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  • help with javamail api

    - by bobby
    import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import javax.mail.*; import javax.mail.internet.*; import javax.mail.event.*; import java.net.*; import java.util.*; public class servletmail extends HttpServlet { public void doPost(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException { PrintWriter out=response.getWriter(); response.setContentType("text/html"); try { Properties props=new Properties(); props.put("mail.transport.protocol", "smtp"); props.put("mail.smtp.host","smtp.gmail.com"); props.put("mail.smtp.port", "25"); props.put("mail.smtp.auth", "true"); Authenticator authenticator = new Authenticator() { protected PasswordAuthentication getPasswordAuthentication() { return new PasswordAuthentication("user", "pass"); } }; Session sess=Session.getDefaultInstance(props,authenticator); Message msg=new MimeMessage(sess); msg.setFrom(new InternetAddress("[email protected]")); msg.addRecipient(Message.RecipientType.TO, new InternetAddress("[email protected]")); msg.setSubject("Hello JavaMail"); msg.setText("Welcome to JavaMail"); Transport.send(msg); out.println("mail has been sent"); } catch(Exception e) { System.out.println("err"+e); } } } im working with above im gettin d following error servletmail.java:22: reference to Authenticator is ambiguous, both class java.ne t.Authenticator in java.net and class javax.mail.Authenticator in javax.mail mat ch Authenticator authenticator = new Authenticator() ^ servletmail.java:22: reference to Authenticator is ambiguous, both class java.ne t.Authenticator in java.net and class javax.mail.Authenticator in javax.mail mat ch Authenticator authenticator = new Authenticator() ^ 2 errors i have followed the example in http://java.sun.com/developer/onlineTraining/JavaMail/contents.html how should i get the output..will the above code...work what are the changes that need to be made..im using thunderbird smtp server

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  • Iphone: TabView + TableView

    - by OneTrickPonySoft
    I think I'm missing something simple, but I can't figure out exactly what it is. I'm trying to set up an App with a UITabViewController, and one of the Tabs will have a UITableView and UISearchBar (but no Navigation Controller). I set up the UITabViewController with all the tabs in interface builder, and the views are in their own xib files. The xib file for the tab with the UITableView is set up and connected as follows. Stuff in the browser: File's owner (Class is my custom class that is a child of UITableViewController) view - View View (class UIView, reference view - File's owner) contains: UITableView (if i try and set references to the data source / delegate, the app breaks) UISearchBar (unconfigured at the moment) This setup displays all the items and doesn't lock up, but I can't assign a DataSource without it crashing when i try and load the tab with the UITableView. What should I do to get data into this table, either in IB or code? My ideas are as follows: Implement custom UITableView class, hook up to table view in IB or to custom tableviewcontroller in Xcode. Pound head or laptop against the wall until it works. Update: Here's the error the simulator pushes to the console when I connect the Tableview's data source and delegate to File Owner (who's class is my custom tableviewcontroller). 2/14/09 6:59:12 PM TabBarWillbeRight[33172] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[UIViewController tableView:numberOfRowsInSection:]: unrecognized selector sent to instance 0x523760'

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  • Base class deleted before subclass during python __del__ processing

    - by Oddthinking
    Context I am aware that if I ask a question about Python destructors, the standard argument will be to use contexts instead. Let me start by explaining why I am not doing that. I am writing a subclass to logging.Handler. When an instance is closed, it posts a sentinel value to a Queue.Queue. If it doesn't, a second thread will be left running forever, waiting for Queue.Queue.get() to complete. I am writing this with other developers in mind, so I don't want a failure to call close() on a handler object to cause the program to hang. Therefore, I am adding a check in __del__() to ensure the object was closed properly. I understand circular references may cause it to fail in some circumstances. There's not a lot I can do about that. Problem Here is some simple example code: explicit_delete = True class Base: def __del__(self): print "Base class cleaning up." class Sub(Base): def __del__(self): print "Sub-class cleaning up." Base.__del__(self) x = Sub() if explicit_delete: del x print "End of thread" When I run this I get, as expected: Sub-class cleaning up. Base class cleaning up. End of thread If I set explicit_delete to False in the first line, I get: End of thread Sub-class cleaning up. Exception AttributeError: "'NoneType' object has no attribute '__del__'" in <bound method Sub.__del__ of <__main__.Sub instance at 0x00F0B698>> ignored It seems the definition of Base is removed before the x._del_() is called. The Python Documentation on _del_() warns that the subclass needs to call the base-class to get a clean deletion, but here that appears to be impossible. Can you see where I made a bad step?

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  • Can't read from RSOP_RegistryPolicySetting WMI class in root\RSOP namespace

    - by JCCyC
    The class is documented in http://msdn.microsoft.com/en-us/library/aa375050%28VS.85%29.aspx And from this page it seems it's not an abstract class: http://msdn.microsoft.com/en-us/library/aa375084%28VS.85%29.aspx But whenever I run the code below I get an "Invalid Class" exception in ManagementObjectSearcher.Get(). So, does this class exist or not? ManagementScope scope; ConnectionOptions options = new ConnectionOptions(); options.Username = tbUsername.Text; options.Password = tbPassword.Password; options.Authority = String.Format("ntlmdomain:{0}", tbDomain.Text); scope = new ManagementScope(String.Format("\\\\{0}\\root\\RSOP", tbHost.Text), options); scope.Connect(); ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope, new ObjectQuery("SELECT * FROM RSOP_RegistryPolicySetting")); foreach (ManagementObject queryObj in searcher.Get()) { wmiResults.Text += String.Format("id={0}\n", queryObj["id"]); wmiResults.Text += String.Format("precedence={0}\n", queryObj["precedence"]); wmiResults.Text += String.Format("registryKey={0}\n", queryObj["registryKey"]); wmiResults.Text += String.Format("valueType={0}\n", queryObj["valueType"]); } In the first link above, it lists as a requirement something called a "MOF": "Rsopcls.mof". Is this something I should have but have not? How do I obtain it? Is it necessary in the querying machine or the queried machine? Or both? I do have two copies of this file: C:\Windows>dir rsop*.mof /s Volume in drive C has no label. Volume Serial Number is 245C-A6EF Directory of C:\Windows\System32\wbem 02/11/2006 05:22 100.388 rsop.mof 1 File(s) 100.388 bytes Directory of C:\Windows\winsxs\x86_microsoft-windows-grouppolicy-base-mof_31bf3856ad364e35_6.0.6001.18000_none_f2c4356a12313758 19/01/2008 07:03 100.388 rsop.mof 1 File(s) 100.388 bytes Total Files Listed: 2 File(s) 200.776 bytes 0 Dir(s) 6.625.456.128 bytes free

