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• Is Classic ADO still viable for a mixed managed/unmanaged App?

  - by Andy Dent

  We have a complex architecture with much logic in unmanaged code that needs database access. Currently this is via ODBC drivers and MFC classes and we're considering the issues of migrating our abstraction layer to use ADO or ADO.Net. In the latter case we'd have to be pushing database logic back up into the .Net layer. I'm trying to decide if the pain of invoking the database via .Net callbacks is offset by the improvements in ADO.Net. The Wikipedia comparison was interesting although I'm not sure I believe all the points in the comparison table (eg: does ADO.Net always use XML to pass data?). A 2005 comparison shows ADO.Net performing dramatically faster. Microsoft's guide to ADO.Net for ADO programmers suggests we will gain much from going to ADO.Net especially the way that data is available in native (.Net) types rather than solely through OLEAutomation's Variant.

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• mac, java 1.5: javax.mail not recognized as a jar file

  - by Helpme

  hello fellow java developers, Having a little issue with creating a java application on a macintosh computer (snow leopard). I've set up my application in eclipse, added all of the appropriate jar files, but for some reason the code is not recognizing some of my variables as valid types. I've imported the libraries via import javax.mail.*; import javax.mail.internet.*; These libraries are not recognized by the application. BUT I've put them on the build path! Any advice on how to fix this?

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• Why does the Scala compiler disallow overloaded methods with default arguments?

  - by soc

  While there might be valid cases where such method overloadings could become ambiguous, why does the compiler disallow code which is neither ambiguous at compile time nor at run time? Example: // This fails: def foo(a: String)(b: Int = 42) = a + b def foo(a: Int) (b: Int = 42) = a + b // This fails, too. Even if there is no position in the argument list, // where the types are the same. def foo(a: Int) (b: Int = 42) = a + b def foo(a: String)(b: String = "Foo") = a + b // This is OK: def foo(a: String)(b: Int) = a + b def foo(a: Int) (b: Int = 42) = a + b // Even this is OK. def foo(a: Int)(b: Int) = a + b def foo(a: Int)(b: String = "Foo") = a + b val bar = foo(42)_ // This complains obviously ... Are there any reasons why these restrictions can't be loosened a bit? Especially when converting heavily overloaded Java code to Scala default arguments are a very important and it isn't nice to find out after replacing plenty of Java methods by one Scala methods that the spec/compiler imposes arbitrary restrictions.

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• How SqlDataAdapter works internally?

  - by tigrou

  I wonder how SqlDataAdapter works internally, especially when using UpdateCommand for updating a huge DataTable (since it's usually a lot faster that just sending sql statements from a loop). Here is some idea I have in mind : It creates a prepared sql statement (using SqlCommand.Prepare()) with CommandText filled and sql parameters initialized with correct sql types. Then, it loops on datarows that need to be updated, and for each record, it updates parameters values, and call SqlCommand.ExecuteNonQuery(). It creates a bunch of SqlCommand objects with everything filled inside (CommandText and sql parameters). Several SqlCommands at once are then batched to the server (depending of UpdateBatchSize). It uses some special, low level or undocumented sql driver instructions that allow to perform an update on several rows in a effecient way (rows to update would need to be provided using a special data format and a the same sql query (UpdateCommand here) would be executed against each of these rows).

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• C++, create an instance from a static method

  - by Manux

  Hello, let's say I want my users to use only one class, say SpecialData. Now, this data class would have many methods, and depending on the type of data, the methods do different things, internally, but return externally similar results. Therefore my wanting to have one "public" class and other "private", child classes that would change the behavior of methods, etc... It would be amazingly more simple for some types of data that need to be built to do something like this: SpecialData& sm = SpecialData::new_supermatrix(); and new_supermatrix() would return a SuperMatrix instance, which inherits from most behaviors of SpecialData. my header: static SpecialData& new_supermatrix(); my cpp: SpecialData& SpecialData::new_supermatrix()(){ return SuperMatrix(MATRIX_DEFAULT_MAGNITUDE,1000,1239,FLOAT32,etc...); } The problem is, I get this error, which is probably logical due to the circumstances: invalid initialization of non-const reference of type ‘SpecialData&’ from a temporary of type ‘SpecialData’ So, any ideas?

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• Generic TypeIdenitifier convertion.How?

