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  • how to update a table in c# using oledb parameters?

    - by sameer
    I am having a table which has three fields, namely LM_code,M_Name,Desc. LC_code is a autogenerated string Id, keeping this i am updating M_Name and Desc. I used normal update command, the value is passing in runtime but the fields are not getting updated. I hope using oledb parameters the fileds can be updated. Any help will be appreciated... Here is my code. public void Modify() { String query = "Update Master_Accounts set (M_Name='" + M_Name + "',Desc='" + Desc + "') where LM_code='" + LM_code + "'"; DataManager.RunExecuteNonQuery(ConnectionString.Constr, query); } In DataManager Class i am executing the query string. public static void RunExecuteNonQuery(string Constr, string query) { OleDbConnection myConnection = new OleDbConnection(Constr); try { myConnection.Open(); OleDbCommand myCommand = new OleDbCommand(query, myConnection); myCommand.ExecuteNonQuery(); } catch (Exception ex) { string Message = ex.Message; throw ex; } finally { if (myConnection.State == ConnectionState.Open) myConnection.Close(); } } private void toolstModify_Click_1(object sender, EventArgs e) { txtamcode.Enabled = true; jewellery.LM_code = txtamcode.Text; jewellery.M_Name = txtaccname.Text; jewellery.Desc = txtdesc.Text; jewellery.Modify(); MessageBox.Show("Data Updated Succesfully"); }

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  • Constructing a WeakReference<T> throws COMException

    - by ChaseMedallion
    The following code: IDisposable d = ... new WeakReference<IDisposable>(d); Has started throwing the following exception on SOME machines. What could cause this? System.Runtime.InteropServices.COMException: Unspecified error (Exception from HRESULT: 0x80004005 (E_FAIL)) EDIT: the machines that experience the error are running Windows Server 2008 R2. Windows Server 2012 and desktop machines running windows 7 work fine. (this is true, but I now think a different issue is the relevant difference... see below). EDIT: as an additional note, this occurred right after updating our codebase to Entity Framework 6.1.1.-beta1. In the above code, The IDisposable is a class which wraps an EF DbContext. EDIT: why the votes to close? EDIT: the stack trace of the failure ends at the WeakReference<T> constructor called in the above code: at System.WeakReference`1..ctor(T target, Boolean trackResurrection) // from here on down it's code we wrote/simple LINQ. None of this code has changed recently; // we just upgraded to EF6 and saw this failure start happening at Core.Data.EntityFrameworkDataContext.RegisterDependentDisposable(IDisposable child) at Core.Data.ServiceFactory.GetConstructorParameter[TService](Type parameterType) at System.Linq.Enumerable.WhereSelectListIterator`2.MoveNext() at System.Linq.Buffer`1..ctor(IEnumerable`1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source) at Core.Data.ServiceFactory.CreateService[TService]() at MVC controller action method EDIT: it turns out that the machines having issues with this were running AppDynamics. Uninstalling that seems to have removed the issue.

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  • Some images fails to load on Windows Server 2008

    - by Guffa
    I have an application running on a Windows Server 2008, that is processing uploaded images. Currently it successfully processes about 8000 images per day, creating 11 different sizes of each image. The problem that I have is that sometimes the application fails to load some images, I get the error "System.Runtime.InteropServices.ExternalException: A generic error occurred in GDI+.". The upload only accepts files with a JPEG extension (jpg/jpeg/jpe) or with a JPEG MIME type, and from what I can tell those images are really JPEG images. If I look at the image file in windows explorer on the server, it can successfully extract the thumbnail from the file, but if I try to open it, I get the error message "This is not a valid bitmap file, or it's format is not currently supported." from Paint. If I copy the image to my own computer, running Windows 7, there is no problem opening the image. It works in Paint, Windows Photo Viewer, Adobe Bridge, and Photoshop. If I try to load the image using Image.FromStream the same way as in the application running on the server, it loads just fine. (I have copied the file back to the server, and it still doesn't work, so there is nothing in the copying process that changes it.) When I look at the image information in Bridge, I see that the images are created using Picasa 3.0, but other than that I can't see anything special about them. I haven't yet found anyone having the same problem, or any known problems like this with the Picasa application. Has anyone had any similar problem, or know if there is something special about images created using Picasa? Is there any image codec that needs installing on the server to handle all kinds of JPEG images?

