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  • Changing variables outside of Scope C#

    - by sam
    Hi, I'm a beginner C# programmer, and to improve my skills I decided to give Project Euler a try. The first problem on the site asks you to find the sum of all the multiples of 3 and 5 under 1000. Since I'm essentially doing the same thing twice, I made a method to multiply a base number incrementally, and add the sum of all the answers togethor. public static int SumOfMultiplication(int Base, int limit) { bool Escape = false; for (int mult = 1; Escape == true; mult++) { int Number = 0; int iSum = 0; Number = Base * mult; if (Number > limit) return iSum; else iSum = iSum + Number; } regardless of what I put in for both parameters, it ALWAYS returns zero. I'm 99% sure it has something to do with the scope of the variables, but I have no clue how to fix it. All help is appreciated. Thanks in advance, Sam

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  • How do I tell if an action is a lambda expression?

    - by Keith
    I am using the EventAgregator pattern to subscribe and publish events. If a user subscribes to the event using a lambda expression, they must use a strong reference, not a weak reference, otherwise the expression can be garbage collected before the publish will execute. I wanted to add a simple check in the DelegateReference so that if a programmer passes in a lambda expression and is using a weak reference, that I throw an argument exception. This is to help "police" the code. Example: eventAggregator.GetEvent<RuleScheduler.JobExecutedEvent>().Subscribe ( e => resetEvent.Set(), ThreadOption.PublisherThread, false, // filter event, only interested in the job that this object started e => e.Value1.JobDetail.Name == jobName ); public DelegateReference(Delegate @delegate, bool keepReferenceAlive) { if (@delegate == null) throw new ArgumentNullException("delegate"); if (keepReferenceAlive) { this._delegate = @delegate; } else { //TODO: throw exception if target is a lambda expression _weakReference = new WeakReference(@delegate.Target); _method = @delegate.Method; _delegateType = @delegate.GetType(); } } any ideas? I thought I could check for @delegate.Method.IsStatic but I don't believe that works... (is every lambda expression a static?)

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  • Dev-C++ and Detours compiling error

    - by Julio
    Hello. As title says I'm trying to compile with Dev-C++ a simple DLL using Detours, but I get this error: syntax error before token '&' on this lines: DetourAttach(&(PVOID &)trueMessageBox, hookedMessageBox) DetourDetach(&(PVOID &)trueMessageBox, hookedMessageBox) The complete code is #include <windows.h> #include <detours.h> #pragma comment( lib, "Ws2_32.lib" ) #pragma comment( lib, "detours.lib" ) #pragma comment( lib, "detoured.lib" ) int (WINAPI * trueMessageBox)(HWND hWnd, LPCSTR lpText, LPCSTR lpCaption, UINT uType) = MessageBox; int WINAPI hookedMessageBox(HWND hWnd, LPCSTR lpText, LPCSTR lpCaption, UINT uType) { LPCSTR lpNewCaption = "You've been hijacked"; int iReturn = trueMessageBox(hWnd, lpText, lpNewCaption, uType); return iReturn; } BOOL WINAPI DllMain( HINSTANCE, DWORD dwReason, LPVOID ) { switch ( dwReason ) { case DLL_PROCESS_ATTACH: DetourTransactionBegin(); DetourUpdateThread( GetCurrentThread() ); DetourAttach(&(PVOID &)trueMessageBox, hookedMessageBox) DetourTransactionCommit(); break; case DLL_PROCESS_DETACH: DetourTransactionBegin(); DetourUpdateThread( GetCurrentThread() ); DetourDetach(&(PVOID &)trueMessageBox, hookedMessageBox) DetourTransactionCommit(); break; } return TRUE; }

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  • How to return all records and whether a related record exists?

