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  • How does throwing an ArgumentNullException help?

    - by Scott Whitlock
    Let's say I have a method: public void DoSomething(ISomeInterface someObject) { if(someObject == null) throw new ArgumentNullException("someObject"); someObject.DoThisOrThat(); } I've been trained to believe that throwing the ArgumentNullException is "correct" but an "Object reference not set to an instance of an object" error means I have a bug. Why? I know that if I was caching the reference to someObject and using it later, then it's better to check for nullity when passed in, and fail early. However, if I'm dereferencing it on the next line, why are we supposed to do the check? It's going to throw an exception one way or the other. Edit: It just occurred to me... does the fear of the dereferenced null come from a language like C++ that doesn't check for you (i.e. it just tries to execute some method at memory location zero + method offset)?

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  • Connecting Android device to multiple Bluetooth serial embedded peers

    - by TacB0sS
    I'm trying to find a solution for this setup: I have a single Android device, which I would like to connect to multiple serial embedded devices... And here is the thing, using the "Normal" way to retrieve the Bluetooth socket, doesn't work on all devices, and while it does, I can connect to multiple devices, and send and receive data to and from multiple devices. public final synchronized void connect() throws ConnectionException { if (socket != null) throw new IllegalStateException("Error socket is not null!!"); connecting = true; lastException = null; lastPacket = null; lastHeartBeatReceivedAt = 0; log.setLength(0); try { socket = fetchBT_Socket_Normal(); connectToSocket(socket); listenForIncomingSPP_Packets(); connecting = false; return; } catch (Exception e) { socket = null; logError(e); } try { socket = fetchBT_Socket_Workaround(); connectToSocket(socket); listenForIncomingSPP_Packets(); connecting = false; return; } catch (Exception e) { socket = null; logError(e); } connecting = false; if (socket == null) throw new ConnectionException("Error creating RFcomm socket for" + this); } private BluetoothSocket fetchBT_Socket_Normal() throws Exception { /* The getType() is a hex 0xXXXX value agreed between peers --- this is the key (in my case) to multiple connections in the "Normal" way */ String uuid = getType() + "1101-0000-1000-8000-00805F9B34FB"; try { logDebug("Fetching BT RFcomm Socket standard for UUID: " + uuid + "..."); socket = btDevice.createRfcommSocketToServiceRecord(UUID.fromString(uuid)); return socket; } catch (Exception e) { logError(e); throw e; } } private BluetoothSocket fetchBT_Socket_Workaround() throws Exception { Method m; int connectionIndex = 1; try { logDebug("Fetching BT RFcomm Socket workaround index " + connectionIndex + "..."); m = btDevice.getClass().getMethod("createRfcommSocket", new Class[]{int.class}); socket = (BluetoothSocket) m.invoke(btDevice, connectionIndex); return socket; } catch (Exception e1) { logError(e1); throw e1; } } private void connectToSocket(BluetoothSocket socket) throws ConnectionException { try { socket.connect(); } catch (IOException e) { try { socket.close(); } catch (IOException e1) { logError("Error while closing socket", e1); } finally { socket = null; } throw new ConnectionException("Error connecting to socket with" + this, e); } } And here is the thing, while on phones which the "Normal" way doesn't work, the "Workaround" way provides a solution for a single connection. I've searched far and wide, but came up with zip. The problem with the workaround is mentioned in the last link, both connection uses the same port, which in my case, causes a block, where both of the embedded devices can actually send data, that is not been processed on the Android, while both embedded devices can receive data sent from the Android. Did anyone handle this before? There is a bit more reference here, UPDATE: Following this (that I posted earlier) I wanted to give the mPort a chance, and perhaps to see other port indices, and how other devices manage them, and I found out the the fields in the BluetoothSocket object are different while it is the same class FQN in both cases: Detils from an HTC Vivid 2.3.4, uses the "workaround" Technic: The Socket class type is: [android.bluetooth.BluetoothSocket] mSocket BluetoothSocket (id=830008629928) EADDRINUSE 98 EBADFD 77 MAX_RFCOMM_CHANNEL 30 TAG "BluetoothSocket" (id=830002722432) TYPE_L2CAP 3 TYPE_RFCOMM 1 TYPE_SCO 2 mAddress "64:9C:8E:DC:56:9A" (id=830008516328) mAuth true mClosed false mClosing AtomicBoolean (id=830007851600) mDevice BluetoothDevice (id=830007854256) mEncrypt true mInputStream BluetoothInputStream (id=830008688856) mLock ReentrantReadWriteLock (id=830008629992) mOutputStream BluetoothOutputStream (id=830008430536) **mPort 1** mSdp null mSocketData 3923880 mType 1 Detils from an LG-P925 2.2.2, uses the "normal" Technic: The Socket class type is: [android.bluetooth.BluetoothSocket] mSocket BluetoothSocket (id=830105532880) EADDRINUSE 98 EBADFD 77 MAX_RFCOMM_CHANNEL 30 TAG "BluetoothSocket" (id=830002668088) TYPE_L2CAP 3 TYPE_RFCOMM 1 TYPE_SCO 2 mAccepted false mAddress "64:9C:8E:B9:3F:77" (id=830105544600) mAuth true mClosed false mConnected ConditionVariable (id=830105533144) mDevice BluetoothDevice (id=830105349488) mEncrypt true mInputStream BluetoothInputStream (id=830105532952) mLock ReentrantReadWriteLock (id=830105532984) mOutputStream BluetoothOutputStream (id=830105532968) mPortName "" (id=830002606256) mSocketData 0 mSppPort BluetoothSppPort (id=830105533160) mType 1 mUuid ParcelUuid (id=830105714176) Anyone have some insight...