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  • C#.NET DataGridView - update database

    - by Geo Ego
    I know this is a basic function of the DataGridView, but for some reason, I just can't get it to work. I just want the DataGridView on my Windows form to submit any changes made to it to the database when the user clicks the "Save" button. On form load, I populate the DataGridView and that's working fine. In my save function, I basically have the following (I've trimmed out some of the code around it to get to the point): using (SqlDataAdapter ruleTableDA = new SqlDataAdapter("SELECT rule.fldFluteType AS [Flute], rule.fldKnife AS [Knife], rule.fldScore AS [Score], rule.fldLowKnife AS [Low Knife], rule.fldMatrixScore AS [Matrix Score], rule.fldMatrix AS [Matrix] FROM dbo.tblRuleTypes rule WHERE rule.fldMachine_ID = '1003'", con)) { SqlCommandBuilder commandBuilder = new SqlCommandBuilder(ruleTableDA); DataTable dt = new DataTable(); dt = RuleTable.DataSource as DataTable; ruleTableDA.Fill(dt); ruleTableDA.Update(dt); } Okay, so I edited the code to do the following: build the commands, create a DataTable based on the DataGridView (RuleTable), fill the DataAdapter with the DataTable, and update the database. Now ruleTableDA.Update(dt) is throwing the exception "Concurrency violation: the UpdateCommand affected 0 of the expected 1 records." Thanks very much!

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  • ASP.Net HttpModule List<> content

    - by test
    We have created an http module that loads data on initialize into a list, and uses that list on every endrequest event of application. However we got a null reference exception on the module at endRequest event complaining that the content is null. Yet we are sure that at module initialization we have put non-null objects correctly. How is this possible? Any ideas? Thanks in advance. The place where i fill the data into the list what named as "Pages" : using (SqlDataReader reader = cmd.ExecuteReader()) { while (reader.Read()) { LandingPageDetails details = new LandingPageDetails(); details.DomainId = Convert.ToInt32(reader["DomainId"]); details.PageId = Convert.ToInt32(reader["TrackingPageId"]); details.PageAddress = Convert.ToString(reader["PageAddress"]); if (!string.IsNullOrEmpty(details.PageAddress)) { Pages.Add(details); } } } // Find the related record on EndRequesst event LandingPageDetails result = Pages.Find ( delegate(LandingPageDetails current) { return current.PageAddress.Equals(url, StringComparison.InvariantCultureIgnoreCase); } ); The line what we get the error return current.PageAddress.Equals(url, StringComparison.InvariantCultureIgnoreCase); "current" is the null object P.S : It works properly, but one day later contents become null. Possibly, there is something wrong on IIS. Our server is Windows 2003, IIS 6.0

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  • A linked list with multiple heads in Java

    - by Emile
    Hi, I have a list in which I'd like to keep several head pointers. I've tried to create multiple ListIterators on the same list but this forbid me to add new elements in my list... (see Concurrent Modification exception). I could create my own class but I'd rather use a built-in implementation ;) To be more specific, here is an inefficient implementation of two basic operations and the one wich doesn't work : class MyList <E { private int[] _heads; private List<E _l; public MyList ( int nbHeads ) { _heads = new int[nbHeads]; _l = new LinkedList<E(); } public void add ( E e ) { _l.add(e); } public E next ( int head ) { return _l.get(_heads[head++]); // ugly } } class MyList <E { private Vector<ListIterator<E _iters; private List<E _l; public MyList ( int nbHeads ) { _iters = new Vector<ListIterator<E(nbHeads); _l = new LinkedList<E(); for( ListIterator<E iter : _iters ) iter = _l.listIterator(); } public void add ( E e ) { _l.add(e); } public E next ( int head ) { // ConcurrentModificationException because of the add() return _iters.get(head).next(); } } Emile

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  • problem with MANIFEST.MF in jar

    - by dhananjay
    I have created my jar file in the following folder: /usr/local/bin/niidle.jar And I have one jarfile which is in the following folder /Projects/EnwelibDatedOct13/Niidle/lib/hector-0.6.0-17.jar And this file 'hector-0.6.0-17.jar' I have to include in MANIFEST.MF in jar. And when I mention class path in MANIFEST.MF as follows: Manifest-Version: 1.0 Main-Class: com.ensarm.niidle.web.scraper.NiidleScrapeManager Class-Path: /Projects/EnwelibDatedOct13/Niidle/lib/hector-0.6.0-17.jar When I run this using command: java -jar /usr/local/bin/niidle.jar It works properly.. But I dont want to give full Class-Path name, I have to give Class-Path as follows: Manifest-Version: 1.0 Main-Class: com.ensarm.niidle.web.scraper.NiidleScrapeManager Class-Path: lib/hector-0.6.0-17.jar And when I run this using command: java -jar /usr/local/bin/niidle.jar It is showing error message: Exception in thread "main" java.lang.NoClassDefFoundError: me/prettyprint/hector/api/Serializer at com.ensarm.niidle.web.scraper.NiidleScrapeManager.main(NiidleScrapeManager.java:21) Caused by: java.lang.ClassNotFoundException: me.prettyprint.hector.api.Serializer at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) ... 1 more Please tell me solution for that...

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  • Why does autoboxing in Java allow me to have 3 possible values for a boolean?