    - by David Glenn
    Using Entity Framework 4 CTP5 I have a basic model and a basic DbContext that works public class Customer { public int CustomerId { get; set; } public int Name { get; set; } //... public ICollection<Address> Addresses { get; set; } public bool HasAddress { get { return Addresses.Count > 0; } } } public class Address { public int AddressId { get; set; } public string StreetLine1 { get; set; } //.... public Customer Customer { get; set; } } How can I query my DbContext to return all customers and whether they have an address? A customer can have multiple addresses and I don't want to return all the addresses for each customer when I am only interested in whether they have an address or not. I use context.Customers.Include(c => c.Addresses) but that returns all addresses for each customer

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  • How `is_base_of` works?

    - by Alexey Malistov
    Why the following code works? typedef char (&yes)[1]; typedef char (&no)[2]; template <typename B, typename D> struct Host { operator B*() const; operator D*(); }; template <typename B, typename D> struct is_base_of { template <typename T> static yes check(D*, T); static no check(B*, int); static const bool value = sizeof(check(Host<B,D>(), int())) == sizeof(yes); }; //Test sample class Base {}; class Derived : private Base {}; //Exspression is true. int test[is_base_of<Base,Derived>::value && !is_base_of<Derived,Base>::value]; Note that B is private base. Note that operator B*() is const. How does this work? Why this works? Why static yes check(D*, T); is better than static yes check(B*, int); ?

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  • Am I using handlers in the wrong way?

    - by superexsl
    Hey, I've never used HTTP Handlers before, and I've got one working, but I'm not sure if I'm actually using it properly. I have generated a string which will be saved as a CSV file. When the user clicks a button, I want the download dialog box to open so that the user can save the file. What I have works, but I keep reading about modifying the web.config file and I haven't had to do that. My Handler: private string _data; private string _title = "temp"; public void AddData(string data) { _data = data; } public bool IsReusable { get { return false; } } public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/csv"; context.Response.AddHeader("content-disposition", "filename=" + _title + ".csv"); context.Response.Write(_data); context.Response.Flush(); context.Response.Close(); } And this is from the page that allows the user to download: (on button click) string dataToConvert = "MYCSVDATA...."; csvHandler handler = new csvHandler(); handler.AddData(dataToConvert); handler.ProcessRequest(this.Context); This works fine, but no examples I've seen ever instantiate the handler and always seem to modify the web.config. Am I doing something wrong? Thanks

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  • Why do I get two clicked or released signals when using a custom slot for a QPushButton ?

    - by Chris
    here's the main code at first I thought is was the message box but setting a label instead has the same effect. #include <time.h> #include "ui_mainwindow.h" #include <QMessageBox> class MainWindow : public QWidget, private Ui::MainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0); void makeSum(void); private: int r1; int r2; private slots: void on_pushButton_released(void); }; MainWindow::MainWindow(QWidget *parent) : QWidget(parent) { setupUi(this); } void MainWindow::on_pushButton_released(void) { bool ok; int a = lineEdit->text().toInt(&ok, 10); if (ok) { if (r1+r2==a) { QMessageBox::information( this, "Sums","Correct!" ); } else { QMessageBox::information( this, "Sums","Wrong!" ); } } else { QMessageBox::information( this, "Sums","You need to enter a number" ); } makeSum(); } void MainWindow::makeSum(void) { r1 = rand() % 10 + 1; r2 = rand() % 10 + 1; label->setText(QString::number(r1)); label_3->setText(QString::number(r2)); } int main(int argc, char *argv[]) { srand ( time(NULL) ); QApplication app(argc, argv); MainWindow mw; mw.makeSum(); mw.show(); return app.exec(); } #include "main.moc"

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  • Should you declare methods using overloads or optional parameters in C# 4.0?

    - by Greg Beech
    I was watching Anders' talk about C# 4.0 and sneak preview of C# 5.0, and it got me thinking about when optional parameters are available in C# what is going to be the recommended way to declare methods that do not need all parameters specified? For example something like the FileStream class has about fifteen different constructors which can be divided into logical 'families' e.g. the ones below from a string, the ones from an IntPtr and the ones from a SafeFileHandle. FileStream(string,FileMode); FileStream(string,FileMode,FileAccess); FileStream(string,FileMode,FileAccess,FileShare); FileStream(string,FileMode,FileAccess,FileShare,int); FileStream(string,FileMode,FileAccess,FileShare,int,bool); It seems to me that this type of pattern could be simplified by having three constructors instead, and using optional parameters for the ones that can be defaulted, which would make the different families of constructors more distinct [note: I know this change will not be made in the BCL, I'm talking hypothetically for this type of situation]. What do you think? From C# 4.0 will it make more sense to make closely related groups of constructors and methods a single method with optional parameters, or is there a good reason to stick with the traditional many-overload mechanism?