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  • C# Open Source software that is useful for learning Design Patterns

    - by Fathom Savvy
    In college I took a class in Expert Systems. The language the book taught (CLIPS) was esoteric - Expert Systems: Principles and Programming, Fourth Edition. I remember having a tough time with it. So, after almost failing the class, I needed to create the most awesome Expert System for my final presentation. I chose to create an expert system that would calculate risk analysis for a person's retirement portfolio. In short, the system would provide the services normally performed by one's financial adviser. In other words, based on personality, age, state of the macro economy, and other factors, should one's portfolio be conservative, moderate, or aggressive? In the appendix of the book (or on the CD-ROM), there was this in-depth example program for something unrelated to my presentation. Over my break, I read and re-read every line of that program until I understood it to the letter. Even though it was unrelated, I learned more than I ever could by reading all of the chapters. My presentation turned out to be pretty damn good and I received praises from my professor and classmates. So, the moral of the story is..., by understanding other people's code, you can gain greater insight into a language/paradigm than by reading canonical examples. Still, to this day, I am having trouble with everyday design patterns such as the Factory Pattern. I would like to know if anyone could recommend open source software that would help me understand the Gang of Four design patterns, at the very least. I have read the books, but I'm having trouble writing code for the concepts in the real world. Perhaps, by studying code used in today's real world applications, it might just "click". I realize a piece of software may only implement one kind of design pattern. But, if the pattern is an implementation you think is good for learning, and you know what pattern to look for within the source, I'm hoping you can tell me about it. For example, the System.Linq.Expressions namespace has a good example of the Visitor Pattern. The client calls Expression.Accept(new ExpressionVisitor()), which calls ExpressionVisitor (VisitExtension), which calls back to Expression (VisitChildren), which then calls Expression (Accept) again - wooah, kinda convoluted. The point to note here is that VisitChildren is a virtual method. Both Expression and those classes derived from Expression can implement the VisitChildren method any way they want. This means that one type of Expression can run code that is completely different from another type of derived Expression, even though the ExpressionVisitor class is the same in the Accept method. (As a side note Expression.Accept is also virtual). In the end, the code provides a real world example that you won't get in any book because it's kinda confusing. To summarize, If you know of any open source software that uses a design pattern implementation you were impressed by, please list it here. I'm sure it will help many others besides just me. public class VisitorPatternTest { public void Main() { Expression normalExpr = new Expression(); normalExpr.Accept(new ExpressionVisitor()); Expression binExpr = new BinaryExpression(); binExpr.Accept(new ExpressionVisitor()); } } public class Expression { protected internal virtual Expression Accept(ExpressionVisitor visitor) { return visitor.VisitExtension(this); } protected internal virtual Expression VisitChildren(ExpressionVisitor visitor) { if (!this.CanReduce) { throw Error.MustBeReducible(); } return visitor.Visit(this.ReduceAndCheck()); } public virtual Expression Visit(Expression node) { if (node != null) { return node.Accept(this); } return null; } public Expression ReduceAndCheck() { if (!this.CanReduce) { throw Error.MustBeReducible(); } Expression expression = this.Reduce(); if ((expression == null) || (expression == this)) { throw Error.MustReduceToDifferent(); } if (!TypeUtils.AreReferenceAssignable(this.Type, expression.Type)) { throw Error.ReducedNotCompatible(); } return expression; } } public class BinaryExpression : Expression { protected internal override Expression Accept(ExpressionVisitor visitor) { return visitor.VisitBinary(this); } protected internal override Expression VisitChildren(ExpressionVisitor visitor) { return CreateDummyExpression(); } protected internal Expression CreateDummyExpression() { Expression dummy = new Expression(); return dummy; } } public class ExpressionVisitor { public virtual Expression Visit(Expression node) { if (node != null) { return node.Accept(this); } return null; } protected internal virtual Expression VisitExtension(Expression node) { return node.VisitChildren(this); } protected internal virtual Expression VisitBinary(BinaryExpression node) { return ValidateBinary(node, node.Update(this.Visit(node.Left), this.VisitAndConvert<LambdaExpression>(node.Conversion, "VisitBinary"), this.Visit(node.Right))); } }