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  • Dynamic GUI Framework Designing

    - by user575715
    There is a Scenario to be developed for a 3-tier Application .We need to design a Framework or a utility sort of thing . In tradional aspect of GUI Designing , either we tend to create a static gui page and code the elements on it along with other properties of the elements such as (disabled/enabled,image source,name ,id ,which function to be called under onclick event.) or we tend to drag and drop the elements from the control pallete provided by variety of gui frameworks. Certain things i need to design a POC so that we can develop this concept. 1) There must a utility ,such that during creation of screen layout , that screen should be saved in the database(RDBMS) with a screen number. 2) All the Events related to that control should be saved in some other table which will be dynamically mapped during the calling of screen number by the user. 3) When the user call that screen ,a generic function should be invoked which'll call the screen file from the database and apply all the properties ,events,etc at runtime and the final output will be displayed to the user. This POC will help the us to customised the screens according to our usage.also all the code will seperated which can easily be used for some other development process. Thanks Amit Kalra

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  • Calling private constructors with Reflection.Emit?

    - by Jakob Botsch Nielsen
    I'm trying to emit the following IL: LocalBuilder pointer = il.DeclareLocal(typeof(IntPtr)); il.Emit(OpCodes.Ldarg_0); il.Emit(OpCodes.Stloc, pointer); il.Emit(OpCodes.Ldloca, pointer); il.Emit(OpCodes.Call, typeof(IntPtr).GetMethod("ToPointer")); il.Emit(OpCodes.Ret); The delegate I bind with has the signature void* TestDelegate(IntPtr ptr) It throws the exception Operation could destabilize the runtime. Anyone knows what's wrong? EDIT: Alright, so I got the IL working now. The entire goal of this was to be able to call a private constructor. The private constructor takes a pointer so I can't use normal reflection. Now.. When I call it, I get an exception saying Attempt by method <built method> to access method <private constructor> failed. Apparently it's performing security checks - but from experience I know that Reflection is able to do private stuff like this normally, so hopefully there is a way to disable that check?

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  • Open closed prinicple, problem

    - by Marcus
    Hi, I'm trying to apply OCP to a code snippet I have that in it's current state is really smelly, but I feel I'm not getting all the way to the end. Current code: public abstract class SomeObject {} public class SpecificObject1 : SomeObject {} public class SpecificObject2 : SomeObject {} // Smelly code public class Model { public void Store(SomeObject someObject) { if (someObject is SpecificObject1) {} else if (someObject is SpecificObject2) {} } } That is really ugly, my new approach looks like this: // No so smelly code public class Model { public void Store(SomeObject someObject) { throw new Expception("Not allowed!"); } public void Store(SpecificObject1 someObject) {} public void Store(SpecificObject2 someObject) {} } When a new SomeObject type comes along I must implement how that specific object is stored, this will break OCP cause I need to alter the Model-class. To move the store logic to SomeObject also feels wrong cause then I will violate SRP (?), becuase in this case the SomeObject is almost like a DTO, it's resposibility it not how to know to store itself. If a new implementation to SomeObject comes along who's store implementation is missing I will get a runtime error due to exception in Store method in Model class, it also feels like a code smell. This is because calling code will in the form of IEnumerable<SomeObject> sequence; I will not know the specific types of the sequence objects. I can't seem to grasp the OCP-concept. Anyone has any concrete examples or links that is a bit more than just some Car/Fruit example?