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  • How to Read Device Data From serial port

    - by Aamir Khurshid
    I have one device which sends data on COM port say on COM13. Now i want to read that data and display it in the RichTextBox or in any text control. I have written the application with the help of IO and IO.Ports but comport.DataRecived event does not fire, even though device is sending data on that port. I have some software on which i define the port number and it successfully display data, which insure me that data is receiving on the Port but i am unable to receive. Is there any way i can read data? comm.Parity = cboParity.Text;//None comm.StopBits = cboStop.Text;//One comm.DataBits = cboData.Text;//8 comm.BaudRate = cboBaud.Text;//9600 comm.DisplayWindow = rtbDisplay;//Null comm.PortName = "COM13"; comm.OpenPort(); cmdOpen.Enabled = false; cmdClose.Enabled = true; cmdSend.Enabled = true; public bool OpenPort() { if (comPort.IsOpen) { comPort.Close(); } comPort.DataReceived += new SerialDataReceivedEventHandler(comPort_DataReceived); comPort.PortName = _portName; comPort.Open();return true; }

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  • Is there a way to restrict access to a public method to only a specific class in C#?

    - by Anon
    I have a class A with a public method in C#. I want to allow access to this method to only class B. Is this possible? UPDATE: This is what i'd like to do: public class Category { public int NumberOfInactiveProducts {get;} public IList<Product> Products {get;set;} public void ProcessInactiveProduct() { // do things... NumberOfInactiveProducts++; } } public class Product { public bool Inactive {get;} public Category Category {get;set;} public void SetInactive() { this.Inactive= true; Category.ProcessInactiveProduct(); } } I'd like other programmers to do: var prod = Repository.Get<Product>(id); prod.SetInactive(); I'd like to make sure they don't call ProcessInactiveProduct manually: var prod = Repository.Get<Product>(id); prod.SetInactive(); prod.Category.ProcessInactiveProduct(); I want to allow access of Category.ProcessInactiveProduct to only class Product. Other classes shouldn't be able to call Category.ProcessInactiveProduct.

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  • ipad tabbar rotation

    - by MaKo
    hi, please help with this noob questions but really making me go crazy if I create a project from scratch (using windows based app) for the ipad, and add a tabbar , with firstviewController, and secondviewController, it works fine, starts in landscape mode, but in info.plist I set it to Landscape(left home button), but really in simulator starts with the button on the right side! in the FirstViewController.m (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { if (interfaceOrientation == UIInterfaceOrientationLandscapeLeft || interfaceOrientation == UIInterfaceOrientationLandscapeRight) return YES; else { return NO; }} so it starts in landscape, and rotates as the simulator rotates, but if I create a template app for iphone tabbar, set the info.plist Initial interface orientation Landscape (left home button) and add the code above, IT DOESNT WORK!!! simulator starts with button at left but tab bar on the side, same problem that I had with an app that Im porting from iphone to ipad, (landscape intended) I get to the landscape start mode, but the tab bar remains on the side! also the only way to make the old ported app to show the simulator on the side was with UIInterfaceOrientation UIIntefaceOrientationLandscapeLeft (didnt work with Initial interface orientation), does not let me choose the value for the key, but it shows the simulator on landscape,, so,, what can I do please to show the tab bar on landscape mode??? the tabbar from scratch was made to see if the code will work , but it didnt?? why does it work in the tab bar made from windows app and not tab bar app? I just want the tab bar to show in landscape ahhh, thanks

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  • Unable to store NSNumber in core data