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  • Tester/Doer pattern: Assume the caller conforms to the pattern or be defensive and repeat the check?

    - by Daniel Hilgarth
    Assume a simple class that implements the Tester/Doer pattern: public class FooCommandHandler : ICommandHandler { public bool CanHandle(object command) { return command is FooCommand; } public void Handle(object command) { var fooCommand = (FooCommand)command; // Do something with fooCommand } } Now, if someone doesn't conform to the pattern and calls Handle without verifying the command via CanHandle, the code in Handle throws an exception. However, depending on the actual implementation of Handle this can be a whole range of different exceptions. The following implementation would check CanHandle again in Handle and throw a descriptive exception: public void Handle(object command) { if(!CanHandle(command)) throw new TesterDoerPatternUsageViolationException("Please call CanHandle first"); // actual implementation of handling the command. } This has the advantage that the exception is very descriptive. It has the disadvantage that CanHandle is called twice for "good" clients. Is there a consensus on which variation should be used?

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  • Feed Reader Fix

    - by Geertjan
    In the FeedReader sample (available in the New Projects window), there's this piece of code: private static Feed getFeed(Node node) { InstanceCookie ck = node.getLookup().lookup(InstanceCookie.class); if (ck == null) { throw new IllegalStateException("Bogus file in feeds folder: " + node.getLookup().lookup(FileObject.class)); } try { return (Feed) ck.instanceCreate(); } catch (ClassNotFoundException ex) { Exceptions.printStackTrace(ex); } catch (IOException ex) { Exceptions.printStackTrace(ex); } return null; } Since 7.1, for some reason, the above doesn't work. What does work, and is simpler, is this, instead of the above: private static Feed getFeed(Node node) { Feed f = FileUtil.getConfigObject("RssFeeds/sample.instance", Feed.class); if (f == null) { throw new IllegalStateException("Bogus file in feeds folder: " + node.getLookup().lookup(FileObject.class)); } return f; } So, the code needs to be fixed in the sample.

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  • What are the best practices to use NHiberante sessions in asp.net (mvc/web api) ?

    - by mrt181
    I have the following setup in my project: public class WebApiApplication : System.Web.HttpApplication { public static ISessionFactory SessionFactory { get; private set; } public WebApiApplication() { this.BeginRequest += delegate { var session = SessionFactory.OpenSession(); CurrentSessionContext.Bind(session); }; this.EndRequest += delegate { var session = SessionFactory.GetCurrentSession(); if (session == null) { return; } session = CurrentSessionContext.Unbind(SessionFactory); session.Dispose(); }; } protected void Application_Start() { AreaRegistration.RegisterAllAreas(); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); BundleConfig.RegisterBundles(BundleTable.Bundles); var assembly = Assembly.GetCallingAssembly(); SessionFactory = new NHibernateHelper(assembly, Server.MapPath("/")).SessionFactory; } } public class PositionsController : ApiController { private readonly ISession session; public PositionsController() { this.session = WebApiApplication.SessionFactory.GetCurrentSession(); } public IEnumerable<Position> Get() { var result = this.session.Query<Position>().Cacheable().ToList(); if (!result.Any()) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.NotFound)); } return result; } public HttpResponseMessage Post(PositionDataTransfer dto) { //TODO: Map dto to model IEnumerable<Position> positions = null; using (var transaction = this.session.BeginTransaction()) { this.session.SaveOrUpdate(positions); try { transaction.Commit(); } catch (StaleObjectStateException) { if (transaction != null && transaction.IsActive) { transaction.Rollback(); } } } var response = this.Request.CreateResponse(HttpStatusCode.Created, dto); response.Headers.Location = new Uri(this.Request.RequestUri.AbsoluteUri + "/" + dto.Name); return response; } public void Put(int id, string value) { //TODO: Implement PUT throw new NotImplementedException(); } public void Delete(int id) { //TODO: Implement DELETE throw new NotImplementedException(); } } I am not sure if this is the recommended way to insert the session into the controller. I was thinking about using DI but i am not sure how to inject the session that is opened and binded in the BeginRequest delegate into the Controllers constructor to get this public PositionsController(ISession session) { this.session = session; } Question: What is the recommended way to use NHiberante sessions in asp.net mvc/web api ?