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  • C# to unmanaged dll data structures interop

    - by Shane Powell
    I have a unmanaged DLL that exposes a function that takes a pointer to a data structure. I have C# code that creates the data structure and calls the dll function without any problem. At the point of the function call to the dll the pointer is correct. My problem is that the DLL keeps the pointer to the structure and uses the data structure pointer at a later point in time. When the DLL comes to use the pointer it has become invalid (I assume the .net runtime has moved the memory somewhere else). What are the possible solutions to this problem? The possible solutions I can think of are: Fix the memory location of the data structure somehow? I don't know how you would do this in C# or even if you can. Allocate memory manually so that I have control over it e.g. using Marshal.AllocHGlobal Change the DLL function contract to copy the structure data (this is what I'm currently doing as a short term change, but I don't want to change the dll at all if I can help it as it's not my code to begin with). Are there any other better solutions?

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  • Java import statement

    - by nattyP
    I am using java on debian 5 java version "1.6.0_20" Java(TM) SE Runtime Environment (build 1.6.0_20-b02) Java HotSpot(TM) Client VM (build 16.3-b01, mixed mode, sharing) Why is there a difference between the following Case 1: import java.util.*; Case 2: import java.util.*; import java.util.Arrays; import java.util.List; Why doesnt the first case cover the second case? The code only compiles when I import Arrays and List explicitly. Code: import java.util.*; import java.util.Arrays; import java.util.List; public class Test { public static void main (String[] args) { List<Integer> i = new ArrayList(Arrays.asList(1,2,3,4,5,6,7,8,9,10)); List<Integer> j = new ArrayList(); ListIterator<Integer> n = i.listIterator(i.size()); while(n.hasPrevious()) { j.add(n.previous()); } println(j); } static void println(Object o) { System.out.println(o); } static void print(Object o) { System.out.print(o); } }

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  • Does the pointer to free() have to point to beginning of the memory block, or can it point to the interior?

    - by Lambert
    The question is in the title... I searched but couldn't find anything. Edit: I don't really see any need to explain this, but because people think that what I'm saying makes no sense (and that I'm asking the wrong questions), here's the problem: Since people seem to be very interested in the "root" cause of all the problem rather than the actual question asked (since that apparently helps things get solved better, let's see if it does), here's the problem: I'm trying to make a D runtime library based on NTDLL.dll, so that I can use that library for subsystems other than the Win32 subsystem. So that forces me to only link with NTDLL.dll. Yes, I'm aware that the functions are "undocumented" and could change at any time (even though I'd bet a hundred dollars that wcstombs will still do the same exact thing 20 years from now, if it still exists). Yes, I know people (especially Microsoft) don't like developers linking to that library, and that I'll probably get criticized for the right here. And yes, those two points above mean that programs like chkdsk and defragmenters that run before the Win32 subsystem aren't even supposed to be created in the first place, because it's literally impossible to link with anything like kernel32.dll or msvcrt.dll and still have NT-native executables, so we developers should just pretend that those stages are meant to be forever out of our reaches. But no, I doubt that anyone here would like me to paste a few thousand lines of code and help me look through them and try to figure out why memory allocations that aren't failing are being rejected by the source code I'm modifying. So that's why I asked about a different problem than the "root" cause, even though that's supposedly known to be the best practice by the community. If things still don't make sense, feel free to post comments below! :)

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  • Behavior difference between UIView.subviews and [NSView subviews]