    - by John
    Reference: http://java.sun.com/j2se/1.5.0/docs/guide/language/autoboxing.html If your program tries to autounbox null, it will throw a NullPointerException. javac will give you a compile-time error if you try to assign null to a boolean. makes sense. assigning null to a Boolean is a-ok though. also makes sense, i guess. but let's think about the fact that you'll get a NPE when trying to autounbox null. what this means is that you can't safely perform boolean operations on Booleans without null-checking or exception handling. same goes for doing math operations on an Integer. for a long time, i was a fan of autoboxing in java1.5+ because I thought it got java closer to be truly object-oriented. but, after running into this problem last night, i gotta say that i think this sucks. the compiler giving me an error when I'm trying to do stuff with an uninitialized primitive is a good thing. I think I may be misunderstanding the point of autoboxing, but at the same time I will never accept that a boolean should be able to have 3 values. can anyone explain this? what am i not getting?

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  • org.hibernate.NonUniqueObjectException Within GWT application using hibernate through gilead

    - by molleman
    Hello Guys, i am working on a project for college that uses GWT,Hibernate and Gilead. Basically for the moment users should be able to add friends and remove them. also a user can see if his or her friends are online or not. my trouble is that when i add a friend that is already related to another friend i get this error org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: [com.example.client.YFUser#4] i have a service class public class TestServiceImpl extends PersistentRemoteService implements TestService { this is my service class for my gwt application. my toruble is here with my implmentation class of my serivce in this method that is called when a user presses add friend button on the client-side public void addYFUserFriend(String userName){ //this retrieves the current user YFUser user = (YFUser)getSession().getAttribute(SESSION_USER); Session session = com.example.server.HibernateUtil.getSessionFactory().getCurrentSession(); session.beginTransaction(); YFUser friend = (YFUser) session.createQuery("select u FROM YFUser u where u.username = :username").setParameter("username", userName).uniqueResult(); System.out.println("user " + friend.getUsername() + " Found"); user.getFriends().add(friend); friend.getBefriended().add(user); session.update(user); session.update(friend); session.getTransaction().commit(); } a scenerio : user1 adds user2 as a friend. this works fine. then user3 adds user2 and the exeception is thrown. any ideas why and where my logic is going wrong Ok so i have changed my code, and i have removed all the getCurrentASession() calls and replaced with openSession() call which are closed at the appropiate point, now the error i am getting is com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract void com.example.client.TestService.addYFUserFriend(java.lang.String)' threw an unexpected exception: org.hibernate.NonUniqueResultException: query did not return a unique result: 3

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  • django+mod_wsgi on virtualenv not working

    - by jwesonga
    I've just finished setting up a django app on virtualenv, deployment went smoothly using a fabric script, but now the .wsgi is not working, I've tried every variation on the internet but no luck. My .wsgi file is: import os import sys import django.core.handlers.wsgi # put the Django project on sys.path root_path = os.path.abspath(os.path.dirname(__file__) + '../') sys.path.insert(0, os.path.join(root_path, 'kcdf')) sys.path.insert(0, root_path) os.environ['DJANGO_SETTINGS_MODULE'] = 'kcdf.settings' application = django.core.handlers.wsgi.WSGIHandler() I keep getting the same error: [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] mod_wsgi (pid=16938): Exception occurred processing WSGI script '/home/kcdfweb/webapps/kcdf.web/releases/current/kcdf/apache/kcdf.wsgi'. [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] Traceback (most recent call last): [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/core/handlers/wsgi.py", line 230, in __call__ [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] self.load_middleware() [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/core/handlers/base.py", line 33, in load_middleware [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] for middleware_path in settings.MIDDLEWARE_CLASSES: [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/utils/functional.py", line 269, in __getattr__ [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] self._setup() [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/conf/__init__.py", line 40, in _setup [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] self._wrapped = Settings(settings_module) [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/conf/__init__.py", line 75, in __init__ [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] raise ImportError, "Could not import settings '%s' (Is it on sys.path? Does it have syntax errors?): %s" % (self.SETTINGS_MODULE, e) [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] ImportError: Could not import settings 'kcdf.settings' (Is it on sys.path? Does it have syntax errors?): No module named kcdf.settings my virtual environment is on /home/user/webapps/kcdfweb my app is /home/user/webapps/kcdf.web/releases/current/project_name my wsgi file home/user/webapps/kcdf.web/releases/current/project_name/apache/project_name.wsgi

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  • NSMutableDictionary with UIButton* as keys - iPhone development

    - by Alejandro A.
    Hi, I'm new to iPhone development and I have a question that may have a very simple answer. I am trying to add buttons to a view and these buttons are associated with a custom class that I defined. When I add the buttons to the view, I would like to know what class these buttons correspond to. This is because when I press the button, I need to get some information about the class, but the receiver of the message is another class. I couldn't find information about an error that I'm getting on the web. The problem I have is that I'm trying to create an NSMutableDictionary where the keys are of type UIButton* and the values are of my custom type: // create button for unit UIButton* unitButton = [[UIButton alloc] init]; [sourceButtonMap setObject:composite forKey:unitButton]; Of course, the sourceButtonMap is defined in the class and initialized in the init function as sourceButtonMap = [[NSMutableDictionary alloc] init]; The error I get when I try to add the key-value pair is: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[UIButton copyWithZone:]: unrecognized selector sent to instance 0x3931e90' Is this happening because I can't store UIButton* as keys? Can anyone point me why I'm getting this error? Thank you all, aa

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  • Open PDF Content files in ASP.NET MVC 2

    - by mcbingo
    I want to provide simple href links to my PDF forms that reside in my Forms folder. I have a created a simple Index.aspx and FormController Index action that simple iterates through the list of PDF files using my FormMetaData.xml file. The links get created just fine but when you click on the links I get a 404 exception. That looks like this: Server Error in '/' Application. The resource cannot be found. Description: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable. Please review the following URL and make sure that it is spelled correctly. Requested URL: /Forms/ccindteamgolfform.pdf Version Information: Microsoft .NET Framework Version:2.0.50727.4927; ASP.NET Version:2.0.50727.4927 This seems like this should open up a new browser window with the PDF in it but perhaps I am making a bad assumption. The PDF content files have Build Action of Content and Copy to Output set to Copy Always. Here is an example output html for the link from my Index.aspx page: <span class="form"> <a href="Forms/ccindteamgolfform.pdf" target="_blank"> <span class="description">Entry Form</span></span> I must be missing something because this does not work. Do I need to add a MapRoute for these documents? Or am I missing something else with the routing? This seems like it should not be that difficult.

