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  • Linq to SQL - How to compare against a collection in the where clause?

    - by Sgraffite
    I'd like to compare against an IEnumerable collection in my where clause. Do I need to manually loop through the collection to pull out the column I want to compare against, or is there a generic way to handle this? I want something like this: public IEnumerable<Cookie> GetCookiesForUsers(IEnumerable<User> Users) { var cookies = from c in db.Cookies join uc in db.UserCookies on c.CookieID equals uc.CookieID join u in db.Users on uc.UserID equals u.UserID where u.UserID.Equals(Users.UserID) select c; return cookies.ToList(); } I'm used to using the lambda Linq to SQL syntax, but I decided to try the SQLesque syntax since I was using joins this time. What is a good way to do this?

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  • Which HRESULT literal constant will fail the SUCCEEDED() macro?

    - by Hamish Grubijan
    Definition of SUCCEEDED(): #define SUCCEEDED(hr) (((HRESULT)(hr)) >= 0) Background: When an Ok button is clicked on a dialog, I need to return an HRESULT value hr such that SUCCEEDED(hr) is true. If Cancel button is clicked, I need to return a negative value. I could have used bools, but that would break the existing pattern (usually the hr values come from depths of system dlls). So, I know I can return S_OK on Ok, but what do I return on Cancel? I could just return (HRESULT)-1;, but there must be a better way - some HRESULT literal constant which has negative value and represents a generic failure. S_FALSE is not it, for it's value is defined as 1L. Please help me find the right constant.

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  • I want to be able to derive from a class internally, but disallow class in other assemblies to derive from the class

    - by Rokke
    Hej I have the following setup: Assembly 1 public abstract class XX<T> : XX where T: YY { } public abstract class XX {} Assembly 2 public class ZZ : YY {} public class ZZFriend : XX<ZZ> {} I use this feature in reflection when in YY: public class YY { public Type FindFriend { return GetType().Assembly.GetTypes().FirstOrDefault( t => t.BaseType != null && t.BaseType.IsGenericType && typeof(XX).IsAssignableFrom(t) && t.BaseType.GetGenericArguments().FirstOrDefault() == GetType()); } } I would like do disallow inheritance of the non generic class XX like: public class ZZFriend: XX {} Alternatively, I need a method like (that can be used in the reflection in YY.FindFrind()): public Type F(Type t) { return GetTypeThatIsGeneric(XX, Type genericTypeParameter); } That can be used in YY as: Typeof(XX<ZZ) == F(typeof(GetType()) Hope that makes sense... Thanks in advance Søren Rokkedal

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  • How would one call std::forward on all arguments in a variadic function?

    - by Noah Roberts
    I was just writing a generic object factory and using the boost preprocessor meta-library to make a variadic template (using 2010 and it doesn't support them). My function uses rval references and std::forward to do perfect forwarding and it got me thinking...when C++0X comes out and I had a standard compiler I would do this with real variadic templates. How though, would I call std::forward on the arguments? template < typename ... Params void f(Params ... params) // how do I say these are rvalue reference? { y(std::forward(...params)); //? - I doubt this would work. } Only way I can think of would require manual unpacking of ...params and I'm not quite there yet either. Is there a quicker syntax that would work?

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  • Accessing facebook sdk result Object using .NET 3.5 API?

    - by John K
    Consider the following in .NET 3.5 (using the Bin\Net35\Facebook*.dll assemblies): using Facebook; var app = new FacebookApp(); var result = app.Get("me"); // want to access result properties with no dynamic ... in the absence of the C# 4.0 dynamic keyword this provides only generic object members. How best should I access the facebook properties of this result object? Are there helper or utility methods or stronger types in the facebook C# SDK, or should I use standard .NET reflection techniques?

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  • [C++] Boost test: catch user defined exceptions

    - by user231536
    If I have user defined exceptions in my code, I can't get Boost test to consider them as failures. For example, BOOST_AUTO_TEST_CASE_EXPECTED_FAILURES(MyTest,1) BOOST_AUTO_TEST_CASE(MyTest) { // code which throws user defined exception, not derived from std::exception. } I get a generic message: Caught exception: .... unknown location(0):.... It does not recognize this error as a failure since it is not a std::exception. So it does not honor the expected_failures clause. How do I enforce that the piece of code should always throw an exception? THis seems to be a useful thing to want. In case future code changes cause the code to pass and the exception is not thrown, I want to know that.

