] args) { AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException); Thread.Sleep(10000); throw new Exception(); } void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e) { } I attached a debugger to the above code in my windows service, setting a breakpoint in CurrentDomain_UnhandledException, but it was never hit. The exception pops up saying that it is unhandled, and then the service stops. I even tried putting some code in the event handler, in case it was getting optimized away. Is this not the proper way to set up unhandled exception handling in a windows service?

    Read the article

  • Travelling MVP #2: Community event at Bucharest, Romania

    - by DigiMortal
    My second trip was to DevReach with two stops. My first stop was at Bucharest where I met with my friend Dimitar Georgiev who is one of authors of Gym Realm service. Romanian MVP Andrei Ignat was our host there and organized meeting with local community guys. With me – it was first time in my life – was one more guy from Estonia visiting DevReach and he made the whole trip with me. Bucharest We arrived to Bucharest 29.09 at night. We stayed at Hotel Michelangelo. It’s small hotel with nice rooms, free WiFi and very good service. Although my room was on the first floor there was no street noise. We visited one restaurant that offers national cuisine and it was really great. Next day we went out with local guys and had some beers in “old town”. Bucharest “old town” is nice and cozy. There are many bars open and I am sure everybody will find there some very okay place. After supper we visited one warm karaoke bar where we had beers with local guys. Andrei Ignat – karaoke star Agu Suur and Andrei Ion Rinea enjoying karaoke and tequila Community event Next day we had community event. I made my session about ASP.NET Web API and Dimitar told about how to port ASP.NET web applications to cloud environment. Sessions were held at study class of one local company. Dimitar Georgiev speaking about porting web apps to Windows Azure. As it was usual community evening and not some bigger event there were about 12 guys attending from Bucharest. There were both IT-PROs and developers and one nice thing about Bucharest community is that they are listening to you very well and they ask questions if something is unclear or if you slide over from topic they are interested in. Okay, we tried to keep up good tempo so people stay awake and I think we succeeded. After sessions we went all together to local Piranha pub that was near event venue. We had some beers with local guys and talked with them on different technology topics. It was another good and interesting evening at Bucharest. I want to go back there for sure. As it was my first trip to Bucharest and mostly I gathered experiences I think my next community trip there will be way stronger. I take it as a challenge. Plus – I have there some new friends and I want to meet them too – be it community event or not. :)

    Read the article

  • Oracle GoldenGate 11gR2 Event Marker System

    - by Doug Reid
    0 false 18 pt 18 pt 0 0 false false false /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Oracle GoldenGate 11gR2 includes a number of refinements to the Event Marker system. Using event markers enables GoldenGate processes to take a defined action based on an event in the data stream. This feature within Oracle GoldenGate simplifies methods to embed specific custom processing in the areas of error handling, alerts, and notification. The event marker system effectively allows for DML driven workflows to be created within GoldenGate and enables customers to craft non-standard processing based on special events. There are a number of supported event actions including: trace, log, checkpoint before, suspend, abort, and several others. With 11gR1 events can now be triggered by DDL operations, plus variables can be passed in and out of the system to shell scripts. Some good use cases for this feature are Automatic switchover to the secondary system during planned outages Better monitoring over source systems’ performance and automated switchover to the standby system in case of an outage with the primary system Automatic switchover from initial load to changed data movement Automatic synchronization of any type of batch processing taking place on both the source and target databases for database consistency Automatic stoppage of the Delivery module to allow end-of-day reporting Finding, tracking, and reporting on transactions that are of interest including the ones that do not have primary keys or transaction record numbers If you would like to see a demo, please visit our youtube channel (http://youtube.com/oraclegoldengate)  To learn more about the new features of Oracle GoldenGate 11gR2 and to ask questions to the PM team, please join us on September 12th  8am or 10am PST for our live webcast. Click here to register.

    Read the article

  • Any good idioms for error handling in straight C programs?