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  • grails scaffolding broken

    - by damian
    Grails scaffoldin does not work in my grails application. When I go from the main page to the specific controller page it output something like this: Error 500: Servlet: default URI: /myapp/myDomain/list Exception Message: Tag [sortableColumn] is missing required attribute [title] or [titleKey] at /webTestDummyDomain/list:25 Caused by: Error processing GroovyPageView: Tag [sortableColumn] is missing required attribute [title] or [titleKey] at /myDomain/list:25 Class: /myDomain/list At Line: [25] Code Snippet: Code snippet empty. If I try to create a new app scaffold works perfectly. Additional data: Application Status * App version: 0.1 * Grails version: 1.2.2 * JVM version: 1.6.0_20 * Controllers: 11 * Domains: 10 * Services: 19 * Tag Libraries: 26 Installed Plugins * i18n - 1.2.2 * filters - 1.2.2 * logging - 1.2.2 * core - 1.2.2 * tomcat - 1.2.2 * webtest - 2.0.4 * functionalTest - 1.2.7 * yui - 2.7.0.1 * rest - 0.3 * jquery - 1.4.2.1 * bubbling - 2.1.2 * urlMappings - 1.2.2 * groovyPages - 1.2.2 * servlets - 1.2.2 * dataSource - 1.2.2 * controllers - 1.2.2 * codecs - 1.2.2 * jqueryUi - 1.8-SNAPSHOT * grailsUi - 1.2-SNAPSHOT * domainClass - 1.2.2 * mimeTypes - 1.2.2 * scaffolding - 1.2.2 * converters - 1.2.2 * hibernate - 1.2.2 * validation - 1.2.2 * services - 1.2.2 Can you give me any pointer?

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  • Virtual properties duplicated during serialization when XmlElement attribute used

    - by Laramie
    The Goal: XML serialize an object that contains a list of objects of that and its derived types. The resulting XML should not use the xsi:type attribute to describe the type, to wit the names of the serialized XML elements would be an assigned name specific to the derived type, not always that of the base class, which is the default behavior. The Attempt: After exploring IXmlSerializable and IXmlSerializable with eerie XmlSchemaProvider methods and voodoo reflection to return specialized schemas and an XmlQualifiedName over the course of days, I found I was able to use the simple [XmlElement] attribute to accomplish the goal... almost. The Problem: Overridden properties appear twice when serializing. The exception reads "The XML element 'overriddenProperty' from namespace '' is already present in the current scope. Use XML attributes to specify another XML name or namespace for the element." I attempted using a *Specified property (see code), but it didn't work. Sample Code: Class Declaration using System; using System.Collections.Generic; using System.Xml.Serialization; [XmlInclude(typeof(DerivedClass))] public class BaseClass { public BaseClass() { } [XmlAttribute("virt")] public virtual string Virtual { get; set; } [XmlIgnore] public bool VirtualSpecified { get { return (this is BaseClass); } set { } } [XmlElement(ElementName = "B", Type = typeof(BaseClass), IsNullable = false)] [XmlElement(ElementName = "D", Type = typeof(DerivedClass), IsNullable = false)] public List<BaseClass> Children { get; set; } } public class DerivedClass : BaseClass { public DerivedClass() { } [XmlAttribute("virt")] public override string Virtual { get { return "always return spackle"; } set { } } } Driver: BaseClass baseClass = new BaseClass() { Children = new List<BaseClass>() }; BaseClass baseClass2 = new BaseClass(){}; DerivedClass derivedClass1 = new DerivedClass() { Children = new List<BaseClass>() }; DerivedClass derivedClass2 = new DerivedClass() { Children = new List<BaseClass>() }; baseClass.Children.Add(derivedClass1); baseClass.Children.Add(derivedClass2); derivedClass1.Children.Add(baseClass2); I've been wrestling with this on and off for weeks and can't find the answer anywhere.

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  • My java.util.Scanner won't work

    - by Kevin Steen Hansen
    Hello Stackoverflow my code is getting this error: Skriv din alder herunder og tryk enter: Exception in thread "main" java.util.NoSuchElementException at java.util.Scanner.throwFor(Scanner.java:907) at java.util.Scanner.next(Scanner.java:1530) at java.util.Scanner.nextInt(Scanner.java:2160) at java.util.Scanner.nextInt(Scanner.java:2119) at Tasteturindtastning.main(Tasteturindtastning.java:20) [Finished in 1.7s with exit code 1] Adn my code is: // Starter java som man plejer, læs i HejVerden.java public class Tasteturindtastning { public static void main(String[] arg) { /* Jeg skal nu angive en variable, men jeg kan ikke bestemme denne variable * Da jeg ønsker at indtastningen fra dette tastetur skal være variablen. * I stedet for int og double bruger jeg så java.util.Scanner, som aflæser * brugerens indtastninger. */ java.util.Scanner tastetur = new java.util.Scanner(System.in); // Printer en opgave/spørgsmål til brugeren System.out.println("Skriv din alder herunder og tryk enter:"); int alder; // Angiver et variablenavn alder = tastetur.nextInt(); // Angiver variablen med værdien fra indtastningen /* Herunder gør jeg brug af et if statement der tjekker værdien for * variablen alder, og ser om den er lig med eller højere end 18, og hvis * dette er tilfældet, så udprinter den en sætning */ if (alder >= 18) System.out.println("Du er myndig, da du er " + alder + " år gammel"); // Printes hvis han er 18 eller ældre } } Can snyone tell me what is wrong?

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  • Can an interface define the signature of a c#-constructor

    - by happyclicker
    I have a .net-app that provides a mechanism to extend the app with plugins. Each plugin must implement a plugin-interface and must provide furthermore a constructor that receives one parameter (a resource context). During the instantiation of the plugin-class I look via reflection, if the needed constructor exists and if yes, I instantiate the class (via Reflection). If the constructor does not exists, I throw an exception that says that the plugin not could be created, because the desired constructor is not available. My question is, if there is a way to declare the signature of a constructor in the plugin-interface so that everyone that implements the plugin-interface must also provide a constructor with the desired signature. This would ease the creation of plugins. I don’t think that such a possibility exists because I think such a feature falls not in the main purpose for what interfaces were designed for but perhaps someone knows a statement that does this, something like: public interface IPlugin { ctor(IResourceContext resourceContext); int AnotherPluginFunction(); } I want to add that I don't want to change the constructor to be parameterless and then set the resource-context through a property, because this will make the creation of plugins much more complicated. The persons that write plugins are not persons with deep programming experience. The plugins are used to calculate statistical data that will be visualized by the app.

