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• After Delete Trigger Fires Only After Delete?

  - by Brandi

  I thought "after delete" meant that the trigger is not fired until after the delete has already taken place, but here is my situation... I made 3, nearly identical SQL CLR after delete triggers in C#, which worked beautifully for about a month. Suddenly, one of the three stopped working while an automated delete tool was run on it. By stopped working, I mean, records could not be deleted from the table via client software. Disabling the trigger caused deletes to be allowed, but re-enabling it interfered with the ability to delete. So my question is 'how can this be the case?' Is it possible the tool used on it futzed up the memory? It seems like even if the trigger threw an exception, if it is AFTER delete, shouldn't the records be gone? All the trigger looks like is this: ALTER TRIGGER [sysdba].[AccountTrigger] ON [sysdba].[ACCOUNT] AFTER DELETE AS EXTERNAL NAME [SQL_IO].[SQL_IO.WriteFunctions].[AccountTrigger] GO The CLR trigger does one select and one insert into another database. I don't yet know if there are any errors from SQL Server Mgmt Studio, but will update the question after I find out.

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• ASP.NEt MVC 2 application error on IIS7 works fine on local machine

  - by aspCoolguy

  My ASP.NET MVC2 application is developed using 1. VS 2010 2. Linq To SQL for Models Here is Call controller code: namespace CallTrackMVC.Controllers { public class CallController : Controller { private CallTrackRepository repository; public CallController():this(new CallTrackRepository()) { } public CallController(CallTrackRepository newRepository) { repository = newRepository; } } } Error on IIS7 when browsing the Call Create page is NullReferenceException: Object reference not set to an instance of an object.] CallTrackMVC.Models.ExecOfficeDataContext..ctor() in C:\ClearCase\rartadi_view\STS_Dev_TEST\CallTrackMVC\Models\ExecOffice.designer.cs:71 CallTrackMVC.Controllers.CallController..ctor() in C:\ClearCase\rartadi_view\STS_Dev_TEST\CallTrackMVC\Controllers\CallController.cs:16 [TargetInvocationException: Exception has been thrown by the target of an invocation.] System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) +0 System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache) +117 System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean skipCheckThis, Boolean fillCache) +247 System.Activator.CreateInstance(Type type, Boolean nonPublic) +106 System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +102 [InvalidOperationException: **An error occurred when trying to create a controller of type 'CallTrackMVC.Controllers.CallController'. Make sure that the controller has a parameterless public constructor.**] System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +541 System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) +85 System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) +165 System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +80 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +389 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +371 Code in Global.asax is protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes); } Any suggestion would be a great help.

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• Dynamic Auto updating (to UI, Grid) binding list in C# Winform?

  - by Dhana

  I'm not even sure if i'm doing this correctly. But basically I have a list of objects that are built out of a class/interface. From there, I am binding the list to a datagrid view that is on a Windows Form (C#) Here the list is a Sync list which will auto update the UI, in this case datagridview. Every thing works fine now, but now i would like to have the List should have an dynamic object, that is the object will have by default two static property (ID, Name), and at run time user will select remaining properties. These should be bind to the data grid. Any update on the list should be auto reflected in the grid. I am aware that, we can use dynamic objects, but i would like to know , how to approach for solution, datagridview.DataSource = myData; // myData is AutoUpdateList<IPersonInfo> Now IPersonInfo is the type of object, need to add dynamic properties for this type at runtime. public class AutoUpdateList<T> : System.ComponentModel.BindingList<T> { private System.ComponentModel.ISynchronizeInvoke _SyncObject; private System.Action<System.ComponentModel.ListChangedEventArgs> _FireEventAction; public AutoUpdateList() : this(null) { } public AutoUpdateList(System.ComponentModel.ISynchronizeInvoke syncObject) { _SyncObject = syncObject; _FireEventAction = FireEvent; } protected override void OnListChanged(System.ComponentModel.ListChangedEventArgs args) { try { if (_SyncObject == null) { FireEvent(args); } else { _SyncObject.Invoke(_FireEventAction, new object[] { args }); } } catch (Exception) { // TODO: Log Here } } private void FireEvent(System.ComponentModel.ListChangedEventArgs args) { base.OnListChanged(args); } } Could you help out on this?