    - by Kamlesh
    Hi all, I am using Core Data in my application.I have an attribute named PINCode which has property Int64. Now,in my app I take the PIN code from a text field,convert it into NSNumber and try to store as an attribute value for an entity.But I am unable to do so.The exception that it shows on the console is:- Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unacceptable type of value for attribute: property = "PINCode"; desired type = NSNumber; given type = NSCFString; value = 121.' Here is the code:- (Conversion to NSNumber):- NSString *str= txtPINCode.text; NSNumber *num = [[NSNumber alloc]init]; int tempNum = [str intValue]; num = [NSNumber numberWithInt:tempNum]; (Storing in core data entity):- NSManagedObjectContext *context = [appDelegate managedObjectContext]; NSManagedObject *newContact; newContact = [NSEntityDescription insertNewObjectForEntityForName:@"MemberTable" inManagedObjectContext:context]; [newContact setValue:num forKey:@"PINCode"]; The app crashes at this point.I am unable to find the reason of crash.I have also tried to check the conversion by the following code:- NSNumber *testNumber = [[NSNumber alloc]init]; id test = num; BOOL testMe = [test isKindOfClass:(Class)testNumber]; Can anybody help me with this?? Thanks in advance.

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  • Second Thread Holding Up Entire Program in C# Windows Form Application

    - by Brandon
    In my windows form application, I'm trying to test the user's ability to access a remote machine's shared folder. The way I'm doing this (and I'm sure that there are better ways...but I don't know of them) is to check for the existence of a specific directory on the remote machine (I'm doing this because of firewall/other security restrictions that I'm confronted with in my organization). If the user has rights to access the shared folder, then it returns in no time at all, but if they don't, it hangs forever. To solve this, I threw the check into another thread and wait only 1000 milliseconds before determining that the share can't be hit by the user. However, when I do this, it still hangs as if it was never run in the same thread. What is making it hang and how do I fix it? I would think that the fact that it is in a separate thread would allow me to just let the thread finish on it's own in the background. Here is my code: bool canHitInstallPath = false; Thread thread = new Thread(new ThreadStart(() => { canHitInstallPath = Directory.Exists(compInfo.InstallPath); })); thread.Start(); thread.Join(1000); if (canHitInstallPath == false) { throw new Exception("Cannot hit folder: " + compInfo.InstallPath); }

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  • With NHibernate and Transaction do I rollback on commit failure or does it auto rollback on single c

    - by mattcodes
    I've built the following Dispose method for my Unit Of Work which essentially wraps the active NH session & transaction (transaction set as variable after opening session as to not be replaced if NH session gets new transaction after error) public void Dispose() { Func<ITransaction,bool> transactionStateOkayFunc = trans => trans != null && trans.IsActive && !trans.WasRolledBack; try { if(transactionStateOkayFunc(this.transaction)) { if (HasErrored) { transaction.Rollback(); } else { try { transaction.Commit(); } catch (Exception) { if(transactionStateOkayFunc(transaction)) transaction.Rollback(); throw; } } } } finally { if(transaction != null) transaction.Dispose(); if(session.IsOpen) session.Close(); } I can't help feeling that code is a little bloated, will a transaction automatically rollback is a discrete Commit fails in the case of non-nested transactions? Will Commit or Rollback automatically Dipose the transaction? If not will Session.Close() automatically dispose the associated transaction?

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  • How do you filter a view of a DataTable in .Net 3.5 sp1 using WPF c# and xaml?