    - by Will Hartung
    Getting back in to some C work. Many of my functions look like this: int err = do_something(arg1, arg2, arg3, &result); With the intent the result gets populated by the function, and the return value is the status of the call. The darkside is you get something naive like this: int err = func1(...); if (!err) { err = func2(...); if (!err) { err = func3(...); } } return err; I could macro it I suppose: #define ERR(x) if (!err) { err = (x) } int err = 0; ERR(func1(...)); ERR(func2(...)); ERR(func3(...)); return err; But that only works if I'm chaining function calls, vs doing other work. Obviously Java, C#, C++ have exceptions that work very well for these kinds of things. I'm just curious what other folks do and how other folks do error handling in their C programs nowadays.

    Read the article

  • ASP.NET Error Handling: Creating an extension method to send error email

    - by Jalpesh P. Vadgama
    Error handling in asp.net required to handle any kind of error occurred. We all are using that in one or another scenario. But some errors are there which will occur in some specific scenario in production environment in this case We can’t show our programming errors to the End user. So we are going to put a error page over there or whatever best suited as per our requirement. But as a programmer we should know that error so we can track the scenario and we can solve that error or can handle error. In this kind of situation an Error Email comes handy. Whenever any occurs in system it will going to send error in our email. Here I am going to write a extension method which will send errors in email. From asp.net 3.5 or higher version of .NET framework  its provides a unique way to extend your classes. Here you can fine more information about extension method. So lets create extension method via implementing a static class like following. I am going to use same code for sending email via my Gmail account from here. Following is code for that. using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Net.Mail; namespace Experiement { public static class MyExtension { public static void SendErrorEmail(this Exception ex) { MailMessage mailMessage = new MailMessage(new MailAddress("[email protected]") , new MailAddress("[email protected]")); mailMessage.Subject = "Exception Occured in your site"; mailMessage.IsBodyHtml = true; System.Text.StringBuilder errorMessage = new System.Text.StringBuilder(); errorMessage.AppendLine(string.Format("<B>{0}</B>:{1}<BR/>","Exception",ex.Message)); errorMessage.AppendLine(string.Format("<B>{0}</B>:{1}<BR/>", "Stack Trace", ex.StackTrace)); if (ex.InnerException != null) { errorMessage.AppendLine(string.Format("<B>{0}</B>:{1}<BR/>", " Inner Exception", ex.InnerException.Message)); errorMessage.AppendLine(string.Format("<B>{0}</B>:{1}<BR/>", "Inner Stack Trace", ex.InnerException.StackTrace)); } mailMessage.Body = errorMessage.ToString(); System.Net.NetworkCredential networkCredentials = new System.Net.NetworkCredential("[email protected]", "password"); SmtpClient smtpClient = new SmtpClient(); smtpClient.EnableSsl = true; smtpClient.UseDefaultCredentials = false; smtpClient.Credentials = networkCredentials; smtpClient.Host = "smtp.gmail.com"; smtpClient.Port = 587; smtpClient.Send(mailMessage); } } } After creating an extension method let us that extension method to handle error like following in page load event of page. using System; namespace Experiement { public partial class WebForm1 : System.Web.UI.Page { protected void Page_Load(object sender,System.EventArgs e) { try { throw new Exception("My custom Exception"); } catch (Exception ex) { ex.SendErrorEmail(); Response.Write(ex.Message); } } } } Now in above code I have generated custom exception for example but in production It can be any Exception. And you can see I have use ex.SendErrorEmail() function in catch block to send email. That’s it.. Now it will throw exception and you will email in your email box like below.   That’s its. It’s so simple…Stay tuned for more.. Happy programming.. Technorati Tags: Exception,Extension Mehtod,Error Handling,ASP.NET

    Read the article

  • Sponsor the Hottest .NET Community Event in Germany: dotnet Cologne 2011

    - by WeigeltRo
    The “dotnet Cologne” conference organized by the NET usergroups Bonn and Cologne quickly has become the .NET community event in Germany. So when we opened the registration for dotnet Cologne 2011 on Monday, we expected some interest. But we didn’t expect the 200 “early bird” seats to be gone in less than three hours! And the registrations at normal price keep coming in, so it looks like this event will sell out even earlier than last year. In December I wrote about sponsorship opportunities at the dotnet Cologne 2011 – and why it’s a good idea to be a sponsor at this particular conference. If you are interested in becoming a sponsor: We still offer a wide variety of sponsorship packages in different sizes. At our new, larger, event location, we still have space for exhibition booths. Last year’s exhibitors were very happy and had many interesting conversations with the attendees. And this year we planned for longer breaks between sessions, which means event more time for presenting your products. And yes, German developers understand English demos. But maybe a booth is a bit too much for you. With the Bronze package, you can make sure the attendees receive promotional material of your company in their bags – for a fraction of what you’d pay at a commercial conference. Or you could sponsor a couple of licenses of your product for the raffle at the end of the day. If you want to learn more, just send an email to Roland.Weigelt at dotnet-koelnbonn.de and I’ll send you our sponsor information.