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• Java - How to declare table[i][j] elements as instance variables?

  - by JDelage

  All, I am trying to code a Connect4 game. For this, I have created a P4Game class and a P4Board class which represents the i X j dimensions of the Connect4 board. In P4Game, I have the following: public class P4Game{ //INSTANCE VARIABLES private int nbLines; private int nbColumns; private P4Board [][] position; //CONSTRUCTOR public P4Game(int nbLines, int nbColumns){ this.nbColumns = nbColumns; this.nbLines = nbLines; P4Board [][] position = new P4Board [nbLines][nbColumns]; //Creates the table to receive the instances of the P4Board object.*/ for (int i=0; i<nbLines; i++){ for (int j=0; j<nbColumns; j++){ this.position[i][j] = new P4Board(i,j); //Meant to create each object at (line=i, column=j) } } } This causes a NullPointerException in the nested loops where I mention this.position[i][j]. I reference those objects in other methods of this class so I need them to be instance variables. I suppose the exception is due to the fact that I have not listed the table element position[i][j] as an instance variable at the beginning of the class. my question to people here is (1) is my assumption correct, and if so (2) what would be the syntax to declare instance variables of this form? Thank you all for your help with what I realize is a very basic question. Hopefully it will also benefit other newbies. Cheers, JDelage

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• Achieving Thread-Safety

  - by Smasher

  Question How can I make sure my application is thread-safe? Are their any common practices, testing methods, things to avoid, things to look for? Background I'm currently developing a server application that performs a number of background tasks in different threads and communicates with clients using Indy (using another bunch of automatically generated threads for the communication). Since the application should be highly availabe, a program crash is a very bad thing and I want to make sure that the application is thread-safe. No matter what, from time to time I discover a piece of code that throws an exception that never occured before and in most cases I realize that it is some kind of synchronization bug, where I forgot to synchronize my objects properly. Hence my question concerning best practices, testing of thread-safety and things like that. mghie: Thanks for the answer! I should perhaps be a little bit more precise. Just to be clear, I know about the principles of multithreading, I use synchronization (monitors) throughout my program and I know how to differentiate threading problems from other implementation problems. But nevertheless, I keep forgetting to add proper synchronization from time to time. Just to give an example, I used the RTL sort function in my code. Looked something like FKeyList.Sort (CompareKeysFunc); Turns out, that I had to synchronize FKeyList while sorting. It just don't came to my mind when initially writing that simple line of code. It's these thins I wanna talk about. What are the places where one easily forgets to add synchronization code? How do YOU make sure that you added sync code in all important places?

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• Server.TransferRequest returns blank page on specific server

  - by jishi

  I'm facing an issue that seems to be related to configuration. I have a webapplication based on MonoRail, where we utilize the routing feature from MonoRail. On the first request after the application has started, the routing isn't initialized. To circumvent this, I have the following code in Application_OnError(): public virtual void Application_OnError() { if ( // identified as routing error ) Server.TransferRequest( Context.Request.RawUrl, false ); return; } Problem beeing that on our development server (which runs server 2008 R2, with IIS 7.5 and .NET 3.5) returns a blank page without headers, but on my workstation (which runs win7, IIS 7.5 and .NET 3.5) it works fine. What could be the cause of this? If the code in Application_OnError() throws an exception, what would be the expected output? I have verified the following: The access-log shows one entry, I'm not sure if a TransferRequest would show up as a second entry when invoked successfully The application actually do some work according to my internal logs, and it doesn't die since a subsequent requests works flawlessly (because routing will be active) Any hints on what to look for would be greatly appreciated!