    - by zpasternack
    I have a piece of code in an iPhone app, which removes all subviews from a UIView subclass. It looks like this: NSArray* subViews = self.subviews; for( UIView *aView in subViews ) { [aView removeFromSuperview]; } This works fine. In fact, I never really gave it much thought until I tried nearly the same thing in a Mac OS X app (from an NSView subclass): NSArray* subViews = [self subviews]; for( NSView *aView in subViews ) { [aView removeFromSuperview]; } That totally doesn’t work. Specifically, at runtime, I get this: *** Collection <NSCFArray: 0x1005208a0> was mutated while being enumerated. I ended up doing it like so: NSArray* subViews = [[self subviews] copy]; for( NSView *aView in subViews ) { [aView removeFromSuperview]; } [subViews release]; That's fine. What’s bugging me, though, is why does it work on the iPhone? subviews is a copy property: @property(nonatomic,readonly,copy) NSArray *subviews; My first thought was, maybe @synthesize’d getters return a copy when the copy attribute is specified. The doc is clear on the semantics of copy for setters, but doesn’t appear to say either way for getters (or at least, it’s not apparent to me). And actually, doing a few tests of my own, this clearly does not seem to be the case. Which is good, I think returning a copy would be problematic, for a few reasons. So the question is: how does the above code work on the iPhone? NSView is clearly returning a pointer to the actual array of subviews, and perhaps UIView isn’t. Perhaps it’s simply an implementation detail of UIView, and I shouldn’t get worked up about it. Can anyone offer any insight?

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  • #include - brackets vs quotes in XCode?

    - by Chris Becke
    In MSVC++ #include files are searched for differently depending on whether the file is enclosed in "" or <. The quoted form searches first in the local folder, then in /I specified locations, The angle bracket form avoids the local folder. This means, in MSVC++, its possible to have header files with the same name as runtime and SDK headers. So, for example, I need to wrap up the windows sdk windows.h file to undefine some macro's that cause trouble. With MSVS I can just add a (optional) windows.h file to my project as long as I include it using the quoted form :- // some .cpp file #include "windows.h" // will include my local windows.h file And in my windows.h, I can pull in the real one using the angle bracket form: // my windows.h #include <windows.h> // will load the real one #undef ConflictingSymbol Trying this trick with GCC in XCode didn't work. angle bracket #includes in system header files in fact are finding my header files with similar names in my local folder structure. The MSVC system means its quite safe to have a "String.h" header file in my own folder structre. On XCode this seems to be a major no no. Is there some way to control this search path behaviour in XCode to be more like MSVC's? Or do I just have to avoid naming any of my headers anything that might possibly conflict with a system header. Writing cross platform code and using lots of frameworks means the possibility of incidental conflicts seems large.

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  • Dereferencing the null pointer

    - by zilgo
    The standard says that dereferencing the null pointer leads to undefined behaviour. But what is "the null pointer"? In the following code, what we call "the null pointer": struct X { static X* get() { return reinterpret_cast<X*>(1); } void f() { } }; int main() { X* x = 0; (*x).f(); // the null pointer? (1) x = X::get(); (*x).f(); // the null pointer? (2) x = reinterpret_cast<X*>( X::get() - X::get() ); (*x).f(); // the null pointer? (3) (*(X*)0).f(); // I think that this the only null pointer here (4) } My thought is that dereferencing of the null pointer takes place only in the last case. Am I right? Is there difference between compile time null pointers and runtime according to C++ Standard?

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  • Should I be using Expression Blend to design really dynamic UIs?

    - by Robert Rossney
    My company's product is, at its core, a framework for developing metadata-driven UIs. I don't know how to characterize it less succinctly than that, and hope I won't need to for purposes of this question, but we'll see. I've been trying to come up to speed on WPF, and have been building UI prototypes here and there, and recently I decided to see if I could use Expression Blend to help with the design of these UIs. And I'm pretty mystified at this point. It appears to me as though Expresssion Blend is designed with the expectation that you already know all of the objects that are going to be present in the UI at design time. But our program generates these object dynamically at runtime. For instance, a data row might be presented in a horizontal StackPanel containing alternating TextBlocks (for captions) and TextBoxes (for data fields). The number of these objects depends on metadata about the number of columns in the data row. I can, pretty readily, write code that runs through a metadata record and populates a StackPanel dynamically, setting up the binding of all of the controls to properties in either the data or metadata. (A TextBox's Width might be bound to metadata, while its Text is bound to data.) But I can't even begin to figure out how to do something like this in Expression Blend. I can manually create all these controls, so that I have a set of controls that I can apply styles to and work out the visual design of the app, but it's really a pain to do this. I can write code that goes through my data model and emits XAML for all these controls, I suppose, and then copy and paste it. But I'm going to feel really stupid if it turns out there a way to do this sort of thing in Expression Blend and I've dropped back and punted because I'm too dim to figure out the right way to think of it. Is this enough information for someone to try formulating an answer?