  - by John

  How do I convert the TypeIdenitifier to a class type? I need to use implicit convertion. type TMyChildArray<T>=class(TMyArray<T>) private FData:Array of T; procedure AddEnd(); end; TTypeIdenitifierParentClass=class(TAnotherParentClass) protected TestField:Cardinal; end; procedure TMyChildArray<T>.AddEnd(); var elem:T; begin for elem in Fdata do TTypeIdenitifierParentClass(elem).TestField:=0; end; I get "Invalid typecast" on the implicit convertion "TTypeIdenitifierParentClass(elem).TestField:=0;". The principle I want to use is that the TypeIdenitifier will represent a class that descends from TTypeIdenitifierParentClass.There are many class types,but all of them descend that class. How do I do this?

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• Xcode automatically converts the object to NSArray

  - by Farrukh Javeid

  I have been working on an app and during the development, I am facing a very strange problem. I have a NSMutableArray tempSortedArray, which is full of objects of Store types. All the objects are valid as I can see them in my GUI, the problem arises when I iterate through the array, at index 90, which can be generally anyone, the XCode converts the Store object to NSMutableArray object. Any idea, why this is happening. This is the code to check out what I am doing: NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"cashBack" ascending:NO]; NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor]; NSArray *sortedArray = [storesArray sortedArrayUsingDescriptors:sortDescriptors]; for (int i = 0; i < [tempSortedArray count]; i++) { Store *currentStore = [tempSortedArray objectAtIndex:i]; NSLog(@"store class: %@", [currentStore.class description]); if (currentStore.cashBackTypeString != (id)[NSNull null]) { //do whatever is required to do here }

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• How do I avoid boxing/unboxing when extending System.Object?

  - by Robert H.

  I'm working on an extension method that's only applicable to reference types. I think, however, it's currently boxing and unboxing the the value. How can I avoid this? namespace System { public static class SystemExtensions { public static TResult GetOrDefaultIfNull<T, TResult>(this T obj, Func<T, TResult> getValue, TResult defaultValue) { if (obj == null) return defaultValue; return getValue(obj); } } } Example usage: public class Foo { public int Bar { get; set; } } In some method: Foo aFooObject = new Foo { Bar = 1 }; Foo nullReference = null; Console.WriteLine(aFooObject.GetOrDefaultIfNull((o) => o.Bar, 0)); // results: 1 Console.WriteLine(nullReference.GetOrDefaultIfNull((o) => o.Bar, 0)); // results: 0

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• Best way to test instance methods without running __init__

  - by KenFar

  I've got a simple class that gets most of its arguments via init, which also runs a variety of private methods that do most of the work. Output is available either through access to object variables or public methods. Here's the problem - I'd like my unittest framework to directly call the private methods called by init with different data - without going through init. What's the best way to do this? So far, I've been refactoring these classes so that init does less and data is passed in separately. This makes testing easy, but I think the usability of the class suffers a little. EDIT: Example solution based on Ignacio's answer: import types class C(object): def __init__(self, number): new_number = self._foo(number) self._bar(new_number) def _foo(self, number): return number * 2 def _bar(self, number): print number * 10 #--- normal execution - should print 160: ------- MyC = C(8) #--- testing execution - should print 80 -------- MyC = object.__new__(C) MyC._bar(8)

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• List<T> add method in C#

  - by Nano HE

  Hello. As I know. List Add method works as below. List<string> cities = new List<string>(); cities.Add("New York"); cities.Add("Mumbai"); cities.Add("Berlin"); cities.Add("Istanbul"); If I designed the data structure as this List<object> lstObj = new List<object>(); if (true) // string members { cities.Add("New York"); cities.Add("Istanbul"); } else // List obj members here { List<object> AListObject= new List<object>(); cities.Add(AListObject); // how to handle this? } Does the List Add method works or not if I add different types members in the same function.

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• Shared WCF client code between .NET and Silverlight apps?

  - by Eduardo Scoz

  I'm developing a .NET application that will have both a WinForms and a Silverlight client. Although the majority of code will be in the server, I'll need to have quite a bit of logic in the clients as well, and I would like to keep the client library code the same. From what I could figure out so far, I need to have two different project types, a class library and a Silverlight class library, and link the files from one project to the other. This seems kind of lame, but it works for simple code. My problem, though, is that the code generated by the SVCUtil.exe to access WCF services is different from the code generated by the slsvcutil.exe, and the silverlight code is actually incompatible with the .NET one: I get a bunch of problems with the System.ServiceModel.Channel classes when I try to import the class into .NET. Has anybody done anything similar to this before? What am I doing wrong?

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• How to determine MIME Type set by htaccess in PHP

  - by Ed Marty

  I have a .htaccess file set up to define specific MIME types in directory root/a/b/, and all of the files are in the same directory. I have a php file that wants to serve those files, in directory root/c/, and needs to determine the content-type as defined by the .htaccess file. Is there any way to do this? PHP version is 5.1.6. mime_content_type returns text/plain, and I'd rather not try to parse the .htaccess file manually. I can move the file if necessary.