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• Way to store a large dictionary with low memory footprint + fast lookups (on Android)

  - by BobbyJim

  I'm developing an android word game app that needs a large (~250,000 word dictionary) available. I need: reasonably fast look ups e.g. constant time preferable, need to do maybe 200 lookups a second on occasion to solve a word puzzle and maybe 20 lookups within 0.2 second more often to check words the user just spelled. EDIT: Lookups are typically asking "Is in the dictionary?". I'd like to support up to two wildcards in the word as well, but this is easy enough by just generating all possible letters the wildcards could have been and checking the generated words (i.e. 26 * 26 lookups for a word with two wildcards). as it's a mobile app, using as little memory as possible and requiring only a small initial download for the dictionary data is top priority. My first naive attempts used Java's HashMap class, which caused an out of memory exception. I've looked into using the SQL lite databases available on android, but this seems like overkill. What's a good way to do what I need?

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• How to Update with LINQ?

  - by DaveDev

  currently, I'm doing an update similar to as follows, because I can't see a better way of doing it. I've tried suggestions that I've read in blogs but none work, such as http://msdn.microsoft.com/en-us/library/bb425822.aspx and http://weblogs.asp.net/scottgu/archive/2007/05/19/using-linq-to-sql-part-1.aspx Maybe these do work and I'm missing some point. Has anyone else had luck with them? // please note this isn't the actual code. // I've modified it to clarify the point I wanted to make // and also I didn't want to post our code here! public bool UpdateMyStuff(int myId, List<int> funds) { // get MyTypes that correspond to the ID I want to update IQueryable<MyType> myTypes = database.MyTypes.Where(xx => xx.MyType_MyId == myId); // delete them from the database foreach (db.MyType mt in myTypes) { database.MyTypes.DeleteOnSubmit(mt); } database.SubmitChanges(); // create a new row for each item I wanted to update, and insert it foreach (int fund in funds) { database.MyType mt = new database.MyType { MyType_MyId = myId, fund_id = fund }; database.MyTypes.InsertOnSubmit(mt); } // try to commit the insert try { database.SubmitChanges(); return true; } catch (Exception) { return false; throw; } } Unfortunately, there isn't a database.MyTypes.Update() method so I don't know a better way to do it. Can sombody suggest what I could do? Thanks. ..as a side note, why isn't there an Update() method?

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• PDO using singleton stored as class properity

  - by Misiur

  Hi again. OOP drives me crazy. I can't move PDO to work. Here's my DB class: class DB extends PDO { public function &instance($dsn, $username = null, $password = null, $driver_options = array()) { static $instance = null; if($instance === null) { try { $instance = new self($dsn, $username, $password, $driver_options); } catch(PDOException $e) { throw new DBException($e->getMessage()); } } return $instance; } } It's okay when i do something like this: try { $db = new DB(DB_TYPE.':host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } catch(DBException $e) { echo $e->getMessage(); } But this: try { $db = DB::instance(DB_TYPE.':host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } catch(DBException $e) { echo $e->getMessage(); } Does nothing. I mean, even when I use wrong password/username, I don't get any exception. Second thing - I have class which is "heart" of my site: class Core { static private $instance; public $db; public function __construct() { if(!self::$instance) { $this->db = DB::instance(DB_TYPE.':hpost='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } return self::$instance; } private function __clone() { } } I've tried to use "new DB" inside class, but this: $r = $core->db->query("SELECT * FROM me_config"); print_r($r->fetch()); Return nothing. $sql = "SELECT * FROM me_config"; print_r($core->db->query($sql)); I get: PDOStatement Object ( [queryString] => SELECT * FROM me_config ) I'm really confused, what am I doing wrong?

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• Download dynamic file with GWT

  - by Maksim

  I have a GWT page where user enter data (start date, end date, etc.), then this data goes to the server via RPC call. On the server I want to generate Excel report with POI and let user save that file on their local machine. This is my test code to stream file back to the client but for some reason I think it does not know how to stream file to the client when I'm using RPC: public class ReportsServiceImpl extends RemoteServiceServlet implements ReportsService { public String myMethod(String s) { File f = new File("/excelTestFile.xls"); String filename = f.getName(); int length = 0; try { HttpServletResponse resp = getThreadLocalResponse(); ServletOutputStream op = resp.getOutputStream(); ServletContext context = getServletConfig().getServletContext(); resp.setContentType("application/octet-stream"); resp.setContentLength((int) f.length()); resp.setHeader("Content-Disposition", "attachment; filename*=\"utf-8''" + filename + ""); byte[] bbuf = new byte[1024]; DataInputStream in = new DataInputStream(new FileInputStream(f)); while ((in != null) && ((length = in.read(bbuf)) != -1)) { op.write(bbuf, 0, length); } in.close(); op.flush(); op.close(); } catch (Exception ex) { ex.printStackTrace(); } return "Server says: " + filename; } } I've red somewhere on internet that you can't do file stream with RPC and I have to use Servlet for that. Is there any example of how to use Servlet and how to call that servlet from ReportsServiceImpl. Do I really need to make a servlet or it is possible to stream it back with my RPC?