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  • Java: Reading images and displaying as an ImageIcon

    - by 11helen
    I'm writing an application which reads and displays images as ImageIcons (within a JLabel), the application needs to be able to support jpegs and bitmaps. For jpegs I find that passing the filename directly to the ImageIcon constructor works fine (even for displaying two large jpegs), however if I use ImageIO.read to get the image and then pass the image to the ImageIcon constructor, I get an OutOfMemoryError( Java Heap Space ) when the second image is read (using the same images as before). For bitmaps, if I try to read by passing the filename to ImageIcon, nothing is displayed, however by reading the image with ImageIO.read and then using this image in the ImageIcon constructor works fine. I understand from reading other forum posts that the reason that the two methods don't work the same for the different formats is down to java's compatability issues with bitmaps, however is there a way around my problem so that I can use the same method for both bitmaps and jpegs without an OutOfMemoryError? (I would like to avoid having to increase the heap size if possible!) The OutOfMemoryError is triggered by this line: img = getFileContentsAsImage(file); and the method definition is: public static BufferedImage getFileContentsAsImage(File file) throws FileNotFoundException { BufferedImage img = null; try { ImageIO.setUseCache(false); img = ImageIO.read(file); img.flush(); } catch (IOException ex) { //log error } return img; } The stack trace is: Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space at java.awt.image.DataBufferByte.<init>(DataBufferByte.java:58) at java.awt.image.ComponentSampleModel.createDataBuffer(ComponentSampleModel.java:397) at java.awt.image.Raster.createWritableRaster(Raster.java:938) at javax.imageio.ImageTypeSpecifier.createBufferedImage(ImageTypeSpecifier.java:1056) at javax.imageio.ImageReader.getDestination(ImageReader.java:2879) at com.sun.imageio.plugins.jpeg.JPEGImageReader.readInternal(JPEGImageReader.java:925) at com.sun.imageio.plugins.jpeg.JPEGImageReader.read(JPEGImageReader.java:897) at javax.imageio.ImageIO.read(ImageIO.java:1422) at javax.imageio.ImageIO.read(ImageIO.java:1282) at framework.FileUtils.getFileContentsAsImage(FileUtils.java:33)

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  • Hazelcast Distributed Executor Service KeyOwner

    - by János Veres
    I have problem understanding the concept of Hazelcast Distributed Execution. It is said to be able to perform the execution on the owner instance of a specific key. From Documentation: <T> Future<T> submitToKeyOwner(Callable<T> task, Object key) Submits task to owner of the specified key and returns a Future representing that task. Parameters: task - task key - key Returns: a Future representing pending completion of the task I believe that I'm not alone to have a cluster built with multiple maps which might actually use the same key for different purposes, holding different objects (e.g. something along the following setup): IMap<String, ObjectTypeA> firstMap = HazelcastInstance.getMap("firstMap"); IMap<String, ObjectTypeA_AppendixClass> secondMap = HazelcastInstance.getMap("secondMap"); To me it seems quite confusing what documentation says about the owner of a key. My real frustration is that I don't know WHICH - in which map - key does it refer to? The documentation also gives a "demo" of this approach: import com.hazelcast.core.Member; import com.hazelcast.core.Hazelcast; import com.hazelcast.core.IExecutorService; import java.util.concurrent.Callable; import java.util.concurrent.Future; import java.util.Set; import com.hazelcast.config.Config; public void echoOnTheMemberOwningTheKey(String input, Object key) throws Exception { Callable<String> task = new Echo(input); HazelcastInstance hz = Hazelcast.newHazelcastInstance(); IExecutorService executorService = hz.getExecutorService("default"); Future<String> future = executorService.submitToKeyOwner(task, key); String echoResult = future.get(); } Here's a link to the documentation site: Hazelcast MultiHTML Documentation 3.0 - Distributed Execution Did any of you guys figure out in the past what key does it want?

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  • The following code to check if a file exists on a server does not work

    - by xplorer2k
    Hi Everyone, I found the following code to check if a file exists on a server, but is not working for me. It tells me that "test1.tx" does not exist even though the file exists and its size is 498 bytes. If I try with Ftp.ListDirectory it tells me that the file does not exist. If I try with Ftp.GetFileSize it does not provide any results and the debugger's immediate gives me the following message: A first chance exception of type 'System.Net.WebException' occurred in System.dll. Using "request.UseBinary = true" does not make any difference. I have posted this same question at this link: http://social.msdn.microsoft.com/Forums/en-US/ncl/thread/89e05cf3-189f-48b7-ba28-f93b1a9d44ae Could someone help me how to fix it? private void button1_Click(object sender, EventArgs e) { string ftpServerIP = txtIPaddress.Text.Trim(); string ftpUserID = txtUsername.Text.Trim(); string ftpPassword = txtPassword.Text.Trim(); try { FtpWebRequest request = (FtpWebRequest)WebRequest.Create("ftp://" + ftpServerIP + "//tmp/test1.txt"); request.Method = WebRequestMethods.Ftp.ListDirectory; //request.Method = WebRequestMethods.Ftp.GetFileSize; request.Credentials = new NetworkCredential(ftpUserID, ftpPassword); //request.UseBinary = true; using (FtpWebResponse response = (FtpWebResponse)request.GetResponse()) { // Okay. textBox1.AppendText(Environment.NewLine); textBox1.AppendText("File exist"); } } catch (WebException ex) { if (ex.Response != null) { FtpWebResponse response = (FtpWebResponse)ex.Response; if (response.StatusCode == FtpStatusCode.ActionNotTakenFileUnavailable) { // Directory not found. textBox1.AppendText(Environment.NewLine); textBox1.AppendText("File does not exist"); } } } } Thanks very much, xplorer2k

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  • Application crashing on getting updated information from database using timer and storing it on loca