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  • The instruction at “0x7c910a19” referenced memory at “oxffffffff”. The memory could not be “read”

    - by ClareBear
    Hello guys/girls I have a small issue, I receive the following error before the .vbs terminates. I don't know why this error is thrown. Below is the process of the .vbs file: Call ImportTransactions() Call UpdateTransactions() Function ImportTransactions() Dim objConnection, objCommand, objRecordset, strOracle Dim strSQL, objRecordsetInsert Set objConnection = CreateObject("ADODB.Connection") objConnection.Open "DSN=*****;UID=*****;PWD==*****;" Set objCommand = CreateObject("ADODB.Command") Set objRecordset = CreateObject("ADODB.Recordset") strOracle = "SELECT query here from Oracle database" objCommand.CommandText = strOracle objCommand.CommandType = 1 objCommand.CommandTimeout = 0 Set objCommand.ActiveConnection = objConnection objRecordset.cursorType = 0 objRecordset.cursorlocation = 3 objRecordset.Open objCommand, , 1, 3 If objRecordset.EOF = False Then Do Until objRecordset.EOF = True strSQL = "INSERT query here into SQL database" strSQL = Query(strSQL) Call RunSQL(strSQL, objRecordsetInsert, False, conTimeOut, conServer, conDatabase, conUsername, conPassword) objRecordset.MoveNext Loop End If objRecordset.Close() Set objRecordset = Nothing Set objRecordsetInsert = Nothing End Function Function UpdateTransactions() Dim strSQLUpdateVAT, strSQLUpdateCodes Dim objRecordsetVAT, objRecordsetUpdateCodes strSQLUpdateVAT = "UPDATE query here SET [value:costing output] = ([value:costing output] * -1)" Call RunSQL(strSQLUpdateVAT, objRecordsetVAT, False, conTimeOut, conServer, conDatabase, conUsername, conPassword) strSQLUpdateCodes = "UPDATE query here SET [value:costing output] = ([value:costing output] * -1) different WHERE clause" Call RunSQL(strSQLUpdateCodes, objRecordsetUpdateCodes, False, conTimeOut, conServer, conDatabase, conUsername, conPassword) Set objRecordsetVAT = Nothing Set objRecordsetUpdateCodes = Nothing End Function It does both the import and update and seems to throw this error after. If I comment out the ImportTransactions it doesnt throw a error, however I have produced similar code for another vbs file and this does not throw any errors Thanks in advance for any help, Clare

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  • Transactions in codeigniter with multiple tables.

    - by Ethan
    Hey SO, I'm new to transactions in general, but especially with CodeIgniter. I'm using InnoDB and everything, but my transactions aren't rolling back when I want them to. Here's my code (slightly simplified). $dog_db = $this->load->database('dog', true); $dog_db->trans_begin(); $dog_id = $this->dogs->insert($new_dog); //Gets primary key of insert if(!$dog_id) { $dog_db->trans_rollback(); throw new Exception('We have had an error trying to add this dog. Please go back and try again.'); } $new_review['dog_id'] = $dog_id; $new_review['user_id'] = $user_id; $new_review['date_added'] = time(); if(!$this->reviews->insert($new_review)) //If the insert fails { $dog_db->trans_rollback(); throw new Exception('We have had an error trying to add this dog. Please go back and try again.'); } //ADD DESCRIPTION $new_description['description'] = $add_dog['description']; $new_description['dog_id'] = $dog_id; $new_description['user_id'] = $user_id; $new_description['date_added'] = time(); if(!$this->descriptions->insert($new_description)) { $dog_db->trans_rollback(); throw new Exception('We have had an error trying to add this dog. Please go back and try again.'); } $booze_db->trans_rollback(); //THIS IS JUST TO SEE IF IT WORKS throw new Exception('We have had an error trying to add this dog. Please go back and try again.'); $booze_db->trans_commit(); } catch(Exception $e) { echo $e->getMessage(); } I'm not getting any error messages, but it's not rolling back either. It should roll back at that final trans_rollback right before the commit. My models are all on the "dog" database, so I think that the transaction would carry into the models' functions. Maybe you just can't use models like this. Any help would be greatly appreciated! Thanks!