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• [hibernate - jpa] @OneToOne annotoation problem (i think...)

  - by blow

  Hi all, im new in hibernate and JPA and i have some problems with annotations. My target is to create this table in db (PERSON_TABLE with personal-details) ID ADDRESS NAME SURNAME MUNICIPALITY_ID First of all, i have a MUNICIPALITY table in db containing all municipality of my country. I mapped this table in this ENTITY: @Entity public class Municipality implements Serializable { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private Long id; private String country; private String province; private String name; @Column(name="cod_catasto") private String codCatastale; private String cap; public Municipality() { } ... Then i make an EMBEDDABLE class Address containing fields that realize a simple address... @Embeddable public class Address implements Serializable { @OneToOne(cascade=CascadeType.ALL) @JoinColumn(name="id_municipality") private Municipality municipality; @Column(length=45) private String address; public Address() { } ... Finally i embedded this class into Person ENTITY @Entity public class Person implements Serializable { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private Long id; private String name; private String surname; @Embedded private Address address; public Person() { } ... All works good when i have to save a new Person record, in fact hibernate creates a PERSON_TABLE as i want, but if i try to retrieve a Person record i have an exception. HQL is simply "from Person" The excpetion is (Entities is the package containing all classes above-mentioned): org.hibernate.AnnotationException: @OneToOne or @ManyToOne on Entities.Person.address.municipality references an unknown entity: Entities.Municipality Is the @OneToOne annotation the problem? Thanks.

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• Outlook Interop: Password protected PST file headache

  - by Ed Manet

  Okay, I have no problem identifying the .PST file using the Outlook Interop assemblies in a C# app. But as soon as I hit a password protected file, I am prompted for a password. We are in the process of disabling the use of PSTs in our organization and one of the steps is to unload the PST files from the users' Outlook profile. I need to have this app run silently and not prompt the user. Any ideas? Is there a way to create the Outlook.Application object with no UI and then just try to catch an Exception on password protected files? // create the app and namespace Application olApp = new Application(); NameSpace olMAPI = olApp.GetNamespace("MAPI"); // get the storeID of the default inbox string rootStoreID = olMAPI.GetDefaultFolder(OlDefaultFolders.olFolderInbox).StoreID; // loop thru each of the folders foreach (MAPIFolder fo in olMAPI.Folders) { // compare the first 75 chars of the storeid // to prevent removing the Inbox folder. string s1 = rootStoreID.Substring(1, 75); string s2 = fo.StoreID.Substring(1, 75); if (s1 != s2) { // unload the folder olMAPI.RemoveStore(fo); } } olApp.Quit();

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• AssemblyResolve event is not firing during compilation of a dynamic assembly for an aspx page.

  - by John

  This one is really pissing me off. Here goes: My goal is to load assemblies at run-time that contain embedded aspx,ascx etc. What I would also like is to not lock the assembly file on disk so I can update it at run-time without having to restart the application (I know this will leave the previous version(s) loaded). To that end I have written a virtual path provider that does the trick. I have subscribed to the CurrentDomain.AssemblyResolve event so as to redirect the framework to my assemblies. The problem is that the when the framework tries to compile the dynamic assembly for the aspx page I get the following: Compiler Error Message: CS0400: The type or namespace name 'Pages' could not be found in the global namespace (are you missing an assembly reference?) Source Error: public class app_resource_pages__version_1_0_0_0__culture_neutral__publickeytoken_null_default_aspx : global::Pages._Default, System.Web.SessionState.IRequiresSessionState, System.Web.IHttpHandle I noticed that if I load the assembly with Assembly.Load(AssemblyName) or Assembly.LoadFrom(filename) I dont get the above error. If I load it with Assembly.Load(byte[]) (so as to not lock it), the exception is thrown but my AssemblyResolve handler, when called is returning the assembly correctly (it is called once). So I am guessing that it is called once when the framework parses the asp markup but not when it tries to create the dynamic assembly for the aspx page.