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  • SSIS String or binary data would be truncated. The statement has been terminated.

    - by Subbarao
    When I run SSIS package from BIDS it runs fine without any error / problem. When I try to call it through a ASP.NET website I get the following error - "String or binary data would be truncated. The statement has been terminated." I checked all the columns / data to see if anything is exceeding the limit, everything is fine. I can run the package through command line using dtexec C:dtexec /f "C:\temp\MyTempPackage.dtsx", it executes without any problem . The problem is when I try to run it through ASP.NET. The following is the code that I am trying to use - //DTS Runtime Application Application app = new Application(); //DTS Package Package package = app.LoadPackage(packagePath, null); //Execute and Get the result DTSExecResult result = package.Execute(); I am making a call to a webservice from asp.net which has the above code. Both the webservice and website have identity impersonation enabled. I have identity enabled in my web.config for this <identity impersonate="true" userName="MyUserName" password="MyPassword"/> This problem is only when I am trying to import a Excel file (.xlsx) when I import a .txt file everything is fine. Excel Import blew up in both 32bit and 64bit enviornments. Help on how to make this to work is greatly appreciated.

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  • How do I prevent qFatal() from aborting the application?

    - by Dave
    My Qt application uses Q_ASSERT_X, which calls qFatal(), which (by default) aborts the application. That's great for the application, but I'd like to suppress that behavior when unit testing the application. (I'm using the Google Test Framework.) I have by unit tests in a separate project, statically linking to the class I'm testing. The documentation for qFatal() reads: Calls the message handler with the fatal message msg. If no message handler has been installed, the message is printed to stderr. Under Windows, the message is sent to the debugger. If you are using the default message handler this function will abort on Unix systems to create a core dump. On Windows, for debug builds, this function will report a _CRT_ERROR enabling you to connect a debugger to the application. ... To supress the output at runtime, install your own message handler with qInstallMsgHandler(). So here's my main.cpp file: #include <gtest/gtest.h> #include <QApplication> void testMessageOutput(QtMsgType type, const char *msg) { switch (type) { case QtDebugMsg: fprintf(stderr, "Debug: %s\n", msg); break; case QtWarningMsg: fprintf(stderr, "Warning: %s\n", msg); break; case QtCriticalMsg: fprintf(stderr, "Critical: %s\n", msg); break; case QtFatalMsg: fprintf(stderr, "My Fatal: %s\n", msg); break; } } int main(int argc, char **argv) { qInstallMsgHandler(testMessageOutput); testing::InitGoogleTest(&argc, argv); return RUN_ALL_TESTS(); } But my application is still stopping at the assert. I can tell that my custom handler is being called, because the output when running my tests is: My Fatal: ASSERT failure in MyClass::doSomething: "doSomething()", file myclass.cpp, line 21 The program has unexpectedly finished. What can I do so that my tests keep running even when an assert fails?

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  • Python: eliminating stack traces into library code?