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  • Throwing exception vs checking null, for a null argument

    - by dotnetdev
    What factors dictate throwing an exception if argument is null (eg if (a is null) throw new ArgumentNullException() ), as opposed to checking the argument if it is null beforehand. I don't see why the exception should be thrown rather than checking for null in the first place? What benefit is there in the throw exception approach? This is for C#/.NET Thanks

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  • Null check error message as "is null" or "was null"

    - by Timo Westkämper
    When doing null checks in Java code, and you throw IllegalArgumentExceptions for null values, what kind of message template do you use? We tend to use something like this public User getUser(String username){ if (username == null){ throw new IllegalArgumentException("username is null"); } // ... } What is better : "is null" or "was null", and why? For me "is null" feels more natural.

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  • How do I get SpecFlow to expect an exception?

    - by Roger Lipscombe
    I'm using SpecFlow, and I'd like to write a scenario such as the following: Scenario: Pressing add with an empty stack throws an exception Given I have entered nothing into the calculator When I press add Then it should throw an exception It's calculator.Add() that's going to throw an exception, so how do I handle this in the method marked [Then]?

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  • problem with two .NET threads and hardware access

    - by mack369
    I'm creating an application which communicates with the device via FT2232H USB/RS232 converter. For communication I'm using FTD2XX_NET.dll library from FTDI website. I'm using two threads: first thread continuously reads data from the device the second thread is the main thread of the Windows Form Application I've got a problem when I'm trying to write any data to the device while the receiver's thread is running. The main thread simply hangs up on ftdiDevice.Write function. I tried to synchronize both threads so that only one thread can use Read/Write function at the same time, but it didn't help. Below code responsible for the communication. Note that following functions are methods of FtdiPort class. Receiver's thread private void receiverLoop() { if (this.DataReceivedHandler == null) { throw new BackendException("dataReceived delegate is not set"); } FTDI.FT_STATUS ftStatus = FTDI.FT_STATUS.FT_OK; byte[] readBytes = new byte[this.ReadBufferSize]; while (true) { lock (FtdiPort.threadLocker) { UInt32 numBytesRead = 0; ftStatus = ftdiDevice.Read(readBytes, this.ReadBufferSize, ref numBytesRead); if (ftStatus == FTDI.FT_STATUS.FT_OK) { this.DataReceivedHandler(readBytes, numBytesRead); } else { Trace.WriteLine(String.Format("Couldn't read data from ftdi: status {0}", ftStatus)); Thread.Sleep(10); } } Thread.Sleep(this.RXThreadDelay); } } Write function called from main thread public void Write(byte[] data, int length) { if (this.IsOpened) { uint i = 0; lock (FtdiPort.threadLocker) { this.ftdiDevice.Write(data, length, ref i); } Thread.Sleep(1); if (i != (int)length) { throw new BackendException("Couldnt send all data"); } } else { throw new BackendException("Port is closed"); } } Object used to synchronize two threads static Object threadLocker = new Object(); Method that starts the receiver's thread private void startReceiver() { if (this.DataReceivedHandler == null) { return; } if (this.IsOpened == false) { throw new BackendException("Trying to start listening for raw data while disconnected"); } this.receiverThread = new Thread(this.receiverLoop); //this.receiverThread.Name = "protocolListener"; this.receiverThread.IsBackground = true; this.receiverThread.Start(); } The ftdiDevice.Write function doesn't hang up if I comment following line: ftStatus = ftdiDevice.Read(readBytes, this.ReadBufferSize, ref numBytesRead);

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  • Implementing INotifyPropertyChanged with PostSharp 1.5