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• Permission denied to access property 'toString'

  - by Anders

  I'm trying to find a generic way of getting the name of Constructors. My goal is to create a Convention over configuration framework for KnockoutJS My idea is to iterate over all objects in the window and when I find the contructor i'm looking for then I can use the index to get the name of the contructor The code sofar (function() { constructors = {}; window.findConstructorName = function(instance) { var constructor = instance.constructor; var name = constructors[constructor]; if(name !== undefined) { return name; } var traversed = []; var nestedFind = function(root) { if(typeof root == "function" || traversed[root]) { return } traversed[root] = true; for(var index in root) { if(root[index] == constructor) { return index; } var found = nestedFind(root[index]); if(found !== undefined) { return found; } } } name = nestedFind(window); constructors[constructor] = name; return name; } })(); var MyApp = {}; MyApp.Foo = function() { }; var instance = new MyApp.Foo(); console.log(findConstructorName(instance)); The problem is that I get a Permission denied to access property 'toString' Exception, and i cant even try catch so see which object is causing the problem Fiddle http://jsfiddle.net/4ZwaV/

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• Windows loader problem - turn on verbose mode

  - by doobop

  Hi, I'm in the process of reorganizing some of the legacy libraries in our application which has unmanaged code calling into libraries of managed code. While I have the code reorganized, it produces the following loader error: ... 'app.exe': Loaded 'C:\WINDOWS\system32\CsDisp.dll' 'app.exe': Loaded 'C:\WINDOWS\system32\psapi.dll' 'app.exe': Loaded 'C:\WINDOWS\system32\shell32.dll' 'app.exe': Loaded 'C:\appCode\Debug\daq206_32.dll', Binary was not built with debug information. 'app.exe': Loaded 'C:\appCode\Debug\SiUSBXp.dll', Binary was not built with debug information. 'app.exe': Loaded 'C:\appCode\Debug\AdlinkDAQ.dll', Symbols loaded. 'app.exe': Loaded 'C:\WINDOWS\system32\P9842.dll', Binary was not built with debug information. LDR: LdrRelocateImageWithBias() failed 0xc0000018 LDR: OldBase : 10000000 LDR: NewBase : 00A80000 LDR: Diff : 0x7c90d6fa0012f6cc LDR: NextOffset : 00000000 LDR: *NextOffset : 0x0 LDR: SizeOfBlock : 0xa80000 Debugger:: An unhandled non-continuable exception was thrown during process load I believe 0xc0000018 error is an overlapping address range. So, I have two questions. First, what linker options may cause this error? I'm currently linking with /DYNAMICBASE:NO and /FIXED:No as this was how some of the previous libraries were set up. Second, is there a way to turn on verbose mode for the loader so I can see what exactly it's trying to load? P9842 is a third party library so I imagine it is getting to one of my libraries after P9842 and failing on that one. Can I narrow it down? Thanks.

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• What is wrong with locking non-static fields? What is the correct way to lock a particular instance?

  - by smartcaveman

  Why is it considered bad practice to lock non-static fields? And, if I am not locking non-static fields, then how do I lock an instance method without locking the method on all other instances of the same or derived class? I wrote an example to make my question more clear. public abstract class BaseClass { private readonly object NonStaticLockObject = new object(); private static readonly object StaticLockObject = new object(); protected void DoThreadSafeAction<T>(Action<T> action) where T: BaseClass { var derived = this as T; if(derived == null) { throw new Exception(); } lock(NonStaticLockObject) { action(derived); } } } public class DerivedClass :BaseClass { private readonly Queue<object> _queue; public void Enqueue(object obj) { DoThreadSafeAction<DerivedClass>(x=>x._queue.Enqueue(obj)); } } If I make the lock on the StaticLockObject, then the DoThreadSafeAction method will be locked for all instances of all classes that derive from BaseClass and that is not what I want. I want to make sure that no other threads can call a method on a particular instance of an object while it is locked.