    Read the article

  • C#: Handling Notifications: inheritance, events, or delegates?

    - by James Michael Hare
    Often times as developers we have to design a class where we get notification when certain things happen. In older object-oriented code this would often be implemented by overriding methods -- with events, delegates, and interfaces, however, we have far more elegant options. So, when should you use each of these methods and what are their strengths and weaknesses? Now, for the purposes of this article when I say notification, I'm just talking about ways for a class to let a user know that something has occurred. This can be through any programmatic means such as inheritance, events, delegates, etc. So let's build some context. I'm sitting here thinking about a provider neutral messaging layer for the place I work, and I got to the point where I needed to design the message subscriber which will receive messages from the message bus. Basically, what we want is to be able to create a message listener and have it be called whenever a new message arrives. Now, back before the flood we would have done this via inheritance and an abstract class: 1:  2: // using inheritance - omitting argument null checks and halt logic 3: public abstract class MessageListener 4: { 5: private ISubscriber _subscriber; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber) 11: { 12: _subscriber = subscriber; 13: _messageThread = new Thread(MessageLoop); 14: _messageThread.Start(); 15: } 16:  17: // user will override this to process their messages 18: protected abstract void OnMessageReceived(Message msg); 19:  20: // handle the looping in the thread 21: private void MessageLoop() 22: { 23: while(!_isHalted) 24: { 25: // as long as processing, wait 1 second for message 26: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 27: if(msg != null) 28: { 29: OnMessageReceived(msg); 30: } 31: } 32: } 33: ... 34: } It seems so odd to write this kind of code now. Does it feel odd to you? Maybe it's just because I've gotten so used to delegation that I really don't like the feel of this. To me it is akin to saying that if I want to drive my car I need to derive a new instance of it just to put myself in the driver's seat. And yet, unquestionably, five years ago I would have probably written the code as you see above. To me, inheritance is a flawed approach for notifications due to several reasons: Inheritance is one of the HIGHEST forms of coupling. You can't seal the listener class because it depends on sub-classing to work. Because C# does not allow multiple-inheritance, I've spent my one inheritance implementing this class. Every time you need to listen to a bus, you have to derive a class which leads to lots of trivial sub-classes. The act of consuming a message should be a separate responsibility than the act of listening for a message (SRP). Inheritance is such a strong statement (this IS-A that) that it should only be used in building type hierarchies and not for overriding use-specific behaviors and notifications. Chances are, if a class needs to be inherited to be used, it most likely is not designed as well as it could be in today's modern programming languages. So lets look at the other tools available to us for getting notified instead. Here's a few other choices to consider. Have the listener expose a MessageReceived event. Have the listener accept a new IMessageHandler interface instance. Have the listener accept an Action<Message> delegate. Really, all of these are different forms of delegation. Now, .NET events are a bit heavier than the other types of delegates in terms of run-time execution, but they are a great way to allow others using your class to subscribe to your events: 1: // using event - ommiting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private bool _isHalted = false; 6: private Thread _messageThread; 7:  8: // assign the subscriber and start the messaging loop 9: public MessageListener(ISubscriber subscriber) 10: { 11: _subscriber = subscriber; 12: _messageThread = new Thread(MessageLoop); 13: _messageThread.Start(); 14: } 15:  16: // user will override this to process their messages 17: public event Action<Message> MessageReceived; 18:  19: // handle the looping in the thread 20: private void MessageLoop() 21: { 22: while(!