    - by Mark Harrison
    When I get a runtime exception from the standard library, it's almost always a problem in my code and not in the library code. Is there a way to truncate the exception stack trace so that it doesn't show the guts of the library package? For example, I would like to get this: Traceback (most recent call last): File "./lmd3-mkhead.py", line 71, in <module> main() File "./lmd3-mkhead.py", line 66, in main create() File "./lmd3-mkhead.py", line 41, in create headver1[depotFile]=rev TypeError: Data values must be of type string or None. and not this: Traceback (most recent call last): File "./lmd3-mkhead.py", line 71, in <module> main() File "./lmd3-mkhead.py", line 66, in main create() File "./lmd3-mkhead.py", line 41, in create headver1[depotFile]=rev File "/usr/anim/modsquad/oses/fc11/lib/python2.6/bsddb/__init__.py", line 276, in __setitem__ _DeadlockWrap(wrapF) # self.db[key] = value File "/usr/anim/modsquad/oses/fc11/lib/python2.6/bsddb/dbutils.py", line 68, in DeadlockWrap return function(*_args, **_kwargs) File "/usr/anim/modsquad/oses/fc11/lib/python2.6/bsddb/__init__.py", line 275, in wrapF self.db[key] = value TypeError: Data values must be of type string or None.

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  • VB.net avoiding cross thread exception with extension method

    - by user574632
    Hello I am trying to implement a solution for updating form controls without using a delegate. I am attempting to use the 1st solution on this page: http://www.dreamincode.net/forums/blog/143/entry-2337-handling-the-dreaded-cross-thread-exception/ Imports System.ComponentModel Imports System.Runtime.CompilerServices Public Module MyInvoke <Extension()> _ Public Sub CustomInvoke(Of T As ISynchronizeInvoke)(ByVal control As T, ByVal toPerform As Action(Of T)) If control.InvokeRequired Then control.Invoke(toPerform, New Object() {control}) toPerform(control) End If End Sub End Module The site gives this as example of how to use: Label1.CustomInvoke(l => l.Text = "Hello World!") But i get 'l' is not declared error. As you can see im very new to VB or any OOP. I can get the second solution on that page to work (using delegates) but i have quite a few things to do in this thread and it seems like i would need to write a new delegate sub for each thing, which seems wasteful. What i need to do is select the 1st item from a combobox, update a textbox.text with the selected item, and pass the selected item to a function. Then wait for x seconds and start again, selecting the second item. I can get it to work in a single threaded application, but i need the interface to remain responsive. Any help greatly appreciated. EDIT: OK so changing the syntax worked for the example. However if i change it from Label1.CustomInvoke(Sub(l) l.text = "hello world!") (which worked just fine) to: Dim indexnumber As Integer = 0 ComboBox1.CustomInvoke(Sub(l) l.SelectedIndex = indexnumber) I get a cross threading error as though i didnt even use this method: Cross-thread operation not valid: Control 'ComboBox1' accessed from a thread other than the thread it was created on. So now im back to where i started? Any further help very much appreciated.

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  • Segmentation fault on certain inputs and not others

    - by Brandon Schwandt
    Heres a function I wrote that has some debugging elements in it already. When i enter either a "y" or a "Y" as the input I get a segmentation fault during runtime. When I enter any other value the code runs. The seg fault kicks out after it scans and gives me the response but before the "scan worked" line is output. DOn't know why it would act like this only on these values. If anyone needs the function call I have that as well. query_user(char *response [10]) { printf("response after query call before clear=%s\n",response); strcpy(response,""); printf("response after clearing before scan=%s\n",response); printf("Enter another person into the line? y or n\n"); scanf("%s", response); printf("response after scan=%s\n",response); printf("scan worked"); } main() { char response [10]; strcpy(response,"y"); printf("response=%s\n",response); printf("When finished with program type \"done\" to exit\n"); while (strcmp(response,"done") != 0) { printf("response after while loop and before query call=%s\n",response); query_user(&response); } } output on error: response after query call before clear=y response after clearing before scan= Enter another person into the line? y or n y response after scan=y Segmentation Fault (core dumped) output on non-error: response after query call before clear=y response after clearing before scan= Enter another person into the line? y or n n response after scan=n scan worked Cycle number 0 (program continues to run outside this function)

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  • Why won't EF4 generate a method to support my Function Import?