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• Getting .NET schema for a stored procedure result

  - by PHeiberg

  I have a couple of stored procedures in T-SQL where each stored procedure has a fixed schema for the result set. I need to map the result sets for each procedure to a POCO object and need the column name and type for each column in the result set. Is there a quick way of accessing the information? The best way I have found so far is accessing each stored procedure from .NET and writing my own extension method on a IDataReader/IDataRecord for dumping the information (column names and types) out. Example, a stored procedure executing the following query: SELECT Id, IntField, NullableIntField, VarcharField, DateField FROM SomeTable would require me to have the mapping information: Id - Guid IntField - System.Int32 NullableIntField - Nullable<System.Int32> VarcharField - String DateField - DateTime

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• Can functions like sin() be redefined, in Fortran, C or Java?

  - by EOL

  Can a mathematical function like sin() be redefined, in Fortran, C or Java code, while preserving the default behavior of other mathematical functions like cos()? Or can another function named sin() but that accepts different argument types be defined in addition to the built-in sin()? I am interested in general features of these languages (I am thinking of applications like the implementation of non-usual number algebras). I tried to define a sin() function in a Fortran 95 program, but the intrinsic sin() function was called instead… Is there a way around this? what about C and Java?

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• How to use #ifdef entities as part of functions in header files

  - by Crazyjavahacking

  I would like to ask if it is possible to use the entities defined in #ifdef block in header files. To be clear, I have following code: #ifdef #include <winsock2.h> #define SOCKET_HANDLE SOCKET #define CONNECTION_HANDLE SOCKET #endif SOCKET_HANDLE createServerSocket(const char* hostAddress, short port); I am Java developer and this seems completely fine for me. However compiler has a problem with this. Can you explain why is that code a problem? Also how can I force to compile it. (The idea is to have generic interface and conditional compilation to determine real types according to running platform at compile time.) Thanks

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• Is INT the correct datatype for ABS(CHECKSUM(NEWID()))?

  - by Chad Sellers

  I'm in the process of creating unique customers ID's that is an alternative Id for external use. In the process of adding a new column "cust_uid" with datatype INT for my unique ID's, When I do an INSERT into this new column: Insert Into Customers(cust_uid) Select ABS(CHECKSUM(NEWID())) I get a error: Could not create an acceptable cursor. OLE DB provider "SQLNCLI" for linked server "SHQ2IIS1" returned message "Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done. I've check all data types on both tables and the only things that has changed is the new column in both tables. The update is being done on one Big @$$ table...and for reasons above my pay grade, we would like to have new uid's that are different form the one's that we currently have "so users don't know how many accounts we actually have." Is INT the correct datatype for ABS(CHECKSUM(NEWID())) ?

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• Cleanest way to store lists of filter coefficients in a C header

  - by Nick T

  I have many (~100 or so) filter coefficients calculated with the aid of some Matlab and Excel that I want to dump into a C header file for general use, but I'm not sure what the best way to do this would be. I was starting out as so: #define BUTTER 1 #define BESSEL 2 #define CHEBY 3 #if FILT_TYPE == BUTTER #if FILT_ROLLOFF == 0.010 #define B0 256 #define B1 512 #define B2 256 #define A1 467 #define A2 -214 #elif FILT_ROLLOFF == 0.015 #define B0 256 #define B1 512 // and so on... However, if I do that and shove them all into a header, I need to set the conditionals (FILT_TYPE, FILT_ROLLOFF) in my source before including it, which seems kinda nasty. What's more, if I have 2+ different filters that want different roll-offs/filter types it won't work. I could #undef my 5 coefficients (A1-2, B0-2) in that coefficients file, but it still seems wrong to have to insert an #include buried in code.

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• Can I serialize a BitArray to XML?

  - by SimonNet

  Hello I have a business class which I need to serialize to xml. It has a BitArray property. I have decorated it with [XmlAttribute] but the serialization is failing with To be XML serializable, types which inherit from ICollection must have an implementation of Add(System.Boolean) at all levels of their inheritance hierarchy. System.Collections.BitArray does not implement Add(System.Boolean). I am not sure whether its possible to serialize to xml? If not what would be an efficient means of serializing the BitArray Thanks for looking

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• Can I attach a .NET TraceListener to an externally running process?