    - by no9
    Hello all. Im new to .NET and WPF so i hope i will ask the question correctly. I am using INotifyPropertyChanged implemented using PostSharp 1.5: [Serializable, DebuggerNonUserCode, AttributeUsage(AttributeTargets.Assembly | AttributeTargets.Class, AllowMultiple = false, Inherited = false), MulticastAttributeUsage(MulticastTargets.Class, AllowMultiple = false, Inheritance = MulticastInheritance.None, AllowExternalAssemblies = true)] public sealed class NotifyPropertyChangedAttribute : CompoundAspect { public int AspectPriority { get; set; } public override void ProvideAspects(object element, LaosReflectionAspectCollection collection) { Type targetType = (Type)element; collection.AddAspect(targetType, new PropertyChangedAspect { AspectPriority = AspectPriority }); foreach (var info in targetType.GetProperties(BindingFlags.Public | BindingFlags.Instance).Where(pi => pi.GetSetMethod() != null)) { collection.AddAspect(info.GetSetMethod(), new NotifyPropertyChangedAspect(info.Name) { AspectPriority = AspectPriority }); } } } [Serializable] internal sealed class PropertyChangedAspect : CompositionAspect { public override object CreateImplementationObject(InstanceBoundLaosEventArgs eventArgs) { return new PropertyChangedImpl(eventArgs.Instance); } public override Type GetPublicInterface(Type containerType) { return typeof(INotifyPropertyChanged); } public override CompositionAspectOptions GetOptions() { return CompositionAspectOptions.GenerateImplementationAccessor; } } [Serializable] internal sealed class NotifyPropertyChangedAspect : OnMethodBoundaryAspect { private readonly string _propertyName; public NotifyPropertyChangedAspect(string propertyName) { if (string.IsNullOrEmpty(propertyName)) throw new ArgumentNullException("propertyName"); _propertyName = propertyName; } public override void OnEntry(MethodExecutionEventArgs eventArgs) { var targetType = eventArgs.Instance.GetType(); var setSetMethod = targetType.GetProperty(_propertyName); if (setSetMethod == null) throw new AccessViolationException(); var oldValue = setSetMethod.GetValue(eventArgs.Instance, null); var newValue = eventArgs.GetReadOnlyArgumentArray()[0]; if (oldValue == newValue) eventArgs.FlowBehavior = FlowBehavior.Return; } public override void OnSuccess(MethodExecutionEventArgs eventArgs) { var instance = eventArgs.Instance as IComposed<INotifyPropertyChanged>; var imp = instance.GetImplementation(eventArgs.InstanceCredentials) as PropertyChangedImpl; imp.OnPropertyChanged(_propertyName); } } [Serializable] internal sealed class PropertyChangedImpl : INotifyPropertyChanged { private readonly object _instance; public PropertyChangedImpl(object instance) { if (instance == null) throw new ArgumentNullException("instance"); _instance = instance; } public event PropertyChangedEventHandler PropertyChanged; internal void OnPropertyChanged(string propertyName) { if (string.IsNullOrEmpty(propertyName)) throw new ArgumentNullException("propertyName"); var handler = PropertyChanged as PropertyChangedEventHandler; if (handler != null) handler(_instance, new PropertyChangedEventArgs(propertyName)); } } } Then i have a couple of classes (user and adress) that implement [NotifyPropertyChanged]. It works fine. But what i want would be that if the child object changes (in my example address) that the parent object gets notified (in my case user). Would it be possible to expand this code so it automaticly creates listeners on parent objects that listen for changes in its child objets?

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  • How to fine tune a Membership Provider?

    - by Venemo
    After all the answers to my last question about fine-tuning turned out to be more useful than I expected, I thought that I would ask another similar Question about the MembershipProviders as well. Okay, so firstly, to clarify: I know what a Membership, Role, and Profile provider is, how to implement my own, and how to configure them, and most of the things about them. Implementing a role and profile provider is pretty straightforward, because they only require simple CRUD most of the time. (A single line of LINQ is enough for about half of the RoleProvider's methods.) However, the Membership provider is a differend beast. Many of you may realize that it violates the SR (Single Responsibility) principle, because it has to do EVERYTHING related to user management. While this leaves a lot of room for customizations, it has its downsides as well. There is no information on the Internet about what their EXACT expected behaviour is, such as when should they throw exceptions or simply return null, and stuff like that. I use this sample implementation for reference, but it also contains several contradictions. For example, it uses its own ValidateUser method for checking for credentials in the ChangePassword method. But the ValidateUser also updates the user's LastLoginDate to the current date. So, does the framework expect that I set it in my own provider as well, or is it simply a mistake in the sample? The other is: the ChangePassword method throws an exception every time when validating the new password, but CreateUser doesn't ever throw an exception, it simply returns false. And last, but not least: it counts the invalid password attempts of the user and locks them if it passes a threshold. While this is good, but it requires manual action to unlock the users. Is it a problem if my provider automatically unlocks the user after a certain amount of time? (EDIT) I almost forgot: the CreateUser method in the sample inserts the ID from the method parameter. I actually think this is bad practice, because I use inters with auto incement as IDs, so inserting them from some method parameter is not an option. Should I just ignore the parameter, or require that its value is null and throw an exception if it isn't? All in all, does ASP.NET have any assumptions about the behaviour of a MembershipProvider? Is there any documentation which describes when should I throw an exception or just return null? I also tried to find a set of generic unit tests which would provide some guidance about the expected behaviour, but no luck, I found plenty of articles about "Unit testing is good", and "How to unit test a MembershipProvider", but not one where there would be any actual tests. Thanks in advance for everyone!