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• Getting a Specified Cast is not valid while importing data from Excel using Linq to SQL

  - by niceoneishere

  This is my second post. After learning from my first post how fantastic is to use Linq to SQL, I wanted to try to import data from a Excel sheet into my SQL database. First My Excel Sheet: it contains 4 columns namely ItemNo ItemSize ItemPrice UnitsSold I have a created a database table with the following fields table name ProductsSold Id int not null identity --with auto increment set to true ItemNo VarChar(10) not null ItemSize VarChar(4) not null ItemPrice Decimal(18,2) not null UnitsSold int not null Now I created a dal.dbml file based on my database and I am trying to import the data from excel sheet to db table using the code below. Everything is happening on click of a button. private const string forecast_query = "SELECT ItemNo, ItemSize, ItemPrice, UnitsSold FROM [Sheet1$]"; protected void btnUpload_Click(object sender, EventArgs e) { var importer = new LinqSqlModelImporter(); if (fileUpload.HasFile) { var uploadFile = new UploadFile(fileUpload.FileName); try { fileUpload.SaveAs(uploadFile.SavePath); if(File.Exists(uploadFile.SavePath)) { importer.SourceConnectionString = uploadFile.GetOleDbConnectionString(); importer.Import(forecast_query); gvDisplay.DataBind(); pnDisplay.Visible = true; } } catch (Exception ex) { Response.Write(ex.Source.ToString()); lblInfo.Text = ex.Message; } finally { uploadFile.DeleteFileNoException(); } } } // Now here is the code for LinqSqlModelImporter public class LinqSqlModelImporter : SqlImporter { public override void Import(string query) { // importing data using oledb command and inserting into db using LINQ to SQL using (var context = new WSDALDataContext()) { using (var myConnection = new OleDbConnection(base.SourceConnectionString)) using (var myCommand = new OleDbCommand(query, myConnection)) { myConnection.Open(); var myReader = myCommand.ExecuteReader(); while (myReader.Read()) { context.ProductsSolds.InsertOnSubmit(new ProductsSold() { ItemNo = myReader.GetString(0), ItemSize = myReader.GetString(1), ItemPrice = myReader.GetDecimal(2), UnitsSold = myReader.GetInt32(3) }); } } context.SubmitChanges(); } } } can someone please tell me where am I making the error or if I am missing something, but this is driving me nuts. When I debugged I am getting this error when casting from a number the value must be a number less than infinity I really appreciate it

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• wpf observableCollection

  - by Asha

  I have an ObservableCollection which is dataContext for my treeview when I try to remove an Item from ObservableCollection I will get an error that Object reference not set to an instance of an object . can you please tell me why this error is happening and what is the solution thanks EDIT 1: The code is something like : class MyClass : INotifyPropertyChanged { //my class code here } public partial class UC_myUserControl : UserControl { private ObservableCollection<MyClass> myCollection = new ObservableCollection<MyClass>(); private void UserControl_Loaded(object sender, RoutedEventArgs e) { myCollection.add(new myClass); myTreeView.DataContext = myCollection ; } private void deleteItem() { myCollection.RemoveAt(0); //after removing I get error Which I guess should be something related //to interface update but I don't know how can I solve it } } Exception Detail : System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object." Source="PresentationFramework" EDIT 3: I have a style which is for my treeitem to keep the treeitems expanded <Style TargetType="TreeViewItem"> <Setter Property="IsExpanded" Value="True" /> </Style> and with commenting this part I wont get any error !!! Now I want to change my question to why having this style is causing error ?