    - by Amit Battan
    In our multi - user application we are continuously interacting with database. We have a common class through which we are sending POST queries to database and obtaining xml files in return. We are using delegates of NSXMLParser to parse the obtained file. The problem with us is we are facing many crashes in it generally when application is idle and changed data in database is being fetched in background through timer which is invoked after every few seconds. We have also dealt with error handling through try and catch but it proves to be of no use in this case and mostly application crashes with following error : Exception Type: EXC_BAD_ACCESS (SIGBUS) Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000020 Strange thing is that many times the fetching of updated data at background works very fine, same methods being successfully executed under similar conditions but suddenly it crashes on one of them. The codes we are using is as follows: // we are using timer in this way: chkOnlineUser=[NSTimer scheduledTimerWithTimeInterval:15 target:mmObject selector:@selector(threadOnlineUser) userInfo:NULL repeats:YES]; // this method being called in timer -(void)threadOnlineUser{//HeartBeat in Thread [NSThread detachNewThreadSelector:@selector(onlineUserRefresh) toTarget:self withObject:nil]; } // this performs actual updation -(void)onlineUserRefresh{ NSAutoreleasePool *pool =[[NSAutoreleasePool alloc]init]; @try{ if(chkTimer==1){ return; } chkTimer=1; if([allUserArray count]==0){ [user parseXMLFileUser:@"all" andFlag:3]; [allUserArray removeAllObjects]; [allUserArray addObjectsFromArray:[user users]]; } [objHeartBeat parseXMLFile:[loginID intValue] timeOut:10]; NSMutableDictionary *tDictOL=[[NSMutableDictionary alloc] init]; tDictOL=[objHeartBeat onLineList]; NSArray *tArray=[[NSArray alloc] init]; tArray=[[tDictOL objectForKey:@"onlineuser"] componentsSeparatedByString:@","]; [loginUserArray removeAllObjects]; for(int l=0;l less than [tArray count] ;l++){ int t;//=[[tArray objectAtIndex:l] intValue]; if([[allUserArray valueForKey:@"Id"] containsObject:[tArray objectAtIndex:l]]){ t = [[allUserArray valueForKey:@"Id"] indexOfObject:[tArray objectAtIndex:l]]; [loginUserArray addObject:[allUserArray objectAtIndex:t]]; } } [onlineTable reloadData]; [logInUserPopUp removeAllItems]; if([loginUserArray count]==1){ [labelLoginUser setStringValue:@"Only you are online"]; [logInUserPopUp setEnabled:YES]; }else{ [labelLoginUser setStringValue:[NSString stringWithFormat:@" %d users online",[loginUserArray count]]]; [logInUserPopUp setEnabled:YES]; } NSMenu *menu = [[NSMenu alloc] initWithTitle:@"menu"]; NSMenuItem *itemOne = [[NSMenuItem alloc] initWithTitle:@"" action:NULL keyEquivalent:@""]; [menu addItem:itemOne]; for(int l=0;l less than [loginUserArray count];l++){ NSString *tempStr= [NSString stringWithFormat:@"%@ %@",[[[loginUserArray objectAtIndex:l] objectForKey:@"user_fname"] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]],[[[loginUserArray objectAtIndex:l] objectForKey:@"user_lname"] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]]; if(![tempStr isEqualToString:@""]){ NSMenuItem *itemOne = [[NSMenuItem alloc] initWithTitle:tempStr action:NULL keyEquivalent:@""]; [menu addItem:itemOne]; }else if(l==0){ NSMenuItem *itemOne = [[NSMenuItem alloc] initWithTitle:tempStr action:NULL keyEquivalent:@""]; [menu addItem:itemOne]; } } [logInUserPopUp setMenu:menu]; if([lastUpdateTime isEqualToString:@""]){ }else { [self fetchUpdatedInfo:lastUpdateTime]; [self fetchUpdatedGroup:lastUpdateTime];// function same as fetchUpdatedInfo [avObject fetchUpdatedInfo:lastUpdateTime];// function same as fetchUpdatedInfo [esTVObject fetchUpdatedInfo:lastUpdateTime];// function same as fetchUpdatedInfo } lastUpdateTime=[[tDictOL objectForKey:@"lastServerTime"] copy]; } @catch (NSException * e) { [queryByPost insertException:@"MainModule" inFun:@"onlineUserRefresh" excp:[e description] userId:[loginID intValue]]; NSRunAlertPanel(@"Error Panel", @"Main Module- onlineUserRefresh....%@", @"OK", nil, nil,e); } @finally { NSLog(@"Internal Update Before Bye"); chkTimer=0; NSLog(@"Internal Update Bye");// Some time application crashes after this log // Some time application crahses after "Internal Update Bye" log } } // The method which we are using to obtain updated data is of following form: -(void)fetchUpdatedInfo:(NSString *)UpdTime{ @try { if(initAfterLoginComplete==0){ return; } [user parseXMLFileUser:UpdTime andFlag:[loginID intValue]]; [tempUserUpdatedArray removeAllObjects]; [tempUserUpdatedArray addObjectsFromArray:[user users]]; if([tempUserUpdatedArray count]0){ if([contactsView isHidden]){ [topContactImg setImage:[NSImage imageNamed:@"btn_contacts_off_red.png"]]; }else { [topContactImg setImage:[NSImage imageNamed:@"btn_contacts_red.png"]]; } }else { return; } int chkprof=0; for(int l=0;l less than [tempUserUpdatedArray count];l++){ NSArray *tempArr1 = [allUserArray valueForKey:@"Id"]; int s; if([[[tempUserUpdatedArray objectAtIndex:l] objectForKey:@"Id"] intValue]==profile_Id){ chkprof=1; } if([tempArr1 containsObject:[[tempUserUpdatedArray objectAtIndex:l] objectForKey:@"Id"]]){ s = [tempArr1 indexOfObject:[[tempUserUpdatedArray objectAtIndex:l] objectForKey:@"Id"]]; [allUserArray replaceObjectAtIndex:s withObject:[tempUserUpdatedArray objectAtIndex:l]]; }else { [allUserArray addObject:[tempUserUpdatedArray objectAtIndex:l]]; } NSArray *tempArr2 = [tempUser valueForKey:@"Id"]; if([tempArr2 containsObject:[[tempUserUpdatedArray objectAtIndex:l] objectForKey:@"Id"]]){ s = [tempArr2 indexOfObject:[[tempUserUpdatedArray objectAtIndex:l] objectForKey:@"Id"]]; [tempUser replaceObjectAtIndex:s withObject:[tempUserUpdatedArray objectAtIndex:l]]; }else { [tempUser addObject:[tempUserUpdatedArray objectAtIndex:l]]; } } NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"user_fname" ascending:YES]; [tempUser sortUsingDescriptors:[NSMutableArray arrayWithObject:sortDescriptor]]; [userListTableView reloadData]; [groupsArray removeAllObjects]; for(int z=0;z less than [tempGroups count];z++){ NSMutableArray *tempMArr=[[NSMutableArray alloc] init]; for(int l=0;l less than [allUserArray count];l++){ if([[[allUserArray objectAtIndex:l] objectForKey:@"GroupId"] intValue]==[[[tempGroups objectAtIndex:z] objectForKey:@"group_id"] intValue]){ [tempMArr addObject:[allUserArray