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  • Designing Relational Survey Questionnaires Database

    - by user1213055
    I'm trying to build a simple sql database for following access database. Currently there is no relationship and I just have two tables male and female with 6 sections in each form. How can I design it a better way so end user can connect to the database and analyze using STATA or SPSS ? I'm really confused whether I should create one table with all fields or break down into different tables. The database is specific to this study only so I'm not looking for a generic survey database where user can create surveys and capture them. Any feedback or suggestion is much appreciated.

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  • When should one let an application crash because of an exception in Java (design issue)?

    - by JVerstry
    In most cases, it is possible to catch exceptions in Java, even unchecked ones. But, it is not necessarily possible to do something about it (for example out of memory). For other cases, the issue I am trying to solve is a design principle one. I am trying to set-up a design principle or a set of rules indicating when one should give up on an exceptional situation, even if it is detected in time. The objective is trying to not crash the application as much as possible. Has someone already brainstormed and communicated about this? I am looking for specific generic cases and possible solutions, or thumb-rules. UPDATE Suggestions so far: Stop running if data coherency can be compromised Stop running if data can be deleted Stop running if you can't do anything about it (Out of memory...) Stop running if key service is not available or becomes unavailable and cannot be restarted If application must be stopped, degrade as gracefully as possible Use rollbacks in db transactions Log as much relevant information as you can Notify the developers

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  • What is the sense of "Feature Oriented Programming" (FOP) in C++, and would it make sense in Java an

    - by ivan_ivanovich_ivanoff
    Hello! Sadly, I can't remember where I read it, but... ...in C++ you can derive a class from a template parameter. Im pretty sure it was called Feature Oriented Programming (FOP) and meant to be somehow useful. It was something like: template <class T> class my_class : T { // some very useful stuff goes here ;) } My questions about this: What is the sense of such pattern? Since this it not possible in Java / C#, how this pattern is achieved in these languages? Can it be expected to be implemented in Java / C# one day? (Well, first Java would need to get rid of type erasure) EDIT: I'm really not talking about generics in Java / C# (where you can't derive a class from a generic type parameter)

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  • Question marks in Java generics.

    - by gnucom
    I tried to make sure this wasn't a duplicate post, sorry if I was blind. This is a small snippet of code taken from some of the examples that accompany the Stanford Parser. I've been developing in Java for about 4 years, but have never had a very strong understanding of what this style of code is supposed to indicate. List<? extends HasWord> wordList = toke.tokenize(); I'm not worried about the details of the code. What I'm confusing about is what exactly the generic expression is supposed to convey, in English. Can someone explain this to me? Thanks!

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  • LINQ Expression help with Func TEntity,TType

    - by Chris Conway
    I have a repository method that accepts an order by parameter in the form: public IEnumerable<TEntity> Get<TEntity>(Expression<Func<TEntity,string>> orderBy) Now that works fine when trying to sort by a property of type string, var entities = rep.Get(x => x.Name); but what if i want to sort by double or int or any other type. Doing something like var entities = rep.Get(x => x.Price); obviously throws a compile error saying I can't convert double to string. How can I make this more generic so I can sort by any property in my entity, or at least the properties where the type implements IComparable or something similar?

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  • How to inherit methods from a parent class in C++

    - by Pat
    When inheriting classes in C++ I understand members are inherited. But how does one inherit the methods as well? For example, in the below code, I'd like the method "getValues" to be accessible not through just CPoly, but also by any class that inherits it. So one can call "getValues" on CRect directly. class CPoly { private: int width, height; public: void getValues (int* a, int* b) { *a=width; *b=height;} }; class CRect: public CPoly { public: int area () { return (width * height); } }; In other words, is there any way to inherit methods for simple generic methods like getters and setters?

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  • How to get the app a Django model is from?