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• HTC Incredible displaying blank ImageView

  - by Todd

  HI, I have an app that displays an an image in an ImageView using the setImageDrawable(Drawable) method. However, with the release of the Droid Incredible the images are coming up as a blank screen. I am using Drawable.createFromPath(Environment.getExternalStorageDirectory() + "\imagefile") to access the image from the SD card. I don't get any sort of error, just a black screen. I will get a null pointer exception if after trying to load the image I try to access a property of the Drawable. This makes me believe that the Drawable wasn't loaded, but I don't know why or how to make it work. This code as been working on all other Android devices, so I'm not sure what is different with the Incredible. Unfortunately I don't have access to an Incredible to test on, so I've got to rely on others to test and send me the log files. Any help you can offer would be greatly appreciated. If anyone knows how to replicate this issue on the emulator, that would be helpful too. I've configured an emulator with firmware 7 and the correct screen resolution, but I was unable to replicate the issue. Thanks.

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• Create new or update existing entity at one go with JPA

  - by Alex R

  A have a JPA entity that has timestamp field and is distinguished by a complex identifier field. What I need is to update timestamp in an entity that has already been stored, otherwise create and store new entity with the current timestamp. As it turns out the task is not as simple as it seems from the first sight. The problem is that in concurrent environment I get nasty "Unique index or primary key violation" exception. Here's my code: // Load existing entity, if any. Entity e = entityManager.find(Entity.class, id); if (e == null) { // Could not find entity with the specified id in the database, so create new one. e = entityManager.merge(new Entity(id)); } // Set current time... e.setTimestamp(new Date()); // ...and finally save entity. entityManager.flush(); Please note that in this example entity identifier is not generated on insert, it is known in advance. When two or more of threads run this block of code in parallel, they may simultaneously get null from entityManager.find(Entity.class, id) method call, so they will attempt to save two or more entities at the same time, with the same identifier resulting in error. I think that there are few solutions to the problem. Sure I could synchronize this code block with a global lock to prevent concurrent access to the database, but would it be the most efficient way? Some databases support very handy MERGE statement that updates existing or creates new row if none exists. But I doubt that OpenJPA (JPA implementation of my choice) supports it. Event if JPA does not support SQL MERGE, I can always fall back to plain old JDBC and do whatever I want with the database. But I don't want to leave comfortable API and mess with hairy JDBC+SQL combination. There is a magic trick to fix it using standard JPA API only, but I don't know it yet. Please help.

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• tracd server problems

  - by deddihp

  Hello, I got the following error while accessing tracd server, what's going on ? Thanks. [oke@localhost Trac-0.11.7]$ sudo tracd -p 8000 /home/deddihp/trac/ Server starting in PID 5082. Serving on 0.0.0.0:8000 view at http://127.0.0.1:8000/ ---------------------------------------- Exception happened during processing of request from ('127.0.0.1', 47804) Traceback (most recent call last): File "/usr/lib/python2.6/SocketServer.py", line 558, in process_request_thread self.finish_request(request, client_address) File "/usr/lib/python2.6/SocketServer.py", line 320, in finish_request self.RequestHandlerClass(request, client_address, self) File "/usr/lib/python2.6/SocketServer.py", line 615, in __init__ self.handle() File "/usr/lib/python2.6/BaseHTTPServer.py", line 329, in handle self.handle_one_request() File "/usr/lib/python2.6/site-packages/Trac-0.11.7-py2.6.egg/trac/web/wsgi.py", line 194, in handle_one_request gateway.run(self.server.application) File "/usr/lib/python2.6/site-packages/Trac-0.11.7-py2.6.egg/trac/web/wsgi.py", line 94, in run response = application(self.environ, self._start_response) File "/usr/lib/python2.6/site-packages/Trac-0.11.7-py2.6.egg/trac/web/standalone.py", line 100, in __call__ return self.application(environ, start_response) File "/usr/lib/python2.6/site-packages/Trac-0.11.7-py2.6.egg/trac/web/main.py", line 346, in dispatch_request locale.setlocale(locale.LC_ALL, environ['trac.locale']) File "/usr/lib/python2.6/locale.py", line 513, in setlocale return _setlocale(category, locale) Error: unsupported locale setting ----------------------------------------

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• javamail api isertion of main class help