objectAtIndex:l]]; } } [groupsArray insertObject:tempMArr atIndex:z]; [tempMArr release]; tempMArr= nil; } for(int n=0;n less than [tempGroups count];n++){ [[groupsArray objectAtIndex:n] addObject:[tempGroups objectAtIndex:n]]; } [groupsListOV reloadData]; if(chkprof==1){ [self profileShow:profile_Id]; }else { } [self selectUserInTable:0]; }@catch (NSException * e) { NSRunAlertPanel(@"Error Panel", @"%@", @"OK", nil, nil,e); } } // The method which we are using to frame select query and parse obtained data is: -(void)parseXMLForUser:(int)UId stringVar:(NSString*)stringVar{ @try{ if(queryByPost) [queryByPost release]; queryByPost=[QueryByPost new]; // common class used to invoke method to send request via POST method //obtaining data for xml parsing NSString *query=[NSString stringWithFormat:@"Select * from userinfo update_time = '%@' AND NOT owner_id ='%d' ",stringVar,UId]; NSData *obtainedData=[queryByPost executeQuery:query WithAction:@"query"]; // method invoked to perform post query if(obtainedData==nil){ // data not obtained so return return; } // initializing dictionary to be obtained after parsing if(obtainedDictionary) [obtainedDictionary release]; obtainedDictionary=[NSMutableDictionary new]; // xml parsing if (updatedDataParser) // airportsListParser is an NSXMLParser instance variable [updatedDataParser release]; updatedDataParser = [[NSXMLParser alloc] initWithData:obtainedData]; [updatedDataParser setDelegate:self]; [updatedDataParser setShouldResolveExternalEntities:YES]; BOOL success = [updatedDataParser parse]; } @catch (NSException *e) { NSLog(@"wtihin parseXMLForUser- parseXMLForUser:stringVar: - %@",[e description]); } } //The method which will attempt to interact 4 times with server if interaction with it is found to be unsuccessful , is of following form: -(NSData*)executeQuery:(NSString*)query WithAction:(NSString*)doAction{ NSLog(@"within ExecuteQuery:WithAction: Query is: %@ and Action is: %@",query,doAction); NSString *returnResult; @try { NSString *returnResult; NSMutableURLRequest *postRequest; NSError *error; NSData *searchData; NSHTTPURLResponse *response; postRequest=[self directMySQLQuery:query WithAction:doAction]; // this method sends actual POST request NSLog(@"after directMYSQL in QueryByPost- performQuery... ErrorLogMsg"); searchData = [NSURLConnection sendSynchronousRequest:postRequest returningResponse:&response error:&error]; returnResult = [[NSString alloc] initWithData:searchData encoding:NSASCIIStringEncoding]; NSString *resultToBeCompared=[returnResult stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; NSLog(@"result obtained - %@/ resultToBeCompared - %@",returnResult,resultToBeCompared); if(![resultToBeCompared isEqualToString:@""]){ }else { sleep(10); postRequest=[self directMySQLQuery:query WithAction:doAction]; searchData = [NSURLConnection sendSynchronousRequest:postRequest returningResponse:&response error:&error]; if(![resultToBeCompared isEqualToString:@""]){ }else { sleep(10); postRequest=[self directMySQLQuery:query WithAction:doAction]; searchData = [NSURLConnection sendSynchronousRequest:postRequest returningResponse:&response error:&error]; if(![resultToBeCompared isEqualToString:@""]){ }else { sleep(10); postRequest=[self directMySQLQuery:query WithAction:doAction]; searchData = [NSURLConnection sendSynchronousRequest:postRequest returningResponse:&response error:&error]; if(![resultToBeCompared isEqualToString:@""]){ }else { sleep(10); postRequest=[self directMySQLQuery:query WithAction:doAction]; searchData = [NSURLConnection sendSynchronousRequest:postRequest returningResponse:&response error:&error]; if(![resultToBeCompared isEqualToString:@""]){ }else { return nil; } } } } } returnResult = [[NSString alloc] initWithData:searchData encoding:NSASCIIStringEncoding]; return searchData; } @catch (NSException * e) { NSLog(@"within QueryByPost , execurteQuery:WithAction - %@",[e description]); return nil; } } // The method which sends POST request to server , is of following form: -(NSMutableURLRequest *)directMySQLQuery:(NSString*)query WithAction:(NSString*)doAction{ @try{ NSLog(@"Query is: %@ and Action is: %@",query,doAction); // some pre initialization NSString *stringBoundary,*contentType; NSURL *cgiUrl ; NSMutableURLRequest *postRequest; NSMutableData *postBody; NSString *ans=@"434"; cgiUrl = [NSURL URLWithString:@"http://keysoftwareservices.com/API.php"]; postRequest = [NSMutableURLRequest requestWithURL:cgiUrl]; [postRequest setHTTPMethod:@"POST"]; stringBoundary = [NSString stringWithString:@"0000ABCQueryxxxxxx"]; contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", stringBoundary]; [postRequest addValue:contentType forHTTPHeaderField: @"Content-Type"]; //setting up the body: postBody = [NSMutableData data]; [postBody appendData:[[NSString stringWithFormat:@"\r\n\r\n--%@\r\n",stringBoundary] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithString:@"Content-Disposition: form-data; name=\"code\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithString:ans] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",stringBoundary] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithString:@"Content-Disposition: form-data; name=\"action\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithString:doAction] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",stringBoundary] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithString:@"Content-Disposition: form-data; name=\"devmode\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithString:[[[NSBundle mainBundle] infoDictionary] objectForKey:@"devmode"]] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",stringBoundary] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithString:@"Content-Disposition: form-data; name=\"q\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithString:query] dataUsingEncoding:NSUTF8StringEncoding]]; [postBody appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",stringBoundary] dataUsingEncoding:NSUTF8StringEncoding]]; [postRequest setHTTPBody:postBody]; NSLog(@"Direct My SQL ok");// Some time application crashes afte this log //Some time application crashes after "Direct My SQL ok" log return [postRequest mutableCopy]; }@catch (NSException * e) { NSLog(@"NSException %@",e); NSRunAlertPanel(@"Error Panel", @"Within QueryByPost- directMySQLQuery...%@", @"OK", nil, nil,e); return nil; } }