    - by e-satis
    I have a model with a generic relation: TrackedItem --- genericrelation ---> any model I would like to be able to generically get, from the initial model, the tracked item. I should be able to do it on any model without modifying it. To do that I need to get the content type and the object id. Getting the object id is easy since I have the model instance, but getting the content type is not: ContentType.object.filter requires the model (which is just content_object.__class__.__name__) and the app_label. I have no idea of how to get in a reliable way the app in which a model is. For now I do app = content_object.__module__.split(".")[0], but it doesn't work with django contrib apps.

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  • Caching Models in rails

    - by jules
    I have a rails application, with a model that is a kind of repository. The records stored in the DB for that model are (almost) never changed, but are read all the time. Also there is not a lot of them. I would like to store these records in cache, in a generic way. I would like to do something like acts_as_cached, but here are the issue I have: I can not find a decent documentation for acts as cached (neither can I find it's repository) I don't want to use memcached, but something simpler (static variable, or something like that). Do you have any idea of what gems I could use to do that ? Thanks

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  • What should I name instances of a twisted.internet.defer.Deferred?

    - by slacy
    I'm writing code using Twisted, and having trouble coming up with a sensible variable name for my twisted internet deferred's. Here are my candidates: d : Too generic, too short, violates pylint rule C0103. def : Conflicts with function defintion builtin. defer : Conflicts with module twisted.internet.defer deferred : OK but pretty long cb : Still too short, violates pylint C0103, conflicts with many callback method names. cback : Too Weird? callback : Conflicts with method Deferred.callback() I'm looking for other suggestions. It seems like most of the Twisted example code uses "d" which is fine for simple invocations, but when you're passing Deferred's around to methods and storing them as member variables, it's really far too descriptive.

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  • Why can't I enforce derived classes to have parameterless constructors?

    - by FrisbeeBen
    I am trying to do the following: public class foo<T> where T : bar, new() { public foo() { _t = new T(); } private T _t; } public abstract class bar { public abstract void someMethod(); // Some implementation } public class baz : bar { public overide someMethod(){//Implementation} } And I am attempting to use it as follows: foo<baz> fooObject = new foo<baz>(); And I get an error explaining that 'T' must be a non-abstract type with a public parameterless constructor in order to use it as parameter 'T' in the generic type or method. I fully understand why this must be, and also understand that I could pass a pre-initialized object of type 'T' in as a constructor argument to avoid having to 'new' it, but is there any way around this? any way to enforce classes that derive from 'bar' to supply parameterless constructors?

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  • JQuery selector: pass on id from array into function

    - by user347256
    I have a list of items <div id="item1">somestuff</div> <div id="item2">somestuff</div> <div id="item3">somestuff</div> When someone clicks on one of these, I need to take some actions based on the id (the number). Let's say hide it. How can I make the function generic, and how can I pass the id into the function? $(document).ready(function() { $("#item-howcanImakethisselectorgeneric?").click(function () { $("#item-andhowcanIpasshteidintohere?").hide(); } } I'm a javascript/jquery newbie, any help (including rtfm) appreciated.

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  • NUnit [Test] is not a valid attribute

    - by tyndall
    I've included the necessary assemblies into a Windows Class project in VS2008. When I start to try to write a test I get a red squiggle line and the message [Test] is not a valid attribute. I've used NUnit before... maybe an earlier version. What am I doing wrong? I'm on version 2.5.2. using System; using System.Collections.Generic; using System.Linq; using System.Text; using NUnit; using NUnit.Core; using NUnit.Framework; namespace AccessPoint.Web.Test { public class LoginTests { [Test] public void CanLogin() { } } }

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  • How to generalize view?

    - by MexicanHacker
    Hey guys, I'm in the process of designing a set of views that use the same model in my app, the difference is that some views will differ in Read Only and Modifiable fields. So for example for view A I want to be able to modify A.One but no A.Two properties and for view B I want to have B.One and B.Two as modifiable fields. I was thinking in having a map that will hold this information and iterate both the modifiable and non-modifiable lists in a generic view, but I was thinking that maybe I can get feedback from you guys. What do you think?