_isHalted) 23: { 24: // as long as processing, wait 1 second for message 25: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 26: if(msg != null && MessageReceived != null) 27: { 28: MessageReceived(msg); 29: } 30: } 31: } 32: } Note, now we can seal the class to avoid changes and the user just needs to provide a message handling method: 1: theListener.MessageReceived += CustomReceiveMethod; However, personally I don't think events hold up as well in this case because events are largely optional. To me, what is the point of a listener if you create one with no event listeners? So in my mind, use events when handling the notification is optional. So how about the delegation via interface? I personally like this method quite a bit. Basically what it does is similar to inheritance method mentioned first, but better because it makes it easy to split the part of the class that doesn't change (the base listener behavior) from the part that does change (the user-specified action after receiving a message). So assuming we had an interface like: 1: public interface IMessageHandler 2: { 3: void OnMessageReceived(Message receivedMessage); 4: } Our listener would look like this: 1: // using delegation via interface - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private IMessageHandler _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler.OnMessageReceived(msg); 28: } 29: } 30: } 31: } And they would call it by creating a class that implements IMessageHandler and pass that instance into the constructor of the listener. I like that this alleviates the issues of inheritance and essentially forces you to provide a handler (as opposed to events) on construction. Well, this is good, but personally I think we could go one step further. While I like this better than events or inheritance, it still forces you to implement a specific method name. What if that name collides? Furthermore if you have lots of these you end up either with large classes inheriting multiple interfaces to implement one method, or lots of small classes. Also, if you had one class that wanted to manage messages from two different subscribers differently, it wouldn't be able to because the interface can't be overloaded. This brings me to using delegates directly. In general, every time I think about creating an interface for something, and if that interface contains only one method, I start thinking a delegate is a better approach. Now, that said delegates don't accomplish everything an interface can. Obviously having the interface allows you to refer to the classes that implement the interface which can be very handy. In this case, though, really all you want is a method to handle the messages. So let's look at a method delegate: 1: // using delegation via delegate - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler(msg); 28: } 29: } 30: } 31: } Here the MessageListener now takes an Action<Message>.  For those of you unfamiliar with the pre-defined delegate types in .NET, that is a method with the signature: void SomeMethodName(Message). The great thing about delegates is it gives you a lot of power. You could create an anonymous delegate, a lambda, or specify any other method as long as it satisfies the Action<Message> signature. This way, you don't need to define an arbitrary helper class or name the method a specific thing. Incidentally, we could combine both the interface and delegate approach to allow maximum flexibility. Doing this, the user could either pass in a delegate, or specify a delegate interface: 1: // using delegation - give users choice of interface or delegate 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // passes the interface method as a delegate using method group 19: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 20: : this(subscriber, handler.OnMessageReceived) 21: { 22: } 23:  24: // handle the looping in the thread 25: private void MessageLoop() 26: { 27: while(!_isHalted) 28: { 29: // as long as processing, wait 1 second for message 30: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 31: if(msg != null) 32: { 33: _handler(msg); 34: } 35: } 36: } 37: } } This is the method I tend to prefer because it allows the user of the class to choose which method works best for them. You may be curious about the actual performance of these different methods. 1: Enter iterations: 2: 1000000 3:  4: Inheritance took 4 ms. 5: Events took 7 ms. 6: Interface delegation took 4 ms. 7: Lambda delegate took 5 ms. Before you get too caught up in the numbers, however, keep in mind that this is performance over over 1,000,000 iterations. Since they are all < 10 ms which boils down to fractions of a micro-second per iteration so really any of them are a fine choice performance wise. As such, I think the choice of what to do really boils down to what you're trying to do. Here's my guidelines: Inheritance should be used only when defining a collection of related types with implementation specific behaviors, it should not be used as a hook for users to add their own functionality. Events should be used when subscription is optional or multi-cast is desired. Interface delegation should be used when you wish to refer to implementing classes by the interface type or if the type requires several methods to be implemented. Delegate method delegation should be used when you only need to provide one method and do not need to refer to implementers by the interface name.