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  • Passing Validation exceptions via WCF REST

    - by Coppermill
    I am using WCF and REST, and I have complex types, which are working fine. Now I need to check for validation, I am thinking of using DataAnnotations e.g. public class Customer { [Required] public string FirstName {get;set;} } Now where the issue is how do I pass this validation down to the REST service? ALso I need to validate the object when it comes back, and throw an exception, if I am to throw an exception then what is the best way of doing this using REST?

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  • right usage of std::uncaught_exception in a destructor

    - by Vokuhila-Oliba
    There are some articles concluding "never throw an exception from a destructor", and "std::uncaught_exception() is not useful", for example: http://www.gotw.ca/gotw/047.htm (written by Herb Sutter) But it seems that I am not getting the point. So I wrote a small testing example (see below). Since everything is fine with the testing example I would very appreciate some comments regarding what might be wrong with it. testing results: ./main Foo::~Foo(): caught exception - but have pending exception - ignoring int main(int, char**): caught exception: from int Foo::bar(int) ./main 1 Foo::~Foo(): caught exception - but *no* exception is pending - rethrowing int main(int, char**): caught exception: from Foo::~Foo() // file main.cpp // build with e.g. "make main" // tested successfully on Ubuntu-Karmic with g++ v4.4.1 #include <iostream> class Foo { public: int bar(int i) { if (0 == i) throw(std::string("from ") + __PRETTY_FUNCTION__); else return i+1; } ~Foo() { bool exc_pending=std::uncaught_exception(); try { bar(0); } catch (const std::string &e) { // ensure that no new exception has been created in the meantime if (std::uncaught_exception()) exc_pending = true; if (exc_pending) { std::cerr << __PRETTY_FUNCTION__ << ": caught exception - but have pending exception - ignoring" << std::endl; } else { std::cerr << __PRETTY_FUNCTION__ << ": caught exception - but *no* exception is pending - rethrowing" << std::endl; throw(std::string("from ") + __PRETTY_FUNCTION__); } } } }; int main(int argc, char** argv) { try { Foo f; // will throw an exception in Foo::bar() if no arguments given. Otherwise // an exception from Foo::~Foo() is thrown. f.bar(argc-1); } catch (const std::string &e) { std::cerr << __PRETTY_FUNCTION__ << ": caught exception: " << e << std::endl; } return 0; }

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  • Wcf exception handling

    - by pdiddy
    I noticed that if you do a throw new InvalidCastException for example, the channel state on the client side is faulted. But if you throw new FaultException, the channel state on the client side is opened. By curiosity, what is the reason why one faults the channel and the other doesn't?

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  • Why should I not wrap every block in "try"-"catch"?

    - by Konrad
    I have always been of the belief that if a method can throw an exception then it is reckless not to protect this call with a meaningful try block. I just posted 'You should ALWAYS wrap calls that can throw in try, catch blocks.' to this question and was told that it was 'remarkably bad advice' - I'd like to understand why. Thanks!

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  • WCF .Net 4.0 is treating WebProtocolException as an unhandled exception

    - by Benjii
    Im trying to build an API using WCF and .Net 4, however when I throw the WebProtocolException, it is not displaying a nice error message like it should, instead it is treating it like an unhandled exception. I am using the WebServiceHost2Factory. Has anyone else used WebProtocolException with .net 4? An example of my call is below throw new WebProtocolException(System.Net.HttpStatusCode.BadRequest, "The DateFrom parameter is invalid", new Error() { Code = 6002, Message = "Please ensure your dates are in the following format: yyyy/MM/dd hh:mm:ss" }, null, null);

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  • `var = something rescue nil` behaviour

    - by JP
    In ruby you can throw a rescue at the end of an assignment to catch any errors that might come up. I have a function (below: a_function_that_may_fail) where it's convenient to let it throw an error if certain conditions aren't met. The following code works well post = {} # Other Hash stuff post['Caption'] = a_function_that_may_fail rescue nil However I'd like to have post['Caption'] not even set if the function fails. I know I can do: begin post['Caption'] = a_function_that_may_fail recsue end but that feels a little excessive - is there a simpler solution?