    - by Deane
    I have a stored proc in my database which returns an integer. I added a Function Import to my model. This appears in the EDMX file: <Function Name="GetTotalEntityCount" Aggregate="false" BuiltIn="false" NiladicFunction="false" IsComposable="false" ParameterTypeSemantics="AllowImplicitConversion" Schema="dbo" /> However, no method actually gets generated for this. It should be top level, right? using (MyContext context = new MyContext()) { context.MyMethodShouldBeRightHere(); } Nothing appears in Intellisense, I've gone through the designer.cs file and there's nothing in there, and reflected the DLL...nothing. The code generator is just not generating any code to support this stored proc. I added another table to my database and updated the model, and that came in, so the model will update, it's just specifically ignoring this stored proc. I've tried everything I can think of, and consulted every resource I can find, and as near as I can tell, I'm doing everything right. I'm using EF4, database-first. (I'm pretty sure on the version, anyway. This shows up in the generated file: Runtime Version:4.0.30319.1 )

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  • OOP design issue: Polymorphism

    - by Graham Phillips
    I'm trying to solve a design issue using inheritance based polymorphism and dynamic binding. I have an abstract superclass and two subclasses. The superclass contains common behaviour. SubClassA and SubClassB define some different methods: SubClassA defines a method performTransform(), but SubClassB does not. So the following example 1 var v:SuperClass; 2 var b:SubClassB = new SubClassB(); 3 v = b; 4 v.performTransform(); would cause a compile error on line 4 as performTransform() is not defined in the superclass. We can get it to compile by casting... (v as SubClassA).performTransform(); however, this will cause a runtime exception to be thrown as v is actually an instance of SubClassB, which also does not define performTransform() So we can get around that by testing the type of an object before casting it: if( typeof v == SubClassA) { (cast v to SubClassA).performTransform(); } That will ensure that we only call performTransform() on v's that are instances of SubClassA. That's a pretty inelegant solution to my eyes, but at least its safe. I have used interface based polymorphism (interface meaning a type that can't be instantiated and defines the API of classes that implement it) in the past, but that also feels clunky. For the above case, if SubClassA and SubClassB implemented ISuperClass that defined performTransform, then they would both have to implement performTransform(). If SubClassB had no real need for a performTransform() you would have to implement an empty function. There must be a design pattern out there that addresses the issue.

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  • java.lang.ClassNotFoundException in Netbeans. 5 hours to fix

    - by user1304281
    Hi I've got to submit an interpreter assignment tonight and all of a sudden it stopped working! It was working yesterday but now when I try to create a class instance at runtime I get classnotfoundexception. My project has no libraries or dependencies, I've written everything myself. I've googled around and it seems to be an issue with classpath but I've had no luck fooling with the project properties on netbeans. Here's some code: package interpreter; import interpreter.bytecode.ByteCode; import java.io.*; import java.lang.reflect.*; class ByteCodeLoader { //.... String codeClass = CodeTable.CodeTable.get(args[0]); ByteCode bytecode = (ByteCode)(Class.forName("interpreter.bytecode."+codeClass).newInstance()); //this throws exception } all of my ByteCodes are contained within a subpackage of interpreter called interpreter.bytecode. I'll be watching this thread so I can answer/clarify any questions immediately. Thanks for your time!

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  • Creating a C++ DLL and then using it in C#

    - by Major
    Ok I'm trying to make a C++ DLL that I can then call and reference in a c# App. I've already made a simple dll using the numberous guides out there, however when I try to reference it in the C# app I get the error Unable to load DLL 'SDES.dll': The specified module could not be found. The code for the program is as follows (bear with me I'm going to include all the files) //These are the DLL Files. ifndef TestDLL_H define TestDLL_H extern "C" { // Returns a + b __declspec(dllexport) double Add(double a, double b); // Returns a - b __declspec(dllexport) double Subtract(double a, double b); // Returns a * b __declspec(dllexport) double Multiply(double a, double b); // Returns a / b // Throws DivideByZeroException if b is 0 __declspec(dllexport) double Divide(double a, double b); } endif //.cpp include "test.h" include using namespace std; extern double __cdecl Add(double a, double b) { return a + b; } extern double __cdecl Subtract(double a, double b) { return a - b; } extern double __cdecl Multiply(double a, double b) { return a * b; } extern double __cdecl Divide(double a, double b) { if (b == 0) { throw new invalid_argument("b cannot be zero!"); } return a / b; } //C# Program using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; namespace ConsoleApplication1 { class Program { [DllImport("SDES.dll")] public static extern void SimulateGameDLL(int a, int b); static void Main(string[] args) { SimulateGameDLL(1, 2); //Error here... } } } Anyone have any idea's what I may be missing in my program? Let me know if I missed some code or if you have any questions.