  - by BBlake

  I am developing an application scheduling program that will run other applications using System.Diagnostics.Process. The external applications are of various types (some .NET and some not). For those external apps that have trace logging enabled, is there a way that I can attach the tracelistener of the parent/calling application to listen to and record all the trace output from the child/called application to the parent application's trace output? This is not primarily for debugging purposes. This is more to track trace output from all the various scheduled applications by collecting it into one place as much as possible. The scheduler app is still in the early design stages, but will be .NET, and I'm trying to clear up potential design issues before I get into it too far.

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• Amazon EC2 prices for Windows Instance?

  - by Abhishek Gupta

  Hello Guys , I want to ask from some Amazon cloud technology Experts , that is it profitable to deploy our web application on amazon cloud as compared to normal server? Currently there are micro,small, large and other types of instances available , if we start from micro instance then we realize that our app needs some more CPU cycle and Ram then how can we dynamically move to next more powerful instance automatically at runtime. What is the approx minimum yearly cost for a single EC2 windows small instance? I wnat to deploy a simple Online quiz application (ASP.net based) on Amazon Cloud which at a time can have maximum of 500 users only. Please suggest me as I m very new to Cloud .Should I go for Azure or Amazon?

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• Is both approach same ?

  - by Harikrishna

  I have one datatable which is not bindided and records are coming from the file by parsing it in the datatable dynamically every time. Now there is three columns in the datatable Marks1,Marks2 and FinalMarks. And their types is decimal. Now for making addition of columns Marks1 and Marks2 's records and store it into FinalMarks column,For that what I do is : datatableResult.Columns["FinalMarks"].Expression="Marks1+Marks2"; It's works properly. It can be done in other way also is foreach (DataRow r in datatableResult.Rows) { r["FinalMarks"]=Convert.ToDecimal(r["Marks1"])+Convert.ToDecimal(r["Marks2"]); } Now I don't know that which is the best way to do this means performance wise. Is first approach same as second approach in background means is both approach same or what?

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• Are C++ Reads and Writes of an int atomic

  - by theschmitzer

  I have two threads, one updating an int and one reading it. This value is a statistic where the order of the read and write is irrelevant. My question is, do I need to synchronize access to this multi-byte value anyway? Or, put another way, can part of the write be complete and get interrupted, and then the read happen. For example, think of value = ox0000FFFF increment value to 0x00010000 Is there a time where the value looks like 0x0001FFFF that I should be worried about? Certainly the larger the type, the more possible something like this is I've always synchronized these types of accesses, but was curious what the community thought.

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• How do I validate that my the openid.op_endpoint when a request is completed.

  - by Sam Saffron

  I have an Open ID based authentication system on my site. Occasionally users will have an account registered under [email protected] and they will attempt to login using the google open id provider https://www.google.com/accounts/o8/id, in this case I would like to automatically associate the account and log them in. When the process is done I get a payload from somewhere claiming that openid.op_endpoint=https://www.google.com/accounts/o8/id. My question: Can I trust openid.op_endpoint to be correct? Can this be spoofed somehow by a malicious openid provider? For illustration, lets say someone types in http://evil.org as their openid provider, can I somehow end up getting a request back that claims openid.op_endpoint is google? Do I need to store extra information against the nonce to validate? The spec is kind of tricky to understand

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• Handling multiple accounts in Android app

  - by bebeTech

  I would like to build an application that caters for multiple accounts (eg. home, work) and account types (e.g. ISP, VoIP, Mobile). Essentially, I would like to get the user to create the accounts they want and then have all the accounts listed on the start page grouped by type. For example: ISP: - Home - Work Mobile: - Mum - Dad When you click on the account, it would take you to another screen where I do a bunch of calcs and display the results. I currently do this via multiple apps but am looking at consolidating into the one app. I am just not sure where to start or how I go about achieving this? The way the Contacts app works is a good example of what I am wanting to do.

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• c++ function overloading, making fwrite/fread act like PHP versions

  - by Newbie

  I'm used to the PHP fwrite/fread parameter orders, and i want to make them the same in C++ too. I want it to work with char and string types, and also any data type i put in it (only if length is defined). I am total noob on c++, this is what i made so far: size_t fwrite(FILE *fp, const std::string buf, const size_t len = SIZE_MAX){ if(len == SIZE_MAX){ return fwrite(buf.c_str(), 1, buf.length(), fp); }else{ return fwrite(buf.c_str(), 1, len, fp); } } size_t fwrite(FILE *fp, const void *buf, const size_t len = SIZE_MAX){ if(len == SIZE_MAX){ return fwrite((const char *)buf, 1, strlen((const char *)buf), fp); }else{ return fwrite(buf, 1, len, fp); } } Should this work just fine? And how should this be done if i wanted to do it the absolutely best possible way?

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