    Read the article

  • Access denied error 3221225578 with file sharing to Windows server

    - by Ian Boyd
    i'm trying to access the shares on a server. The credential box appears, and i enter in a correct username and password, and i get access denied. The silly thing is that i can Remote Desktop to the server (using the same credentials), and i can check the Security event log for the access denied errors: Event Type: Failure Audit Event Source: Security Event Category: Account Logon Event ID: 681 Date: 3/19/2011 Time: 11:54:39 PM User: NT AUTHORITY\SYSTEM Computer: STALWART Description: The logon to account: Administrator by: MICROSOFT_AUTHENTICATION_PACKAGE_V1_0 from workstation: HARPAX failed. The error code was: 3221225578 and Event Type: Failure Audit Event Source: Security Event Category: Logon/Logoff Event ID: 529 Date: 3/19/2011 Time: 11:54:39 PM User: NT AUTHORITY\SYSTEM Computer: STALWART Description: Logon Failure: Reason: Unknown user name or bad password User Name: Administrator Domain: stalwart Logon Type: 3 Logon Process: NtLmSsp Authentication Package: NTLM Workstation Name: HARPAX Looking up the error code (3221225578), i get an article on Technet: Audit Account Logon Events By Randy Franklin Smith ... Table 1 - Error Codes for Event ID 681 Error Code Reason for Logon Failure 3221225578 The username is correct, but the password is wrong. Which would seem to indicate that the username is correct, but the password is wrong. i've tried the password many times, uppercase, lowercase, on different user accounts, with and without prefixing the username with servername\username. What gives that i cannot access the server over file sharing, but i can access it over RDP?

    Read the article

  • Nodejs removing event listeners [migrated]

    - by JeffH
    Looking to get some help. I'm new to Nodejs and wondering if it is possible, to remove this custom event emitter. Most of this code comes from the Hand on nodejs by Pedro Teixeira. My function at the bottom is attempting to remove the custom event emitter you setup in the book. var util = require('util'); var EventEmitter = require('events').EventEmitter; // Pseudo-class named ticker that will self emit every 1 second. var Ticker = function() { var self = this; setInterval(function() { self.emit('tick'); }, 1000); }; // Bind the new EventEmitter to the sudo class. util.inherits(Ticker, EventEmitter); // call and instance of the ticker class to get the first // event started. Then let the event emitter run the infinante loop. var ticker = new Ticker(); ticker.on('tick', function() { console.log('Tick'); }); (function tock() { setInterval(function() { console.log('Tock'); EventEmitter.removeListener('Ticker',function() { console.log("Clocks Dead!"); }); }, 5000); })();

    Read the article

  • Prototype Multi-Event Observation for Multi-Elements

    - by Phonethics
    ['element1','element2','element3'].each(function(e){ Event.observe(e, 'click', function(event){ ... }); Event.observe(e, 'blur', function(event){ ... }); Event.observe(e, 'mousedown', function(event){ ... }); Event.observe(e, 'mouseover', function(event){ ... }); }); Is there a way to reduce this so that I can do ['element1','element2','element3'].each(function(e){ Event.observe(e, ev, function(event){ switch(e){ switch (ev) } }); }); ?

    Read the article

  • Event notification for ::SCardListReaders() [migrated]

    - by dpb
    In the PC/SC (Personal Computer Smart Card) Appln, I have (MSCAPI USB CCID based) 1) Calling ::SCardListReaders() returns SCARD_E_NO_READERS_AVAILABLE (0x8010002E). This call is made after OS starts fresh after reboot, from a thread which is part of my custom windows service. 2) Adding delay before ::SCardListReaders() call solves the problem. 3) How can I solve this problem elegantly ? Not using delay & waiting for some event to notify me. since a) Different machines may require different delay values b) Cannot loop since the error code is genuine c) Could not find this event as part of System Event Notification Service or similar COM interface d) platform is Windows 7 Any Help Appreciated.

    Read the article

  • SF Bay Area Event, November 1st: SPARC 25th Anniversary at Computer History Museum

    - by Larry Wake
    For those of you in the Bay Area, there's going to be what promises to be a very interesting event at the Computer History Museum on Thursday, November 1st at 11 AM: "SPARC at 25: Past, Present and Future". The panel event will feature Sun Microsystems founders Bill Joy and Andy Bechtolsheim, SPARC luminaries such as Anant Agrawal and David Patterson, former Sun VP Bernard Lacroute, plus Oracle executives Mark Hurd, John Fowler and Rick Hetherington. For those of you who can't attend, we expect to have video of the event afterward, but if you can make it in person, this is a unique opportunity to hear from industry pioneers, as well as get insights into future SPARC innovations. Plus, you can see SPARC (and non-SPARC) related exhibits from both the Computer History Museum and the personal collections of some of the panel participants. I hope you can join us; Register today.