    - by Tony
    I found the MSDN example code for getting the default view of a collection and adding a filter to the view, but most of it is for .Net 4.0. I'm on a team that is not currently switching to 4.0, so I don't have that option. None of the examples I found used a DataTable as the source, so I had to adapt it a little. I'm using a DataTable because the data is comming from a DB ans it's easy to populate. After trying to implement the MSDN examples, I get a "NotSupportedException" when I try to set the Filter. This is the c# code I have: protected DataTable _data = new DataTable(); protected BindingListCollectionView _filteredDataView; ... private void On_Loaded(Object sender, RoutedEventArgs e) { _filteredDataView = (BindingListCollectionView)CollectionViewSource.GetDefaultView(_data); _filteredDataView.Filter = new Predicate(MatchesCurrentSelections); // throws NotSupportedException } ... public bool MatchesCurrentSelections(object o){...} It seems that either BindingListCollectionView does not support filtering in .Net 3.5, or it just doesn't work for a DataTable. I looked at setting it up in XAML instead of the C# code, but the XAML examples use collections in resources instead of a collection that is a memberof the class, so I have no idea how to set that up. Does any one know how to filter a view to a DataTable?

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  • wrapping aspx user controls commands in a transaction

    - by Hans Gruber
    I'm working on heavily dynamic and configurable CMS system. Therefore, many pages are composed of a dynamically loaded set of user controls. To enable loose coupling between containers (pages) and children (user controls), all user controls are responsible for their own persistence. Each User Control is wired up to its data/service layer dependencies via IoC. They also implement an IPersistable interface, which allows the container .aspx page to issue a Save command to its children without knowledge of the number or exact nature of these user controls. Note: what follows is only pseudo-code: public class MyUserControl : IPersistable, IValidatable { public void Save() { throw new NotImplementedException(); } public bool IsValid() { throw new NotImplementedException(); } } public partial class MyPage { public void btnSave_Click(object sender, EventArgs e) { foreach (IValidatable control in Controls) { if (!control.IsValid) { throw new Exception("error"); } } foreach (IPersistable control in Controls) { if (!control.Save) { throw new Exception("error"); } } } } I'm thinking of using declarative transactions from the System.EnterpriseService namespace to wrap the btnSave_Click in a transaction in case of an exception, but I'm not sure how this might be achieved or any pitfalls to such an approach.

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  • Are finalizers ever allowed to call other managed classes' methods?

    - by romkyns
    I used to be pretty sure the answer is "no", as explained in Overriding the Finalize method and Object.Finalize documentation. However, while randomly browsing through FileStream in Reflector, I found that it can actually call just such a method from a finalizer: private SafeFileHandle _handle; ~FileStream() { if (this._handle != null) { this.Dispose(false); } } protected override void Dispose(bool disposing) { try { ... } finally { if ((this._handle != null) && !this._handle.IsClosed) // <=== HERE { this._handle.Dispose(); // <=== AND HERE } [...] } } I started wondering whether this will always work due to the exact way in which it's written, and hence whether the "do not touch managed classes from finalizers" is just a guideline that can be broken given a good reason and the necessary knowledge to do it right. I dug a bit deeper and found out that the worst that can happen when the "rule" is broken is that the managed object being accessed had already been finalized, or may be getting finalized in parallel on a separate thread. So if the SafeFileHandle's finalizer didn't do anything that would cause a subsequent call to Dispose fail then the above should be fine... right? Question: so there might after all be situations in which a method on another managed class may be called reliably from a finalizer? I've always believed this to be false, but this code suggests that it's possible and that there can be good enough reasons to do it. Bonus: Observe that the SafeFileHandle will not even know it's being called from a finalizer, since this is just a normal call to Dispose(). The base class, SafeHandle, actually has two private methods, InternalDispose and InternalFinalize, and in this case InternalDispose will be called. Isn't this a problem? Why not?...

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  • Large flags enumerations in C#