  - by bobby

  import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import javax.mail.*; import javax.mail.internet.*; import javax.mail.event.*; import javax.mail.Authenticator; 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.googlemail.com"); props.put("mail.smtp.port", "995"); props.put("mail.smtp.auth", "true"); javax.mail.Authenticator authenticator = new javax.mail.Authenticator() { protected javax.mail.PasswordAuthentication getPasswordAuthentication() { return new javax.mail.PasswordAuthentication("[email protected]", "password"); } }; Session sess=Session.getDefaultInstance(props,authenticator); sess.setDebug (true); Transport transport =sess.getTransport ("smtp"); 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.connect(); transport.send(msg); out.println("mail has been sent"); } catch(Exception e) { System.out.println("err"+e); } } } how to insert main class in above java code and how to pass arguments of "from" and "to"

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• Java ternary operator and boxing Integer/int?

  - by Markus

  I tripped across a really strange NullPointerException the other day caused by an unexpected type-cast in the ternary operator. Given this (useless exemplary) function: Integer getNumber() { return null; } I was expecting the following two code segments to be exactly identical after compilation: Integer number; if (condition) { number = getNumber(); } else { number = 0; } vs. Integer number = (condition) ? getNumber() : 0; . Turns out, if condition is true, the if-statement works fine, while the ternary opration in the second code segment throws a NullPointerException. It seems as though the ternary operation has decided to type-cast both choices to int before auto-boxing the result back into an Integer!?! In fact, if I explicitly cast the 0 to Integer, the exception goes away. In other words: Integer number = (condition) ? getNumber() : 0; is not the same as: Integer number = (condition) ? getNumber() : (Integer) 0; . So, it seems that there is a byte-code difference between the ternary operator and an equivalent if-else-statement (something I didn't expect). Which raises three questions: Why is there a difference? Is this a bug in the ternary implementation or is there a reason for the type cast? Given there is a difference, is the ternary operation more or less performant than an equivalent if-statement (I know, the difference can't be huge, but still)?

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• When does the call() method get called in a Java Executor using Callable objects?

  - by MalcomTucker

  This is some sample code from an example. What I need to know is when call() gets called on the callable? What triggers it? public class CallableExample { public static class WordLengthCallable implements Callable { private String word; public WordLengthCallable(String word) { this.word = word; } public Integer call() { return Integer.valueOf(word.length()); } } public static void main(String args[]) throws Exception { ExecutorService pool = Executors.newFixedThreadPool(3); Set<Future<Integer>> set = new HashSet<Future<Integer>>(); for (String word: args) { Callable<Integer> callable = new WordLengthCallable(word); Future<Integer> future = pool.submit(callable); //**DOES THIS CALL call()?** set.add(future); } int sum = 0; for (Future<Integer> future : set) { sum += future.get();//**OR DOES THIS CALL call()?** } System.out.printf("The sum of lengths is %s%n", sum); System.exit(sum); } }

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• PHP rewrite to included file - is this a valid script?

  - by Poni

  Hi all! I've made this question: http://stackoverflow.com/questions/2921469/php-mutual-exclusion-mutex As said there, I want several sources to send their stats once in a while, and these stats will be showed at the website's main page. My problem is that I want this to be done in an atomic manner, so no update of the stats will overlap another one running in the background. Now, I came up with this solution and I want you PHP experts to judge it. stats.php <?php define("my_counter", 12); ?> index.php <?php include "stats.php"; echo constant("my_counter"); ?> update.php <?php $old_error_reporting = error_reporting(0); include "stats.php"; define("my_stats_template",' <?php define("my_counter", %d); ?> '); $fd = fopen("stats.php", "w+"); if($fd) { if (flock($fd, LOCK_EX)) { $my_counter = 0; try { $my_counter = constant("my_counter"); } catch(Exception $e) { } $my_counter++; $new_stats = sprintf(constant("my_stats_template"), $my_counter); echo "Counter should stand at $my_counter"; fwrite($fd, $new_stats); } flock($fd, LOCK_UN); fclose($fd); } error_reporting($old_error_reporting); ?> Several clients will call the "update.php" file once every 60sec each. The "index.php" is going to use the "stats.php" file all the time as you can see. What's your opinion?

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