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  • Data is not saved in MS Access database

    - by qwerty
    Hello, I have a visual C# project and i'm trying to insert data in a MS Access Database when i press a button. Here is the code: private void button1_Click(object sender, EventArgs e) { try { OleDbDataAdapter adapter=new OleDbDataAdapter(); adapter.InsertCommand = new OleDbCommand(); adapter.InsertCommand.CommandText = "insert into Candidati values ('" + maskedTextBox1.Text.Trim() + "','" + textBox1.Text.Trim() + "', '" + textBox2.Text.Trim() + "', '" + textBox3.Text.Trim() + "','" + Convert.ToDouble(maskedTextBox2.Text) + "','" + Convert.ToDouble(maskedTextBox3.Text) + "')"; con.Open(); adapter.InsertCommand.Connection = con; adapter.InsertCommand.ExecuteNonQuery(); con.Close(); MessageBox.Show("Inregistrare adaugata cu succes!"); maskedTextBox1.Text = null; maskedTextBox2.Text = null; maskedTextBox3.Text = null; textBox1.Text = null; textBox2.Text = null; textBox3.Text = null; maskedTextBox1.Focus(); } catch (AdmitereException exc) { MessageBox.Show("A aparut o exceptie: "+exc.Message, "Eroare!", MessageBoxButtons.OK, MessageBoxIcon.Error); } } The connection string is: private static string connectionString; OleDbConnection con; public AddCandidati() { connectionString = "Provider=Microsoft.JET.OLEDB.4.0;Data Source=Admitere.mdb"; con = new OleDbConnection(connectionString); InitializeComponent(); } Where AddCandidati is the form. The data is not saved in the database, why? I have the .mdb file in the project folder.. What i'm doing wrong? I did not got any exception when i press the button.. Thanks!

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  • Best Practice - Removing item from generic collection in C#

    - by Matt Davis
    I'm using C# in Visual Studio 2008 with .NET 3.5. I have a generic dictionary that maps types of events to a generic list of subscribers. A subscriber can be subscribed to more than one event. private static Dictionary<EventType, List<ISubscriber>> _subscriptions; To remove a subscriber from the subscription list, I can use either of these two options. Option 1: ISubscriber subscriber; // defined elsewhere foreach (EventType event in _subscriptions.Keys) { if (_subscriptions[event].Contains(subscriber)) { _subscriptions[event].Remove(subscriber); } } Option 2: ISubscriber subscriber; // defined elsewhere foreach (EventType event in _subscriptions.Keys) { _subscriptions[event].Remove(subscriber); } I have two questions. First, notice that Option 1 checks for existence before removing the item, while Option 2 uses a brute force removal since Remove() does not throw an exception. Of these two, which is the preferred, "best-practice" way to do this? Second, is there another, "cleaner," more elegant way to do this, perhaps with a lambda expression or using a LINQ extension? I'm still getting acclimated to these two features. Thanks. EDIT Just to clarify, I realize that the choice between Options 1 and 2 is a choice of speed (Option 2) versus maintainability (Option 1). In this particular case, I'm not necessarily trying to optimize the code, although that is certainly a worthy consideration. What I'm trying to understand is if there is a generally well-established practice for doing this. If not, which option would you use in your own code?

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  • Can I ignore a SIGFPE resulting from division by zero?

    - by Mikeage
    I have a program which deliberately performs a divide by zero (and stores the result in a volatile variable) in order to halt in certain circumstances. However, I'd like to be able to disable this halting, without changing the macro that performs the division by zero. Is there any way to ignore it? I've tried using #include <signal.h> ... int main(void) { signal(SIGFPE, SIG_IGN); ... } but it still dies with the message "Floating point exception (core dumped)". I don't actually use the value, so I don't really care what's assigned to the variable; 0, random, undefined... EDIT: I know this is not the most portable, but it's intended for an embedded device which runs on many different OSes. The default halt action is to divide by zero; other platforms require different tricks to force a watchdog induced reboot (such as an infinite loop with interrupts disabled). For a PC (linux) test environment, I wanted to disable the halt on division by zero without relying on things like assert.

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  • Altering lazy-loaded object's private variables

    - by Kevin Pang
    I'm running into an issue with private setters when using NHibernate and lazy-loading. Let's say I have a class that looks like this: public class User { public int Foo {get; private set;} public IList<User> Friends {get; set;} public void SetFirstFriendsFoo() { // This line works in a unit test but does nothing during a live run with // a lazy-loaded Friends list Users(0).Foo = 1; } } The SetFirstFriendsFoo call works perfectly inside a unit test (as it should since objects of the same type can access each others private properties). However, when running live with a lazy-loaded Friends list, the SetFirstFriendsFoo call silently fails. I'm guessing the reason for this is because at run-time, the Users(0).Foo object is no longer of type User, but of a proxy class that inherits from User since the Friends list was lazy-loaded. My question is this: shouldn't this generate a run-time exception? You get compile-time exceptions if you try to access another class's private properties, but when you run into a situation like this is looks like the app just ignores you and continues along its way.

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