    - by LorenVS
    Hey everyone, got a quick question that I can't seem to find anything about... I'm working on a project that requires flag enumerations with a large number of flags (up to 40-ish), and I don't really feel like typing in the exact mask for each enumeration value: public enum MyEnumeration : ulong { Flag1 = 1, Flag2 = 2, Flag3 = 4, Flag4 = 8, Flag5 = 16, // ... Flag16 = 65536, Flag17 = 65536 * 2, Flag18 = 65536 * 4, Flag19 = 65536 * 8, // ... Flag32 = 65536 * 65536, Flag33 = 65536 * 65536 * 2 // right about here I start to get really pissed off } Moreover, I'm also hoping that there is an easy(ier) way for me to control the actual arrangement of bits on different endian machines, since these values will eventually be serialized over a network: public enum MyEnumeration : uint { Flag1 = 1, // BIG: 0x00000001, LITTLE:0x01000000 Flag2 = 2, // BIG: 0x00000002, LITTLE:0x02000000 Flag3 = 4, // BIG: 0x00000004, LITTLE:0x03000000 // ... Flag9 = 256, // BIG: 0x00000010, LITTLE:0x10000000 Flag10 = 512, // BIG: 0x00000011, LITTLE:0x11000000 Flag11 = 1024 // BIG: 0x00000012, LITTLE:0x12000000 } So, I'm kind of wondering if there is some cool way I can set my enumerations up like: public enum MyEnumeration : uint { Flag1 = flag(1), // BOTH: 0x80000000 Flag2 = flag(2), // BOTH: 0x40000000 Flag3 = flag(3), // BOTH: 0x20000000 // ... Flag9 = flag(9), // BOTH: 0x00800000 } What I've Tried: // this won't work because Math.Pow returns double // and because C# requires constants for enum values public enum MyEnumeration : uint { Flag1 = Math.Pow(2, 0), Flag2 = Math.Pow(2, 1) } // this won't work because C# requires constants for enum values public enum MyEnumeration : uint { Flag1 = Masks.MyCustomerBitmaskGeneratingFunction(0) } // this is my best solution so far, but is definitely // quite clunkie public struct EnumWrapper<TEnum> where TEnum { private BitVector32 vector; public bool this[TEnum index] { // returns whether the index-th bit is set in vector } // all sorts of overriding using TEnum as args } Just wondering if anyone has any cool ideas, thanks!

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  • Why does Microsoft advise against readonly fields with mutable values?

    - by Weeble
    In the Design Guidelines for Developing Class Libraries, Microsoft say: Do not assign instances of mutable types to read-only fields. The objects created using a mutable type can be modified after they are created. For example, arrays and most collections are mutable types while Int32, Uri, and String are immutable types. For fields that hold a mutable reference type, the read-only modifier prevents the field value from being overwritten but does not protect the mutable type from modification. This simply restates the behaviour of readonly without explaining why it's bad to use readonly. The implication appears to be that many people do not understand what "readonly" does and will wrongly expect readonly fields to be deeply immutable. In effect it advises using "readonly" as code documentation indicating deep immutability - despite the fact that the compiler has no way to enforce this - and disallows its use for its normal function: to ensure that the value of the field doesn't change after the object has been constructed. I feel uneasy with this recommendation to use "readonly" to indicate something other than its normal meaning understood by the compiler. I feel that it encourages people to misunderstand the meaning of "readonly", and furthermore to expect it to mean something that the author of the code might not intend. I feel that it precludes using it in places it could be useful - e.g. to show that some relationship between two mutable objects remains unchanged for the lifetime of one of those objects. The notion of assuming that readers do not understand the meaning of "readonly" also appears to be in contradiction to other advice from Microsoft, such as FxCop's "Do not initialize unnecessarily" rule, which assumes readers of your code to be experts in the language and should know that (for example) bool fields are automatically initialised to false, and stops you from providing the redundancy that shows "yes, this has been consciously set to false; I didn't just forget to initialize it". So, first and foremost, why do Microsoft advise against use of readonly for references to mutable types? I'd also be interested to know: Do you follow this Design Guideline in all your code? What do you expect when you see "readonly" in a piece of code you didn't write?