    Read the article

  • Hold The Date: GlassFish Community Event and Party @ JavaOne 2012 - Sep 30

    - by arungupta
    A yearly tradition for the past 5 years (2007, 2008, 2009, 2010, 2011) is back again this year ... GlassFish Community Event is a gathering of GlassFish community members attending JavaOne. GlassFish Party is for everybody who are, or would like to be friends of GlassFish, in and around the San Francisco Bay Area. This year, again, both the events will be happening on the Sunday of JavaOne. The exact coordinates are a TBD but save the date while you are booking flights/hotels. GlassFish Community Event When: Sep 30, 11am - 1pm Where: TBD GlassFish Party When: Sep 30, 8pm - 10pm Where: The Thirsty Bear Note, a separate JavaOne registration is required to attend the community event. The party is open to everybody, and no JavaOne registration is required. RSVP details are still being worked upon and will be shared soon. 10 reasons to attend these events allows you to build your case with the management :-)

    Read the article

  • Java Application for handling records(CRUD)

    - by LivingThing
    I am new to JavaEE and am faced with a tight situation here. I have to develop a Java application for (CRUD) handling records and saving and loading an XML concerning that record. Obviously, I won't be asking you to do this for me. What I would be asking you is to give me some hints/pointer. Initially I thought JAXB would be enough for this but after putting a lot of time learning it and implementing the program I realized that it just can create the XML and read it but for update, delete I would have to do something else. Even if it wasn't for update and delete features requirement for my project I would still think that by just using JAXB is not a good implementation. I was wondering if "REST with Java (JAX-RS) using Jersey" should do the trick for me. ?

    Read the article

  • Why doesn't my GameMaker step event work?

    - by exceltior
    So I want to make some kind of floor that which the player when walks in gets his movement reduced but im having thousand of different issues implementing this since it doesnt appear to do anything ... So i have tried different way: 1 - I have tried Step Event which had the following script: if keyboard_check(ord('A')) { player.x = -5; } if keyboard_check(ord('D')) { player.x = -5; } if keyboard_check(ord('W')) { player.x = -5; } if keyboard_check(ord('S')) { player.x = -5; } 2 - I have tried a Collision Event with the same code 3- I have tried a Step event with collision detection on a script None of these options seem to work at all ... Can you help me?

    Read the article

  • Handling different screen densities in Android Devices?

    - by DevilWithin
    Well, i know there are plenty of different-sized screens in devices that run Android. The SDK I code with deploys to all major desktop platforms and android. I am aware i must have special cares to handle the different screen sizes and densities, but i just had an idea that would work in theory, and my question is exactly about that method, How could it FAIL ? So, what I do is to have an ortho camera of the same size for all devices, with possible tweaks, but anyway that would grant the proper positioning of all elements in all devices, right? We can assume everything is drawn in OpenGLES and input handling is converted to the proper camera coordinates. If you need me to improve the question, please tell me.

    Read the article

  • How To Initialize Object Which May Be Used In Catch Clause?

    - by Onorio Catenacci
    I've seen this sort of pattern in code before: //pseudo C# code var exInfo = null; //Line A try { var p = SomeProperty; //Line B exInfo = new ExceptionMessage("The property was " + p); //Line C } catch(Exception ex) { exInfo.SomeOtherProperty = SomeOtherValue; //Line D } Usually the code is structured in this fashion because exInfo has to be visible outside of the try clause. The problem is that if an exception occurs on Line B, then exInfo will be null at Line D. The issue arises when something happens on Line B that must occur before exInfo is constructed. But if I set exInfo to a new Object at line A then memory may get leaked at Line C (due to "new"-ing the object there). Is there a better pattern for handling this sort of code? Is there a name for this sort of initialization pattern? By the way I know I could check for exInfo == null before line D but that seems a bit clumsy and I'm looking for a better approach.

    Read the article

< Previous Page | 20 21 22 23 24 25 26 27 28 29 30 31  | Next Page >