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  • C# problem with two threads and hardware access

    - by mack369
    I'm creating an application which communicates with the device via FT2232H USB/RS232 converter. For communication I'm using FTD2XX_NET.dll library from FTDI website. I'm using two threads: first thread continuously reads data from the device the second thread is the main thread of the Windows Form Application I've got a problem when I'm trying to write any data to the device while the receiver's thread is running. The main thread simply hangs up on ftdiDevice.Write function. I tried to synchronize both threads so that only one thread can use Read/Write function at the same time, but it didn't help. Below code responsible for the communication. Note that following functions are methods of FtdiPort class. Receiver's thread private void receiverLoop() { if (this.DataReceivedHandler == null) { throw new BackendException("dataReceived delegate is not set"); } FTDI.FT_STATUS ftStatus = FTDI.FT_STATUS.FT_OK; byte[] readBytes = new byte[this.ReadBufferSize]; while (true) { lock (FtdiPort.threadLocker) { UInt32 numBytesRead = 0; ftStatus = ftdiDevice.Read(readBytes, this.ReadBufferSize, ref numBytesRead); if (ftStatus == FTDI.FT_STATUS.FT_OK) { this.DataReceivedHandler(readBytes, numBytesRead); } else { Trace.WriteLine(String.Format("Couldn't read data from ftdi: status {0}", ftStatus)); Thread.Sleep(10); } } Thread.Sleep(this.RXThreadDelay); } } Write function called from main thread public void Write(byte[] data, int length) { if (this.IsOpened) { uint i = 0; lock (FtdiPort.threadLocker) { this.ftdiDevice.Write(data, length, ref i); } Thread.Sleep(1); if (i != (int)length) { throw new BackendException("Couldnt send all data"); } } else { throw new BackendException("Port is closed"); } } Object used to synchronize two threads static Object threadLocker = new Object(); Method that starts the receiver's thread private void startReceiver() { if (this.DataReceivedHandler == null) { return; } if (this.IsOpened == false) { throw new BackendException("Trying to start listening for raw data while disconnected"); } this.receiverThread = new Thread(this.receiverLoop); //this.receiverThread.Name = "protocolListener"; this.receiverThread.IsBackground = true; this.receiverThread.Start(); } The ftdiDevice.Write function doesn't hang up if I comment following line: ftStatus = ftdiDevice.Read(readBytes, this.ReadBufferSize, ref numBytesRead);

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  • How do I use the information about exceptions a method throws in .NET in my code?

    - by dotnetdev
    For many methods in .NET, the exceptions they can potentially throw can be as many as 7-8 (one or two methods in XmlDocument, Load() being one I think, can throw this many exceptions). Does this mean I have to write 8 catch blocks to catch all of these exceptions (it is best practise to catch an exception with a specific exception block and not just a general catch block of type Exception). How do I use this information? Thanks

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  • Should the PHP community start using more discriptive Exceptions?

    - by fireeyedboy
    I work with Zend Framework a lot and I just took a peek at Kohana, and it strikes me as odd that this is a typical scenario in these frameworks: throw Some_Componenents_Exception( 'invalid argument' ); Where I believe this wouldn't be mouch more useful: throw Some_Components_InvalidArgumentException( 'whatever discription' ); Because it is easier to catch. I suspect, but immediately admit it's prejudiced, that the former practice is common in the PHP community. Should we, the PHP community, start using these descriptive types of expections more?

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  • Working with hibernate/DAO problems

    - by Gandalf StormCrow
    Hello everyone here is my DAO class : public class UsersDAO extends HibernateDaoSupport { private static final Log log = LogFactory.getLog(UsersDAO.class); protected void initDao() { //do nothing } public void save(User transientInstance) { log.debug("saving Users instance"); try { getHibernateTemplate().saveOrUpdate(transientInstance); log.debug("save successful"); } catch (RuntimeException re) { log.error("save failed", re); throw re; } } public void update(User transientInstance) { log.debug("updating User instance"); try { getHibernateTemplate().update(transientInstance); log.debug("update successful"); } catch (RuntimeException re) { log.error("update failed", re); throw re; } } public void delete(User persistentInstance) { log.debug("deleting Users instance"); try { getHibernateTemplate().delete(persistentInstance); log.debug("delete successful"); } catch (RuntimeException re) { log.error("delete failed", re); throw re; } } public User findById( java.lang.Integer id) { log.debug("getting Users instance with id: " + id); try { User instance = (User) getHibernateTemplate() .get("project.hibernate.Users", id); return instance; } catch (RuntimeException re) { log.error("get failed", re); throw re; } } } Now I wrote a test class(not a junit test) to test is everything working, my user has these fields in the database : userID which is 5characters long string and unique/primary key, and fields such as address, dob etc(total 15 columns in database table). Now in my test class I intanciated User added the values like : User user = new User; user.setAddress("some address"); and so I did for all 15 fields, than at the end of assigning data to User object I called in DAO to save that to database UsersDao.save(user); and save works just perfectly. My question is how do I update/delete users using the same logic? Fox example I tried this(to delete user from table users): User user = new User; user.setUserID("1s54f"); // which is unique key for users no two keys are the same UsersDao.delete(user); I wanted to delete user with this key but its obviously different can someone explain please how to do these. thank you

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