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  • How to rewrite the following?(C#3.0)

    - by Newbie
    I am trying to write the following double sum_res = 0.0; double yhat = 0; double res = 0; int n = 0; for(int i=0;i<x.Count;i++) { yhat = inter + (slp*x[i]); res = yhat - y[i]; n++; } using lambda but somehow not able to get it work(compile time error) Enumerable.Range(0, x.Count).Select(i => { yhat = inter + (slp * x[i]); res = yhat - y[i]; sum_res += res * res; n++; }); Error: The type arguments for method 'System.Linq.Enumerable.Select(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly. Help needed. Thanks

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  • SQL compare entire rows

    - by zmaster
    In SQL server 2008 I have some huge tables (200-300+ cols). Every day we run a batch job generating a new table with timestamp appended to the name of the table. The the tables have no PK. I would like a generic way to compare 2 rows from two tables. Showing which cols having different values is sufficient, but showing the values would be perfect. Thanks a lot Thanks for the answers. I ended up writing my own C# tool to do the job - as Im not allowed to install 3rd party software in my company.

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  • How to join by column name

    - by Daniel Vaca
    I have a table T1 such that gsdv |nsdv |esdv ------------------- 228.90 |216.41|0.00 and a table T2 such that ds |nm -------------------------- 'Non-Revenue Sales'|'ESDV' 'Gross Sales' |'GSDV' 'Net Sales' |'NSDV' How do I get the following table? ds |nm |val --------------------------------- 'Non-Revenue Sales'|'ESDV'|0.00 'Gross Sales' |'GSDV'|228.90 'Net Sales' |'NSDV'|216.41 I know that I can this by doing the following SELECT ds,nm,esdv val FROM T1,T2 WHERE nm = 'esdv' UNION SELECT ds,nm,gsdv val FROM T1,T2 WHERE nm = 'gsdv' UNION SELECT ds,nm,nsdv val FROM T1,T2 WHERE nm = 'nsdv' but I am looking for a more generic/nicer solution. I am using Sybase, but if you can think of a way to do this with other DBMS, please let me know. Thanks.

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  • Does Adding more namespace in the code file affect performace ?

    - by Harikrishna
    If we imports more namespace in the code file(cs file) then it affects on perfomance ? Like we should add namespace in the cs file as needed. That is adding more namespace in the cs file affects performance ? Like using System; using System.Data.Sql; using System.Collections.Generic; using System.Data; using System.IO; using System.Linq; using System.Text.RegularExpressions; using System.Windows.Forms; using System.Xml; using System.Data.SqlClient; using System.ComponentModel;

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  • Single C++/CLI method to wrap many type specific C functions

    - by T33C
    I am wrapping a C library using C++/CLI so that the C library can be used easily from C# in a C#'ish way. Some of the functions in this library are for putting a value into a container. There are no generics in C so there exists a function per type CLIB_SetBool(BOOL value), CLIB_SetInt(int value), CLIB_SetString(char* string) and so on. To make it easier to use from C#, I have created a single Set function which takes a System::Object. I have two related questions: With my method how would you use a switch statement on the type of System::Object to call the correct CLIB_Setxxxx function. [typeid is only for unmanaged code and I can't seem to use GetType.] Is there a better way to wrap these functions like using a Generic? [I started using template specialisation but then realised that C# doesn't see templates.] Thanks.

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  • C# Console Application Output to .csv file

    - by Zinn
    I am trying to make a program that will show the numbers: 1, 10 +30 2, 40 (the scale goes up in this pattern by adding 20 to the last number added) 3, 90 +50 4, 160 5, 250 +70 So far I have this code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO;// namespace Myloop { class Program { static void Main(string[] args) /// </summary> { StreamWriter myOutputStream = new StreamWriter("loopdata.csv"); int forloop; for (forloop = 1; forloop < 21; forloop++) Console.WriteLine(forloop); Console.ReadLine(); myOutputStream.Close(); } } } This is showing the first sequence of numbers 1 - 20, but could anyone give me any guidance how to do the other sequence next to it in the console application and how I can output these to a .csv file, as the information I have so far doesn't appear in the .csv file

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