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  • Reflecting over classes in .NET produces methods only differing by a modifier

    - by mrjoltcola
    I'm a bit boggled by something, I hope the CLR gearheads can help. Apparently my gears aren't big enough. I have a reflector utility that generates assembly stubs for Cola for .NET, and I find classes have methods that only differ by a modifier, such as virtual. Example below, from Oracle.DataAccess.dll, method GetType(): class OracleTypeException : System.SystemException { virtual string ToString (); virtual System.Exception GetBaseException (); virtual void set_Source (string value); virtual void GetObjectData (System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context); virtual System.Type GetType (); // here virtual bool Equals (object obj); virtual int32 GetHashCode (); System.Type GetType (); // and here } What is this? I have not been able to reproduce this with C# and it causes trouble for Cola as it thinks GetType() is a redefinition, since the signature is identical. My method reflector starts like this: static void DisplayMethod(MethodInfo m) { if ( // Filter out things Cola cannot yet import, like generics, pointers, etc. m.IsGenericMethodDefinition || m.ContainsGenericParameters || m.ReturnType.IsGenericType || !m.ReturnType.IsPublic || m.ReturnType.IsArray || m.ReturnType.IsPointer || m.ReturnType.IsByRef || m.ReturnType.IsPointer || m.ReturnType.IsMarshalByRef || m.ReturnType.IsImport ) return; // generate stub signature // [snipped] }

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  • What is the best method for updating all changed data in EF 4?

    - by Soul_Master
    I try to create some method that can update any changed data from changed Data object (this object is generated by ASP.NET MVC) to old Data object (this object is retrieved from current data in DBMS) like the following code. public static bool UpdateSomeData(SomeEntities context, SomeModelType changedData) { var oldData = GetSomeModelTypeById(context, changedData.ID); UpdateModel(oldData, changedData); return context.SaveChanges() > 0; } I try to create method for saving any changed data without affects other unchanged data like the following source code. public static void UpdateModel<TModel>(TModel oldData, TModel changedData) { foreach (var pi in typeof(TModel).GetProperties() .Where ( // Ignore Change ID property for security reason x => x.Name.ToUpper() != "ID" && x.CanRead && x.CanWrite && ( // It must be primitive type or Guid x.PropertyType.FullName.StartsWith("System") && !x.PropertyType.FullName.StartsWith("System.Collection") && !x.PropertyType.FullName.StartsWith("System.Data.Entity.DynamicProxies") ) ) { var oldValue = pi.GetValue(oldData, null); var newValue = pi.GetValue(changedData, null); if (!oldValue.Equals(newValue)) { pi.SetValue(oldData, newValue, null); } } } I am not sure about the above method because it is so ugly method for updating data. From recent bug, it realizes me that if you update some property like Navigation Properties (related data from other table), it will remove current record from database. I don't understand why it happened. But it is very dangerous for me. So, do you have any idea for this question to ensure me about updating data from ASP.NET MVC? Thanks,

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  • Displaying Plist data into UItableview

    - by Christien
    I have a plist with Dictionary and numbers of strings per dictionary.show into the url below.and this list of items is in thousands in the plist. I need to display these plist data into the UItableview . How to do this? My Code: - (void)viewWillAppear:(BOOL)animated { // get paths from root direcory NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [documentPaths objectAtIndex:0]; NSString *documentPlistPath = [documentsDirectory stringByAppendingPathComponent:@"p.plist"]; NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:documentPlistPath]; valueArray = [dict objectForKey:@"title"]; self.mySections=[valueArray copy]; NSLog(@"value array %@",self.mySections); } - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return [self.mySections count]; } -(NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section { NSString *key = [[self.mySections objectAtIndex:section]objectForKey:@"pass"]; return [NSString stringWithFormat:@"%@", key]; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 5; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier]; } // Configure the cell... NSUInteger section = [indexPath section]; NSUInteger row = [indexPath row]; cell.textLabel.text = [[self.mySections objectAtIndex:row] objectForKey:@"title"]; cell.detailTextLabel.text=[[self.mySections objectAtIndex:section] objectForKey:[allKeys objectAtIndex:1]]; return cell; } Error is 2012-12-17 16:21:07.372 Project[2076:11603] * Terminating app due to uncaught exception 'NSRangeException', reason: '-[__NSCFArray objectAtIndex:]: index (4) beyond bounds (4)' * First throw call stack: (0x1703052 0x1523d0a 0x16aba78 0x16ab9e9 0x16fcc60 0x1d03a 0x391e0f 0x392589 0x37ddfd 0x38c851 0x337301 0x1704e72 0x277592d 0x277f827 0x2705fa7 0x2707ea6 0x2707580 0x16d79ce 0x166e670 0x163a4f6 0x1639db4 0x1639ccb 0x1505879 0x150593e 0x2f8a9b 0x2158 0x20b5) terminate called throwing an exceptionkill

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  • Is this a safe/valid hash method implementation?