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  • Can I have the gcc linker create a static libary?

    - by Lucas Meijer
    I have a library consisting of some 300 c++ files. The program that consumes the library does not want to dynamically link to it. (For various reasons, but the best one is that some of the supported platforms do not support dynamic linking) Then I use g++ and ar to create a static library (.a), this file contains all symbols of all those files, including ones that the library doesn't want to export. I suspect linking the consuming program with this library takes an unnecessary long time, as all the .o files inside the .a still need to have their references resolved, and the linker has more symbols to process. When creating a dynamic library (.dylib / .so) you can actually use a linker, which can resolve all intra-lib symbols, and export only those that the library wants to export. The result however can only be "linked" into the consuming program at runtime. I would like to somehow get the benefits of dynamic linking, but use a static library. If my google searches are correct in thinking this is indeed not possible, I would love to understand why this is not possible, as it seems like something that many c and c++ programs could benefit from.

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  • Code Contracts: Do we have to specify Contract.Requires(...) statements redundantly in delegating me

    - by herzmeister der welten
    I'm intending to use the new .NET 4 Code Contracts feature for future development. This made me wonder if we have to specify equivalent Contract.Requires(...) statements redundantly in a chain of methods. I think a code example is worth a thousand words: public bool CrushGodzilla(string weapon, int velocity) { Contract.Requires(weapon != null); // long code return false; } public bool CrushGodzilla(string weapon) { Contract.Requires(weapon != null); // specify contract requirement here // as well??? return this.CrushGodzilla(weapon, int.MaxValue); } For runtime checking it doesn't matter much, as we will eventually always hit the requirement check, and we will get an error if it fails. However, is it considered bad practice when we don't specify the contract requirement here in the second overload again? Also, there will be the feature of compile time checking, and possibly also design time checking of code contracts. It seems it's not yet available for C# in Visual Studio 2010, but I think there are some languages like Spec# that already do. These engines will probably give us hints when we write code to call such a method and our argument currently can or will be null. So I wonder if these engines will always analyze a call stack until they find a method with a contract that is currently not satisfied? Furthermore, here I learned about the difference between Contract.Requires(...) and Contract.Assume(...). I suppose that difference is also to consider in the context of this question then?

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  • Java: Copying an exe-file and launching afterwards fails

    - by Philip
    Hi, I want to copy an existing .exe-file from one directory to another and launch it afterwards with Java. Like this: FileIO.copy( new File( sourceFile ), new File( targetFile ) ); System.out.println( "Existing: " + new File( targetFile ).exists() ); System.out.println( "Launching " + targetFile ); String cmd[] = { targetFile }; Process p = Runtime.getRuntime().exec( cmd ); p.waitFor(); System.out.println( "Result: " + p.exitValue() ); The output is like this: Existing: true Launching C:\test\Launcher.new.exe Result: 2 So Java says that the file is valid and existing, but Windows just can't launch the process because it thinks the file is not there. The pathes are absolute and with backslashes. I also have all permissions on the files so I'm allowed to execute them. The Launcher.new.exe is generated by Launch4j, so it's more or less standalone. At least it doesn't depend on DLLs in the same folder. But strange: It works when I copy and launch the notepad.exe. One more strange thing: If I don't copy the file by Java but by hand, the launching also fails with the same error. OS is Vista with SP1. Any clue?

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