    - by Sean
    I have a set of classes to represent some objects loaded from a database. There are a couple variations of these objects, so I have a common base class and two subclasses to represent the differences. One of the key fields they have in common is an id field. Unfortunately, the id of an object is not unique across all variations, but within a single variation. What I mean is, a single object of type A could have an id between, say, 0 and 1,000,000. An object of type B could have an id between, 25,000 and 1,025,000. This means there's some overlap of id numbers. The objects are just variations of the same kind of thing, though, so I want to think of them as such in my code. (They were assigned ids from different sets for legacy reasons.) So I have classes like this: @class BaseClass @class TypeAClass : BaseClass @class TypeBClass : BaseClass BaseClass has a method (NSNumber *)objectId. However instances of TypeA and TypeB could have overlapping ids as discussed above, so when it comes to equality and putting these into sets, I cannot just use the id alone to check it. The unique key of these instances is, essentially, (class + objectId). So I figured that I could do this by making the following hash function on the BaseClass: -(NSUInteger)hash { return (NSUInteger)[self class] ^ [self.objectId hash]; } I also implemented isEqual like so: - (BOOL)isEqual:(id)object { return (self == object) || ([object class] == [self class] && [self.objectId isEqual:[object objectId]]); } This seems to be working, but I guess I'm just asking here to make sure I'm not overlooking something - especially with the generation of the hash by using the class pointer in that way. Is this safe or is there a better way to do this?

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  • C# 4.0 'dynamic' doesn't set ref/out arguments

    - by Buu Nguyen
    I'm experimenting with DynamicObject. One of the things I try to do is setting the values of ref/out arguments, as shown in the code below. However, I am not able to have the values of i and j in Main() set properly (even though they are set correctly in TryInvokeMember()). Does anyone know how to call a DynamicObject object with ref/out arguments and be able to retrieve the values set inside the method? class Program { static void Main(string[] args) { dynamic proxy = new Proxy(new Target()); int i = 10; int j = 20; proxy.Wrap(ref i, ref j); Console.WriteLine(i + ":" + j); // Print "10:20" while expect "20:10" } } class Proxy : DynamicObject { private readonly Target target; public Proxy(Target target) { this.target = target; } public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { int i = (int) args[0]; int j = (int) args[1]; target.Swap(ref i, ref j); args[0] = i; args[1] = j; result = null; return true; } } class Target { public void Swap(ref int i, ref int j) { int tmp = i; i = j; j = tmp; } }

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  • Null reference exceptions in .net

    - by Carlo
    Hello, we're having this big problem with our application. It's a rather large application with several modules, and thousands and thousands lines of code. A lot of parts of the application are designed to exist only with a reference to another object, for example a Person object can never exists without a House object, so if you at any point in the app say: bool check = App.Person.House == null; check should always be false (by design), so, to keep using that example, while creating modules, testing, debugging, App.Person.House is never null, but once we shipped the application to our client, they started getting a bunch of NullReferenceException with the objects that by design, should never have a null reference. They tell us the bug, we try to reproduce it here, but 90% of the times we can't, because here it works fine. The app is being developed with C# and WPF, and by design, it only runs on Windows XP SP 3, and the .net framework v3.5, so we KNOW the user has the same operative system, service pack, and .net framework version as we do here, but they still get this weird NullReferenceExceptions that we can't reproduce. So, I'm just wondering if anyone has seen this before and how you fixed it, we have the app running here at least 8 hours a day in 5 different computers, and we never see those exceptions, this only happens to the client for some reason. ANY thought, any clue, any solution that could get us closer to fixing this problem will be greatly appreciated. Thanks!

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